Spe file about spinners

8/18/2019 Spe file about spinners

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SPE 125028

Improving the Process of Understanding Multiprobe Production LoggingTools From the Field to Final AnswerG. Frisch, D. Dorffer, and M. Jung, Halliburton Energy Services; A. Zett and M. Webster, BP Exploration andProduction

Copyright 2009, Society of Petroleum Engineers

This paper was prepared for presentation at the 2009 SPE Annual Technical Conference and Exhibition held in New Orleans, Louisiana, USA, 4–7 October 2009.

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not beenreviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, itsofficers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission toreproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.

AbstractThe newest generation of production logging tools consists of multiple sensors in multiple locations around the wellbore that

incorporate 12 resistivity and capacitance probes and six spinners. The capacitance array tool (CAT™) determines the water,

oil, and gas holdup in the wellbore. The resistivity array tool (RAT™) determines the holdup of hydrocarbons and water.

Likewise, the spinner array tool (SAT™) consists of six bowspring mounted micro-spinners that enable the measurement of

the velocity profile. These new tools provide a detailed examination of the flowing fluids in all types of wells, includinghighly deviated and horizontal wellbores, that is not available with the traditional center sample tools because of the wellbore

conditions, especially with fluid segregation. With these 30 measurements, a system of quality control and processing was

developed to enable both experienced and non-experienced engineers to determine whether or not the data was correct andvalid.

A quick analysis tool was developed to enable the field engineer and company representative to enter raw values from the

two holdup devices and calibration values, and to determine the holdups from the two sensors. Similarly, entering the raw

spinner counts, cable speed, and estimated spinner slopes into the quick analysis tool will provide an estimate of the velocity

profile for the SAT spinners and the other spinners that are run. This quick analysis tool graphically shows the holdups andvelocity in an easy-to-understand presentation for people who are not production logging (PL) experts.

After the raw data in the field is validated, a complete analysis is provided. This analysis includes horizontal, vertical, and

3D images of holdup and velocity profiles; continuous displays of flow profiles; and a complete flow analysis consisting of

the split of oil, gas, and water rates at both downhole and surface conditions. This PL data can be presented in standard logformats, spreadsheets, and other methods as needed. This process can be modified by either the service company or customer.

Several examples are provided that show the capabilities of the new logging tools and the interpretation method used todetermine the results.

IntroductionPhase segregation occurs in many wells, including those with little deviation from vertical; the lighter phases migrate to thehigh side of the wellbore, and the heavier phases migrate to the low side. In highly deviated and horizontal wellbores,

traditional PL sensors, which are center sample tools or have single point measurements, may not provide the most accurate

data as a result of the wellbore and well flowing conditions. These PL tools measure fluid properties, such as velocity,

density, capacitance, temperature, and pressure. Tool position, or more accurately sensor position, may lead to incorrect

interpretations regarding the flow environment of the well. New PL tools have been developed to help address the issues in deviated or horizontal wells. These new tools include two

types of holdup measurements, capacitance and resistivity, as well as multiple velocity measurements. These new tools will

be referred to as Production Array Logs (PAL) to distinguish them from the standard PL logs. These tools provide a relative bearing measurement that enables the location of each sensor to be determined. The velocity tool also includes an inclination

measurement to aid in the analysis of the PAL data. The holdup tools have 12 measurement probes, and the velocity tool has

six spinners. These tools, when run in conjunction with the standard tool string, provide multiple measurements around the

entire wellbore. The interpretation of each tool individually is complex and, when combined with the other PALmeasurements, the complexity increases dramatically. A new interpretation process was developed that combines the benefits

of the newer sensors and addresses problems caused by the deviated and horizontal wellbores in the standard PL

interpretation procedures.


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2 SPE 125028

The completion of the example well consisted of a 7 5/8-in. casing with three zones of perforations. The deviation of the

wellbore over the perforated zones ranges from 25 to 35 degrees. The logging tools used for this well consisted of the

standard PL string which included a radioactive fluid density, (DENR), fluid capacitance (CWH), pressure (QP), temperature(TEMP), inline spinner (ILS), and fullbore spinner (CFB). The additional fullbore tools that were run included the three array

tools: CAT, RAT, and SAT.

Holdup Tools

One of the challenges of production logging is the identification of the fluid types and the point of entry of those fluids intothe wellbore. Standard holdup tools normally measure the density and capacitance of the wellbore fluids and are usually

centered sample measurements. The density measurement is based on either a tool with a radioactive source or a gradio(pressure) arraignment. Both of these tools have advantages and disadvantages that should be considered when selecting the

proper tool. For example, a radioactive source may be considered as an environmental hazard, while a tool based on pressure

is inadequate in horizontal wellbores. The challenge of obtaining accurate holdup measurements is addressed by two tools,

the Capacitance Array Tool (CAT) and the new Resistivity Array Tool (RAT). Both tools have 12 sensors that are located

radially on flexible bowsprings that measure the capacitance and resistivity of the wellbore fluids.

