渤海新近纪—第四纪隐性走滑断层发育机理与判识方法探究  

Development mechanism and identification methods of subtle strike-slip faults in the Neogene-Quaternary of Bohai Sea

作　　者：任健 杨波 陈兴鹏 裴小刚 高曦龙 郭颖 REN Jian;YANG Bo;CHEN Xingpeng;PEI Xiaogang;GAO Xilong;GUO Ying(Research Institute of Bohai Oil Field,Tianjin Branch of CNOOC(China)Ltd.,Tianjin 300452,China;Shandong Institute of Petroleum and Chemical Technology,Dongying 257061,China)

机构地区：[1]中海石油(中国)天津分公司渤海石油研究院,天津300452 [2]山东石油化工学院石油工程学院,东营257061

出　　处：《海洋地质前沿》2024年第12期11-17,共7页Marine Geology Frontiers

基　　金：中海石油(中国)有限公司“七年行动计划”重大科技专项“渤海油田稳产3 000万吨,上产4 000万吨关键技术研究”(CNOOC-KJ 135ZDXM 36 TJ);中国海洋石油有限公司综合科研项目“渤海大中型天然气田形成条件、富集规律与勘探方向研究”(KJZH-2024-2107)。

摘　　要：渤海海域新近系—第四系地层中发育大量地震资料中难以识别的“隐性走滑断层”,其断面陡立、断续分布、断距较小。在油气勘探过程中,隐性断层认识失败导致圈闭失效、勘探失利的现象时有发生,因此亟需从断层发育机理上重新认识且有效刻画隐性走滑断层。基于渤海新近纪—第四纪构造背景以及三维地震资料,对隐性走滑断层发育机理以及识别方法进行探究,结果表明,渤海新近纪—第四纪隐性走滑断层为先存断层斜向拉伸构造背景之下发育的位移分异式走滑断层,不受基底走滑断层直接控制;先存边界断层与斜向拉伸方向夹角α、先存边界断层与斜拉伸展断层夹角θ以及走滑分异概率P之间存在特定关系,利用这一原理可以判断分异型隐性走滑断层是否发育,并取得了良好的应用效果。本研究明确了渤海新近纪—第四纪隐性走滑断层发育机理与判识方法,为油气勘探提供了重要指导。A large number of "subtle strike-slip faults" are developed in the Neogene-Quaternary strata in the Bohai Sea,which are difficult to identify in seismic data.These faults are steep,discontinuous,and have small fault throws.The existence of subtle faults could destroy the trap.In the process of oil and gas exploration,failure to identify subtle faults will lead to exploration failure.Therefore,it is urgent to re-understand subtle strike-slip faults from the perspective of fault development mechanism and guide their effective characterization.Based on the Neogene-Quaternary tectonic background of the Bohai Sea and three-dimensional seismic data,the development mechanism and identification method of subtle strike-slip faults were explored.Results show that the NeogeneQuaternary subtle strike-slip faults in the Bohai Sea are displacement-partitioned strike-slip faults developed under the oblique extensional tectonic background of pre-existing faults,and they are not directly controlled by basement strike-slip faults.There is a specific relationship among the angle α between the pre-existing boundary fault and the oblique extension direction,the angle θ between the pre-existing boundary fault and the oblique extension faults,and the probability P of displacement partitioning of strike-slip.This principle was used to effectively determine whether the subtle strike-slip fault was developed,and good application results were achieved.This study clarified the development mechanism and identification method of subtle strike-slip faults in the Neogene-Quaternary in the Bohai Sea,providing important guidance for oil and gas exploration.

关 键 词：隐性走滑 走滑分异 分散式变形 斜向拉伸 先存断裂 新近纪—第四纪 渤海海域 

分 类 号：P736[天文地球—海洋地质] P738[天文地球—海洋科学]