摘要
以准噶尔盆地南缘地区深层致密砂岩储层为研究对象,通过室内实验和数值模拟的手段综合研究深层致密砂岩裂缝应力敏感性及其影响因素,并讨论支撑剂、裂缝角度、地层孔隙压力、水平应力差等因素对裂缝开度和裂缝闭合量的影响。研究结果表明:岩石支撑缝渗透率随有效应力增大而减小,剪切、劈裂破坏岩样的平均不可逆渗透率损害率分别为86.15%、62.19%,剪切破坏岩样应力敏感性小于劈裂破坏岩样,地层剪切裂缝更有利于后期的生产开发;支撑剂对岩样支撑缝渗透率影响较大,铺设、未铺设支撑剂的平均不可逆损害率分别为26.61%和74.17%,支撑剂能为裂缝面提供有效的支撑作用,减缓裂缝开度闭合的速度,降低裂缝应力敏感性,铺设支撑剂后裂缝岩样的最大渗透率损害率、不可逆渗透率均大幅度下降,卸载后渗透率恢复较高,支撑缝渗透率得到保持;在数值模拟实验中,人工裂缝与水平最大主应力夹角增大、地层孔隙压力减小或水平应力差增大都会导致裂缝面位移量逐渐增大,裂缝面上受到的应力增大,等效裂缝开度减小和裂缝闭合量增大,裂缝逐渐闭合,最终使支撑缝渗透率降低。
This study focuses on deep tight sandstone reservoir in the southern margin of the Junggar Basin.A comprehensive investigation of the stress sensitivity of deep tight sandstone fractures and their influencing factors was conducted through laboratory experiments and numerical simulations.The study also discussed the effects of proppant,fracture angle,formation pore pressure,and horizontal stress difference on fracture aperture and closure.The research findings indicate that the permeability of the rock fractures decreases with increasing effective stress.The average irreversible permeability damage rates for shear and tensile failure rock samples are 86.15%and 62.19%,respectively.This suggests that shear failure rock samples exhibit lower stress sensitivity compared to tensile failure rock samples.It had made formation shear fractures more conducive to later-stage production and development.The average irreversible damage rates with and without proppant are 26.61%and 74.17%,respectively.Proppant can provide effective support to the fracture surface,slow down the rate of fracture aperture closure,reduce the stress sensitivity of the fracture,and decrease the maximum damage rate and irreversible permeability damage rate of fractured rock samples.After unloading,the permeability recovery is relatively high,and the permeability of the supported fractures is maintained.In numerical simulation experiments,an increase in the angle between artificial fractures and the maximum horizontal stress,a decrease in formation pore pressure,or an increase in horizontal stress differences all lead to gradually increasing displacement of fracture surfaces.This results in increased stress on the fracture surfaces,reduced equivalent fracture aperture,and increased closure,ultimately leading to a decrease in fracture permeability.
作者
熊健
朱梦渊
刘伟
刘峻杰
刘向君
梁利喜
丁乙
XIONG Jian;ZHU Mengyuan;LIU Wei;LIU Junjie;LIU Xiangjun;LIANG Lixi;DING Yi(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Huanqing Oil Production Plant of CNPC Yumen Oilfield Branch Company,Yumen 735200,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2024年第4期563-572,共10页
Natural Gas Geoscience
基金
国家自然科学基金(编号:42272190)
四川省自然科学基金青年科学基金项目(编号:2022NSFSC1065)联合资助。
关键词
人工裂缝
应力敏感性
破坏模式
支撑剂
地层孔隙压力
水平应力差
Artificial fractures
Stress sensitivity
Destruction mode
Proppant
Formation pore pressure
Horizontal stress difference
