Abstract:Normal and tangential weaknesses are sensitive to fluid type in fractured reservoirs. In order to make the best use of AVOZ information included in seismic data, we discuss normal and tangential weaknesses direct inversion method based on azimuthal elastic inversion, which can be used to guide fluid identification in fractured reservoirs. Firstly, using the relationship among anisotropic rock physics parameters, we build an azimuthal elastic impedance equation based on the anisotropic weaknesses. Then, aimed at the instability of extracted anisotropic parameters, we put forward a stable normal and tangential weaknesses extracting method, which can improve the inversion accuracy of normal and tangential weaknesses. Finally, fracture weaknesses parameters obtained from the inversion are used for fluid identification in fractured reservoirs. Model and real data tests indicate that the proposed method can efficiently identify fractured gas reservoirs.
Teng Jiwen, Zhang Zhongjie, Wang Aiwu et al. The study of anisotropy in elastic medium:evolution, present situation and questions. Progress in Geophysics, 1992, 7(4):14-28.
Mao Ningbo, Xie Tao, Yang Kai et al. Azimuthal AVO forward model for fractured reservoirs and its application. Journal of Oil and Gas Technology, 2008, 30(5):59-63.
Li Pei, Zhu Shengwang, Qu Shouli et al. Analysis on P-wave seismic response of vertical fractures. GPP, 2010, 49(2):125-132.
[8]
Sun S Z, Xiao X, Chen L et al. P-wave fracture prediction algorithm using data with limited azimuthal distribution. The Leading Edge, 2012, 31(2):198-205.
[9]
Chen H, Zhang G, Yin X. AVAZ inversion for elastic parameter and fracture fluid factor. SEG Technical Program Expanded Abstracts, 2012, 31:.
[10]
Miao X, Qiu R, Qin H. Unconventional gas detection by AVAZ and elastic inversion. SEG Technical Program Expanded Abstracts, 2013, 32:.
[11]
Peng L, Sun S Z, et al. Fracture prediction and its fluid identification of complex carbonate reservoir:a case study in Ha7 area, Tarim Basin. SEG Technical Program Expanded Abstracts, 2013, 32:.
[12]
Alhussain M and Sen M K. Quantitative estimation of fracture parameters after removing anisotropic overburden effect. SEG Technical Program Expanded Abstracts, 2013, 32:.
[13]
Mahmoudian F, Margrave G F. AVAZ inversion for fracture orientation and intensity-A physical modeling study. 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013, 2013.
[14]
Skopintseva L, Alkhalifah T. An analysis of AVO inversion for postcritical offsets in HTI media. Geophysics, 2013, 78(3):N11-N20.
[15]
Martins J L. An approach for elastic impedance in weakly anisotropic media. SEG Technical Program Expanded Abstracts, 2002, 21:.
Yin Xingyao, Li Chao, Zhang Shixin. Seismic fluid discrimination based on two-phase media theory. Journal of China University of Petroleum(Edition ofNatural Science), 2013, 37(5):38-43.
Chen Huaizhen, Yin Xingyao, Du Bingyi et al. Azimuth anisotropic elastic impedance inversion in fractured layered carbonate rock reservoir. Progress in Geophysics. 2013, 28(6):3073-3079.
Chen Huaizhen, Yin Xingyao, Gao Chengguo et al. AVAZ inversion for fluid factor based on fracture anisotropic rock physics theory. Chinese J Geophys, 2014, 57(3):968-978.
[23]
Schoenberg M, Sayers C M. Seismic anisotropy of fractured rock. Geophysics, 1995, 60(1):204-211.
[24]
Hsu C J, Schoenberg M. Elastic waves through a simulated fractured medium. Geophysics, 1993, 58(7):964-977.
[25]
Bakulin A, Grechka V, Tsvankin I. Estimation of fracture parameters from reflection seismic data-Part Ⅰ:HTI model due to a single fracture set. Geophysics, 2000, 65(6):1788-1802.
Li Chunpeng, Yin Xingyao, Zhang Feng. Influence of HTI medium saturated fluid properties and fracture density on azimuthal reflectivity. GPP, 2013, 52(1):1-10.