渤海湾盆地辽中凹陷南洼走滑转换带特征及其对大、中型油田的控制作用  

Characteristics of strike-slip transition zone in southern Liaozhong Sag,Bohai Bay Basin and its control on large/medium-sized oilfields

作　　者：王冰洁 王德英 王鑫 惠冠洲 薛明旺 Wang Bingjie;Wang Deying;Wang Xin;Hui Guanzhou;Xue Mingwang(Tianjin Branch of CNOOC Ltd.,Tianjin 300452,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300452

出　　处：《石油与天然气地质》2022年第6期1347-1358,共12页Oil & Gas Geology

基　　金：中海油重大科技专项(CNOOC-KJ-135-ZDXM-36-TJ-08-TJ)。

摘　　要：渤海湾盆地辽中凹陷南洼发育走滑转换带,是大、中型油田形成的有利位置。利用三维地震资料解释结果,结合勘探实践,对该区走滑转换带的特征及构造圈闭的形成、古近系砂体展布和油气垂向运移这3个成藏要素进行分析。结果表明:①依附于5条走滑断层,研究区形成了断边走滑转换带、断间走滑转换带和断梢走滑转换带3种类型,每种又可分为压扭型和张扭型2个亚类,对应形成增压型和释压型构造圈闭;②压扭型走滑转换带发育的构造圈闭规模大(即增压型的构造圈闭面积大),为大、中型油田的形成提供了有利的圈闭条件;③走滑转换带古近系砂体在走滑作用下表现出明显的迁移性,导致其在横向上分布范围更广,可接受来自不同位置烃源岩的原油充注,在平面上形成多构造含油的特征;④走滑转换带伴生调节断层发育,有利于油气的垂向运移,最终形成多层系和多断块含油的特点。综上所述,辽中凹陷南洼走滑转换带控制了大规模构造圈闭的形成、控制了古近系砂体在横向上的分布以及原油在垂向上的运移等大、中型油田形成的基本成藏要素。The strike-slip transition zone developed in the southern Liaozhong Sag is a favorable position for the formation of large-and medium-sized oilfields.The study analyzes the characteristics of the strike-slip transition zone,as well as accumulation factors of the formation of structural traps,distribution of the Paleogene sand bodies and vertical hydrocarbon migration based on the interpretation results of three-dimensional seismic data,coupled with exploration practice.As indicated by the results,the study area develops three types of fault-edge transition zone,fault-overlapping transition zone and faultterminal transition zone along five main strike-slip faults,each of which can be subdivided into transpressional subtype and transtensional subtype,corresponding to structural traps of the pressure buildup type and the pressure relief type produced thereby.Second,the structural traps developed in a transpressional strike-slip transition zone are large in scale(that is,the structural traps of the pressure buildup type are large in area),favorable for the formation of large-and medium-sized oilfields.Third,the Paleogene sand bodies in the strike-slip transition zone show obvious migration under strike-slipping,resulting in a wider lateral distribution,capable of accepting oil charging from different source rocks;thus the area features hydrocarbon enrichment in multiple structures on map view.Fourth,the strike-slip transition zone associated with the development of adjustment faults,is conducive to the vertical hydrocarbon migration,ultimately resulting in oil enrichment in multiple horizons and multiple fault blocks.In all,the strike-slip transition zone in southern Liaozhong Sag controls the basic hydrocarbon accumulation factors in the formation of large-and medium-sized oilfields,including the formation of large-scale structural traps,the lateral distribution of the Paleogene sand bodies,and the vertical hydrocarbon migration.

关 键 词：圈闭条件 运移条件 走滑控砂 走滑转换带 辽中凹陷南洼 渤海湾盆地 

分 类 号：TE122.3[石油与天然气工程—油气勘探]