湘中涟源凹陷杨家佬石炭系天然气成藏规律  

Accumulating laws of Carboniferous system gas in Yangjialao area of Lianyuan Sag in central Hunan Province

作　　者：赵芸[1] 李波 龚文平[1] 朱锐[1] 董晶晶[2] ZHAO Yun;LI Bo;GONG Wenping;ZHU Rui;DONG Jingjing(School of Geosciences,Yangtze University,Wuhan 430100,China;Heavy Oil Developing Branch of PetroChina Xinjiang Oilfield Company,Karamay 834000,China)

机构地区：[1]长江大学地球科学学院,湖北武汉430100 [2]中国石油新疆油田分公司重油开发公司,新疆克拉玛依834000

出　　处：《大庆石油地质与开发》2022年第2期26-35,共10页Petroleum Geology & Oilfield Development in Daqing

摘　　要：湘中涟源凹陷是目前扬子板块页岩气和页岩油的热点地区。该地区经历多期构造抬升,地层剥蚀严重,构造极为复杂,为油气藏的预测带来了极大困难。杨家佬地区是涟源凹陷中优质的含气区块,通过对该地区的天然气特征、储盖条件及成藏期次进行分析,总结其成藏规律,为该地区乃至涟源凹陷的天然气勘探开发提供明确的方向。研究结果表明:研究区天然气以甲烷为主,氮气次之,系天然气单独成藏;研究区主要储层为下石炭统的生屑灰岩、云质灰岩、含泥质较少的微—细晶灰岩以及薄层状含砂泥页岩,储集空间为次生的溶蚀孔隙和构造破裂缝;研究区石炭系发育的测水段煤层区域分布完整,可作为良好的区域性盖层,与储集层之间形成良好的组合关系,形成了构造圈闭和岩性圈闭2种主要圈闭类型,但圈闭形成后多次的构造运动对本区盖层造成了较大影响,从而破坏了天然气保存;本区的气藏成藏包括近源富集成藏、后期改造二次成藏以及晚期成藏3种天然气富集成藏模式。Lianyuan Sag in central Hunan Province is a hot spot of shale gas and oil research in the Yangtze plate. The area has experienced multi-stage tectonic uplift, and the strata in the area were seriously denuded, causing extremely difficulty for hydrocarbon reservoir prediction. Yangjialao area is a high-quality gas-bearing block in Lianyuan Sag. Through analyzing natural gas characteristics, reservoir-seal conditions and accumulation period-times in the area, the accumulation laws are summarized, providing directions of gas exploration and development for the area and Lianyuan sag. The results show that natural gas in this study area is mainly composed of methane and secondly nitrogen, which accumulates individually. The main reservoirs in the study area include Lower Carboniferous bioclastic limestone, dolomitized limestone, micro-fine crystalline limestone with less mud content and thin bedded sand-bearing mud shale, and accumulation spaces are secondary dissolved pore and structural fracture. Coalbeds developed in Carboniferous water-measured interval in the study area are distributed completely and regionally, being favorable regional seal and forming better combination with reservoirs. 2 main types of structural and lithological traps developed, but after the traps formation, several tectonic movements since Indosinian period caused a great influence on the regional seal in this area, and thus damaged gas preservation. There are 3 types of gas accumulating laws in the area: early proximal type, later-reformed secondary accumulation type and late accumulation type.

关 键 词：成藏模式 储层 成藏条件 石炭系 涟源凹陷 

分 类 号：TE122[石油与天然气工程—油气勘探]