Prosper Complete

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Petroleum xperts

PROSPER

Single Well Systems Analysis

Version 8

October,2003

USER GUIDE


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The information in this document is subject to change as major improvements and/oramendments to the program are generated. When necessary, Petroleum Experts will issue theproper documentation.

The software described in this manual is furnished under a licence agreement. The softwaremay be used or copied only in accordance with the terms of the agreement. It is against thelaw to copy the software on any medium except as specifically allowed in the license

agreement. No part of this documentation may be reproduced or transmitted in any form or byany means, electronic or mechanical, including photocopying, recording, or information storageand retrieval systems for any purpose other than the purchaser's personal use, unless expresswritten consent has been given by Petroleum Experts Limited.

All names of companies, wells, persons or products contained in this documentation are part ofa fictitious scenario or scenarios and are used solely to document the use of a PetroleumExperts product.

Address: Registered Office:Petroleum Experts Limited Petroleum Experts LimitedSpectrum House Spectrum House2 Powderhall Road 2 Powderhall RoadEdinburgh, Scotland Edinburgh, ScotlandEH7 4GB EH7 4GBTel : (44 131) 474 7030Fax : (44 131) 474 7031Email : [email protected] Site: http://www.petex.com


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1- 12 TABLE OF CONTENTS

PETROLEUM EXPERTS LTD


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TABLE OF CONTENTS 2- 12

SEPTEMBER 2003 PROSPERMANUAL


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Welcome to PROSPER, Petroleum Experts Limited's advanced duction and ystems

formance analysis software. PROSPERcan assist the production or reservoir engineer

to predict tubing and pipeline hydraulics and temperatures with accuracy and speed.PROSPER's powerful sensitivity calculation features enable existing designs to beoptimised and the effects of future changes in system parameters to be assessed.

By separately modelling each component of the producing well system, then allowing theuser to verify each model subsystem by performance matching, PROSPERensures that thecalculations are as accurate as possible. Once a system model has been tuned to realfield data, PROSPERcan be confidently used to model the well in different scenarios and tomake forward predictions of reservoir pressure based on surface production data.

PROSPERis a fundamental element in the as definedby Petroleum Experts, linking to GAP, the production network optimisation

program for gathering system modelling and MBAL, the reservoir engineeringand modelling tool, for making fully integrated total system modelling andproduction forecasting.

PROSPER has a PVT section which can generate fluid properties using standardcorrelations and allows them to be modified to better fit measured lab data.PROSPERallows detailed PVT data in the form of tables to be imported for use

in the calculations. A third option is to use the Equation of State method. This

option also allows the user to enter the equation of state model parameters anduses the standard Peng-Robinson EOS model to generate properties given amulti-stage separator scheme. With this option the users can also import allPVT data in the form of tables, which could have been generated using theirown proprietary EOS models.

PROSPERcan be used to model reservoir inflow performance (IPR) for single, multilayer, ormultilateral wells with complex and highly deviated completions, optimising allaspects of a completion design including perforation details and gravel packing.

PROSPER can be used to accurately predict both pressure and temperature profiles inproducing wells and along surface flow lines.

PROSPERsensitivity calculations easily allow the engineer to model and optimise tubing,choke and surface flow line performance.

PROSPERcan be used to design, optimise and troubleshoot gas lifted, ESP equipped or

HSP (hydraulic pump) equipped wells.

PROSPERs choke calculator can be used to predict flow rates given the choke size, or thechoke size for a specified production rate and of course, the pressure dropacross a known choke at a specified rate.

PROSPER uses multiphase flow correlations which have can be adjusted to match

measured field data to generate vertical lift performance curves (VLP) for use insimulators and network models.


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2- 10 CHAPTER 1 - INTRODUCTION

PROSPER can utilise externally programmed dynamic link libraries (DLL) for multiphaseflow correlations, Equation of State (EOS) PVT calculations, choke calculationsand Inflow (IPR) models.

PROSPERcan be used in a matching or predictive mode. Matching of real data is availablein the PVT, IPR, Gradient matching and VLP matching sections.

In matching mode, real data can be entered and matched using non-linearregression methods to create custom correlations that fit the input data.

In predictive mode, the correlations created can be used to make estimatesof future well performance.

PROSPER can be used to model complex (topographically) and extensive (in length)

surface pipelines. PROSPERcan also perform some complex steady state sluganalysis taking into account slug build up and decay due to pipeline topography,giving an indication of expected slug length and frequency.

PROSPER accepts Black Oil PVT tables directly from Petroleum Experts PVTP

thermodynamics analysis program. EOS fluid characterisation parameters canalso be directly imported.

PROSPERhas a flexible units system. Data may be input using one set of units and outputusing a second set of units. Validation limits and display resolution can beindependently set for each variable type.

PROSPERhas the utility for flagging of potential hydrate formation, if the user chooses thisin the options. The additional input required for this calculation is the hydrationformation tables as a part of PVT.

PROSPERcan model the following types of problems:

Pressure Only

Pressure and Temperature Offshore

Pressure and Temperature on Land

Enthalpy Balance

Rough Approximation

Improved Approximation

Oil and Water (Black oil or Equation of State PVT)

Dry and Wet Gas (Black oil or Equation of State PVT)

Retrograde Condensate (Black Oil PVT)

Retrograde Condensate (Equation of State PVT)

Emulsion viscosity can be optionally applied for any combination of inflow,tubing and ESPs or HSPs.

Tubing or Annular flow or Tubing + Annular flow

Producer or Injector

Naturally flowing well



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Chapter 1 3-10

Gas lifted well

Electric submersible pump (ESP)

Hydraulic drive downhole pump (HSP)

Progressive Cavity Pumps

Gas Lift with Coil Tubing

Cased Hole

Open Hole

Gravel Pack

Single-Stage

Two-Stage

Multi-Stage (Compositional model only)

Single WellMulti-lateral Well in a Multi-layered Reservoir

Gas Coning (Rate dependent GOR calculator)

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Chapter 1 5-10

Provided sufficiently accurate field data is available, robust PVT, IPR and VLP models canbe prepared by performance matching. Each model component is separately validated,therefore dependency on other components of the well model is eliminated. Troubleshooting changes in production rates is simplified as the matching process can eliminatemany variables that could otherwise confuse the situation.

PROSPER

PROSPER can predict either Pressure Only or Pressure and Temperature. The

Pressure Onlyoption makes PROSPERa "Systems Analysis" package in the traditional

sense. In Pressure Onlymode, the well temperature profile be input by the user.Temperature data is normally recorded whenever a pressure survey is made, as thetemperature is required to correct the downhole pressure readings. This type of calculationis fast and sufficiently accurate for the majority of pressure loss calculation purposes.

The Pressure and Temperature calculation option will generate both temperature and

pressure profiles. Three temperature models are provided. The Rough Approximationmodel utilises a user-input overall heat transfer coefficient. It determines the steady statetemperature profile from the mass flow rates of oil, water and gas before commencing thepressure loss calculations. This method runs quickly, but unless calibrated usingmeasured temperature data, it is not accurate. The Improved Approximation modelextends the Rough Approximation model by allowing the variation of heat transfercoefficient by depth and pipe section and the addition of a temperature gradient in the sea.

The Enthalpy Balancemodel calculates the heat transfer coefficients at each calculationstep by considering heat flow and enthalpy changes. The Joule Thomson effect,convection and radiation are modelled. These calculations require considerably more inputdata than for pressure only calculations and must commence from a known temperature

and pressure (the sand face for producers, or wellhead for injectors). Computation timesare longer than for the Rough Approximationoption, but this method is predictive andgives accurate results over a wide range of conditions. The Enthalpy Balance model iscompletely transient and can be used to study temperature changes over time.Temperature prediction is useful for generating temperature profiles in:

long pipelines transporting Retrograde Condensate.

subsea wells with long flowlines

high pressure/temperature exploration wells

predicting temperature/pressure profiles to help predict wax/hydrate deposits

The production riser is properly accounted for by PROSPER. The user-input riser geometrydetermines the heat loss coefficients calculated by the program between the seabed andwellhead.

