摘要
针对西湖凹陷古近系致密砂岩气成藏机制与成藏模式尚不明确等问题,综合分析了烃源岩的特征与生排烃期次,研究异常高压的成因与分布特点,以及大型储集体的展布与物性特征,建立了致密砂岩气的成藏模式。研究结果表明:烃源岩、异常高压和致密储层“三元耦合控藏”是西湖凹陷致密砂岩气藏成藏关键因素,其中古近系煤系烃源岩条件优越,生气高峰期与储层致密形成时间一致,生烃增压同时提供了富厚的物质基础;异常高压改善储层物性,同时利于致密砂岩气的长距离运移和聚集;大规模的砂岩储集体发育,致密砂岩气在异常高压作用下汇聚成藏。西湖凹陷致密砂岩气藏呈现出“自源侧向-垂向”的成藏模式,共发育“原生型”和“改造型”2类致密砂岩气藏,具有良好的勘探前景。
For the mechanism and mode of the hydrocarbon accumulation of tight sandstone gas reservoir are unclear in the Paleogene of Xihu Sag,the characteristics and hydrocarbon generation and expulsion stages of the source rocks were comprehensively analyzed,the genesis and distribution characteristics of abnormally high pressure,as well as the distribution and physical characteristics of large reservoirs were researched,and the hydrocarbon accumulation mode of tight sandstone gas reservoirs was established.The research results indicate that the“ternary factors coupling for controlling reservoir”of source rocks,abnormally high pressure,and tight reservoir are the key factors for hydrocarbon accumulation of tight sandstone gas reservoirs in Xihu Sag.Among them,the Paleogene coal series source rocks have superior conditions,and the peak gas generation stages are consistent with the formation time of tight reservoirs.At the same time,hydrocarbon generation and pressurization provide a rich material foundation.Abnormally high pressure improves reservoir physical properties while facilitating long-distance migration and accumulation of tight sandstone gas.Large scale sandstone reservoirs are well developed,and tight sandstone gas accumulates under abnormally high pressure to form reservoirs.The tight sandstone gas reservoirs in Xihu Sag exhibit a“self source lateral-vertical”hydrocarbon accumulation mode,and the“primary”and“modified”tight sandstone gas reservoirs are developed,which have good exploration prospects.
作者
张年念
程超
余逸凡
鞠颢
陈波
ZHANG Niannian;CHENG Chao;YU Yifan;JU Hao;CHEN Bo(CNOOC China Limited,Shanghai Branch,Shanghai 200335,China)
出处
《非常规油气》
2024年第3期27-34,共8页
Unconventional Oil & Gas
基金
中海石油(中国)有限公司科技项目“东海上产560万吨关键技术研究”(CNOOC-KJ135ZDXM 39 SH03)。
关键词
三元耦合控藏
异常高压
成藏模式
致密砂岩气
ternary factors coupling for controlling reservoir
abnormal high pressure
accumulation mode
tight sandstone gas
