IP characteristics and anisotropy experiment of hydraulic fracturing shale
TONG Xiaolong1,2, YAN Liangjun2, XIANG Kui2, TAN Gongxian2
1. Key Laboratory of Drilling and Production Engineering for Oil and Gas, Hubei Province, Wuhan, Hubei 430100, China; 2. Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, Yangtze University, Wuhan, Hubei 430100, China
Abstract：Hydraulic fracturing is the core technology to improve the physical properties of unconventional reservoirs and effectively develop unconventional oil and gas resources.Different from microseismic monitoring, the electromagnetic monitoring method has a better physical basis based on the complex resistivity differences between fracturing fluids and surrounding rocks.The fractured reservoirs formed by hydraulic fracturing of tight shale and other unconventional reservoirs have complex structures and often have various induced polarization (IP) mechanisms, which causes certain difficulties in IP modeling of actual formations and limits the evaluation of electromagnetic fracturing monitoring.Therefore, this paper carries out IP modeling based on dual pore media and combines the IP characteristics of tight shale in Wufeng Formation before and after fracturing with the experiment.The differences in IP parameters and anisotropy characteristics of reservoir samples before and after fracturing are analyzed in the condition of different pressure, saturation, and proppant filling.The results show that the IP physical features of fractured reservoirs after fracturing are greatly affected by the fracture surface, and the enhanced pore connectivity of reservoirs is the main reason for the resistivity decrease.Meanwhile, the directional distribution of proppants is beneficial to enhance the anisotropy of fractured reservoirs, which provides a theoretical and experimental basis for IP modeling of reservoirs.
邹才能, 杨智, 朱如凯, 等.中国非常规油气勘探开发与理论技术进展[J].地质学报, 2015, 89(6):979-1007.ZOU Caineng, YANG Zhi, ZHU Rukai, et al.Progress in China's unconventional oil & gas exploration and development and theoretical technologies[J].Acta Geologica Sinica, 2015, 89(6):979-1007.
[2]
ZHANG P, OZOWE W, RUSSELL R T, et al.Characterization of an electrically conductive proppant for fracture diagnostics[J].Geophysics, 2021, 86(1):E13-E20.
[3]
WARPINSKI N R R, DU J, ZIMMER U.Measurements of Hydraulic-Fracture-Induced seismicity in gas shales[J].SPE Production & Operations, 2012, 27(3):240-252.
[4]
HOVERSTEN G M, COMMER M, HABER E, et al.Hydro-frac monitoring using ground time-domain electromagnetics[J].Geophysical Prospecting, 2015, 63(6):1508-1526.
[5]
HE Z, HU Z, GAO Y, et al.Field test of monitoring gas reservoir development using time-lapse continuous electromagnetic profile method[J].Geophysics, 2015, 80(2):WA127-WA134.
[6]
YAN L, CHEN X, TANG H, et al.Continuous TDEM for monitoring shale hydraulic fracturing[J].Applied Geophysics, 2018, 15(1):26-34.
[7]
王新宇, 严良俊, 毛玉蓉.电性源瞬变电磁法油气藏动态监测模拟分析[J].石油地球物理勘探, 2022, 57(2):459-466.WANG Xinyu, YAN Liangjun, MAO Yurong.Simulation and analysis of dynamic monitoring of oil and gas reservoir based on grounded electric source TEM[J].Oil Geophysical Prospecting, 2022, 57(2):459-466.
[8]
邓继新, 史謌, 刘瑞珣, 等.泥岩、页岩声速各向异性及其影响因素分析[J].地球物理学报, 2004, 47(5):862-868.DENG Jixin, SHI Ge, LIU Ruixun, et al.Analysis of the velocity anisotropy and its affection factors in shale and mudstone[J].Chinese Journal of Geophysics, 2004, 47(5):862-868.
[9]
王小琼, 葛洪魁, 王文文, 等.致密储层岩石应力各向异性与材料各向异性的实验研究[J].地球物理学报, 2021, 64(12):4239-4251.WANG Xiaoqiong, GE Hongkui, WANG Wenwen, et al.Experimental study on stress-related and matrix-related anisotropy in tight reservoirs[J].Chinese Journal of Geophysics, 2021, 64(12):4239-4251.
