北部湾盆地迈陈凹陷“双源两控”油气成藏模式与勘探实践  

Hydrocarbon accumulation pattern of "double provenance sources and fault/fan controlled traps" and its example in Maichen Sag,Beibuwan Basin

作　　者：刘宏宇 LIU Hongyu(Exploration and Development Research Institute of Jiangsu Oilfield Company,SINOPEC,Yangzhou 225009,China)

机构地区：[1]中石化江苏油田分公司勘探开发研究院,江苏扬州225009

出　　处：《复杂油气藏》2019年第1期7-10,32,共5页Complex Hydrocarbon Reservoirs

基　　金：中国石化科技项目"北部湾盆地中部地区油气成藏条件与勘探潜力"(P14088);中国石化江苏油田分公司科技项目"北部湾盆地徐闻探区油气成藏动力学系统及勘探方向"(JS13002)资助

摘　　要：北部湾盆地迈陈凹陷是一个"南断北超"的箕状断陷,自北向南可划分为斜坡带、深洼带和断裂带。断裂带下降盘一侧以近源快速堆积的水下扇和扇三角洲等沉积体系为主,深洼带以半深湖-深湖相沉积体系为主,斜坡带以河流-三角洲沉积体系为主。受沉积体系和断裂结构的影响,迈陈凹陷的南部和北部在物源特征、沉积体系、圈闭类型、成藏模式等方面具有差异性,通常表现为"双源两控"特点。"双源"即指具有两套物源体系,分别来自斜坡带方向和断裂带方向,斜坡带的河流～三角洲沉积体系和断裂带的砂砾岩扇体沉积体系;"两控"即指两种不同类型的圈闭类型和成藏模式,通常斜坡带以"断控型"圈闭发育为主,断裂带以"扇控型"圈闭发育为主,从而形成了"断控型油气成藏模式"和"扇控型油气成藏模式"。因此勘探过程中应运用"双源两控"模式针对不同区带进行研究和部署。The Maichen Sag of Beibuwan Basin is a dustpan-shaped graben with the feature of “faulted in the south and onlapped in the north” while it can be divided into three structural units from north to south as: slope zone, deep depression zone and slope-controlled zone. In the down thrown side of the fault-controlled zone, there is fan delta sedimentary system built by near-source provenance;in the deep depression zone, there is consisted by semi-deep and deep lacustrine sedimentary system and fluvial-delta sedimentary system in the slope-controlled zone. Due to sedimentary system and fault structure, the Maichen Sag illustrates a regularity in the features of provenance, sedimentary system, trap type and accumulation pattern, in particular can be called “Double provenance sources and fault/fan controlled traps” pattern.“Double provenance sources” means that dustpan-shaped graben usually has two sets of provenance system from the direction of the slope zone to the fault controlled zone which also formed two sets of sedimentary system such as fluvial-delta sedimentary system in the slope zone and the fan sedimentary system in the fault controlled zone.“Fault/fan controlled traps” means that there exists two types traps and two accumulation patterns.“Fault controlled trap” is usually existed in the slope zone and “fan controlled trap” usually existed in the fault controlled zone, thus creating two hydrocarbon accumulation patterns of “fault controlled”and “fan controlled ”. Therefore ,“double provenance sources and fault/fan controlled traps” can be used in the exploration study and deployment to focus on the different features of different structural units.

关 键 词：箕状断陷 双物源 断控型圈闭 扇控型圈闭 油气成藏模式 迈陈凹陷 

分 类 号：TE122[石油与天然气工程—油气勘探]