Capacitance Array Tool. The CAT is an upgraded version of the tool originally described by Ryan and Hayes (2001) and

Frisch et al. (2002, 2009). The major difference between the original version and the upgraded version is that the sensors are

now placed on bowsprings, whereas the original tool included sensors located on motorized arms. This modificationimproves the reliability of the mechanical portion of the tool and enables logging in both directions, rather than only up logs,

as with the previous tool. The first step in quality control and interpretation is to calibrate the sensor readings so that eachsensor will read the same counts for each type of fluid. This calibration enables a standard interpretation color scheme for

each CAT pass and a quick interpretation of the holdups.

ft

9500

,

RCAP07S3,U1[cps]250 0





RCAP12 S3 U1 [cps]50 0 cps50 200

,

CN7NS4,U1[cps]250 0

CN8NS4,U1[cps]250 0

CN9NS4,U1[cps]250 0

CN10NS4,U1[cps]250 0


CN12N S4 U1 [cps]50 0 cps50 200

XX50

XX00

A

B

C

RAW CATMAPHI------LOW------HI

50 200

CATMAP

HI------LOW------HI50 200

RAW

CAT COUNTS250 0

DENSITY

.1 1.1HYDRO

0 2

TEMPERATURE

171 177PRESSURE

2750 2800

CALIBRATED

CAT COUNTS250 0

ft

9500

,






RCAP12 S3 U1 [cps]50 0 cps50 200

,

CN7NS4,U1[cps]250 0

CN8NS4,U1[cps]250 0

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CN12N S4 U1 [cps]50 0 cps50 200

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A

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50 200

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HI------LOW------HI50 200

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CAT COUNTS250 0

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.1 1.1HYDRO

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171 177PRESSURE

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50 200

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HI------LOW------HI50 200

RAW

CAT COUNTS250 0

DENSITY

.1 1.1HYDRO

0 2

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.1 1.1HYDRO

0 2

TEMPERATURE

171 177PRESSURE

2750 2800

TEMPERATURE

171 177PRESSURE

2750 2800

CALIBRATED

CAT COUNTS250 0

Figure. 1–Logs showing the CAT data before and after the calibration rout ine.

Figure. 1 shows a section form the first log example that illustrates the CAT data before and after the calibration process.

Rather than presenting 12 holdup curves, images are generated from the raw and/or processed data. These images are createdfrom the input data from each tool, using the relative bearing to determine the position of each sensor. After the relative

position of each sensor is known, the data is interpolated from one reading to the next. The image is presented, from left to

right, as high–low–high. This arrangement will always display the low side of the wellbore in the center of the track. From

the legacy center sampling holdup devices, the fluid density, capacitance, and location of the oil/water (XX86) and gas/oil


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SPE 125028 3

(XX60) contacts in this well are evident. The color coding for all the CAT images are based on the normalized data in which

water (blue) has a value of 50, oil (green) has a value of 150, and gas (red) has a value of 200. If the well consists only of two

phases, the colors are modified to show only the phases expected; however, it is always recommended to show water in theimages, even if the production stream is water-free.

The raw and calibrated data are used to create the two images shown in Figure. 1. This routine is performed after

acquiring the data; however, a spreadsheet has been developed to enable the logging engineer to determine the holdups on

location. The spreadsheet will be discussed in a following section. When using this technique, the low side in the middle of

the track should always display the heavier fluid, as shown at A. At this point, the low side of the track shows a pure streak ofoil; immediately above this streak, a mixture of oil and gas trending to almost a pure gas phase displays on the upper section

of the wellbore (left and right sides of the track).Zone C appears to consist of 100% water, as shown by the hydro and CAT tool, with a density reading of 1.01 gm/cc. The

density tool reads 0.73 gm/cc in zone B, indicating a mixture of oil with a small portion of gas. However, the CAT tool is

detecting a mixture of oil and water on the low side of the wellbore, trending to almost a pure oil, then to a mixture of gas and

oil on the high side.

Resistivity Array Tool. The RAT tool consists of an array of 12 microsensors that detects very small, fast moving bubbles of

conductive water and the non-conductive hydrocarbons. Real-time software provides a mean value and a standard deviation

for the resistance values of the 12 sensors over for the period being summarized .

NEW

RATMAPHI------LOW------HI

0 1

XX00

RAT MN.2 1.2

DENSITY.1 1.1

HYDRO

0 2

AVRATMN1 0

TEMPERATURE171 177

PRESSURE

2750 2800

GAMMA0 100

XX50

A

B

C

RAT SD.0 .1

PUBLISHED

RATMAP

HI------LOW------HI0 1

YWRATA NEW

1 0

YWRATA1 0

NEW

RATMAPHI------LOW------HI

0 1

XX00

RAT MN.2 1.2

DENSITY.1 1.1

HYDRO

0 2

AVRATMN1 0

TEMPERATURE171 177

PRESSURE

2750 2800

GAMMA0 100

XX50

A

B

C

RAT SD.0 .1

PUBLISHED

RATMAP

HI------LOW------HI0 1

YWRATA NEW

1 0

YWRATA1 0

Figure. 2–Raw and processed RAT data over the same zone as Figure. 1.

Figure. 2 shows the RAT data in the same well over the same zone as the CAT log in Figure. 1. The RAT map uses blue

to indicate water and green to indicate hydrocarbons, with the interpolation between the blue and green as a mixture,

depending upon the percentage of water. If gas/water is present, green is replaced with red to make the visualization of theimages easier. The RAT MN data is the average mean value from the 12 sensors, and the RAT SD is the standard deviation

of the same data. There are two methods that can be used to determine the holdups from the RAT tool. The published method

which is described later uses both the mean and standard deviation data to determine the water holdup. The new method uses

the average mean measurements, a water value, and hydrocarbon value. Both methods show almost the same result when


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SPE 125028 5

- 8 0 0 8 0

-6 .

