摘要
为准确评价东海盆地K区平湖组断层侧向封闭性及其对油气成藏的控制作用,基于前人对断层侧向封闭性机制、影响因素的分析,从断层侧向封闭类型出发,分别针对岩性对接型及断层岩型封闭断层建立评价模型及下限,以此开展断层侧向封闭性评价,并以N-1井区为例开展封闭性对油气成藏的控制作用分析。研究结果表明:K区平湖组断层侧向封闭类型以断层岩型封闭为主,断层封闭性受断层岩泥质含量(SGR)影响,封闭下限值为15%;纵向上平湖组断层岩SGR值自下而上逐渐降低,封闭能力逐渐变差,部分封闭断层逐渐转为开启;平面上K区中北部长时间活动的大规模断层侧向封闭能力明显强于南部断层。考虑到断层的侧向封闭性与油气能否在储层中聚集成藏是两个相互制约的地质要素,只有当断层岩SGR值介于15%~58%时,断层侧向封闭且储层发育,受断层遮挡的相关圈闭才能成为油气聚集成藏的有效圈闭。研究成果对明确东海盆地K区油气成藏规律,降低钻探风险具有较高的理论和实践意义。
This study accurately evaluated the lateral sealing ability of faults in the Pinghu formation in the K area of the East China Sea Basin and its influence on hydrocarbon accumulation.Based on a previous analysis of the fault lateral sealing mechanism and influencing factors,starting from the fault lateral sealing type,the evaluation model and lower threshold were established for lithologic juxtaposition type and fault rock type sealing faults,respectively,in order to evaluate the fault lateral sealing property and ability.The N-1 well block was used as an example to analyze the control effect of sealing on hydrocarbon accumulation.The results indicated that the fault lateral sealing type of the Pinghu formation in the K area is mainly of the fault rock type.The fault sealing ability is affected by the clay content of the fault rock(SGR),and the lower threshold of fault lateral sealing is 15%.In this section,the SGR value of the Pinghu formation fault rocks gradually decreases from bottom to top,the sealing ability gradually weakens,and some sealed faults gradually turn open.On the plane,the lateral sealing ability of large-scale faults with long-term activity in the central and northern areas was clearly stronger than that of the southern faults.Considering that the lateral sealing property of the fault and whether hydrocarbons can accumulate in the reservoir are the two geological factors that restrict each other,the fault is laterally sealed and the reservoir is developed only when the SGR value of the fault rock is between 15%and 58%.Therefore,fault-related traps are conducive to hydrocarbon accumulation.These research results have high theoretical and practical significance for clarifying the law of hydrocarbon accumulation and risks of reducing drilling in the K area of the East China Sea Basin.
作者
孙鹏
李宁
胡欣蕾
刘禹
袁红旗
SUN Peng;LI Ning;HU Xinlei;LIU Yu;YUAN Hongqi(Research Institute of CNOOC Shanghai Branch,Shanghai 200335,China;School of Earth Sciences,Northeast Petroleum University,Heilongjiang Daqing 163318,China)
出处
《上海国土资源》
2023年第2期140-147,共8页
Shanghai Land & Resources
基金
“十四五”国家重大科技项目“弧后盆地深层/超深层油气成藏条件与成藏机制研究-西湖凹陷”(KJGG2022-0402)。
关键词
东海盆地
平湖组地层
断层
封闭性评价
断层岩泥质含量
控藏作用
油气储层
East China Sea Basin
Pinghu formation
fault
sealing ability evaluation
clay content of fault rock
accumulation controlling effect
oil and gas reservoir