PROSPER is also able to predict condensate liquid drop out using either black oil or

compositional models.

PROSPERuses a "Smart Menu" system. Only data relevant to a particular problem needbe entered.

The flow chart shown over leaf gives an outline of the calculation steps required to carryout a simple systems analysis using PROSPER.



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Chapter 1 7-10

To help illustrate the power of PROSPER, examples are provided with the program. Wesuggest you run through them to become familiar with the program and its various options.These examples are in PR SP R directory. The location of this directorydepends on where the program has been installed.

Oilwell.outThe objectives of this example are to:

Show how removing skin can increase production.

Show how increasing the tubing size can increase production.

Generate lift curves for a reservoir simulator.

This example demonstrates how to:

Match the PVT correlations to real data.Match the multiphase flow correlations to real data using VLP matching.

Use IPR matching to determine reservoir pressure.

Run a system analysis with sensitivities.

Run a pressure versus depth gradient calculation.

Generate vertical lift tables for a reservoir simulator.

Gaslift.outThe objectives of this example are to:

Find the maximum production rate achievable using gas lift.Determine the optimum lift gas injection rate and depth.

Design the operating and unloading valves.


Setup the gas lift design parameters.

Calculate the design production and gas injection rates.

Space out the valves.

Determine the valve trim sizes and dome pressures.

Calculate production sensitivities using the gas lift design.

flowline.outThe objectives of this example are to:

Model a flowline using PROSPER.

Apply the Rough Approximation temperature model.

Examine the effect of the flowline on production rate sensitivities.



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enthalpy.outThis test example shows how to use the Enthalpy Balancetemperature model to predictthe wellhead flowing temperature (WHFT) of a high pressure / high temperature oil well.

espwell.outThe objectives of this example are to:

Determine the pump duty required to meet a specified offtake rate

Select a suitable combination of pump, motor and cable for the service

Determine the maximum water cut at which the pump can still operate with thedesign offtake rate.


Use existing PVT and VLP data as the basis of a new analysis

Calculate pump intake and outlet pressures

Design an ESP systemEvaluate pump operating point sensitivities

Calculate a flowing gradient for an ESP equipped well.

hspwell.outThe objectives of this example are to:

Select a suitable combination of pump, turbine and cable for the service


Use existing PVT and VLP data as the basis of a new analysis

Calculate pump intake and outlet pressures

Design an HSP system

Evaluate pump operating point sensitivities



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Chapter 1 9-10

condex.out, condex2.out, condex3.outThe objectives of this example are to:

Calculate condensate PVT using convergence pressure, equation of state (EOS)and black oil methods

Compare the production rate results obtained from each method

Calculate and compare pressure traverses from each method


Enter reservoir fluid composition data and calculate phase behaviour

Match laboratory and predicted PVT properties

gravel.outThe objectives of this example are to:

Design a gravel packed completion for a high rate gas well

Determine the allowable offtake for a specified drawdown on the formation


Enter the gravel pack and completion parameters

Calculate sensitivities on gravel pack and perforation variables

Calculate the pressure loss across the completion and thereby determine thedrawdown at the sandface.

hwell.out

The example shows how to set up the input data for a Horizontal well - Friction dP IPRmodel. It is based on the OILWELL example file. Note that the reservoir permeability mustbe increased from 50 in the base example to 500 milli-darcies in order to see the frictionpressures drop along the wellbore.

mlayer.outThe example shows how to set up the input data for a Multi-Layer IPR model. It is basedon the OILWELL example file.



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multilat1.outThe example shows how to set up the input data for an ordinary multilateral well.

PROSPER

multilat2.out

The objectives of this example are to:

Show how a complex smart well completion can be modelled by using themultilateral option in PROSPER

Show how different tubing sizes can affect the IPR curve

multilat3.out


Go through the step-by-step procedure for defining a multi-lateral gas injector.

Determine the gas injection rate into the reservoirs for a series of wellheadpressures.

See the effect of varying the choke opening on the injectivity.


Build multi-lateral gas injectors in PROSPER.

How to perform sensitivity calculation in multilateral wells.

multilat-PCP.out


Go through the step-by-step procedure for defining a multi-lateral well model.

Determine if the well can flow on its own.

Considering multilateral model set a PCP pump and determine the pumprequirements to keep the well flowing.


Build multi-lateral well model in PROSPER.

How to set design the pump requirements.


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PROSPER

User's Guide

PROSPER

PROSPER

GAP

Petroleum Experts

PROSPER


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PROSPER

Petroleum Experts

PROSPER

Petroleum Experts

Petroleum Experts

Petroleum Experts

GAP,MBAL PROSPER

Saving 'old' versions of the program on your hard disk is not

recommended, as it takes up valuable disk space and potentially leads to file/programincompatibility

that file can no

longer be opened by earlier versions!PROSPER


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PROSPER

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PR SP R

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R E M O T E

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PROSPER

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Pressure Only Pressure andTemperature


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3 File Management

This section describes the menus, options and procedures used in PROSPERto create new

files and open or save existing files. The Units system and how to define printer settingsare also outlined. The menus described in this section are the PROSPERFile menu and

Units menu.

The File menu provides additional options such as defining the default data directory, aswell as the facility to establish access links to other programs running under Windows.

PROSPER will (optionally) open the last file accessed when it starts. PROSPER alsodisplays a file status screen that shows the application options selected in summary format:input PVTP and IPR data, the equipment type summary and the analysis output.

To protect your work, you should save your data on a regular basis. This simple procedurecould potentially prevent hours of input and analysis being lost.

3.1 PROSPERFiles

PROSPERuses a flexible file structure that enables data to be easily exchanged betweenfiles and other application programs. In PROSPERinformation is grouped into the followingcategories:

PVTP SystemAnalysis Output

and saved into the following types of data file:

3.1.1 PVT Data (*.PVT)

File containing the well fluid data, PVTP match data and any PVTP tables entered underthe PVTP menu. You can save PVTP files separately under different names, and usethem with other input, analysis and output files in PROSPER. This feature is useful whenanalysing a number of wells from the same producing pool.

3.1.2 Input Data (*.SIN)

SIN files contain the options selected under the Options menu, in addition to the well IPRand equipment data entered under the System menu. When you open and save an inputfile, the program automatically opens and saves a .PVTP file with the same name.


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2- 19 CHAPTER 3 - FILE MANAGEMENT

3.1.3 Analysis Data (*.ANL)

This file contains the analyses and sensitivity input data for the calculations selected underthe Analysis menu. When you open and save an analysis file, the program automaticallyopens and saves a .PVT & .SIN file with the same name. GAPand PRODMAN manipulate

.ANL files to batch calculate well lift curves.

3.1.4 Output Data (*.OUT)

This file contains the results of the calculations. When you open and save an output file,the program automatically opens and saves a .PVT, .SIN & .ANL file of the same name.

PROSPERfiles are ranked by their order of input, which essentially reflects the way data

should be entered into the program, that is from the LEFT to the RIGHT of the PROSPERmenu. You will note that the order of files also corresponds to options on the menu bar asyou move through the program.

The file hierarchy does not prevent you from creating and combining any number of inputand output data files. Until you become familiar with the program, we recommend that youalways work with *.OUT files. This can avoid confusion as the program will automaticallyopen and save the required data files to run a complete analysis cycle.

More experienced users can take advantage of the flexible file structure to combine thedata files from different wells. This "sharing" of data is useful in areas where wells havesimilar fluid properties or reservoir IPR's. If disk space is a concern, the data contained ina .ANL file together with its complementary .PVT and .SIN files can be used to re-create agiven set of calculation outputs, therefore avoiding the need to always save large .OUTfiles on disk.