-4

-2

0

2

4

6 .

Line Speed

Spinner RPS

- 8 0 0 8 0

-6 .

-4

-2

0

2

4

6 .

Line Speed

Spinner RPS

Figure. 3–Spinner calibration p lot for sp inner 1 using six d ifferent passes to determine threshold and slopes.

XX00

CFB SPIN-50 50

ILS SPIN-50 50

XX50

SATMAP-104 152

171 TEMP 1772750 PRES 28800 GAMMA 100-100 LINE SPD 100

-15 SPIN1 15-15 SPIN2 15-15 SPIN3 15-15 SPIN4 15-15 SPIN5 15-15 SPIN6 15

-100 VA1 150-100 VA2 150-100 VA3 150-100 VA4 150-100 VA5 150-100 VA6 150

CFB VA-100 150

ILS VA-100 150

AVG.SAT VA-100 150

A

B

XX00

CFB SPIN-50 50

ILS SPIN-50 50

XX50

SATMAP-104 152



-100 VA1 150-100 VA2 150-100 VA3 150-100 VA4 150-100 VA5 150-100 VA6 150

CFB VA-100 150

ILS VA-100 150

AVG.SAT VA-100 150

XX00

CFB SPIN-50 50

ILS SPIN-50 50

CFB SPIN-50 50

ILS SPIN-50 50

XX50

SATMAP-104 152





-100 VA1 150-100 VA2 150-100 VA3 150-100 VA4 150-100 VA5 150-100 VA6 150

-100 VA1 150-100 VA2 150-100 VA3 150-100 VA4 150-100 VA5 150-100 VA6 150

CFB VA-100 150

ILS VA-100 150

AVG.SAT VA-100 150

A

B

Figure. 4–Log show ing both r aw data and calculated velociti es from inli ne, fullbore, and SAT spinners.


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6 SPE 125028

The SAT, inline, and fullbore spinner data is shown in Figure. 4. The raw data from each of the six SAT spinners are

shown in track 3, with the corresponding calculated velocities shown in tracks 4 and 5. For comparison, the apparent velocity

from fullbore and inline spinners are ploted against the average of the six SAT velocities is in track 4. These three velocitiesshould track or follow the same general trend, but may not perfectly overlay or match because of the tool position and flow

profiles.

The last track is the image created from the six SAT calculated velocities and the SAT tool relative bearing. The images

from the SAT are divided into two sets of colors, indicating both direction and velocity. White to black indicates downflow,

with black being the highest value and white being 0; likewise, yellow to magenta indicates positive flow up the wellbore,ranging from 0 to maximum velocity. Between A and B, the pattern indicates fluid flow down the wellbore or possible fluid

fallback. The fluid flowing downhole should be the heavier fluids as a result of gravity segregation and, when compared withthe CAT and RAT logs, it should be possible to determine whether or not this is correct. Therefore, the lightest fluids should

be flowing on the high side of the wellbore with the highest velocity, which is the case for this well.

Raw Data Quality ControlUsing the 12 sensors on the CAT and RAT and the six spinners on the SAT, several methods were designed and implementedfor the quality control (QC) of these measurements. The initial QC rests with the field engineer’s decision of whether or not

the sensor readings are accurate and repeatable for a steady and consistent flow conditions. The standard log presentations

provide the basic readings for the 24+ holdup sensors and the 6+ velocity sensors. However, when a reading behaves

differently from the others, is it a result of tool malfunction or possible changes in the flow patterns or wellbore conditions?Is the data consistent enough to provide a quality PL interpretation, or are more PL runs needed? Is it a tool problem

requiring complete sensor replacement? Or do the multiple sensors provide enough coverage to provide the necessary orrequired data to solve the initial problem or needs of the customer? These are some of the questions that must be answered

when evaluating data quality at the well site with these new tools. To help provide a consistent QC platform, a quicklook

spreadsheet, with standard interpretation and 3D images provides a method to help the field personnel decide whether or not

the data is adequate for analysis. An additional benefit from the QC program is that it helps educate both experienced and

non-experienced users of PL data about the complicated fluid profiles found in vertical, deviated, and horizontal wellbores.

There are two ways in which to calculate multi-sensor holdups. The easiest method is to determine the holdup at eachsensor, then divide the number of sensors in the phase by the total number of sensors. The holdups that use the averaging

method in which each sensor has equal weight will be Ywe, Yoe, and Yge for water, oil and gas respectivly. The wellbore

cross-sectional area associated with each sensor must, however, also be considered to make a correct determination ofholdup. The contribution of each sensor to the total holdup measurement will vary as a function of the sensor’s location

relative to the top of the wellbore. The ratio of the total cross-sectional area for the sensors indicating the phase to the pipe

cross sectional area provides another method for calculating for phase holdup. The cross-sectional area indicating water canreadily be computed from elemental geometry. The holdups calculated from this method will be Ywa, Yoa, and Yga for

water, oil and gas respectfully. The post-processing software uses both methods to determine holdups for both the CAT andRAT logs.

