“连续型”气藏及其大气区形成机制与分布--以四川盆地上三叠统须家河组煤系大气区为例  

Formation and distribution of "continuous" gas reservoirs and their giant gas province:A case from the Upper Triassic Xujiahe Formation giant gas province,Sichuan Basin

作　　者：邹才能[1] 陶士振[1] 朱如凯[1] 袁选俊[1] 李伟[1] 张光亚[1] 张响响 高晓辉[1] 刘柳红[1] 徐春春[2] 宋家荣[2] 李国辉[2] 

机构地区：[1]中国石油勘探开发研究院,100083 [2]中国石油西南油气田公司

出　　处：《石油勘探与开发》2009年第3期307-319,共13页Petroleum Exploration and Development

基　　金：国家大型气田及煤层气开发(20082X05001);中国石油科技风险创新研究项目(07-06D-01-04-01-03)

摘　　要：基于对四川盆地上三叠统油气地质背景、成藏条件、运聚机理和分布规律的综合分析,提出了须家河组天然气聚集是发育于含煤地层的"连续型"气藏、层状岩性大气区,煤系烃源岩大面积层状蒸发式排烃,盆缘造山带"幕式"冲断挤压背景下多物源间断性快速注入形成大平原、小前缘的粗粒三角洲体系,平缓构造背景下低—特低渗透砂体内天然气运聚过程中浮力作用受限,达西和非达西渗流机制并存,形成气-水-干层共生的混相成藏系统等新认识。对成岩相进行了定量分类,确定了8种成岩亚相、20种成岩微相。运用压实率、胶结率、溶蚀率等指标定量表征成岩相,运用Ro值、地层水参数等定量剖析了成岩相的成因。"连续型"气藏形成的大气区主要发育于中国中部构造稳定的大型陆相坳陷、前陆平缓斜坡或海陆交互相环境,具有大面积层状展布、无明显的圈闭界限和直接盖层、连片砂体弥漫式含气并有"甜点"、资源规模大、储量丰度较低和开采技术要求高的特点。The comprehensive analysis of geological setting, accumulation condition, trapping mechanism and distribution regularity of oil gas of the Upper Triassic in Sichuan Basin reveals that the gas accumulation in Xujiahe Formation is a layered lithologic giant gas province. Coal source rocks in layers expelled hydrocarbon evaporatively. Under the setting of the episodic fold-thrusting and compression in the boundary orogen, multi-sources charged quickly and formed a coarse deltaic environment with a large-scale delta plain and a small-scale delta front. In gentle structures, Darcy and non-Darcy flow mechanisms coexist because of the limited buoyancy of low permeability sandstone, thus forming the coexisting oil gas-water system. This paper classifies the diagenetic facies quantitatively using compaction percentage, cementation percentage and corrosion percentage, and defines eight diagenetic subfacies and twenty diagenetic microfacies. Besides, the origin of diagenetic facies is analyzed by using Ro and formation water parameter. This kind of giant gas province originated mainly from stable large-scale continental depressions, gentle foreland slopes and paralic facies in central China. It is characterized by large-area layered distribution, no obvious trap and cap formation, large-scale resource, low-abundance reserves, and difficult to exploit.

关 键 词：煤系烃源岩 层状大气区 层状蒸发式排烃 差异分流汇聚 非常规圈闭 “连续型”油气藏 

分 类 号：TE122.1[石油与天然气工程—油气勘探]