For example, if you wanted to run an analysis with the PVTPdata of Well 1, the input data

(*.SIN) data of Well 2, and the analysis data of Well 3, take the following steps:

Open Well 3.ANL

Open Well 2.SIN

Recall Well 1.PVTPunder the PVTPmenu.

Under the Options menu, select your processing options.

Modify the data files if necessary.

Next, select the Save As command and save the data under a new file name.



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CHAPTER 3 3- 19

3.1.5 Creating a New File

While working with PROSPER, new input or output data files can be created at any time. Tocreate a new file, from the File menu choose the New command. This command does notactually create a new and separate file, but reinitialises the program input/output data.

3.1.6 Opening an Existing File

Existing data files can be opened quickly and easily at any time during the current workingsession. To open a file, from the File menu choose the Open option. You can select oneof the following file types:

Input Data (. SIN)

Input and Analysis Data (. ANL)

Input, Analysis and Output Data (. OUT)

by using the Files of Type dropdown box.

The program displays a dialogue box in which the files matching your selection criteria arelisted in alphabetic order as in the following example:

Figure 3-1

File Dialog

The default data directory files are automatically displayed first. To open a file, point and

click the filename to recall and press or click on Open. The alternative method ofopening a file is to double-click on the file name. If the file you want is not listed, it ispossible that:

1) It is in a different sub directory2) It is on a different drive3) It is of a different file type.



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3.1.7 Saving a File

When files are opened in PROSPER, the program copies the selected file into the

computer's memory. Any changes to the file are made to the copy in memory. In the event

of a power failure or computer crash, these changes would be completely lost. To preventthis, we recommend you save your data on a regular basis and especially before quittingthe program.

The Save command stores all the changes made in the active file. By default, the Savecommand saves a file under its original name and to the drive and directory last selected.You will be prompted to select one of the following file types:

Input Data (.SIN)

Automatically saves the input file and corresponding .PVTP file.

Input and Analysis Data (.ANL)

Automatically saves the analysis data and corresponding .SIN & .PVTP datafiles.

Input, Analysis and Output Data (.OUT)

Automatically saves the output results and corresponding .SIN, .PVTP & .ANLfiles if a file of the same name exists in the selected directory, the file isoverwritten. If you do not want to overwrite an existing file, use the Save Ascommand.

3.1.8 Copying a FileThe Save As command allows you to make more than one copy or version of an existingfile. With this command, you can save a file under the same name but to a different drive,or under a different name on the same drive. Before saving a copy to another disk, werecommend the file be first saved on your hard disk!

Selecting Save As prompts you to select one of the following file types:

Input Data (. SIN)

Input and Analysis Data (. ANL)

Input, Analysis and Output Data (. OUT)

The program displays a dialogue box listing all the current files that match your selectioncriteria. Your default data directory is automatically displayed first. To copy a file, enter anew name in the Filename field - up to eight characters are allowed. Select a different

directory or drive if desired, then press or click on OK.



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3.2 Preferences

The Preferencesscreen is used to customise the program to your particular requirements.Click Preferences from the File menu to customise PROSPER. Click on the appropriate tabat the top of the data entry section in order to change the option you require. The various

tabs are described below:

3.2.1 Screen

Figure 3-2

Preferences: Screen Tab

This tab is used to customise the appearance of the PROSPER front screen and all dataentry (dialog) screens.

Dialog FontYou can change the font type and size used to display all data entry screens. This may beuseful to make all dialogs smaller if you have a low-resolution screen or larger to improvereadability if you have a high-resolution screen. Use the Resetbutton to reset the dialogscreen font to its default value.

Status ScreenIf you selectYesthe screen status information will be continuously displayed and updatedas you use the program. If you select No the screen status information screen will not bedisplayed (apart from whenever you open a new file).

Font HeightIf the font height is modified then an attempt is made to scale the font so that all informationdisplayed in each panel on the status screen will be visible. This will vary depending onthe relative size of the program window to the total screen. If the font height is not modifiedthen some information may not be displayed as you vary the size of the program window.

Screen FontUse this option to change the font type and size used to display information on the status(front) screen of the program.



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Label ColourChange the colour used to display labels on the status screen

Text Colour

Change the colour used to display text on the status screen

BackgroundChange the colour used for the background of the status screen

Box ColourChange the colour used for the background of each panel on the status screen

Box ShadowChange the colour used for the 3D shadow effect on the status screen panels

Box Highlight

Change the colour used for the 3D-highlight effect on the status screen panels

For all of the above Colour options the Choosebutton to the right will bring up a dialogscreen to select an appropriate colour.



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CHAPTER 3 7- 19

3.2.2 File

Figure 3-3

Preferences:File Tab

Use this tab to customise various options relating to file management.

Default Data DirectoryThe directory where data files are normally stored.

Use the Browsebuttons to browse for the appropriate directories.

Default Data Directory ChoiceThis option determines the directory that is used as the default in file dialog. The choicesare either to always use the default data directory (see above) or to use the directory of thelast file opened or saved.

Location of PROSPER.INIThe PROSPER.INI file is used to store all the customised information for your version of

PROSPER. The normal location is in the WINDOWS directory. If you have a networkinstallation of the program (or windows), then this option can to used to ensure that eachuser of the program can maintain their own customised settings locally.

Location of ESP DatabasesThe ESP option in PROSPER is driven by a database of pumps, motors and cables. Thisoption allows you to specify the location of these databases.

Location of Hydraulic Pump DatabasesThe HSP option in PROSPERis driven by a database of pumps and turbines. This optionallows you to specify the location of these databases.

Location of Report Output Files

Use this option to specify the default location of output files from the reporting subsystem.

Location of User-Created Report Files



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Use this option to specify the default location of user-created report templates from thereporting subsystem

Reload Last File On Start UpSpecify whether the last file that you were working with should be automatically reloadedon program start up.

Number of File Names SavedSpecify the number of previously used files that are to be displayed on the file menu.

Confirm CalculationsSwitch (on or off) the message that appears at the end of any calculation function.

3.2.3 Plot

Figure 3-4

PreferencesPlot Tab

Use this tab to set defaults for all aspects of the plot.

Always Use Plot Defaults

Each time a plot is done default values will be used rather than the last selected values foreach particular plot type

X Grid BlocksNumber of GAPs between grid lines on X-axis. (Range 1-20)

Y Grid BlocksNumber of GAPs between grid lines on Y-axis. (Range 1-20)

Plot LabelsShow or hide the plot labels.

Plot ScalesShow or hide the plot scales



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CHAPTER 3 9- 19

Plot LegendShow or hide the plot legend. If the legend is hidden, the body of the plot will expand to fillthe whole window.

Scaling Method

Endpointor rounded. Endpointmeans the scales are taken from the exact extremities ofthe data being plotted. Rounded means that ranges are chosen to surround the data butwith whole numbers ensured for the end points and the gridline intervals.

Grid Line TypeSelect from dotted lines, dashed lines, solid lines or tick marks.

Mouse ReadoutSwitch the mouse cursor position readout no or off.

Date Stamp TitleSelect to append the current data and time to the plot title or not

Line ThicknessTo select the thickness of plotted lines

Vertical FontSelect the default font for all vertical text (Y-axis)

Horizontal FontSelect the default font for all horizontal text

Default ColoursSet the default colour scheme for the plot



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3.2.4 User Applications

Figure 3-5

PreferencesUser Applications Tab

This tab allows you add up to four of your favourite or most-often used Windowsapplications to the PROSPER menu. Although PROSPER has a very flexible reporting

system you may wish to use a spreadsheet (such as EXCEL), a word processor (such as

WORD) and a presentation package (such as Power Point) to build presentation quality

reports using PROSPERoutput in a slick and efficient manner.

Any output (plots and reports) produced by PROSPER is automatically copied to theClipboard. From there it can easily be pasted into one of the above-mentioned applicationsusing one simple keystroke. Using the power and flexibility of your chosen application,high quality reports and presentations can be easily prepared.