Quicklook SpreadsheetsA spreadsheet was developed (Figure. 5) that uses all of the post-processing algorithms to enable the field engineer or user to

enter the basic logging parameters and logging data into the yellow cells and obtain an estimate of the holdups and velocity

from both the PAL tools and standard PL string. This easy-to-use spreadsheet can be exchanged between the field operationsand interested parties. Various options enable the engineer to select the type of phases in the wellbore and to enter some of

the parameters. The data itself can be manually entered or cut and pasted from an averaging program that was also developed

for the PAL tools.


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SPE 125028 7

Figure. 5–The modified spreadsheet enabling a quick look interpretation of the holdup data.

RAT holdupsCAT holdups

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

XX88-XX93 XX70-XX80 XX20-XX30

0.00

0.10

0.20

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0.50

0.60

0.70

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0.90

1.00


RAT holdupsCAT holdups

0.00

0.10

0.20

0.30

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0.90

1.00


0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00


Figure. 6–A quick visualization of the PAL holdups .

The holdups calculated are the averaging method described above because of the complexities involved using the areacalculations. Figure. 6 shows a quick visualization of the holdups calculated from the CAT and RAT sensors. The averaging

method for holdup calculations has some errors that were previously described. Phase holdups from all of the available

sensors are shown in tablular form in Figure. 7.

Figure. 7–A numerical presentation of bo th PAL holdups and conventional PL tool s.

A similar spreadsheet is also used to determine the velocities from the SAT spinners along with the inline and fullbore

data. The user can enter data in the yellow cells and the spreadsheet will provide the calculated values in the green cells. The

slopes and thresholds for the tools can be calculated with multiple passes, as previously explained, or use standard defaults.

In this case, there was not a no flow area or shut in passes run, so the analyst used a common value for all sensors.

DENSITY HYDRO

WATER 1.0050 2 ZONE DENR CWH

OIL 0.7600 1 1 1.0049 1.9829

GAS 0.1330 0 2 0.7271 0.9751

CAT MASTER WATER 50 3 0.1645 0.2807

CAT MASTER OIL 150

CAT MASTER GAS 200PHASES 3 0=water/gas,1=oil/gas,2=water/oil,3=water/oil/gasHALRAD 0 1=new, 0=publishedUSERAT 0 0=USE RATHY, 1= RATHY01-12

RATHY 0.9919

RATWAT 0.5059

CAT CALIBRATIONS RCAP01 RCAP02 RCAP03 RCAP04 RCAP05 RCAP06 RCAP07 RCAP08 RCAP09 RCAP10 RCAP11 RCAP12

WATER 55 53 54 50 50 55 53 60 55 57 51 56

OIL 157 139 132 153 131 127 150 145 150 141 141 149

GAS 205 185 181 205 171 171 191 185 191 184 178 185

READINGS FROM LOGS

ZONEDEPTH / DESCRIPTION RCAP01 RCAP02 RCAP03 RCAP04 RCAP05 RCAP06 RCAP07 RCAP08 RCAP09 RCAP10 RCAP11 RCAP12

1 XX88-XX93 55 53 57 49 51 55 54 61 55 60 57 562 XX70-XX80 166 150 141 161 119 110 149 144 150 143 152 1603 XX20-XX30 190 172 158 189 131 163 172 163 171 161 170 182

ZONEDEPTH / DESCRIPTION RATMN01 RATMN02 RATMN03 RATMN04 RATMN05 RATMN06 RATMN07 RATMN08 RATMN09 RATMN10 RATMN11 RATMN12

1 XX88-XX93 0.4931 0.4973 0.5207 0.5074 0.5004 0.4982 0.5104 0.5169 0.4995 0.5053 0.5067 0.5148

2 XX70-XX80 0.9922 0.9923 0.9927 0.9920 0.9923 0.9921 0.9927 0.9926 0.9920 0.9926 0.9923 0.99233 XX20-XX30 0.9910 0.9904 0.9910 0.9906 0.9908 0.9917 0.9918 0.9912 0.9913 0.9919 0.9920 0.9910

ZONEDEPTH / DESCRIPTION RATSD01 RATSD02 RATSD03 RATSD04 RATSD05 RATSD06 RATSD07 RATSD08 RATSD09 RATSD10 RATSD11 RATSD12

1 XX88-XX93 0.0078 0.0090 0.0075 0.0081 0.0092 0.0088 0.0090 0.0091 0.0094 0.0090 0.0107 0.01102 XX70-XX80 0.0185 0.0186 0.0199 0.0192 0.0195 0.0203 0.0195 0.0197 0.0198 0.0196 0.0189 0.0194

3 XX20-XX30 0.0222 0.0214 0.0206 0.0217 0.0215 0.0200 0.0202 0.0211 0.0206 0.0202 0.0196 0.0225

ZONE DEPTH / DESCRIPTION Yw Yo Yg Yw Yo Yg Ywe Yoe Yge YWRE YHRE

1 XX88-XX93 0.9996 0.0004 0.0000 0.9829 0.0171 0.0000 0.9854 0.0146 0.0000 0.9996 0.0004

2 XX70-XX80 0.0000 0.9475 0.0525 0.0000 0.9751 0.0249 0.0339 0.8481 0.1181 0.0007 0.9993

3 XX20-XX30 0.0000 0.0502 0.9498 0.0000 0.2807 0.7193 0.0000 0.4061 0.5939 0.0015 0.9985

HYDRO ANALYSIS CAT ANALYSIS RAT ANALYSISDENSITY ANALYSIS


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8 SPE 125028

Figure. 8–The modified spreadsheet enabling a quick look i nterpretation of the spinner data.

