edinburgh anisotropy project applied seismic anisotropy 7 phase ...

EDINBURGH ANISOTROPY PROJECT 

APPLIED SEISMIC ANISOTROPY 

TH 

7 PHASE RESEARCH PROGRAMME 

2006-2009

THE EDINBURGH ANISOTROPY PROJECT 

APPLIED SEISMIC ANISOTROPY 

7 TH PHASE RESEARCH PROGRAMME 2006-2009 

EXCUTIVE SUMMARY 

The Edinburgh Anisotropy Project (EAP) conducts research into applied seismic anisotropy, and how 

to utilize such information for the understanding of hydrocarbon reservoirs. EAP is supported by a 

consortium of major oil, service and software companies. The EAP research programme is guided by 

industry requirements and is primarily focused on fracture characterization and anisotropy imaging. 

The programme covers a wide variety of topics including data processing, interpretation, modelling 

and acquisition design, as well as fundamental wave propagation issues. 

EAP was established in July 1988 with seventeen years of experience in seismic anisotropy. EAP has 

organised its research programme in three-year phases. The project is now in its 6 th Phase, which ends 

in June 2006. 

The 7 th Phase Research Programme (2006-09) 

The programme proposed for the 7 th Phase is a continuation of the 6 th Phase, but with a particular 

emphasis on frequency-dependent anisotropy, arising from discussions with sponsors. The 

programme has three components: 

o AVD technology for fracture characterization 

Extension of traditional AVD (attributes versus direction) methods to exploit frequencydependent 

anisotropy for robust fracture density information together with fluid saturation and 

dominant scale length 

o Converted-wave analysis for improved imaging of reservoir structure 

Extension of current converted-wave imaging tools (e.g. CXtools) to account for diodic 

converted-wave effects and further development of depth-imaging tools for building a common 

anisotropic earth model 

o Anisotropic rock physics for analysing frequency-dependent anisotropy 

Progress towards gaining more insights into the information content of frequency-dependent 

anisotropy through experimental studies, calibrated theoretical developments and analysis of 

time-lapse VSP data 

An important aspect of EAP research is that the development of theory, methodology and algorithms 

is combined with application to real data, supplied by the sponsors, to demonstrate the value of the 

technology produced.

Deliverables and Technology Transfer 

o Research results in the form of annual reports, technical papers and software releases 

o Courses on applied seismic anisotropy, tailored to individual sponsor’s requirements 

o Special consultancy and joint studies of company-specific anisotropy-related issues 

o PhD research studentships 

EAP believes in maintaining close links with each member of the consortium so that the technology 

developed is transferred efficiently, and the research programme remains dynamic and evolutionary. 

Fees 

For the 7 th Phase the annual fees will be set at a flat rate of £31k. 

For new sponsors there is, in addition to the annual subscription, a joining fee of £30k, or £10k plus 

some negotiable equivalent in the form of software or data. 

Meetings 

The main annual EAP Technical and Business Meeting is held in Edinburgh, usually immediately 

following the annual EAGE conference. A further meeting is held at the annual SEG conference. 

Consortium members 

EAP is currently sponsored by eighteen service and oil companies and one software company: Agip, 

BG, BGP, BP, Chevron, CNPC, ConocoPhillips, ExxonMobil, GX Technology, KerrMcGee, 

Marathon, Norsk Hydro, PDVSA, Schlumberger, Shell, SinoPec, Total, Veritas DGC and Landmark. 

Project Resources 

Staff: A team of 5 scientific staff and 6 PhD students (see Appendix A). 

Computing: a 24-node PC cluster, Sun Ultrasparc/Sparc Workstations, Intel-Based destop PCs, 

Terabyte Raid System For Data Storage. 

Datasets: EAP benefits from access to datasets supplied by the sponsors. A list of the datasets 

available to the project during the 6 th Phase is given in Appendix B. 