All plots can be saved in Windows Metafile format. These can be easily read by a wordprocessing package or presentation graphics package and give the maximum flexibility foruser customisation.

All reports can be saved in TSV (Tab Separated Variable) format using the Export facilitythat means they will automatically be tabulated when read into your favourite spreadsheet.

Enter a description and a command line for each application that you wish to add to thePROSPERmenu.

The description is the data that appears on the menu.

The command lineis the full path name of the program you want to execute.

Use the Browsebuttons to browse for the application you require. Use the Clearbuttonsto initialise the appropriate application information.



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CHAPTER 3 11- 19

3.2.5 Limits

Figure 3-6

Preferences

Limits Tab

This tab allows you add up to specify Limiting Values for the following options.

Maximum AOF for OILMaximum AOF for GASMaximum AOF for RETROGRADE CONDENSATE

Minimum GLR Injected for GAPPerformance Curves.

You can also control the display of large VLP values in SYSTEM calculations.HSP calculation settings can be set in this screen as well.



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3.2.6 Units

Figure 3-7

PreferencesUnits Tab

This tab allows you add up to specify the default Units Systems to use for new files.

If you set the option "Always Use Default Units" to "Yes". Then the units displayed for anyfile read in will always be set to your default choice, regardless of the settings in the file.

3.3 Software Key Maintenance

Viewing the Software KeyThe Software Key command activates the REMOTEsoftware utility program that allowsyou to read the software protection key. This facility lets you see what programs arecurrently enabled, their expiry date, and user authorisation codes and key number. Thisutility is also used to update the software key. Software keys must be updated when newprograms or modules are required or the key expiry date changed. Section 2.3 describeshow to use the REMOTEutility.



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CHAPTER 3 13- 19

3.4 User Correlations

PROSPER has been designed to accept outside calculation modules for fluid flowcorrelations, Equation of State PVTP calculations, choke calculations (pressure lossthrough restrictions) and inflow performance calculations. Users can obtain an authoring

kit from Petroleum Expertsto enable the building of a compatible Dynamic Link Library for use inPROSPER.

Before a DLL can be accessed, it must first be installed into PROSPER. This is done by

clicking File User Correlations. Select either Flow Correlation, Equation of State Model,Choke Correlation or Inflow Performance Model. PROSPER will display a list of the

currently installed DLLs of the selected type. To add a correlation, click Add and select theappropriate file from the file dialogue. Click OK and it will be hooked into PROSPER.

MODEL EXTENSION

Flow Correlation .COR

Equation of State PVTPModel .EOS

Choke Correlation .CHK

Inflow Performance Model .RSM

Information about particular correlations can be obtained by clicking the Info button. Ascreen similar to the following will be displayed.

Figure 3-8

Flow Correlation

Information



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3.5 Printing

3.5.1 Preparing to Print

Once you have selected a printer and selected the appropriate set-up options, printingreports is simple. When you are ready to print, always verify your printer is plugged in, on-line and connected to your machine. The Printer Setup command of the File menu allowsyou to select a printer and define its set-up options. The following option screen appears:

Figure 3-9

Printer Setup

3.5.2 Selecting a Printer

Select the correct printer from the list box provided. Only printers that have been installedunder Windows will be displayed. Next, select the port to which the printer is attached,usually LPT1 for a local printer. Click on the Setup command button or press OK.

As all printers have varying printing capabilities, the dialogue box that appears willcorrespond with the printer selected. Most printers allow you to select paper size andsource, page orientation and number of copies. The set-up screen example that follows is

for a HP 4000N printer.



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CHAPTER 3 15- 19

Figure 3-10

*Printer Setup Options(Windows XP)

3.5.3 Printing Export Data

Prior to printing export data, it is always a good idea to save your data file(s). In theunlikely event that a printer error or some other unforeseen problem occurs, this simpleprocedure could prevent your work from being lost.

To print export data, select the Output menu and the Export option. Select the sectionsyou wish to report on the dialogue box. The program will lead you through a series of inputscreens to set up the required report sections. From the main dialogue box, select adestination for your data. Details of how to set up export data are given in Section 12.2.



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Figure 3-11

Output Results Reports

The appearance of printed reports is controlled by the export data set-up options that havebeen set.Click Setup to display the following screen:

Figure 3-12

Export Data PrinterOptions

Select a suitable font and set the margins etc. that will be used for printed export data.Only non-proportional fonts are allowed in reports to maintain vertical alignment of thecolumns.

PROSPER default font is recognised by most print set-ups. To avoid

potential printing problems, always set up the system to use a font that issupported on your system prior to printing PROSPER export data for the

first time.



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CHAPTER 3 17- 19

Click OK to return to the output screen. Clicking Print initiates generation of the exportdata and sends it to your selected destination.

Export data can be sent to your choice of:

Printer- the primary printer as set up under Windows.

File - Creates an ASCII data file and saves it. Clicking Print will display adialogue box that requests a file name and destination. Enter a suitablefile name (the program automatically appends a ".PRN" extension) andclick OK to save the file. The Fixed Formatoption saves a file in a printerready format that can be imported into a DOS based word processor ortext editor. Use the Tab Delimited format to save a file suitable forimporting directly into a spreadsheet such as EXCEL.

Clipboard- Clicking Print after selecting this option copies the data onto the Windowsclipboard. From the Clipboard, you can view, edit and paste the datadirectly into another Windows application. E.g. a word processingprogram. Tab delimited data can be pasted directly into spreadsheets.

Screen - Clicking Print after selecting this option allows you to view the report onthe screen. Scroll through the data using the scrolling thumbs or arrows.When finished viewing, click OK to return to the main menu.

3.5.4 Selecting a Exported Data to Print

You do not have to be in PROSPER to print a report. Providing you have previouslygenerated a report file (*.PRN), a report can easily be opened and imported into any wordor spreadsheet program. If the Tab Delimited option was selected, this will allow you toeasily create tables and/or format the data using your word processor.

3.5.5 Word Processing in PROSPER

The WordPad command on the File menu gives you direct access to the Windows wordprocessing package. This application can be used to make notes of your current analysisfor later inclusion in reports. If no alternative word processing package is available, youcan use WordPadto edit, format and print your reports.

3.5.6 Clipboard Command

The Clipboard command on the File menu gives you direct access to the Windowsclipboard viewer. This feature is useful for checking data input or intermediate results frome.g. gas lift design calculations that are written to the clipboard by PROSPER.



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3.6 Command Buttons

The following command buttons are used in PROSPER.

All This command button is used in the Equipment and Gas Lifted (safetyequipment) option screens. It will select all input parameters and data pointsfor automated editing.

Calculate Performs the various calculations on the input parameters for the correlationsselected.

Cancel Returns you to the previous screen. Any changes or modifications will beignored by the system.

Continue Continues to the next input screen. Any changes to the fields will be savedand retained in memory for later calculations. A warning message will bedisplayed when fields requiring input data are left blank.

Copy To copy existing data points, select the line entries to duplicate and click onCopy. Next, select the destination line(s) and click on Copy again.Subsequent line entries will be not be overwritten by this operation.

Correlations Displays the results of any matching performed under the VLP/IPR Matchoption.

Delete This command button is used in the Equipment and Gas Lifted (safetyequipment) option screens. It allows you to delete individual or several datapoints.To delete, select the line entries to erase and click on Delete. If you wish to

delete all existing line entries, click All and then Delete. The program willclear the input screen.

Done Returns you to the previous menu. Any changes or modifications will beretained in memory by the program.

Edit This command button is used in the main Equipment screen. One or moreitems can be modified at a time. When used with 'All', all items will beselected for editing.

Export Brings up the Data Export interface. This will be specific to the data on theactive window.

Help Provides on screen help for PROSPER. For general information, press the

'ALT' and 'H' keys together in the Main menu, or the Index button under anyhelp screen. Specific help screens are also available for each window.

Import Calls up the general import interface that allows you to grab data from any textfile. This button will usually be found where tabular data is to be input.

