prestack waveform inversion: an onshore application in the us gulf coast
DESCRIPTION
Prestack Waveform Inversion: an Onshore Application in the US Gulf Coast. August Lau, Chuan Yin, Mike Greenspoon, Apache Corp; Anthony Vassiliou, GeoEnergy September 2007. Well to Seismic Tie. - PowerPoint PPT PresentationTRANSCRIPT
The following discussions contain certain “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995 including, without limitation, estimates, expectations, plans and goals regarding Apache’s production, reserves, financings, acquisitions, exploration and exploitation prospects, energy prices, operating costs, and results of operations. Such forward-looking statements involve estimates, assumptions and uncertainties. No assurance can be given that Apache’s expectations or goals will be realized, and actual results may differ materially from those expressed in the forward-looking statements. For reconciliations of non-GAAP financial measures, see our web site www.apachecorp.com.
CORPORATIONCORPORATIONPrestack Waveform Inversion: an Onshore Application in the US Gulf
Coast
Prestack Waveform Inversion: an Onshore Application in the US Gulf
Coast
August Lau, Chuan Yin, Mike Greenspoon, Apache Corp; Anthony
Vassiliou, GeoEnergy
September 2007
August Lau, Chuan Yin, Mike Greenspoon, Apache Corp; Anthony
Vassiliou, GeoEnergy
September 2007
CORPORATIONCORPORATION
Well-to-seismic tie: zero-offset synthetic and PSTM final stack. Displayed panels are (L to R): gamma-ray log, resistivity log, sonic log, bulk density log, full-stack overlaid with zero-offset synthetic, cross-correlation of the synthetic to surface seismic.
Well to Seismic TieWell to Seismic Tie
CORPORATIONCORPORATIONPost-stack Rock PropertiesPost-stack Rock Properties
CORPORATIONCORPORATION
Pay sand has lower Vp / Vs and P- imp
Pay sand has lower Vp / Vs and P- imp
Sand with Pay has Lower Vp / Vs Ratio and Lower P-impedanceSand with Pay has Lower Vp / Vs Ratio and Lower P-impedance
Pre-Stack Rock PropertiesPre-Stack Rock Properties
CORPORATIONCORPORATIONWorkflowWorkflow
CORPORATIONCORPORATION
Input PSTM Gather (Left) and Modeled GatherInput PSTM Gather (Left) and Modeled Gather
CORPORATIONCORPORATIONStarting and Final ModelsStarting and Final Models
DensityDensityInitialInitial FinalFinal
Vp Vp InitialInitial FinalFinal
Vs Vs InitialInitial FinalFinal
CORPORATIONCORPORATION
Estimation of Vp, Vs, density, Zp, Zs and their uncertainties for fluid and lithology discrimination
Through calibration and interpretation, thickness estimation, net to gross estimation, porosity estimation
Interpretation of small-scale or localized features, such as narrow channels, slump faults, etc.
Estimation of Vp, Vs, density, Zp, Zs and their uncertainties for fluid and lithology discrimination
Through calibration and interpretation, thickness estimation, net to gross estimation, porosity estimation
Interpretation of small-scale or localized features, such as narrow channels, slump faults, etc.