Further Information 

Enquiries about EAP activities and membership details should be addressed to: 

Professor Xiang-Yang Li, Technical Director 

Edinburgh Anisotropy Project, British Geological Survey, 

Murchison House, West Mains Road, Edinburgh EH9 3LA, UK 

Tel: +44 (0)131 667 1000/Fax: +44 (0)131 667 1877/E-mail: xyl@bgs.ac.uk 

Further information can also be found at http://www.eap.bgs.ac.uk

7 th PHASE RESEARCH PROGRAMME 

Introduction 

During the 6 th Phase (2003-2006), we have focused on consolidating our ideas and findings for 

technology transfer. This led to the release of three software packages, i.e. CXtools for convertedwave 

imaging, RU for rock physics and fracture modelling, and GeoLab for depth model building and 

imaging. Major progress has been made in the following areas in the past five years: 

o Converted-waves analysis 

- New theories and algorithms for converted-wave imaging are consolidated into CXtools, 

which makes it possible to perform anisotropic imaging with high accuracy but low cost 

- A number of successful case studies (e.g. Lomond 2D 4C data, Afflect 3D 4C data) 

- Ideas for decoupled migration to perform multiwave type prestack depth imaging 

o Fracture characterization 

- Frequency-dependent P- and S-wave attributes to characterize fluid saturation and dominant 

scale length 

- A number of successful case studies (e.g. Clair and Emilio 3D 4C data ) 

o Time-lapse seismic data analysis 

- Improved dynamic rock physical model with multi-scale fluid flow 

- Ideas of frequency-dependent time-lapse anisotropy for discriminating the effects of pore 

pressure and saturation 

These developments have been endorsed and well received by all sponsors. During this Phase, EAP 

has also attracted a record number of sponsors, which encourages us to continue developing our work 

through real data applications during the next phase from 2006 to 2009, with a primary focus on 

integrated studies and the delivery of user-friendly tools. 

EAP activities seek to address the needs of industry (fractures, converted waves, imaging in 

complex areas), while retaining a component of basic strategic science for future developments 

(frequency-dependent anisotropy, fluid flow). It is EAP’s intention to achieve a healthy balance 

between applied and basic research as well as ‘blue-sky’ research. 

In addition to the industrial sponsorship, every year EAP also receives matching funds from the 

Natural Environment Research Council through its science budget. This provides great value for 

money for EAP’s members. From time to time EAP also receives government grants through 

competitive tender and review exercises. These matching funds and research grants enable us to carry 

out more basic and curiosity-driven research. As a whole, EAP research builds on a solid foundation 

of theoretical expertise and field-data analysis in seismic anisotropy developed over the past 

seventeen years. The following sections describe the major components of the 7 th Phase programme.

Converted wave analysis 

Interest in converted-waves was rekindled by the emergence of 4C OBC technology in the mid 

1990’s. Since then, more than a decade has elapsed. Despite an intensive effort in research and 

development of the converted-wave technology, the anticipated breakthrough into a mainstream 

technology has still to be realized. A general consensus is that the processing and interpretation of 

converted-wave data appears to lag behind the corresponding acquisition technology that has evolved 

from analogue phones to digital sensors, from line receivers to point receivers, from dragged cables to 

permanently installed trench-buried systems. The difficulties in processing the converted waves lie in 

two main areas. In onshore applications, the near-surface is still the main obstacle for obtaining highquality 

and high resolution converted-wave data; whilst offshore, converted-wave imaging suffers 

from the wide occurrence of anisotropy in marine sediments together with the asymmetric raypaths 

and the diodic velocity effects due to shallow inhomogeneities, which has even made the data 

acquired with permanently installed systems un-interpretable. Due to these problems, there is a 

general lack of user-friendly and reliable tools for processing and interpreting the converted-waves. 