Insert This allows you to add one or several data points providing there are sufficiententry fields. Select the line number where you wish to add a new entry andclick on Insert. The program will move existing line entries down toaccommodate the inserted line(s).



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CHAPTER 3 19- 19


Main Returns you to the Main Application Menu. Any changes or modifications willbe saved and retained in memory by the program.

Match Displays a variable screen where you may enter data in order to adjustexisting correlations to fit real data.

Move Move allows you to re-arrange data points. Select the line(s) to transfer andclick on Move. Next, select the destination line(s) and click on Move again.Subsequent line entries will be moved down to accommodate the transferredline(s).

Plot Plots any calculated results and displays them on screen. Hard copies of thescreen display can be printed by selecting the Hardcopy command button onthe Plot screen.

Recall Allows you to recall and existing PVTP file. You will be prompted for thedirectory and name of the file.

Report Calls up the reporting interface with a report that is specific to the activewindow. This is generally found on windows that display the results ofcalculations. You can then choose to print this report. The report is generatedfrom a system report template.

Reset Resets the Match parameters in order to reinstate the original textbookcorrelations.

Save Saves a current PVTP file. If this is a new data file, you will be prompted for afile name.

Summary Displays a summary screen of the input equipment parameters or systemunits.

The following command buttons are used in the Plot Menu and Plot screens.

Clipboard Sends black and white or colour copies of the screen plot to the WindowsClipboard where it may be retrieved by a word processing program forinclusion in reports.

Colours Allows you define the screen display colours of your plot labels, scales, grids,etc.

Finish Returns you to the previous menu or screen.

Hardcopy Generates black and white or colour print copies of the screen plot. It isautomatically sent to the device selected in \.

Labels Allows you to label your plot. All plot labels are stored in memory and savedwhen Output files are generated.

Replot Re-displays the original screen.

Scales Allows you to re-define the minimum and maximum values for the X and Yplot axes.


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This section describes the main menu and the input data required before an

analysis can be performed. Data should be entered by working through themenus from left to right and top to bottom. The following menus are described in thissection:

Main menu

Options menu

All functions are listed as menu options. Simply select the required menu and

choose an item from the list displayed. This will activate an option or display the relevant

screen.

Problem solving with is approached systematically by working from left to rightthrough the main menu. Calculation menus are activated only when the necessary inputdata has been entered.

To start , select the appropriate icon and press or double-click the program

icon. A screen similar to the following will appear:

Main Menu

The menu options across the top of the screen are the main menu options.Each is described below.


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2- 11 CHAPTER 4 GENERAL DATA INPUT

The File menu is a management menu with commands that enable you to open, save orcreate new data files. You can use this menu to define your default data directory, printerset-ups options and hook in external DLLs. A facility for accessing other Windowsprograms via is also provided.

The Options menu is the starting point of and the key to the program. Use thismenu to define your application and principal well features such as - prediction method,artificial lift type and fluid type. The options you select are unique to the current file andapply until changed by the user, or another file is recalled. These options also determinethe subsequent screens, menus and commands that are displayed.

Use the menu to define well fluid properties and select fluid property correlations. PVTcorrelations can be modified to match laboratory-measured data using a non-linearregression technique. Alternatively, detailed PVT data may be entered in tables.

The System menu is used to define the well's downhole and surface equipment as well asthe reservoir inflow performance. When applicable, gas lift and ESP or HSP equipmentdata for artificially lifted wells are entered from this menu.

The Matching menu allows comparison of field data with calculated pressure drops in welltubing and surface piping. All available correlations can be compared to allow selection ofthe model that best suits your field conditions.

The Calculation menu provides you with the relevant calculation options. Calculations todetermine pressure and temperature profiles, perform sensitivity analyses, make gradientcomparisons and generate lift curve tables are available in this menu.

ESP, HSP and PCP sizing as well as gas lift mandrel placement and valve setting pressurecalculations are available from the Design menu. Access to the databases that hold gas liftvalve, ESP, HSP and PCP equipment characteristics is via the Design menu also.

The Output menu is used to generate reports, to export data and to plot data. Report

templates are provided and user templates can also be defined. The data used can beinput data, analysis data, results or plots. Reports can be saved in various file formats(RTF, TXT and native) and can be displayed or sent to a printer. Export data can beviewed on screen, sent to the Windows clipboard, sent to a printer or saved in a file. Plots



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CHAPTER 4 3- 11

can be printed directly, saved to a report file or a Windows metafile. Selected plots canalso be sent to the clipboard where they can be retrieved by other Windows-basedprograms.

This menu is used to define the input and output units of measurement. A flexible systemof units is provided allowing you to customise the internal units system.

Provides on-line help for . You can get help on specific tasks, fields orcommands. Help is also given on the keyboard and miscellaneous Windows commands.

SEPTEMBER 2003 MANUAL


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The Options menu is used to define the characteristics of the well. The options selectedestablish the input data required and the calculation options available. The selectionsmade apply to the current session. The data entry screens, input fields and variables arelimited to those relevant to your particular application. Input options may be changed at

any stage of the processing. New choices may require other information to be supplied.Therefore the user is advised to ensure that all relevant input is still valid for the new optionselection. The System | Equipment | Summary is a convenient way to check that theequipment description is correct for new Options.

To access the Options menu, point to the menu name and click the mouse or press ALT O.

The following data entry screen will appear:

SystemOptionsSummary

The entry screen is divided in two sections - System optionsand User information.

Under the System optionssection, define your well characteristics such as fluid type, wellcompletion, lift method, etc. These selections determine information you will be required toenter later. The lower section of the screen comprises the header information andcomments that identify your well and will appear on the report and screen plot titles.

To select an option, click on the arrow to the right of the required field. The list of availablechoices will be displayed.



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CHAPTER 4 5- 11

Water and Oil (Producers and Injectors)

Dry and Wet Gas (Producers and Injectors)

Wet gas is handled under the assumption that condensation occurs at theseparator. The liquid is put back into the gas as an equivalent gas quantity.The pressure drop is therefore calculated on the basis of a single-phase gas,unless water is present.

Retrograde Condensate (Black Oil Model or Compositional)

Black Oil or Compositional models can be used. These models take intoaccount liquid drop out in the tubing.

Black Oil

This option uses industry standard Black Oil models. Five correlations areavailable for oil producers. For gas condensate systems an internally developedmodel is used. These correlations can be adjusted to match measured datausing non-linear regression.

Equation of State

Reservoir fluid is modelled by pseudo components having user-specifiedproperties. The original Peng-Robinson equation of state is used byto predict PVT properties.

This sub-menu is available in case Equation of State is selected under

Peng-Robinson (Equation of State PVTOnly)User EOS DLLs can also be linked into .



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Single Stage

This available for black oil option for following fluids:

Oil and water

Dry and Wet Gas

Retrograde Condensate

Two Stage

This option is available for Black oil model in case of Oil and Water fluid typeonly.

Separator and tank properties are entered and recombined by .

Multi Stage (Compositional)

This option is available for Equation of State option only.Up to 5 stages of separation can be modelled for compositional applications.

No or Emulsion + Pump viscosity correction

Select Emulsion + Pump viscosity correctionto allow input of Emulsion viscosityin the section. This option must be selected to turn on ESP or HSPviscosity corrections.

Disable Warning or Enable Warning

Select Enable Warning to allow flagging of hydrates formation in calculationscreens. You will need to go to the section and enter or import thehydrates formation table.

Use Default Correlation or Use Pressure Corrected Correlation

When the default correlation is used, the water viscosity will be sensitive to thewater salinity and temperature. When the pressure corrected correlation isused, the water viscosity will be sensitive to the water salinity, temperature andpressure.

No Calculation or Calculate Condensed Water Vapour

This option is only available for Dry and Wet Gas mode. If CalculateCondensed Water Vapour is selected, the condensation of water vapour will be

taken into account when performing pressure drop calculation.