The results of the spreadsheet shown in Figure. 8 for the 6 SAT spinners show both positive and negative flow at the

same depths, which appears to be almost random in the determination of the velocity profile. However, when a simple graph

is generated (Figure. 9), the velocity profile becomes apparent and assists in the evaluation of the data.

- 150 .0

-100 .0

-50.0

0 .0

50 .0

100 .0

.

S AT 1 SA T 2 SAT 3 SA T 4 S A T 5 SAT 6 FU L LB OR E IN LIN E

X X 88-X X93 X X 70-X X 80 X X20-X X 30 Figure. 9–A graphical representation of the velocit y data presented in Figure. 8.

The graph used to evaluate the SAT velocities indicates that spinner 2 has the highest velocity and spinner 5 has the

slowest (actually negative) velocity especially, in the zone xx20-30. This trend suggests that spinner 2 is on the high side, andthat spinner 5 is on the low side of the wellbore. The spreadsheets provide a means to review the data to help determine

whether or not the raw data is suitable for analysis.

Combined InterpretationAlthough the PAL data can be used to make interpretations by using each tool individually, the real benefit comes from

combining the multiple tools and sensors into one complete interpretation package. Because the CAT and RAT tools provide

up to 24 holdup measurements and the SAT tool provides six velocity measurements, the PAL logs provide the advantage of

a complete flow analysis.

The basic flow equation is as follows:

V AQ ×= Equation 5

where: Q = Flow rate A = Pipe area available for flow

V = Velocity

POSITIVE

THRESH

POSITIVE

SLOPE

NEGATIVE

THRESH

NEGATIVE

SLOPE

FULLBORE 5.00 0.567 -5.00 0.522

INLINE 5.00 0.168 -5.00 0.153

SAT 5.00 0.082 -5.00 0.076

ZONE DEPTH / DESCRIPTION CS ILS CFB SPIN1 SPIN2 SPIN3 SPIN4 SPIN5 SPIN6

1 XX88-XX93 59.83 -8.499 -34.414 -3.983 -2.941 -3.228 -4.419 -0.403 -3.449

2 XX70-XX80 60.00 -10.561 -39.593 -3.960 -0.752 -1.864 -3.449 -5.018 -4.961

3 XX20-XX30 60.91 -0.539 -14.578 -2.581 0.423 -0.854 -4.645 -8.494 -6.270

SAT 1 SAT 2 SAT 3 SAT 4 SAT 5 SAT 6 FULLBORE INLINE

ZONE DEPTH / DESCRIPTION

1 XX88-XX93 2.4171 16.1342 12.3526 -3.3158 49.5263 9.4421 -11.1012 -0.7266

2 XX70-XX80 2.9028 45.1054 30.4818 9.6199 -11.0196 -10.2801 -20.8475 -14.0227

3 XX20-XX30 21.9586 71.0674 44.6757 -5.2059 -55.8493 -26.5809 27.9863 52.3929


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SPE 125028 9

Breaking the equation 5 into phase flow rates yields the following:

VwYw AQw

VoYo AQo

VgYg AQg

××=

××=

××= Equation 6

where: i = Phase component (gas, oil, and water)

Yi = Phase holdupVi = Phase velocity

The major unknown in PL interpretation is the use of slip velocities to solve for the phase velocities that are required to

solve for equation 6. Historically, multiple equations and relationships have been developed to determine these slip

velocities, which then are used to match the downhole flow rates to the surface flow rates in most PL software packages.Because the PAL tools provide both holdup and velocity measurements, the combined results should eliminate the need to

use the slip velocities to determine flow rates for each phase. However, since these tools can be arranged in any position in the

tool string, each sensor may not be in the same radial position in the wellbore as the other tool sensors, as shown in Figure. 10.

Correlating the individual position of each sensor is necessary to solve the flow equations without the use of slip velocities.Because each PAL tool has an independent relative bearing sensor, the azimuthal or radial position of each sensor can be

determined with respect to the high side of the wellbore. This yields the horizontal and vertical position of each sensor. Also,

assuming a 0 relative bearing, it is possible to determine the area of the wellbore above and below the highest and lowest sensor

position in the well. By examining the data in the vertical plane, the measurements can be separated into segments.

YYYY

1 ATOP

ABOT

SATCAT or RAT Vert ical s l ic ing o f wellbore

YYYY

1 ATOP

ABOT

YYYY

1 ATOP

ABOT

YYYY

1 ATOP

ABOT

SATCAT or RAT Vert ical s l ic ing o f wellbore

Figure. 10–Possible tool and sensor posit ions f or the SAT, CAT, and RAT, and segmented slic ing of the wellbore.