Since the onset of Phase 5 (2000-03), we have made significant progress in bridging the above gap for 

converted-wave imaging. During Phase 5 (2003-03), we have developed a common theoretical 

framework to describe the converted-wave behaviour in anisotropic media in terms of convertedwavefield 

attributes. This paved the way for the use of standard procedures such as semblance 

analysis and Kirchhoff summation to implement converted-wave anisotropic processing with high 

accuracy but low cost. During Phase 6 (2003-06), we extended the previous developments into 3D- 

4C data for both anisotropic imaging and parameter estimation, and consolidated our achievement 

into an user-friendly software, referred to as CXtools. Using this tool, we have reprocessed a number 

of 2D and 3D-4C dataset from the North Sea , and in each case, a substantially improved subsurface 

image was obtained that has made significant impact on the development of the relevant oilfield. 

During Phase 7, our emphasis is to extend CXtools to account for the diodic converted-wave effects 

and further development of our depth-imaging tools for building a common anisotropic earth model, 

and our aim is to fill the wide acknowledged gap in converted-wave processing with CXtools. 

Areas of interest and deliverables for the 7 th Phase: 

o diodic decomposition for 3D 4C data; 

o the corresponding depth imaging work flows using PP-independent PS imaging approach; 

o decoupled migration and associated work flows for anisotropic inversion; 

o conversion point signature from 3D 4C data; 

o anisotropic estimation in TTI media; 

o case studies of 3D-4C data from permanently installed systems in the North Sea; 

o user-friendly fully-documented algorithms/software for PC cluster. 

Datasets available for the 7 th Phase: 

o Valhall LoFS (Life of Field Seismic) 3D-4C data, North Sea; 

o BG 4C data 

o Shenli 3D-3C data, Yellow River Delta

TH 


CONVERTED-WAVE ANALYSIS 

2006-09 

Research developments 

-Diodic PS decomposition for building a 

common earth model from 3D-4C data 

- Anisotropic estimation in orthorhombic 

or TTI media 

- Optimizing anisotropic depth model 

through a prestack time migration 

- Case studies of 3D 4C seismic data 

- User-friendly algorithms and software 

CXtools for anisotropic model building 

Affleck: EAP Line 60, through Tor penetration (PS data in PP time) 

(a) EAP processing 

Tor 

Top Tor Tie 

(b) isotropic/conventional 

The Afflect 3D-4C experience (courtesy of KerrMcGee): (a) Reprocessed by 

EAP using the Cxtools; and (b) conventional isotropic processing.

AVD technology for fracture characterization 

EAP has pioneered the use of seismic anisotropy for characterization of natural fractured reservoirs. 

Currently, we are extending our expertise to go beyond what the conventional anisotropy concept for 

fracture imaging can offer by developing innovative methods to evaluate the dominant scale length 

from 3D VSP, 3D surface and 3D 4C-OBC seismic data. Our new theories and methods allow the 

seismic response across a broad band of seismic frequencies to be computed, making it possible to 

observe and analyse the directional spectral/dispersion/attenuation variation and frequency-dependent 

anisotropy in seismic data and then to invert these variations for the properties of the fracture 

distribution. This will require advanced techniques for extracting spectral/dispersion and attenuation 

characteristics from seismic data using, for example, multi-instantaneous attribute analysis and 

modern spectral decomposition techniques. 

EAP is also developing advanced numerical methods to simulate wave propagation in media with 

discrete fracture systems using the discrete dynamic rock physics model, which allows us to develop 

inversion techniques to obtain information about discrete formation or meso-scale fractures. The work 

so far focused on 2D will be extended to 3D with an aim to develop a discrete fracture network (DFN) 

model by using seismic anisotropy attributes as inputs to combine with other geological/ geophysical 

data. 

