TY - JOUR
T1 - Study of a fractured reservoir by using the anisotropy of seismic wave attenuation
AU - Bouchaala, Fateh
AU - Ali, Mohammed Y.
AU - Matsushima, Jun
AU - Bouzidi, Youcef
AU - Takam Takougang, Eric M.
AU - Mohamed, Aala A.I.
N1 - Funding Information:
We would like to thank Abu Dhabi National Oil Company (ADNOC) for financial support of this project and for permission to use the data used in this project.
Publisher Copyright:
© 2019 SEG
PY - 2019/8/10
Y1 - 2019/8/10
N2 - The dense geometry of a 3D VSP survey which was carried out in an oilfield located in the Emirate of Abu Dhabi, United Arab Emirates, enables us to perform high resolution azimuthal study of seismic wave attenuation, in order to investigate a fractured reservoir in the oilfield. We obtained the orientation of fractures in three reservoir units by using the concept suggesting that the strike direction of fractures corresponds to the azimuth of the minimum attenuation ϕ0 . We defined ϕ0 as the azimuth of the minimum attenuation Q-1 that we estimated at several azimuths and offsets by using the spectral ratio method. The rose diagrams gathering ϕ0 obtained at several offsets, are in agreement with those gathering the strike direction of open and cemented fractures, obtained from cores interpretation. This is due to the fact that the attenuation Q-1 is caused by a combination of scattering and fluid-related mechanisms. It is physical evidence that fractures, regardless their type, are an important source of scattering mechanism, and also of fluid-related mechanisms if they are open. Another way to define ϕ0 is by using a cosine least square fitting of azimuthal variation of the relative attenuation ΔQ-1 , that we estimated at several azimuths and offsets by using a modified spectral ratio method. In this case, the rose diagrams gathering ϕ0 defined at several offsets, are in agreement with those gathering strike direction of open fractures obtained from cores and Full-bore Formation Microimager interpretation. This agreement is due to the fact that the cosine least square fitting is based on the squirt flow mechanism that is caused by fluid movement between grain pores and fractures. Accordingly, comparison between the rose diagrams of ϕ0 estimated by using the two approaches, can be a good way to separate between open and cemented fractures. Such, finding is very interesting for petroleum industry and can help in Enhanced Oil Recovery (EOR) studies.
AB - The dense geometry of a 3D VSP survey which was carried out in an oilfield located in the Emirate of Abu Dhabi, United Arab Emirates, enables us to perform high resolution azimuthal study of seismic wave attenuation, in order to investigate a fractured reservoir in the oilfield. We obtained the orientation of fractures in three reservoir units by using the concept suggesting that the strike direction of fractures corresponds to the azimuth of the minimum attenuation ϕ0 . We defined ϕ0 as the azimuth of the minimum attenuation Q-1 that we estimated at several azimuths and offsets by using the spectral ratio method. The rose diagrams gathering ϕ0 obtained at several offsets, are in agreement with those gathering the strike direction of open and cemented fractures, obtained from cores interpretation. This is due to the fact that the attenuation Q-1 is caused by a combination of scattering and fluid-related mechanisms. It is physical evidence that fractures, regardless their type, are an important source of scattering mechanism, and also of fluid-related mechanisms if they are open. Another way to define ϕ0 is by using a cosine least square fitting of azimuthal variation of the relative attenuation ΔQ-1 , that we estimated at several azimuths and offsets by using a modified spectral ratio method. In this case, the rose diagrams gathering ϕ0 defined at several offsets, are in agreement with those gathering strike direction of open fractures obtained from cores and Full-bore Formation Microimager interpretation. This agreement is due to the fact that the cosine least square fitting is based on the squirt flow mechanism that is caused by fluid movement between grain pores and fractures. Accordingly, comparison between the rose diagrams of ϕ0 estimated by using the two approaches, can be a good way to separate between open and cemented fractures. Such, finding is very interesting for petroleum industry and can help in Enhanced Oil Recovery (EOR) studies.
UR - http://www.scopus.com/inward/record.url?scp=85121876831&partnerID=8YFLogxK
U2 - 10.1190/segam2019-3214834.1
DO - 10.1190/segam2019-3214834.1
M3 - Conference article
AN - SCOPUS:85121876831
SN - 1052-3812
SP - 338
EP - 342
JO - SEG Technical Program Expanded Abstracts
JF - SEG Technical Program Expanded Abstracts
T2 - Society of Exploration Geophysicists International Exposition and 89th Annual Meeting, SEG 2019
Y2 - 15 September 2019 through 20 September 2019
ER -
