1. Northwest Branch, Research Institute of Petroleum Exploration and Development, PetroChina, Lanzhou, Gansu 730020, China; 2. School of Geoscience, China University of Petroleum(East China), Qingdao, Shandong 266580, China; 3. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
Abstract：In-situ stress seismic data-based prediction approaches of shale reservoirs usually apply the elastic parameters to calculate differential horizontal stress ratios （DHSR）. However， there are shortcomings. First， the anisotropy parameters （fracture weakness） are included in the prediction formula and cannot be solved easily， making it difficult to predict in-situ stress； second， parameters such as Young's modulus and Poisson's ratio in the prediction formula are obtained by indirect inversion， and the accuracy is low， which is difficult to meet the requirements of shale gas geoengineering integration. Therefore， an in-situ seismic data-based prediction approach of shale reservoirs based on fracture density inversion is proposed. For enhancing the prediction accuracy， a longitudinal wave azimuthal anisotropy AVO formula based on Young's modulus， Poisson's ratio， and fracture density is established to directly invert elastic parameters， and the DHSR formula expressed by Poisson's ratio and fracture density is derived. The anisotropic petrophysical modeling of shale reservoirs is carried out according to well data， and pre-stack azimuthal anisotropy inversion is performed. The inverted Poisson's ratio and fracture density are applied to the estimated DHSR. The in-situ stress properties of shale reservoirs can be evaluated by the estimated DHSR. A real example verifies that smaller DHSR indicates that more orthogonal and complex fracture networks will be generated by hydraulic fracturing in different directions， which is beneficial for modifying the physical properties and seepage channels of the reservoir. A larger volume of reservoir reconstruction is more conducive to reservoir fracturing. In addition， larger DHSR means that hydraulic fracturing will generate non-orthogonal plane fractures parallel to the maximum horizontal principal stress， forming isolated fractures that are not beneficial for volume transformation. Meanwhile， the estimated DHSR result agrees with existing well logging in-situ stress calculation， fracturing monitoring， and production testing， and it fits with the geology recognition， revealing that the approach is effective and reliable.
邹才能,董大忠,王玉满,等.中国页岩气特征、挑战及前景(一)[J].石油勘探与开发, 2015, 42(6):689-701.ZOU Caineng,DONG Dazhong,WANG Yuman,et al.Shale gas in China:Characteristics,challenges and prospects(Ⅰ)[J].Petroleum Exploration and Development,2015, 42(6):689-701.
[2]
邹才能,董大忠,王玉满,等.中国页岩气特征、挑战及前景(二)[J].石油勘探与开发, 2016, 43(2):166-178.ZOU Caineng, DONG Dazhong, WANG Yuman, et al. Shale gas in China:Characteristics,challenges and prospects(Ⅱ)[J].Petroleum Exploration and Development, 2016, 43(2):166-178.
[3]
董大忠,邹才能,戴金星,等.中国页岩气发展战略对策建议[J]. 天然气地球科学, 2016, 57(3):397-406.DONG Dazhong,ZOU Caineng,DAI Jinxing,et al.Suggestion on the development strategy of shale gas in China[J].Natural Gas Geoscience,2016, 57(3):397-406.
[4]
印兴耀,马妮,马正乾,等.地应力预测技术的研究现状与进展[J].石油物探, 2018, 57(4):488-504.YIN Xingyao, MA Ni, MA Zhengqian, et al. Review of in-situ stress prediction technology[J].Geophysical Prospecting for Petroleum, 2018, 57(4):488-504.
[5]
张少华,邓小江,冯许魁,等.川南地区深层页岩气地球物理勘探技术新进展与攻关方向[J].石油地球物理勘探,2023,58(1):238-248.ZHANG Shaohua,DENG Xiaojiang,FENG Xukui,et al.New progress and research direction of geophysical prospecting techniques for deep shale gas in southern Sichuan Basin[J].Oil Geophysical Prospecting,2023,58(1):238-248.
[6]
刘建伟,张云银,曾联波,等.非常规油藏地应力和应力甜点地球物理预测——渤南地区沙三下亚段页岩油藏勘探实例[J]. 石油地球物理勘探,2016,51(4):792-800.LIU Jianwei,ZHANG Yunyin,ZENG Lianbo,et al.Geophysical prediction of stress and stress desserts in unconventional reservoirs:an example in Bonan area[J].Oil Geophysical Prospecting,2016, 51(4):792- 800.
[7]
张帆,何振华,黄德济, 等. 预测裂隙发育带的构造应力场数值模拟技术[J]. 石油地球物理勘探, 2000,35(2):154-163.ZHANG Fan,HE Zhenhua,HUANG Deji,et al.Structural stress field numerical simulation technique for fracture zone prediction[J].Oil Geophysical Prospecting,2000,35(2):154-163.
[8]
胡耀方.页岩储层地应力场数值模拟方法[D].北京:中国石油大学(北京), 2018.
[9]
张恒荣,肖立志,曾少军,等.基于裂缝柔度和地应力模型的声电测井正、反演方法及应用[J].石油地球物理勘探,2023,58(2):431-442.ZHANG Hengrong,XIAO Lizhi,ZENG Shaojun,et al.Forward and inversion methods and application of acoustoelectric logging based on fracture compliance and crustal stress model[J].Oil Geophysical Prospecting,2023,58(2):431-442.
[10]
袁龙,章海宁,李国利,等.库车前陆盆地强挤压应力条件下的测井电阻率校正方法[J].石油地球物理勘探,2018,53(5):1085-1094.YUAN Long,ZHANG Haining,LI Guoli,et al.Logging resistivity correction under the strong extrusion stress condition in the Kuqa foreland basin[J].Oil Geophysical Prospecting,2018,53(5):1085-1094.
