摘要
前人研究泥岩盖层封闭性时并没有考虑断裂的破坏程度,且对已被断裂破坏泥岩盖层封闭性演化史的研究目前尚未见到文献报道,而这些问题对含油气盆地断裂发育区油气勘探至关重要.在被断裂破坏泥岩盖层封闭机理及其封闭演化特征研究的基础上,通过比较泥岩盖层断接厚度与其封油气所需的最小断接厚度的相对大小,将被断裂破坏泥岩盖层封闭分为未被断裂破坏和已被断裂破坏泥岩盖层封闭2种,并通过泥岩盖层和断层岩古排替压力恢复,确定泥岩盖层封闭能力形成距今时间、断层岩开始压实成岩距今时间和封闭能力形成距今时间,建立了一套被断裂破坏泥岩盖层封闭性演化史的恢复方法,并将其应用于渤海湾盆地南堡5号构造被f2断裂破坏东二段泥岩盖层封闭性演化史的恢复中.结果表明:在L1、L3、L4、L5、L6、L7和L9测线处,f2断裂未破坏东二段泥岩盖层封闭,仍是东二段泥岩盖层封闭,其封闭性演化经历了不封闭和封闭阶段,目前具有较强的封闭能力.在L2和L8测线处f2断裂已破坏了东二段泥岩盖层封闭,为f2断裂断层岩封闭,其封闭能力演化经历了压实不封闭、成岩不封闭和成岩封闭3个阶段,目前也已具较强封闭能力,均有利于油气在东二段泥岩盖层之下储层中聚集与保存.与目前东二段泥岩盖层之下储层中已发现油气分布相吻合,表明该方法用于恢复被断裂破坏泥岩盖层封闭性演化史是可行的.
The failure degree of mudstone caprock was not considered in the previous study,and the study on the evolution history of the sealing characteristics of fractured mudstone caprock has not been reported in the literature,however,these problems are very important for oil and gas exploration in fault development area of petroliferous basin.On the basis of the study of the sealing mechanism and the closed evolution characteristics of fractured mudstone cap rock,by comparing the relative size of the fault contact thickness of the mudstone cap rock and the minimum fault contact thickness required for sealing oil and gas,the fractured mudstone cap rock sealling type is divided into 2 kinds,including non-fractured and fractured mudstone cover.And the mudstone cap rock sealing formation time,fault rock compaction time and sealing capacity formation time were determined by recovering the ancient displacement pressure of mudstone cap rock and fault rock.A restoration method of the closed evolution history of fractured mudstone cap rock is established,then it was applied on the restoration of closed evolution history of the fractured mudstone cap rocks damaged by f2 fault of Ed2,Nanpu 5 structure,Bohai Bay basin.The results show that fault f2 did not destroy the Ed2 mudstone cap rock sealing ability in L1,L3,L4,L5,L6,L7 and L9 test line,and is still mudstone cap rock sealling of Ed2,its closed evolution has experienced non-closed and closed phases.At present,it has strong sealing ability.The Ed2 mudstone cap rock sealing in L2 and L8test lines was destroyed by fault f2,its sealing ability comes from f2 fault rock,the evolution of its sealing ability has experienced 3 stages：compaction period not closure,diagenetic periodnot closure and diagenetic period closure.At present,it has a strong ability of closure,which is favorable for the accumulation and preservation of oil and gas in the reservoir under the mudstone caprock of Ed2.The prediction results are consistent with the discovered oil and gas distribution in the reservoir under the Ed2 mudstone cap rock,which shows this method is feasible to restore the closed evolution history of mudstone cap rock.
作者
付广
李世朝
Fu Guang Li Shizhao(College of Earth Sciences, Northeast Petroleum University, Daqing 163318, China)
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
2017年第9期1590-1598,共9页
Earth Science-Journal of China University of Geosciences
基金
国家自然基金项目(No.41372153)
关键词
泥岩盖层
断裂破坏
封闭性
演化史
恢复方法
石油地质
mudstone cap rock
fracture failure
sealing property
evolution history
recovery method
petroleum geology