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CHAPTER 4 7- 11

Tubing Flow

Annulus FlowThis option models production up the casing / tubing annulus.

Tubing +Annulus FlowThis option models production up the tubing and annulus space simultaneously

Producer

InjectorInjection of single-phase water or gas is supported.

The following 4 lift method options are available when Oil is selected as a fluid type.

Naturally Flowing

No artificial lift.

Gas Lifted

Three different approaches are provided. Annular gas lift is handled by. If the Flow Type isAnnular Flow and a Gas Liftmethod is selected,

then automatically switches to model gas injection down the tubing,and production up the annulus.

Electric Submersible Pump

An ESP installation can be analysed or designed using this option.

The user has choice to select standard pump or Subsea Pump (framo)

Hydraulic Drive Downhole Pump

An HSP installation can be analysed or designed using this option.

Progressive Cavity Pumps

A PCP installation can be analysed or designed using this option.

Coil Tubing Gas Lift

Coil Tubing with gas lift can be analysed or designed using this option.

If is the chosen method, then the following types are available.

No Friction Loss In Annulus

It is the classic approach for the annulus gas gradient. The pressure drop dueto friction in the annulus is ignored and the gas gradient is determined by the topcasing pressure and the temperature profile.



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Friction Loss In Annulus

The pressure drop due to friction in the annulus is taken into account, but thetop casing pressure is assumed constant. If this option is selected the tubingequipment screens will automatically change and require tubing OD and casingID data to be entered.

Safety Equipment

Surface delivery lines, chokes, the gas lift injection string and safety valves inthe annulus are taken into account. Top casing pressures will change withinjection rate.

If is the chosen method, then the following types areavailable.

Commingled Annular Supply

The power fluid for the turbine is supplied via the annulus and returns tosurface, commingled with the produced fluid via the tubing.

Commingled Tubing SupplyThe power fluid for the turbine is supplied via the tubing and returns to surface,commingled with the produced fluid via the annulus.

Closed Loop Supply

The power fluid for the turbine is supplied via the outer annulus and returns tosurface via the inner annulus. The reservoir fluid is produced through thetubing. There is commingling of produced and power fluids.

If is the chosen method, then the following types are available.

Sucker Rod DriveThe program will assume that you have a surface drive head from which yourequire rods in order to move the rotor across the pump.

Downhole motor drive

The program assumes that you have a downhole motor instead of surface drivemotor.

The program is capable of predicting either pressure only or pressure and temperaturechanges simultaneously.

Pressure Only

If this option is taken, the flowing temperature profile must be entered. Thiscalculation option is fast and provides accurate pressure profiles.

Pressure and Temperature (Land and Off shore)

This option will calculate both pressure and temperature profiles using themethod specified in Temperature Model.



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CHAPTER 4 9- 11

Enthalpy Balance

This rigorous thermodynamic model considers heat transfer by conduction, radiation, andforced and free convection. Heat transfer coefficients are calculated using values held in auser-definable database. The temperature prediction calculations are transient, allowing

sensitivities against flowing time to be run. This temperature model requires considerablymore input data and computation time for either Predicting Pressure Only or the RoughApproximation temperature model.

The production riser is properly taken into account. Therefore the heat loss predictionbetween the seabed and wellhead will be accurate. Due to increased computation times,we recommend that this option be used only when temperature prediction rather thanpressure loss is the required result (for e.g. process calculations and material selection).

The Enthalpy Balance temperature model is capable of accurate flowing temperatureprediction for a wide range of conditions.

The temperature prediction is useful for generating temperature profiles in:

long pipelines

subsea wells

high pressure/temperature exploration wells

predicting temperature/pressure profiles to help predict wax/hydratedeposits.

These models also account for Joule-Thompson Effects.

The temperature calculation must commence from a known condition. This is usually thereservoir pressure and temperature. As a consequence, calculating from a downstreamnode (unknown temperature) to an upstream node (known temperature) is not meaningful

Rough Approximation

Calculates the heat loss from the well to the surroundings using an overall heat transfercoefficient, the temperature difference between the fluids and the surrounding formationand the average heat capacity of the well fluids. The geothermal gradient entry screen isused to input formation temperatures (e.g. from logging runs) at measured depth points. Aminimum of the surface and first node temperatures are required. Temperatures enteredshould be the extrapolated static temperatures, and should not be confused with the entryof measured flowing temperatures required for the Predicting pressure only case.

The Rough Approximation temperature model requires calibration using measuredtemperature data. It is not accurate in a predictive mode.

Improved Approximation

Calculates the heat loss from the well to the surroundings using an overall heat transfercoefficient (which can be varied along the well bore and pipeline), the temperaturedifference between the fluids and the surrounding formation and the average heat capacityof the well fluids. The geothermal gradient entry screen is used to input formationtemperatures (e.g. from logging runs) at measured depth points. A temperature gradient inthe sea can be entered for offshore applications. A minimum of the surface and first nodetemperatures are required. Temperatures entered should be the extrapolated statictemperatures, and should not be confused with the entry of measured flowing temperaturesrequired for the Predicting pressure only case.



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The Improved Approximation temperature model requires calibration using measuredtemperature data. It is not accurate in a predictive mode.

Full System

Calculations for pipelines, tubing and reservoir

Pipeline Only

Calculations for pipelines only

Show calculating Data

Hide calculating Data

Select Hide to speed up calculations by not updating calculation screendisplays. This will automatically be set to Hidewhen run from

Cased Hole or Open Hole

This selection determines the appropriate IPR Completion models to use.

Yes or NoGravel pack pressure drops will be calculated when Yesis selected.



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CHAPTER 4 11- 11


Single Branch or Multilateral Well

In the single branch option the IPR screen comes with various standard inflowmodels from which the user selects one.

For the multi-lateral selection, the IPR screen requires detailed drawing of thedownhole completion.

Yes or No

Rate dependant GOR will be modelled and calculated when Yesis selected.This option is only available for Single Branch type wells.

These fields are optional. The details entered here provide the header information thatidentifies your well in the screen plots and printed reports. The Comments area is used toenter free format text describing the details of the analysis. A Date stamp feature isprovided to mark either the comment text or the header data for future reference.

We recommend that comments be used to summarise any assumptions made in your

analysis. Whenever an existing model is modified, appending a summary of changes anda date stamp will greatly assist current and future users working with the file.


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5 PVT Data Input

5.1 Introduction

To predict pressure and temperature changes from the reservoir, along the well bore andflow line tubular, it is necessary to accurately predict fluid properties as a function ofpressure and temperature. The user must enter data that fully describes the fluidproperties or enables the program to calculate them. There are three possible approaches:

1. If only limited data is available (a minimum of solution GOR, oil gravity, gas gravity andformation water salinity for oils) the program will use one of several correlations tocalculate the fluid properties. The user decides, the correlation to be selected.

2. If both limited fluid property data and PVT laboratory measured data is available, theprogram can be used to tune the standard correlations to best fit the measured datausing a non-linear regression technique. The matched correlations can then be used tocalculate all the fluid properties required in the multiphase flow calculations.

3. The PVT data may be also entered in tabular format. The program can be instructed touse the tabular data where available. Data should be available to cover a range oftemperatures. Normally this is not recommended.

The program also allows fluid properties to be calculated and plotted for specified pressureand temperature ranges. The PVT menu has three options - Report, Input and Export.Select Report to inspect previously entered data, Export to save data to a text file, or Inputto set up a new problem or edit an existing one.

Recommended Steps

Only Limited PVTData Available ( Minimum required for correlations)

Enter data as requested on PVT input data screen and select correlations thatare known to best fit the region or oil type.

Limited PVTData and Laboratory Measured Data Available

Enter the data requested in the PVT input data screen.

Enter PVT laboratory data in the PVT Match data menu. The laboratory PVTdata and the fluid properties entered on the data input screen must beconsistent. Flash Data must be used. Up to 5 tables of laboratorymeasurements made at different temperatures may be entered. Use the Tablesbuttons to switch between tables. Click OK to return to the PVT input screen.

