渤海湾盆地南堡凹陷奥陶系潜山油气地质特征与成藏主控因素

2004年，渤海湾盆地黄骅坳陷南堡凹陷老堡南1井奥陶系潜山测试获日产700m³高产油流，南堡油田被发现。综合岩心、钻井、地震及测井等多种资料，分析探区油气地质特征，对影响油气聚集成藏的主控因素进行总结。研究表明：①南堡凹陷奥陶系潜山有利储层的发育是受多旋回构造运动与多期岩溶作用控制的断裂裂缝-岩溶复合储集体，储集空间主要是断裂裂缝、溶蚀孔洞及溶洞充填沉积的溶积砂岩、砂砾岩原生孔隙；②沙三段发育优质烃源岩，是油气的主要来源；③油气藏分布受优势储层控制，由断裂和不整合组成的纵横交错的网状输导体系为油气纵向和横向运移创造条件，有效烃源岩与潜山有利圈闭空间良好配置是油气能否运聚成藏的关键，潜山高部位是油气聚集的有利区带，潜山低部位只要储层发育也可聚集油气;④储层是控制油气成藏的最为重要的要素，南堡凹陷奥陶系潜山油气勘探主攻方向是多旋回构造-岩溶作用形成的断裂裂缝-岩溶复合储集体。

Geological Characteristics of Ordovician Buried Hill and Main Factors of Oil/Gas Accumulation in Nanpu Sag,Bohai Bay Basin,China

Laopunan1 well,which recorded a prolific high oil flow of 700m3/d in an Ordovician buried hill in 2004,discovered the Nanpu oilfied in Nanpu sag,Huanghua sub-basin,Bohai Bay basin.In this paper we discusse the oil/gas geological features and the controlling factors of oil/gas accumulation in the Nanpu Ordovician buried hill based on core drilling,seismic and logging data.The results indicate that:(1) Main kind of reservoir in the Nanpu Ordovician buried hill is fracture fissure-karstic composite reservoir,which is controlled by polycyclic tectonic movement and multiphase karstification;the reservoir spaces are mainly of crack,caverns and primary pores of cave filling sandstone and conglomerate deposition.(2) High quality source rock in the 4 sub-member of Sha 3 member is the main source of oil and gas.(3) Oil/gas reservoir distribution is controlled by predominant reservoir;in the crisscross transport system the longitudinal and transverse net which is composed of the faults and unconformities is the pathway of oil and gas migration;the key factor of oil/gas accumulation is favorable configuration of effective source rocks and buried hill traps;the high zone of buried hill is beneficial for petroleum accumulation and the hydrocarbon can also be accumulated in the low position if the reservoir develops well.(4) Reservoir is the most important factor to control the oil and gas accumulation,so the main target of oil/gas exploration should be focused on the polycyclic tectonic-karstic controlled fracture fissure-karst composite traps in the Nanpu Ordovician buried hill.