At every depth increment, it is possible to provide the holdup, velocity, and area for each slice and therefore, the flow rate

for each slice. The highest and lowest vertical sensor position for each PAL tool is determined and extrapolated to the slices

labeled ATOP or ABOT. Expanding Equation 6 for each slice will yield Equation 7. By determining the holdup, velocity,area, and flow rate of each slice, the total flow of each phase can be ascertained without the need to use any slip velocity

correlations. This technique removes several areas of concern related to the typical PL analysis, especially with deviated and

horizontal wells and multiphase stratified flow regimes.

( )

( )

( )∑

∑

∑

××=

××=

××=

i

i

i

VwiYwi AiQw

VoiYoi AiQo

VgiYgi AiQg

1

1

1

Equation 7

where: Qg = Gas flow rate

Qo = Oil flow rate

Qw = Water flow rate

Ai = Area of each sliceYg = Gas holdup of each slice

Yo = Oil holdup of each slice

Yw = Water holdup of each sliceVi = Slice velocity


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10 SPE 125028

PAL Log PresentationsIn addition to the horizontal image, a new image enables the visualization of the wellbore in a vertical plane. This image

is presented from the low side to the high side. The high side will always be on the right side of the track and will include ‘X’in the image presentation name. A slight modification of this image incorporates the TVD data and will include ‘T’ in the

name.

XX50

XX00

PUBLISHED

RATMAP

HI--------LOW--------HI

0 1

PUBLISHED

XRATMAP

LOW--------------------HI

0 1

SATMAP

HI--------LOW--------HI

-104 152

XSATMAP

LOW--------------------HI

-104 152

CATMAP

HI--------LOW--------HI

50 200

XCATMAP

LOW--------------------HI

50 200

TEMPERATURE

171 177

PRESSURE

2750 2800HYDRO

0 2

FLUID DENSITY

0.1 1.1

GAMMA

0 100

A

B

C

E

FD

G

H

XX50

XX00

PUBLISHED

RATMAP

HI--------LOW--------HI

0 1

PUBLISHED

XRATMAP

LOW--------------------HI

0 1

SATMAP

HI--------LOW--------HI

-104 152

XSATMAP

LOW--------------------HI

-104 152

CATMAP

HI--------LOW--------HI

50 200

XCATMAP

LOW--------------------HI

50 200

TEMPERATURE

171 177

PRESSURE

2750 2800HYDRO

0 2

FLUID DENSITY

0.1 1.1

GAMMA

0 100

XX50

XX00

PUBLISHED

RATMAP

HI--------LOW--------HI

0 1

PUBLISHED

XRATMAP

LOW--------------------HI

0 1

SATMAP

HI--------LOW--------HI

-104 152

XSATMAP

LOW--------------------HI

-104 152

CATMAP

HI--------LOW--------HI

50 200

XCATMAP

LOW--------------------HI

50 200

TEMPERATURE

171 177

PRESSURE

2750 2800HYDRO

0 2

FLUID DENSITY

0.1 1.1

GAMMA

0 100

A

B

C

E

FD

G

H

Figure. 11–PAL horizontal and vertical images showing both phase segregation and fluid dow nflow.

Figure. 11 provides images from the three PAL tools along with quality control plots. The white dashed lines in the CAT

and RAT logs indicate the low side of the wellbore in the third track, and the magenta line indicates the same position in theSAT log. The vertical center of the wellbore in the vertical maps is indicated by the same line and shows where the centersample tools would be positioned when properly centralized. The quality control plots in the CAT and RAT logs are used to

show six of the 12 holdup measurements around the wellbore, with sensor one indicated by the blue line. The length of each

arm indicates the type of fluid, with water having the shortest length and hydrocarbons having the longest length. On the

CAT quality control plot, the gas component is slightly longer than the oil phase. The CAT and RAT quality control plots

indicate the heavier fluids on the low side. The SAT quality control plot shows the six velocity calculations in a cross-sectional view. The longer arms indicate the highest velocity at that depth, whereas the shorter arms indicate the slowest

velocity, including negative velocity. The blue arm is the location of spinner #1. This log shows that segregated flow is

occurring in the well.The CAT log indicates a pure gas on the high side of the wellbore at point A. From the center to the right side of the

track, a mixture of gas and oil is found. The almost-pure oil in the lower side of the wellbore, indicated by the CAT log from

A to B, is not sensed by the center sample tools, which indicate almost a 100% gas phase over the same zone. Points B and C

indicate oil on the low side, with a mixture of gas and oil on the higher side of the wellbore with some segregation of thesetwo phases. The density tool reads approximately 0.7 gm/cc, which indicates a mixture of oil and gas. At point C, the

XCATMAP image indicates a mixture of oil and gas and confirms the center sample tool readings. The CAT and RAT data

indicate water at point D, which correlates with the centralized sensors fluid density (DENR) and capacitance (CWH) logs.

At point F, the interface between the oil and gas is not visible on the RAT log because of the differences between capacitance

and resistivity readings. At point E, the water shown seems out of place, but because this is a perforated interval, it appearsthat water is entering the wellbore on the high side of the well. The SAT log shows that segregated flow is occurring in the

well. Point H is characterized by negative velocity on the low side with a higher positive fluid velocity on the high side of thewell. Point G also indicates a segregated velocity profile.

