西湖凹陷A洼陷异常高压封存箱成因机制与控藏作用  

Origin mechanism of abnormal high-pressure compartment in A sub-sag of Xihu sag and its controlling effect on reservoir formation

作　　者：刘金水 张国栋 刘云 LIU Jinshui;ZHANG Guodong;LIU Yun(CNOOC China Limited,Shanghai Branch,Shanghai 200335,China)

机构地区：[1]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《中国海上油气》2023年第3期25-33,共9页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司“十三五”重大专项“东海深层大型气田勘探评价技术研究(编号:CNOOC-KJ135ZDXM39SH)”部分研究成果。

摘　　要：近年来勘探实践表明,西湖凹陷斜坡带A洼陷岩性目标普遍发育高压,高压封存箱内为主要油气富集区。从高压封存箱的判别方法入手,引入“开放压力系统”的概念,从地质成藏的角度重新认识和定义高压,并利用地质录井、测井和地震等资料,对A洼的优质烃源岩(煤层)发育特征、高压成因、高压对成藏的控制作用等方面开展对比研究。研究结果表明:(1)西湖凹陷斜坡带A洼平湖组高压源于生烃增压,且高压封存箱内的砂体具有层层成藏特征;(2)平湖组“先增压再降压”的特殊压力系统特征是煤层发育丰度、热演化程度和砂体发育广度三者耦合的结果;(3)高压封存箱是砂体尖灭和源灶生烃叠合的指示标志,其边界的有效刻画,将显著提高油气钻探成功率。本项研究对于生烃增压型盆地的岩性油气藏勘探具有一定借鉴意义。Exploration practices in recent years have shown that the lithological targets in A sub-sag in the slope zone of Xihu sag generally develop high pressure,and the high-pressure compartment is the main oil and gas enrichment area.This paper starts with the identification method of high-pressure compartment,introduces the concept of"open pressure system",re-recognizes and defines high pressure from the perspective of geological reservoir formation,and uses geological logging,logging and seismic data to carry out a comparative study on the development characteristics of high-quality source rock(coal seam),causes of high pressure,and the controlling effect of high pressure on reservoir formation in A sub-sag.The research results indicate that:①the high pressure of A sub-sag in the slope zone of Xihu sag is derived from hydrocarbon-generating pressurization,and all sand bodies in the high-pressure compartment are filled with hydrocarbon;②the special pressure system with the characteristics of“pressurization first and then depressurization”in Pinghu Formation is the result of the coupling of coal seam development abundance,thermal evolution degree and sand body distribution range;③the high-pressure compartment is an indicator of sand body pinching out and source kitchen hydrocarbon generation overlap,and the effective characterization of its boundary will significantly improve the success rate of oil and gas drilling.This study has certain reference significance for the exploration of lithologic oil and gas reservoirs in hydrocarbon-generating pressurized basins.

关 键 词：西湖凹陷 异常高压 封存箱 平湖组 岩性油气藏 

分 类 号：TE122.1[石油与天然气工程—油气勘探]