Seismic and Petrophysics

7/30/2019 Seismic and Petrophysics

1/19

1

PETR 220B TechnicalPresentation

SEISMIC & PETROPHYSICS


2/19

2

PETROPHYSICS

Definition

Petrophysics may be defined as the synergistic

process of integrating data sets from multiplesources, disciplines, and scales to characterizeand quantify rock, pore and fluid systems(modified version of Archies 1950 definition).

Multiple methods are used to describe the sameparameter so as to minimize uncertainty.


3/19

3

PETROPHYSICS

PETROPHYSICS

GEOLOGY GEOPHYSICS

DRILLING ENGINEERING

RESERVOIR

Facies characterization

- Structural

- Sand bodiesdistribution

- Seismic facies

- Rock Physics

- Synthetic seismic/Tie-in

- Rock mechanics

- Data Acquisition

- Real time drilling

optimization

- Fluids /contatcs

- Pressure/Compartments

- Relativepermeability

Where todrill andwhat typeof rocks toexpect

Optimize no.Of wells and

position

Build Model

Extract Maps

CalculateVolumes

compartments

Model update(4D)


4/19

4

SEISMIC

Rock physics transforms petrophysicalresults into elastic properties that can be

used for seismic interpretation.


5/19


6/19

6

Petrophysics SeismicIntegration

INTEGRATION

Well test

Formation tester

sampling

Well logging:

density, neutron,

resistivity, NMR,

Sonic,spectrometry

.

SCAL

SEM

The goal: 3D visualisation

of the reservoir

The integration of all the aspects of the

reservoir is the key to achieve the 3Dvisualisation

seismic
http://www.slb.com/content/services/evaluation/scanner/index.asp?http://www.bakerhughesdirect.com/cgi/hello.cgi/INTEQ/coring/images/coringoverviewhires.jpg


7/19

7

Petrophysics SeismicIntegration
http://www.freeusp.org/RaceCarWebsite/TechTransfer/OnlineTraining/SeisPetro/FlowChart.maphttp://www.freeusp.org/RaceCarWebsite/TechTransfer/OnlineTraining/SeisPetro/FlowChart.map


8/19

8

Petrophysical Assesment of the

Reservoir Process of using information obtainedfrom boreholes to determine the physicaland chemical properties of rocks and theirfluid content.

Used to determine

Reservoir thickness

Porosity & Permeability Hydrocarbon Saturation & Mobility


9/19

9

Petrophysical Assesment of the

Reservoir Reservoir thickness

Porosity

Hydrocarbon Saturation


10/19

10

Identification of PertinentAcoustic Properties

Conventional seismic modelling, Compressional sonic, shear sonic, and density logs and core

measurements provide the information necessary to model the

seismic expression of a logged interval

Cross-plotting well-log-scale acousticproperties vs petrophysical properties, Acoustic Impedance orVp/Vs versus Water Saturation

Acoustic Impedance orVp/Vs versus Volume of Shale


11/19

11

Identification of PertinentAcoustic Properties

Overlaying capillary pressure and acousticproperties,

Overlaying Lorenz/Modified Lorenz plots andacoustic information,

Overlaying porosity-permeability and acousticproperties,

Backus averaging acoustic well-logmeasurements to upscale to the seismic scale.


12/19

12

Seismic Modelling

This step involves forging an understanding ofthe acoustic response of the reservoir. Thisinvolves:

Building end-member reservoir models frompetrophysical rock and fluid types Computing seismic responses for each model,

and

Varying the reservoir thickness/net-to-grosswithin each model to understand tuningeffects.NB: Flow-unit seismic expressions are modelledand understood at this stage


13/19

13

Seismic Data Acquisition

Energy propagation bouncing sound waves off boundaries between different types of rock, on land

truck mounted vibrators, sea-air guns

The Seismogram The synthetic seismogram The seismic record

Energy Sources Land-dynamite, Marine-Air gun

Geophones and hydrophones

seismic transducer, or seismometer The seismic recorder

Digital recorders are used in all modern seismic work Computer compatibility, Large dynamic range


14/19

14

Seismic Data Acquisition

Vibroseis


15/19

15

Upscaling PetrophysicalProperties to the Seismic Scale

Scoping at the Well-Log Scale

Sensitivity Analysis for Upscaling

Predicting Petrophysical Propertiesfrom Seismic Impedance


16/19

16

Seismic Data Processing

Spatial phase stabilization quality control-Short window slabs of data are extracted surrounding

each picked horizon-Average phase distribution map is computed

-Maps are phase vector summed to get average phasedistributed.

-If flat response then no correction is needed-

If not-Trace is phase rotated by phase value-Quality control procedure is repeated


17/19

17


18/19

18

Calibrations of real seismicattributes to modelled seismic

attributes Waveform characteristics from real seismic data

is compared to waveform characteristic from

modelled seismic data. Similarities strengthen the calibrations while

dissimilarities show inadequate data andconceptual framework or mathematical model.

Used along with 3D seismic to map 3D flow unitgeometries


19/19

19

Conclusion

An integrated model increases accuracy of the final analysis, makingit easy to iterate between petrophysics and rock physics whilemaintaining consistency.

Benefits include:

Increased credibility and hence greater acceptance of decisions Increased efficiencies Faster project turn-around More timely delivery of results to engineers and geophysicists Improved well placement Reduced drilling risk for more precise reservoir management Increased field productivity since a better drilling program can be

devised A more complete and credible view of company assets.

Seismic and Petrophysics

Documents

Transcript of Seismic and Petrophysics