With the myriad of options available to examine the PAL data, the use of the vertical displays seems to enable a better

understanding of the complex flow regimes and fluid segregation in these deviated wells. A definite correlation exists

between the phases sensed by the CAT and the velocity patterns sensed by the SAT. At point A, the fluids are a mixture of oiland gas on the high side, tending to a pure oil component on the low side. This oil is either stationary or flowing slightly


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SPE 125028 11

downhole while the gas/oil mixture is flowing up hole. The high side of the wellbore has a higher percentage of gas and is

flowing at higher velocity. At point B, the CAT log shows an entry of gas into the wellbore on the lower side. Immediately

below this point, there is apparent fluid downflow on the low side with a gas/oil mixture flowing uphole on the high side ofthe wellbore.

Flow CalculationsFinal processing of the PAL data set was performed using Kappa’s Emeraude software. After the data is ported into

Emeraude, the analyst must determine which of the multitude of options to use to perform the final analysis. With multiplevelocity and holdup measurements, there are multiple variations and options to determine final flow. The standard

interpretation that is normally used consists of the PAL process described earlier using the CAT and SAT data (Figure. 12).

Z QP

psia2700 2800TEMP

°F165 178QG

B/D-5000 20000QO

B/D-5000 10000Q

B/D-1000 15000QZT

B/D-1000 15000QZI

B/D-2000 10000

All PASSES

PRESSURE2700 2800

All PASSES

TEMPERATURE165 178

All PASSES

Q GAS B/D-5000 20000

All PASSES

Q OIL B/D-5000 10000

DOWNHOLE

Q-1000 15000

DOWNHOLE

ZONAL Q-1000 15000

DOWNHOLE

INCREMENTAL-2000 10000

PREVIOUSZONE

PERFS

PERFS

PERFS

Q ZONE

Q ZONE

Q ZONE

Z QP

psia2700 2800TEMP

°F165 178QG

B/D-5000 20000QO

B/D-5000 10000Q

B/D-1000 15000QZT

B/D-1000 15000QZI

B/D-2000 10000

All PASSES

PRESSURE2700 2800

All PASSES

TEMPERATURE165 178

All PASSES

Q GAS B/D-5000 20000

All PASSES

Q OIL B/D-5000 10000

DOWNHOLE

Q-1000 15000

DOWNHOLE

ZONAL Q-1000 15000

DOWNHOLE


PREVIOUSZONE

Z QP

psia2700 2800TEMP

°F165 178QG

B/D-5000 20000QO

B/D-5000 10000Q

B/D-1000 15000QZT

B/D-1000 15000QZI

B/D-2000 10000

All PASSES

PRESSURE2700 2800

All PASSES

TEMPERATURE165 178

All PASSES

Q GAS B/D-5000 20000

All PASSES

Q OIL B/D-5000 10000

DOWNHOLE

Q-1000 15000

DOWNHOLE

ZONAL Q-1000 15000

DOWNHOLE


PREVIOUSZONE

PERFS

PERFS

PERFS

Q ZONE

Q ZONE

Q ZONE

Figure. 12–Flow analysis using Emeraude over the entir e well.

The pressure data indicates that the well is not in a steady state. The first pass in the well is shown in red, and the first up

pass is shown in green. After these two passes are made, the well becomes nearly stable. Likewise, a comparison of the gasflow rate passes shows that all of the passes are similar, except for the first down pass shown in red (Figure. 12). The other

passes show that the flow of oil and gas is consistent at every depth, even though there are variations in the CAT, SAT, and

RAT data between each pass. Although the individual tools show changes between passes, the total flow rate remainsconstant.

The flow rates are the average of the seven steady passes and are at downhole conditions. Emeraude uses a procedure to

match the known inputs (measured) to the calculated inputs (calculated) to determine the final flow with minimal error. The

software enables the user to weight each input and to select multiple PVT and slip options. The more inputs that are selected,

the more possible variations are in the final answer. The use of all of these options is possible with the PAL data; however,


12/14

12 SPE 125028

because the downhole flow is already determined, the surface production rate is calculated by using the PVT options to

correct the downhole flow rate of each phase to the surface rate. This calculation removes the problems related to the

standard PL analysis that use slip velocity to break down the calculated velocity into phase velocity.

EXPANDED

LOG

DEPTH

XY00

XX00

EXPANDED

LOG

DEPTH

XX00

3-D

LOG

3-D

LOG

EXPANDED

LOG

DEPTH

XY00

XX00

EXPANDED

LOG

DEPTH

XX00

EXPANDED

LOG

DEPTH

XY00

XX00

EXPANDED

LOG

DEPTH

XX00

3-D

LOG

3-D

LOG

Figure. 13–CHIME images including 3D view of CAT-RAT logs.

To further improve QC and interpretation, another software program, CHIME, is used to generate 3D images of the PAL

data. This software is designed so that the user can manipulate the data and derive images over zones of interest. CHIMEexpands the zones of interest as shown in Figure. 13. The black squares are 10 ft long and the data enclosed by the square is

expanded to the tracks labeled CATMAP and XCATMAP. The RAT data is also shown and expanded the same way. The last portion is the 3D image. The gray line in all the tracks highlights the depth that is shown in the cross-section in Figure. 14.

On both the CATMAP and XCATMAP images, a portion of 100% water is present on the lower side of the wellbore, but this

is not displayed on the RATMAP and XRATMAP images.