Applications of Pre-Stack InversionApplications of Pre-Stack Inversion
CORPORATIONCORPORATIONFull Stack Amplitude ExtractionFull Stack Amplitude Extraction
ARB LINE
ARB LINE
ARB LINE
ARB LINE
2000’2000’2000’2000’
Well EWell EWell EWell E
Well CWell CWell CWell C
Well BWell BWell BWell B
Well AWell AWell AWell A
Well FWell FWell FWell F
Well DWell DWell DWell D
Well 3Well 3Well 3Well 3
CORPORATIONCORPORATIONFull StackFull Stack
Main Producing FieldMain Producing Field
Horizon AHorizon AHorizon AHorizon A
Horizon BHorizon BHorizon BHorizon B
WELL E WELL C WELL BWELL A
WELL F
Cross Section
CORPORATIONCORPORATION5-20 Angle Stack5-20 Angle Stack
Main Producing FieldMain Producing Field
Horizon AHorizon AHorizon AHorizon A
Horizon BHorizon BHorizon BHorizon B
WELL E WELL C WELL BWELL A
WELL F
Cross Section
CORPORATIONCORPORATION
Arbitrary Line-Interpreted Lithology CubeArbitrary Line-Interpreted Lithology Cube
Main Producing FieldMain Producing Field
Horizon AHorizon AHorizon AHorizon A
Horizon BHorizon BHorizon BHorizon B
WELL C WELL BWELL A
WELL F
Cross Section
WELL E
CORPORATIONCORPORATIONVp/Vs VolumeVp/Vs Volume
ARB LINE
ARB LINE
ARB LINE
ARB LINE
2000’2000’2000’2000’
Well EWell EWell EWell E
Well CWell CWell CWell C
Well BWell BWell BWell B
Well AWell AWell AWell A
Well FWell FWell FWell F
Well DWell DWell DWell D
Well 3Well 3Well 3Well 3
CORPORATIONCORPORATIONDZPDZP
ARB LINE
ARB LINE
ARB LINE
ARB LINE
2000’2000’2000’2000’
Well EWell EWell EWell E
Well CWell CWell CWell C
Well BWell BWell BWell B
Well AWell AWell AWell A
Well FWell FWell FWell F
Well DWell DWell DWell D
Well 3Well 3Well 3Well 3
CORPORATIONCORPORATIONDZSDZS
ARB LINE
ARB LINE
ARB LINE
ARB LINE
2000’2000’2000’2000’
Well EWell EWell EWell E
Well CWell CWell CWell C
Well BWell BWell BWell B
Well AWell AWell AWell A
Well FWell FWell FWell F
Well DWell DWell DWell D
Well 3Well 3Well 3Well 3
CORPORATIONCORPORATION
Major Differences between Pre-stack Waveform Inversion applied to gathers and angle-stack inversions:Major Differences between Pre-stack Waveform Inversion applied to gathers and angle-stack inversions:
Pre-stack waveform inversion is applied directly on gathers with NMO removed, preserving all amplitude, phase, offset information
Pre-stack waveform inversion is seismic data driven. Angle stack inversion commonly well log driven
Assuming long enough acquisition cable, pre-stack waveform inversion estimates directly Vp, Vs, density
Pre-stack waveform inversion is applied directly on gathers with NMO removed, preserving all amplitude, phase, offset information
Pre-stack waveform inversion is seismic data driven. Angle stack inversion commonly well log driven
Assuming long enough acquisition cable, pre-stack waveform inversion estimates directly Vp, Vs, density
Inversion Technique DifferencesInversion Technique Differences
CORPORATIONCORPORATION
Pre-stack waveform inversion can work with either only primary reflections or with both primary and multiple reflections
Pre-stack waveform inversion applied directly on gathers does not have to deal with the NMO stretch effect for long cables
Pre-stack waveform inversion makes use of interval velocities.
Pre-stack waveform inversion applied on gathers is not sensitive to starting low frequency Vp / Vs / density model
Pre-stack waveform inversion can work with either only primary reflections or with both primary and multiple reflections
Pre-stack waveform inversion applied directly on gathers does not have to deal with the NMO stretch effect for long cables
Pre-stack waveform inversion makes use of interval velocities.
Pre-stack waveform inversion applied on gathers is not sensitive to starting low frequency Vp / Vs / density model
Inversion Technique Differences con’t.Inversion Technique Differences con’t.
CORPORATIONCORPORATIONConclusionsConclusions
Pre Stack Inversion is a faster, cheaper, and more accurate method than traditional well-based inversion techniques
Various output volumes can be calibrated with well control for net pay estimations
Prospects can be qualified with multi-cube interpretation
A detailed geologic input model is not necessary to produce results
Pre Stack Inversion is a faster, cheaper, and more accurate method than traditional well-based inversion techniques
Various output volumes can be calibrated with well control for net pay estimations
Prospects can be qualified with multi-cube interpretation
A detailed geologic input model is not necessary to produce results
CORPORATIONCORPORATIONAcknowledgementsAcknowledgements
Seismic Data Courtesy of Seitel Seismic Data Courtesy of Seitel