[10]
刘云鹤, 殷长春, 蔡晶, 等.电磁勘探中各向异性研究现状和展望[J].地球物理学报, 2018, 61(8):3468-3487.LIU Yunhe, YIN Changchun, CAI Jing, et al.Review on research of electrical anisotropy in electromagnetic prospecting[J].Chinese Journal of Geophysics, 2018, 61(8):3468-3487.
[11]
邓少贵, 袁习勇, 王正楷, 等.裂缝性地层方位侧向测井响应数值模拟[J].地球物理学报, 2018, 61(8):3457-3467.DENG Shaogui, YUAN Xiyong, WANG Zhengkai, et al.Numerical simulation of azimuthal laterolog response in fractured formation[J].Chinese Journal of Geophysics, 2018, 61(8):3457-3467.
[12]
葛新民, 范宜仁, 李军, 等.井旁裂缝的双侧向测井物理模拟及特征分析[J].地球物理学报, 2019, 62(1):354-360.GE Xinmin, FAN Yiren, LI Jun, et al.Experimental studies and investigations on the dual lateral log response of near borehole fractures[J].Chinese Journal of Geophysics, 2019, 62(1):354-360.
[13]
潘保芝, 阿茹罕, 郭宇航, 等.裂缝性岩石低频下复电阻率与饱和度关系研究[J].地球物理学报, 2021, 64(10):3774-3787.PAN Baozhi, A Ruhan, GUO Yuhang, et al.Study on the relationship between complex resistivity and water saturation in fractured rock at low frequency[J].Chinese Journal of Geophysics, 2021, 64(10):3774-3787.
[14]
沈金松, 苏本玉, 郭乃川.裂缝性储层的电各向异性响应特征研究[J].地球物理学报, 2009, 52(11):2903-2912.SHEN Jinsong, SU Benyu, GUO Naichuan.Study on the anisotropic characteristics of the electric response to fractured reservoir[J].Chinese Journal of Geophysics, 2009, 52(11):2903-2912.
[15]
WELLER A, ZHANG Z, SLATER L.High-salinity polarization of sandstones[J].Geophysics, 2015, 80(3):D309-D318.
[16]
NIU Q, REVIL A.Connecting complex conductivity spectra to mercury porosimetry of sedimentary rocks[J].Geophysics, 2016, 81(1):E17-E32.
[17]
PARK J, LEE K H, SEO H, et al.Role of induced electrical polarization to identify soft ground/fractured rock conditions[J].Journal of Applied Geophysics, 2017, 137:63-72.
[18]
ZHOU T, ZHANG S, YANG L, et al.Experimental investigation on fracture surface strength softening induced by fracturing fluid imbibition and its impacts on flow conductivity in shale reservoirs[J].Journal of Natural Gas Science and Engineering, 2016, 36, Part A:893-905.
[19]
林鹤, 李德旗, 周博宇, 等.天然裂缝对压裂改造效果的影响[J].石油地球物理勘探, 2018, 53(增刊2):156-161, 167.LIN He, LI Deqi, ZHOU Boyu, et al.Influences of natural cracks on fracturing[J].Oil Geophysical Prospecting, 2018, 53(S2):156-161, 167.
[20]
WARREN J E, ROOT P J.The behavior of naturally fractured reservoirs[J].Society of Petroleum Engineers Journal, 1963, 3(3):245-255.
[21]
王雷, 张士诚.压裂液返排速度对支撑剂回流量及其在裂缝内分布的影响[J].油气地质与采收率, 2008, 15(1):101-102, 110.WANG Lei, ZHANG Shicheng.Influence of the backflow velocity of fracturing fluid on the backflow volume and distribution of proppant in fractures[J].Petroleum Geology and Recovery Efficiency, 2008, 15(1):101-102, 110.
[22]
董文波, 桂志先, 王亚楠, 等.水平井压裂微地震监测成果的不对称性分析[J].石油地球物理勘探, 2023, 58(1):161-169.DONG Wenbo, GUI Zhixian, WANG Ya, nan, et al.Asymmetry analysis of microseismic monitoring results of horizontal well fracturing[J].Oil Geophysical Prospecting, 2023, 58(1):161-169.
[23]
NORDSIEK S, WELLER A.A new approach to fitting induced-polarization spectra[J].Geophysics, 2008, 73(6):F235-F245.