Areas of interest and deliverables for the 7 th Phase: 

o Characteristics of directional dispersion/spectral/attenuation variations in P- and converted-wave 

data and their applications for determining fracture properties such as the dominant scale length, 

and fluid saturation; 

o Generation of realistic fracture networks and patterns at the meso-scale for seismic modelling, and 

computation of 3D synthetic VSP and reflection dataset using realistic reservoir models with 

discrete fracture distributions; 

o Analysis and inversion procedure to quantify fracture size and fracture porosity (storability) from 

3D VSP, 3D surface and 3D-4C OBC data including both synthetic and real data; 

o Multi-Attribute Analysis, including coherency analysis, multi-component instantaneous 

polarization analysis, and spectral decomposition of seismic data to reveal anomalies that are 

related subsurface fracture distributions; 

o Comprehensive software packages for fracture modelling and seismic imaging including 

enhanced 3D modelling capability to simulate seismic wave propagation in fractured media and 

software to extract information on fracture properties (size/storability, density, orientations, and 

fluid properties). 


o Emilio 3D 4C seismic dataset 

o The Clair field OBC data and associated VSPs 

o Physical modeling 3D datasets (CNPC Key Labs) 

o Wind River 3D surface data.

TH 


Fracture characterization 

2006-09 

Research developments 

- Analysis of P-wave attenuation anisotropy/shear-wave splitting 

- Dominant scale length and fluid saturation from 3D-4C seismic 

- Techniques for modeling the seismic response of large fractures 

- multi-scale decomposition and attributes analysis 

- analysis procedures/user-friendly algorithms & software 

Azimuthal frequency anomalies in 3D seismic data 

East-west azimuth 

North-south azimuth 

Wind River Basin (Queen and Lynn 2003) 

0.44 

39.039.239.439.639.8 

0.46 

Ti me 

0.48 

0.50 

Frequency-independent Frequency-dependent Perpendicular Parallel 

0.52

Anisotropic rock physics for frequency-dependent anisotropy 

Frequency-dependent geophysical properties have attracted more and more interests from the research 

communities and the industry, which potentially links the subsurface seismic response to permeability 

and the dominant scale length of the heterogeneities in the subsurface. The situation regarding this 

subject is comparable to that of research on seismic anisotropy in the 80’s: the potential is high yet 

more work needs to be done towards both the understanding of the phenomenon and its implications. 

During the 6 th Phase, we have developed a dynamic rock physical model accounting for changes in 

both pore pressure and saturation. A range of observable effects was predicted, including the 

frequency dependence of shear-wave time delays, differential attenuation between fast and slow 

shear-waves and P-wave attenuation anisotropy. We have analysed a series of VSP datasets in order 

to evaluate these effects, including multicomponent VSPs, walkway VSPs and time-lapse VSPs. 

These studies have confirmed that these effects are detectable in field data and can be related to 

fracture properties such as dominant scale length and fluid saturation, using robust modelling and 

inversion procedures. 

Phase 7 will develop these ideas across a spectrum of activities, encompassing further theoretical 

development, laboratory calibration, development of processing techniques and application to field 

data. The goal of the research will be to use the modern ideas in spectral decomposition and 

poroelastic theory to establish a robust link between seismic anisotropy and the petrophysical 

properties of rock, particularly the anisotropic variation of permeability. We will continue to analyse 

VSP surveys including time-lapse VSP data, to consolidate our understanding, but the new direction 

of Phase 7 will be the emphasis on applying our ideas to surface seismic data. 

Areas of interest and deliverables for the 6 th phase 

o improved rock physics models, calibrated against field and laboratory data, which relate the 

frequency dependent anisotropic response to fracturing, fluid saturation and stress state; 

o finite difference modeling for wave propagation through a discrete fracture network, to establish 

the effect of scattering from fractures of different sizes on the anisotropic response; 

o use of attenuation measurements for reservoir characterisation, in particular a comprehensive 

theory for interpretation of azimuthal AVO in the presence of frequency dependent anisotropy; 

o Analysis of time-lapse multi-azimuth VSP data to establish the relationship between the 

anisotropic seismic response and pressure and saturation variations. 

o a fully tested comprehensive rock physics subroutine library 


o Laboratory measurements of synthetic fractured rocks with known fracture geometries 

o Multi-azimuths VSPs from the Wyoming Basin 

o Time lapse 3D VSPs from Weyburn 

o Time lapse VSPs from Quarnalam/PDO.