CAT

Yg = .013

Yo = .893

Yw = .094

RAT

Ywra = 0

Yhra = 1

CAT

Yg = .013

Yo = .893

Yw = .094

CAT

Yg = .013

Yo = .893

Yw = .094

RAT

Ywra = 0

Yhra = 1

Figure. 14–CHIME cross-sectional display of logs in Figure. 13. Black dots show the sensor positions; the white dot indicatessensor 1.

Figure. 14 presents the data in a cross-sectional display for both the CAT and RAT logs. By examining the sensor position of both tools, it can be determined why the water streak is not detected by the RAT tool. The CAT sensors are

almost in the highest and lowest sections of the wellbore, whereas the RAT sensors are slightly off this vertical plan. The

sensor position is the primary reason that the RAT does not sense the water portion detected by the CAT. Even with multiplesensors, not all phases may be detected, depending upon sensor position. However, with multiple passes, the possibility of


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SPE 125028 13

detecting most phases will be improved because the tool will probably not have the same rotational patterns in all the passes.

The layering pattern on the CAT tool also shows slight differences that are not detected by the RAT, but the components are

gas, oil, and water, and unlike the CAT, the RAT cannot differentiate between the oil and gas.

EXPANDED

LOG

DEPTH

SAT MIN =-101.78

SAT MAX = 60.93

SAT AVG = 60.93

XX00

XY00

3-D

LOG

EXPANDED

LOG

DEPTH

SAT MIN =-101.78

SAT MAX = 60.93

SAT AVG = 60.93

XX00

XY00

EXPANDED

LOG

DEPTH

SAT MIN =-101.78

SAT MAX = 60.93

SAT AVG = 60.93

SAT MIN =-101.78

SAT MAX = 60.93

SAT AVG = 60.93

XX00

XY00

3-D

LOG

Figure. 15–SAT CHIME display with 3D images and cross section.

Figure. 16–SAT CHIME display with 3D images.


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14 SPE 125028

Figure. 15 and Figure. 16 highlight some of the capabilities of CHIME to present the PAL data in images and cross-

sections that enable easier interpretation of the flowing patterns. In this case, there is definite fluid segregation with some of

the fluids flowing downhole as indicated by the white to black shading while the fluids on the high side are flowing upholeindicated by the yellow to magenta shading. The images are over the same zone with different presentations.

All of the CHIME data, including the software, can be downloaded to either a USB flash drive or a CD to enable

customer manipulation of the data. This manipulation is limited to only the 3D portion, however, rather than to re-calculation

of the PAL data. In addition to the images shown, CHIME can also present scalar data ranging from the raw data to the final

calculated flowrates.

ConclusionsThe availability of the PAL tools provides multiple options to calculate holdups, velocity, and flowrates depending upon well

conditions, flowing phases, and other factors that may not be the most advantageous to conventional production logging.

With all of these sensors, quality control is an issue that is addressed by spreadsheets and analysis programs, including 3D

displays. The spreadsheets help to determine the quality of the raw data and whether more logging passes are required or the

tools need to be replaced. After quality data is recorded, several options are available to maximize the interpretation. Holdupscan be determined by a single PAL tool or by multiple tools, if necessary. There are currently four holdup options that use the

CAT and RAT data. Likewise, the velocity profile can be determined from the SAT, or from the inline or continuous spinners

if the SAT data is inconclusive. The flowrates are then determined by using the desired holdup and velocity data and is

converted to surface rates using Emeraude. The final product can be then visualized and quality controlled by the use of theCHIME software. CHIME will provide 3D images to illustrate the complexities of the flowing conditions of wellbores,

including deviated and horizontal wells. The same procedure is then used to determine the flow rate of each componentwithout using any slip velocity correlations. This procedure will help in the analysis of horizontal wells, especially when

crests and troughs play havoc with the flow patterns and when a blocking heavy phase is present.

The use of the PAL tools with new interpretation practices improves the interpretation of production logging in both

deviated and horizontal wells. Although the example shown was a high rate oil/gas well with deviation of approximately 45

degrees, the process has shown definite benefits for horizontal wells. Removing the dependence upon slip velocity

relationships reduces some of the uncertainties in the area of multiphase production log interpretation.

AcknowledgmentsThe PAL sensors described in this paper were developed in part through cooperation with Sondex. The authors wish to thankBP for permission to reproduce the log examples used here and for the support in the introduction of the PAL tools. The

authors also gratefully acknowledge the management of Halliburton Energy Services for allowing this paper to be published.

A special thanks to Tegwyn Perkins and Ron Stamm for the development of the 3D software to allow the imaging of the PLdata.

ReferencesFrisch, G., Jung, M., Alldredge, P., Zett, A., and Webster, M. 2009. Providing Accurate PL Interpretation with Multi-probe, Multi-Sensor

Tools in Segregated Flow Environments. Paper X presented at the SPWLA 50th Annual Logging Symposium, The Woodlands, Texas,USA 21-24.

Frisch, G., Perkins, T., and Quirein, J. 2002. Integrating wellbore flow images with a conventional production log interpretation method.Paper SPE 77782 presented at SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 29 September-

2 October.Ryan, N.D. and Hayes, D. 2001. A new multiphase holdup tool for horizontal wells. Paper V presented at the SPWLA 42nd Annual

Logging Symposium, Houston, Texas, USA, 17-20 June.

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