seismic and petrophysics
TRANSCRIPT
-
7/30/2019 Seismic and Petrophysics
1/19
1
PETR 220B TechnicalPresentation
SEISMIC & PETROPHYSICS
-
7/30/2019 Seismic and 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.
-
7/30/2019 Seismic and Petrophysics
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)
-
7/30/2019 Seismic and Petrophysics
4/19
4
SEISMIC
Rock physics transforms petrophysicalresults into elastic properties that can be
used for seismic interpretation.
-
7/30/2019 Seismic and Petrophysics
5/19
-
7/30/2019 Seismic and Petrophysics
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 -
7/30/2019 Seismic and Petrophysics
7/19
7
Petrophysics SeismicIntegration
http://www.freeusp.org/RaceCarWebsite/TechTransfer/OnlineTraining/SeisPetro/FlowChart.maphttp://www.freeusp.org/RaceCarWebsite/TechTransfer/OnlineTraining/SeisPetro/FlowChart.map -
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
9/19
9
Petrophysical Assesment of the
Reservoir Reservoir thickness
Porosity
Hydrocarbon Saturation
-
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
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.
-
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
14/19
14
Seismic Data Acquisition
Vibroseis
-
7/30/2019 Seismic and Petrophysics
15/19
15
Upscaling PetrophysicalProperties to the Seismic Scale
Scoping at the Well-Log Scale
Sensitivity Analysis for Upscaling
Predicting Petrophysical Propertiesfrom Seismic Impedance
-
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
17/19
17
-
7/30/2019 Seismic and Petrophysics
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
-
7/30/2019 Seismic and Petrophysics
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.