摘要
构造裂缝是库车坳陷KT1气藏白垩系亚格列木组深层致密砂砾岩储层获得高产天然气的重要条件,开展构造裂缝分布规律与有效性研究,有助于亚格列木组的有利储层预测。综合岩心和成像测井资料,对KT1气藏亚格列木组的构造裂缝特征进行了描述,并采用有限元方法对构造裂缝的分布规律进行了半定量预测,从时间有效性和空间有效性两个方面对构造裂缝的有效性进行了评价,最后开展了水平应力不变、上覆岩层重力载荷依次增加条件下的构造裂缝数值模拟。结果表明:①KT1气藏亚格列木组砂砾岩储层发育张性裂缝和剪切裂缝,以中—高角度为主,优势走向为NW—SE向,与NNW向的区域最大古构造应力方位有较好的对应关系。②KT1气藏亚格列木组至少发育2期裂缝:第1期裂缝为无效裂缝,形成于新近系康村组沉积期之前;第2期裂缝为有效裂缝,形成于上新世库车组沉积期—第四纪(5 Ma至今),该期裂缝与天然气充注具有良好的匹配关系,是天然气大规模充注成藏的重要条件。③裂缝空间有效性主要受控于裂缝的密度和开度。KT1气藏背斜高部位裂缝密度相对翼部较低,但裂缝开度大,裂缝渗透率显著高于翼部。这是位于翼部的KT204井裂缝密度最大、但产气量最低的重要原因。④数值模拟结果表明:在一定深度范围内,随储层埋深增大,构造裂缝密度降低,但开度与渗透率显著增大、有效性显著变好,更有利于天然气在储层中的高效渗流。
Structural fracture is an important condition for obtaining high gas yield from the deep tight glutenite reservoir of the Cretaceous Yageliemu Formation in KT-1 gas reservoir of Kuqa Depression.To study the distribution and effectiveness of structural fracture is conducive to favorable reservoir prediction of Yageliemu Formation.Based on core and imaging logging data,the characteristics of structural fractures in Yageliemu Formation of KT-1 gas reservoir are described,and the distribution of structural fractures is semi-quantitatively predicted by finite element method.The effectiveness of structural fractures is evaluated from two aspects:time and space effectiveness.Finally,the numerical simulation of structural fracture is carried out under the condition of constant horizontal stress and increasing gravity load of overlying strata.The results show that the glutenite reservoir of Yageliemu Formation in KT-1 gas reservoir develops tensile fractures and shear fractures,mainly at medium-high angles,and the dominant trend is NW-SE,which has a good correspondence with the maximum paleotectonic stress orientation in the NNW direction.There are at least two stages of fracture in Yageliemu Formation of KT-1 gas reservoir.The first stage of fracture is invalid,which was formed before the depositional period of the Neogene Kangcun Formation.The second stage of fracture is effective formed in the depositional period of the Pliocene Kuqa Formation-Quaternary(5 Ma until now),which has a good matching relationship with natural gas charging,and is an important condition for the formation of large-scale natural gas reservoir.The fracture spatial effectiveness is mainly controlled by the fracture density and fracture opening.The fracture density in the high position of anticline of KT-1 gas reservoir is lower than that in the wing,but the fracture opening is larger and the fracture permeability is significantly higher than that in the wing,which is an important reason why Well KT204 located in the wing has the highest fracture density but the lowest gas production.The numerical simulation results show that in a certain depth range,with the increase of reservoir buried depth,the density of structural fractures decreases,but the aperture and permeability increase significantly,and the effectiveness becomes significantly better,which is more conducive to the efficient flow of natural gas in the reservoir.
作者
何巧林
王珂
胡春雷
王俊鹏
邓建忠
张知源
孙金佳杰
黄箐璇
刘渊
HE Qiaolin;WANG Ke;HU Chunlei;WANG Junpeng;DENG Jianzhong;ZHANG Zhiyuan;SUN-JIN Jiajie;HUANG Qingxuan;LIU Yuan(Research Institute of Petroleum Exploration&Development,PetroChina Tarim Oilfield Company,Korla,Xinjiang 841000,China;Exploration and Development Technology Research and Development Center for Ultra Deep Complex Oil and Gas Reservoirs,CNPC;PetroChina Hangzhou Research Institute of Geology,Hangzhou,Zhejiang 310023,China)
出处
《海相油气地质》
CSCD
北大核心
2024年第4期437-447,共11页
Marine Origin Petroleum Geology
基金
中国石油天然气股份有限公司基础性前瞻性课题“叠合盆地中下组合油气成藏与保持机制研究”(编号:2023ZZ02)
国家自然科学基金企业创新发展联合基金集成项目“环青藏高原盆山体系动力学与天然气富集机理”(编号:U22B600002)联合资助。
关键词
深层
致密砂砾岩储层
构造裂缝
数值模拟
裂缝有效性
亚格列木组
库车坳陷
deep strata
tight glutenite reservoir
structural fracture
numerical simulation
fracture effectiveness
Yage⁃liemu Formation
Kuqa Depression