[11]
刘忠华,宋连腾,王长胜,等.各向异性快地层最小水平主应力测井计算方法[J].石油勘探与开发, 2017,44(5):745-752.LIU Zhonghua,SONG Lianteng,WANG Changsheng,et al. Evaluation method of the least horizontal principal stress by logging data in anisotropic fast formations[J].Petroleum Exploration and Development,2017,44(5):745-752.
[12]
WARPINSKI N R.Rock mechanics and fracture geometry//Hydraulic Fracturing:Fundamentals and Advancements[M]. Society of Petroleum Engineers,2019,47-73.
[13]
LIU H, LING Y, GUO X,et al. Fracture prediction based on stress analysis and seismic information:a case study[C].SEG Technical Program Expanded Abstracts,2011,30:1118-1123.
[14]
DUBINYA N,BAYUK I O,TIKHOTSKIY S,et al.Localization and characterization of hydraulically conductive fractured zones at seismic scale with the help of geomecha[C].Extended Abstracts of 80th EAGE Conference and Exhibition,2018,DOI:10.3997/2214-4609.201800722.
[15]
杜炳毅,杨午阳,王恩利,等.基于杨氏模量、泊松比和各向异性梯度的裂缝介质AVAZ反演方法[J].石油物探,2015,54(2):218-225.DU Bingyi,YANG Wuyang,WANG Enli,et al.AVAZ inversion based on Young's modulus,Poisson's ratio and anisotropy gradient in fracture media[J].Geophysical Prospecting for Petroleum,2015, 54(2):218-225.
[16]
CHEN H,JI Y,INNANEN K A.Estimation of modified fluid factor and dry fracture weaknesses using azimuthal elastic impedance[J].Geophysics,2018,83(1):WA73-WA88.
[17]
PAN X, ZHANG G. Fracture detection and fluid identification based on anisotropic Gassmann equation and linear-slip model[J]. Geophysics,2019,84(1):R99-R112.
[18]
PAN X,ZHANG G.Bayesian seismic inversion for estimating fluid content and fracture parameters in a gas-saturated fractured porous reservoir[J].Science China Earth Sciences,2019,62(5):798-811.
[19]
PAN X,ZHANG G,YIN X.Azimuthally pre-stack seismic inversion for orthorhombic anisotropy driven by rock physics[J]. Science China Earth Sciences,2018,61(4):425-440.
[20]
GRAY D, ANDERSON P, LOGEL J,et al.Estimation of stress and geomechanical properties using 3D seismic data[J].First Break,2012,DOI:10.3997/1365-2397.2011042.
[21]
马妮,印兴耀,孙成禹,等.基于方位地震数据的地应力反演方法[J].地球物理学报,2018,61(2):697-706.MA Ni,YIN Xingyao,SUN Chengyu,et al.Inversion for crustal stress based on azimuthal seismic data[J].Chinese Journal of Geophysics, 2018, 61(2):697- 706.
[22]
马妮,印兴耀,孙成禹,等.基于正交各向异性介质理论的地应力地震预测方法[J].地球物理学报,2017,60(12):4766-4775.MA Ni,YIN Xingyao,SUN Chengyu,et al. The in-situ stress seismic prediction method based on the theory of orthorhombic anisotropic media[J]. Chinese Journal of Geophysics, 2017, 60(12):4766-4775.
[23]
PEREZ M,GOODWAY B,PURDUE G.Stress estimation through seismic analysis[C].SEG Technical Program Expanded Abstracts,2012,31,SEG-2012-1480.
[24]
STARR J.Closure stress gradient estimation of the Marcellus shale from seismic data[C].SEG Technical Program Expanded Abstracts,2011,30:1789-1793.
[25]
宗兆云,印兴耀,吴国忱.基于叠前地震纵横波模量直接反演的流体检测方法[J].地球物理学报,2012,55(1):284-292.ZONG Zhaoyun,YIN Xingyao,WU Guochen.Fluid identification method based on compressional and shear modulus direct inversion[J].Chinese Journal of Geophysics,2012,55(1):284-292.
[26]
张广智,陈娇娇,陈怀震,等.基于页岩岩石物理等效模型的地应力预测方法研究[J].地球物理学报,2015,58(6):2112-2122.ZHANG Guangzhi,CHEN Jiaojiao,CHEN Huaizhen,et al. Prediction for in-situ formation stress of shale based on rock physics equivalent model[J].Chinese Journal of Geophysics,2015,58(6):2112-2122.
[27]
DU B,YANG W,ZHANG J,et al.Stress prediction and evaluation of heterogeneous reservoir[C].Extended Abstracts of 80th EAGE Conference and Exhibition,2018,DOI:https://DOI.org/10.3997/2214-4609.201800717.
[28]
DOWNTON J,GRAY D.AVAZ parameter uncertainty estimation[C].SEG Technical Program Expanded Abstracts,2006,25:234-238.
[29]
陈怀震,印兴耀,高成国,等.基于各向异性岩石物理的缝隙流体因子AVAZ反演[J].地球物理学报,2014,57(3):968-978.CHEN Huaizhen,YIN Xingyao,GAO Chengguo,et al.AVAZ inversion for fluid factor based on fracture anisotropic rock physics theory[J].Chinese Journal of Geophysics,2014,57(3):968-978.
[30]
RÜGER A.Reflection Coefficients and Azimuthal AVO Analysis in Anisotropic Media[D].Colorado School of Mines,1996.
[31]
BAKULIN A,GRECHKA V,TSVANKIN I.Estimation of fracture parameters from reflection seismic data-Part I:HTI model due to a single fracture set[J]. Geophysics, 2000, 65(6):1788-1802.
[32]
SCHOENBERG M,SAYERS C.Seismic anisotropy of fractured rock[J]. Geophysics,1995,60(1):204-211.