At this point, you can optionally Calculate PVT using a correlation and Plot thecalculated and match data to see how closely the non-optimised correlation fits.

Select Regression, then Match All. A non-linear regression will be performed tobest fit each correlation to the measured lab data. Once the calculation isfinished, select Parameters and identify the correlation that best fits themeasured data. This correlation should then be selected and this modifiedcorrelation will be used in all further calculations of fluid property data. The fitparameters are the multiplier and shift applied to the correlation in order to fit thelab data. If the correlation were a perfect fit to the match data, Parameter 1would be set to 1.0 and Parameter 2 would be zero.

In order to see how well the tuned correlations fit the data, on the regressionscreen there is plot utility, which will plot the variable values from the matchedcorrelations, and the data entered simultaneously, to allow the user to see howgood the fit is. Select Plot to display both the calculated and measured PVT


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2- 28 CHAPTER 5 - PVT DATA INPUT

data. Select the Variables option on the plot menu bar to choose the fluidproperty data to display.

PVTData supplied as Tables.

Select Tables and enter data in the tables.

Because it interpolates the tables, PROSPER cannot account for

temperature changes when PVTdata is available for only one temperature.In such cases, the PVT recommendations should be followed. If nodata for a particular variable is available, the program will calculate thenecessary values using the selected correlation. For the correlations to takeover, there must be table entries for a particular variable .

Whether PVT tables have been input or not, PROSPER will use correlationsunless the Use Tables box on the PVT Input screen has been selected. Do notselect Use Tables unless complete PVT tables have been entered. Data at onlyone temperature (e.g. reservoir temperature) is not adequate.



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CHAPTER 5PVT DATA INPUT 3- 28

5.2 Black Oil - Oil and Water

5.2.1 Input Data

Select the PVT Input option from the main menu to display the following PVT Input datascreen:

Figure 5-1

PVT Input Screen

Enter the required data in the fields provided. You can move from one box to another by

pressing the TAB key. Next, select a Pb, Rs and Bo correlation and a viscosity correlationto use then click OK.

Enter the oil solution GOR. This should not include free gas production. For gasproduction in wells producing injection or gas cap gas the solution GOR shouldstill be entered. The balance of free gas production is accounted for elsewhere.

refers to the separator gas stream composition.

5.2.1.1 Emulsions

If you have allowed emulsions on the options screen you will have the option to selectwhere the emulsion viscosity corrections will take place. The Flowline Emulsion Databutton will take you to the Emulsion Data entry screen.

You can also enter the water cut at this point that will then be used to calculate theemulsion viscosity in the PVT calculation section. Refer to section 5.2.10 for moreinformation.



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5.2.2 Tables

In PROSPERthe PVT data can also be entered as tables. This is done by clicking Tables.Up to ten separate tables may be entered, each at a different temperature. If the programrequires data for which there are , it will calculate values using the selectedblack oil correlation. The program will use the data from the tables in all furthercalculations provided the Use Tables option has been selected on the input data screen.This option should be used only when extensive table data is available for a range oftemperatures.

Figure 5-2

PVT Tables

Rather than entering the values by hand, PROSPERcan read in tables of Black Oil PVT

properties. To do this, click the Import button from the Tables screen, and you will beprompted to enter the name of an ASCII file containing the PVT data. Petroleum Experts PVT

Package can be used to calculate and export Black Oil PVT tables. An example of thePVT Table import file format is given in Appendix E.



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5.2.3 Match Data

Click the Match Data button and enter PVT laboratory measured data to match to asshown on the example screen below:

Figure 5-3

PVT Match Data Screen

Since gas evolution in the tubing is a constant composition process, Flash data, notdifferential liberation data should be used for matching. For each match data table, enterthe temperature and bubble point, then enter pressure versus gas oil ratio, oil FVF and oilviscosity. Where data is incomplete or not available, leave the field blank. Use the GORand FVF at bubble point plus the viscosity if available. Enter only the minimum number ofpoints to ensure a good match.

Where only differential liberation PVT data is available, a PVT simulationprogram can be used to calculate the flash properties using a model that hasbeen matched to the lab data.


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5.2.4 Regression

This option is used to perform the non-linear regression, which adjusts the correlations tobest fit laboratory measured PVT data. The non-linear regression matching technique canbe used on up to five PVT match tables, each with a different temperature. The followingPVT properties can be used as match variables:

Pb Bubble point pressure.GOR Gas oil ratio versus pressure.FVF Oil formation volume factor versus pressure.Oil viscosity Oil viscosity versus pressure.

It is not necessary to match on all properties for all applications. In cases where the PVTdata is incomplete or of poor quality, better results can often be obtained by matching onthe best characterised parameters only. However, because bubble point can be difficult toaccurately predict from correlations, it is recommended that, where possible, it is used as amatch parameter. The minimum data required to perform a regression match is the bubblepoint and GOR.

The form of the correlations for FVF is different above and below the bubble point. Ifthe FVF at bubble point is not available, the regression may not achieve good results.When matching the oil FVF, . Do not enter manymatch points, use the minimum number to define the shape of the correlation curves.In most cases, only data at the bubble point is required.

Figure 5-4

PVT Regression Screen

5.2.4.1 Match

From the Regression screen, individual correlations can be matched to selected measuredPVT data by:

Selecting the correlations

Selecting the fluid properties to match to

Clicking Match



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5.2.4.2 Match All

All correlations can be matched to all the fluid property data in one keystroke by selectingthe Match All command button.

5.2.4.3 ParametersHaving performed the matching process, the match parameters are displayed by clickingthe Parameters button. The non-linear regression technique applies a multiplier -Parameter 1, and a shift - Parameter 2 to the correlations. The standard deviation is alsodisplayed, which represents the overall closeness of fit. The lower the standard deviation,the better the fit. The best overall model is the one that has Parameter 1 closest to unity.

5.2.4.4 Viewing the Match Parameters

The Parametersbutton displays the PVT correlations parameters screen. This shows the

match parameters and the standard deviation for each matched correlation. Use thesestatistics to select the best correlation for your application. A plot should be made (refercalculation and plot sections) and a visual check of the fit quality performed before makingyour final selection. The match parameters can all be reset (i.e. returned to the un-matched state) by selecting the reset option. The following is an example of a correlationparameters screen:

Figure 5-5

PVT MatchParameters



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5.2.4.5 Matching FVF above Bubble Point

The standard correlations do not always accurately model the FVF above bubble point(especially for heavy or waxy oils). Additional match parameters (Parameter 3 and 4) havebeen introduced to allow the FVF to be independently tuned below (P1 and P2) and above(P3 and P4) the bubble point.

In all circumstances, always enter match data at the bubble point to ensure that nodiscontinuities occur.

5.2.5 Calculations

In order to make a plot or listing of fluid property data, PROSPERmust first calculate thevalues over a specified range of temperatures and pressures. Using the calculated datapoints, plots of fluid properties versus temperature or pressure can be generated. The

following is an example of the PVTCalculations screen. If the correlations have beenmatched, then the fluid properties will be calculated using the modified correlations.

The calculation procedure is optional and used only to generate fluid property datafor display and quality control purposes. During the computation of a pressuretraverse, PROSPERcalculates fluid properties at each pressure and temperaturestep or node as required by the application.

5.2.5.1 Calculating PVTData

Figure 5-6

PVT CalculationSetup

To generate tables and plots of PVT data:

Select Correlations (use the best matched one)

Select Automatic generation of Data Points

Enter the temperature range and number of steps

Enter the pressure range and number of steps

Click OK



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Click Calculate to compute PVT data for the entire range of pressures andtemperatures required by your application. The following calculation screen willbe displayed:

Figure 5-7PVT calculationResults

The PVT section can be used as a convenient calculator by entering user selected datapoints, then entering specific temperatures and pressures to calculate fluid properties.