APPENDIX A – PROJECT PERSONNEL 

The EAP team presently comprises five members of BGS staff, a senior consultant in the Unversity of 

Edinburgh, and six PhD Students. It also benefits from its close association with BGS staff working in 

other areas of seismology, and associated academic staff in the University of Edinburgh. 

EAP Staff 

Technical director: 

Professor Xiang-Yang Li (Multicomponent seismology) 

Principal Geophysicist: 

Dr. Enru Liu (Associate director and Fracture imaging) 

Senior Geophysicists: 

Dr. Hengchang Dai (Anisotropic imaging) 

Dr. Mark Chapman (Rock physics model and fluid-rock interaction) 

Senior Consultant: 

Professor Stuart Crampin (Fundamentals of anisotropy) 

(University of Edinburgh) 

Associated Staff 

Senior Seismologist: 

Technical Engineer: 

Dr David Booth (Project support) 

Mr Brian Bainbridge (Technical and computing support) 

Associated Academics 

University of Edinburgh: 

Professor Ian Main (Rock Physics) 

Dr Roger Scrutton (Log data intepretation) 

Dr Andrew Curtis (Exploration seismology) 

EAP Students 

Jinghua Zhang (4C seismic and converted-wave) 

Lifeng Wang (4C seismic and fractures) 

Isabel Varela (Fracture modelling) 

Zhongping Qian (4C seismic and fractures) 

Adam Wilson (Frequency-dependent anisotropy) 

Joao Marcos Ferreira (Micro seismic monitoring)

APPENDIX B - EAP ACTIVITIES AND DATASETS 

Converted-waves COMPLETED ONGOING PROMISED 

Marine 4C seismics 

BP – Valhall(2D) 

Agip – Johnd Field 2D 

BP - Lomond 2D 

Agip – Emilio 3D 4C 

BG – 4C 

BP-Vauhall Life 

of Field Seismic 

Mahagony 2D 

Chevron Alba 2D 

Afflect 3D 4C 

Shell – Guilemot 2D 

Chevron – Alba 3D 

Land 3C data Changqing 2D SinoPec 3D 3C 

Petro-China 2D 3C 

Offset VSPs/ 

3D VSPs 

PetroChina – Ordos 

VSPs 

Fractures COMPLETED ONGOING PROMISED 

Agip – Emilio 3D 

Clair – 3D 4C 

Marine 4C seismics 

2D/3D seismics 

Saga 2D (Geophone 

coupling) 

Shell – Guilemot 2D 

Shenli 3D wide azimuth 

Fina – 2D +3D lines 

Norsk hydro 

Grange 3D 

Physical modelling 3D wide DOE – Wyoming; 

azimuth data 

wind river basin 

Walkaway VSPs / 

3D VSPs 

Bluebell – VSPs 

San Juan Basin VSPs 

NW Colorado VSPs 

BP Clair VSP 

BP Egypt VSP 

TIME LAPSE 

SEISMIC 

Repeat VSPs/ 

COMPLETED ONGOING PROMISED 

Mobil – Camelot 

Shell – Quarn Alam 

Weyburn VSPs 

Saga –Snorre, 15 nearoffset 

VSPs 

Micro-seismicity 

USGS microseismicity 

data 

Marine 4C seismics Teal South 3D Vauhall LoFS data 

COMPLEX AREAS COMPLETED ONGOING PROMISED 

Surface seismic Amera Hess – long offset Marathon 3D 

two-boat shoot (Flare) 

Veritas DGC - 12km 

cable 

Low frequency data Texaco-2D lines 

Veritas – 2D lines

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