摘要
东营凹陷已发现的中深层裂解气主要分布在利津—民丰地区的古近系沙河街组第四段储层中,其来源为洼陷区沙四下亚段烃源岩。以沙四下亚段烃源岩的生烃史恢复为基础,结合成岩矿物流体包裹体和天然气成藏地质背景,对该区中深层裂解气藏的形成时间和充注期次进行了分析。结果表明,利津—民丰地区沙四下亚段烃源岩具有两期生烃过程,第一期以生油为主,第二期生成大量油气;沙四下亚段自下而上3套烃源岩达到生成裂解气的时期分别为东营组沉积初期、东营组沉积末期和馆陶组沉积末期;沙四下亚段储层具有两期油气充注过程:第一期为沙二段—东营组沉积末期,以充注原油为主;第二期从馆陶组沉积末期开始,一直持续至今,该期又可分为两个阶段:馆陶—明化镇组沉积初期以充注原油为主,明化镇组沉积中期至今以充注裂解气为主;构造高部位地区仅存在第二期原油的充注。
The middle-deep cracked gas discovered in the Dongying sag are mainly distributed in ES4 (the fourth member of the Paleogene Shahejie Formation) and were sourced from the source rocks in the lower of ES4 in the low-lying area. The accumulation time and charging stages of the middle-deep cracked gas in the study area were analyzed based on reconstruction of hydrocarbon generation history of the source rocks in the lower ES4 and in combination with the study of fluid inclusion in diagenetic minerals and the geologic settings. The source rocks in the lower of ES4 generated hydrocarbons in two stages, one of which was dominated by generation of oil and the other by oil and gas. Three sets of source rocks recognized in the lower of ES4 from bottom to top began to generate cracked gas in the early Dongying, the end of Dongying and the end of Guantao ages respectively. Two hydrocarbon charging stages were identified in the lower ES4 reservoirs, with the first one occurring during ES2-end of Dongying and being dominated by oil, while the second one occurring from the end of Guantao till now. The latter can be further divided into two periods, with the first being the Guantao-Minghuazhen period and dominated by oil charging, while the second being from Minghuazhen till now and dominated by cracked gas charging. Only the second stage of oil charging occurred in the structural high.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2009年第4期14-17,38,共5页
Natural Gas Industry
关键词
东营凹陷
利津-民丰地区
裂解气
成藏期
生烃史
Dongying sag, Lijin-Minfeng area, cracked gas, hydrocarbon pooling stage, hydrocarbon generation history