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5.2.5.2 Displaying the Calculated Data on the screen

The calculated data is displayed on the screen as default. However, you have the option ofchoosing the calculated variables to be displayed by using Layout button on the screenabove. Pressing this displays the list of all calculated variables, out of which the selection

can be made.

Figure 5-8PVT calculation Layout



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5.2.5.3 Plotting the Calculated Data

The calculated data can be displayed on a plot. The variables, which are plotted, aredefined under the Variables option on the plot. After performing a PVT calculation clickPlot from the PVT calculation screen. Display the selected results by following thisprocedure:

Click Variables.Select Pressurefor the X-axis.

Select GOR for the Y-axis.

Click OK to display a plot showing both the calculated values and the measuredvalues similar to the following:

Figure 5-9

PVT Results Plot

Carefully examine the PVT plots for consistency with your match data. If necessary, selecta different correlation and repeat the PVT calculations until you are satisfied with theresults.

5.2.5.4 Saving PVTtables from Calculated Data

The calculated data can be saved in the form of .ptb files by the button provided at top ofthe calculation output screen in Figure 5-7.

There is also the possibility of transferring the displayed calculation to the Tables bypressing on the Tables button.



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5.2.6 Saving the PVT Data

This option allows a PVT data set to be saved under a separate name. A dialogue box willappear prompting you to name the PVT file. The PVT extension is automatically providedby the program. If you omit this step, the program will automatically save the (matched)PVT data in a .PVT file with the same name as the input (.SIN) file.

5.2.7 Recalling a PVTFile

This option allows a previously saved PVT data set to be recalled into the open file. Adialogue box will appear prompting you to select a PVT file. If this step is carried out afterrecalling a .SIN file, this will overwrite the PVT data from the original file.

For multi-well projects, set up matched PVT models for each producing area first.This will save time and reduce the potential for error by recalling the relevant PVTdata into each well file.

5.2.8 Correlations

This options displays the match parameters and standard deviations for each matchedcorrelation. See section 5.1.4.4 for a more detailed explanation of this

5.2.9 Composition

In the PVT Input Data screen, click the Composition button, and PROSPERwill use the PVTproperties (Oil Gravity, GOR) to estimate the composition of the reservoir fluid. The

estimated composition is used internally by PROSPER to calculate thermodynamicproperties needed in the choke and enthalpy balance temperature models. The followingis an example of an estimated Black Oil composition:



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Figure 5-10

Estimated Composition

Click BI Coefficients and PROSPER will display the Binary Interaction coefficients to beused in an EOS description of the fluid. An example BI Coefficients display is shown

below:

Figure 5-11

BI Coefficients forEstimatedComposition

Estimation of reservoir fluid composition is available for Oil and Retrograde Condensate

fluids.



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5.2.10 Non-Newtonian Fluid

PROSPER can model the effect of non-Newtonian fluids. The implementation of the modelis based on drilling fluid models developed by TotalFinaElf. This will enable foams in heavyoils to be modelled more accurately.

Figure 5-12

PVT input data

To enter the required non-Newtonian fluid viscosity data, select Rheological Parametersfrom the PVT Input Data screen:



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Figure 5-12

Viscosity Modelling(InformationRequired)

5.2.11 Emulsions

PROSPERcan model the effect of Oil/Water emulsions on mixture viscosity for Black OilPVT systems. The behaviour of emulsions in producing well equipment is not wellunderstood. Emulsion PVT in PROSPERprovides a means to assess possible effects ofincreased emulsion viscosity by curve fitting experimentally determined data. It must beemphasised that the method is empirical and does not represent any rigorous model ofemulsion behaviour.

In the laboratory, stable emulsions can be prepared from many crude oil / water systems.Emulsion samples in surface separation equipment does not necessarily imply thatemulsions are present in the well. Field experience shows that the effect of emulsions isusually less than predicted by laboratory tests. Emulsion PVT should be used with caution

and only when it is certain that emulsions are present and it is necessary to evaluate theireffect on calculated pressures.

To enable emulsion PVT in PROSPER, the Emulsion option must first be selected on theOptions screen. Emulsion viscosity will replace the mixture viscosity for selected elementsof the production system. Experimental or empirical emulsion viscosity data can beentered and curve-fitted using non-linear regression. The fitted curve is used to optionallyreplace the oil/water mixture viscosity in IPR, VLP and pump calculations. When selected,emulsion viscosity for the user-entered value of water cut will be substituted for the fluidmixture viscosity.

Drop down the Emulsion box and select from the following:

Turns off emulsion viscosity corrections



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Emulsion viscosity for IPR, VLP and pump if present

Emulsion viscosity for casing, tubing and pump if present

Emulsion viscosity for pump only

Emulsion viscosity in pump and tubing above pump

Emulsion viscosity in tubing and pipe only

The selection of system elements affected by emulsion can be changed at a later time

Even if has been selected on the PVT screen, pump

viscosity corrections will be applied whenever Options Emulsions is selected.Produced fluid viscosity, not emulsion viscosity, will then be used for corrections.

To set up the emulsion model, select Emulsion , (otherwise emulsion viscositywill not be active for the PVT calculations) then click the Emulsion Databutton and thefollowing screen will be displayed.

Figure 5-13

Emulsion Match DataEntry

The screen is divided into 3 sections:

Experimental data for matching

Experimental base conditions

Results of regression



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The pressure and temperature that correspond to the experimental conditions are enteredin Experimental Parameters. This enables PROSPERto correct the emulsion viscosity fortemperature and pressure.

must be selected before plotting the emulsion viscosity

curve. The emulsion viscosity entered for zero water cut should be compatible

with the 100% oil viscosity at the experimental temperature and pressure.

Emulsion viscosity is modelled as a function of water cut in 3 stages:

Sharp increase at low water cut Plateau with a constant maximum viscosity for intermediate water cuts Tail that declines to the viscosity of water after the plateau

The parameters define the maximumplateau region. To calculate emulsion viscosity:

Enter pairs of water cut and emulsion viscosity data points in the Emulsion Datatable.

Enter the Click the Match button.

When the regression has stopped, click Plot to display the matched mixture viscosity:

Figure 5-14

Emulsion Viscosity Plot

Match data is plotted as crosses, whereas the calculated viscosity is shown as a solid line.

When Emulsions have been selected, the calculated Oil Viscosity in the PVTsection will be replaced by the emulsion viscosity for the value of Water Cut entered.

5.2.12 Hydraulic Pump Power Fluid Data

If you have selected HSP (Hydraulic Pump) as the Artificial Lift method, then you mustsupply some details of the power fluid in order that its fluid properties can be estimated.

There are two choices for power fluid type:

Water Other Fluid


If you select Water, then the only other data required is the salinity of the power fluid. Theprogram will then estimate fluid properties using the normal water PVT model.


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Figure 5-16

Hydrates FormationTable Data Entry

Up to one hundred data points may be entered. Please ensure that the table spans withinthe expected range of conditions that will be encountered.



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5.3 Black Oil - Dry And Wet Gas

All the condensate drop out is assumed to occur at the separator. Free water production inthe tubing is considered. For pressure drop calculations, an equivalent gas rate is usedwhich allows for the condensate and water production by ensuring that a mass balance is

observed.

5.3.1 Input Data

When is selected as the PVT option, the following Input data screen isdisplayed:

Figure 5-17

Dry and Wet Gas PVT

The bottom part of the screen will only appear when the option Calculate CondensateWater Vapour is selected in the Option section. If this option is selected, the effects ofcondensation of water vapour on the pressure drop calculation in the tubing / pipeline willbe taken into account.

This model applies to most gas wells. The condensate production is included in the gasstream as an increase in density - the flow remains single-phase gas plus free water ifpresent. The separator temperature is assumed to be the same as the top nodetemperature. If there is significant hydrocarbon liquid drop out in the tubing, a retrogradecondensate model should be used.

The VLP co

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