吐哈盆地致密砂岩气成藏特征及模式  

Characteristic and Model for Tight Sandstone Gas Accumulation in Tuha Basin

作　　者：俞益新[1] 张金川[1] 尹腾宇[1] 朱亮亮[1] 

机构地区：[1]中国地质大学能源学院,北京100083

出　　处：《新疆石油地质》2012年第3期283-287,共5页Xinjiang Petroleum Geology

基　　金：中石油重大专项(2010B-0107)

摘　　要：吐哈盆地下侏罗统发育大范围煤系烃源岩及与其直接接触的辫状河三角洲砂岩,为致密砂岩气藏的形成创造了条件。明确致密砂岩气藏的成藏模式,对提高致密砂岩气藏的勘探成功率极为重要。通过烃源岩与天然气地球化学特征、不同岩性烃源岩的产气率实验模拟、各个地史时期盆地生气量模拟,并结合储集层岩石学、成岩演化及流体包裹体等相关地质要素的综合研究,表明吐哈盆地下侏罗统煤岩各项地球化学指标都远优于泥岩,是致密砂岩气藏的主要气源,于晚侏罗世-早白垩世开始生气,并在镜质体反射率大于1.1%时进入生气高峰;受快速深埋、成岩压实等因素作用,储集层致密化时间为晚侏罗世;这种"先期致密""、后期生气"的源储配置关系有利于吐哈盆地大范围发育以垂向近生气中心聚集的致密砂岩气藏。受喜马拉雅运动影响,吐哈盆地发育"过渡型"与"典型"型2种致密砂岩气藏类型。The Lower Jurassic in Tuha basin is characterized by large-scale coal-measure source rocks and directly contacting braided-del- ta sandstone, which created conditions to forming tight sandstone gas reservoir. This paper presents the geochemistry of source rocks and natural gas, the gas-conductivity modeling of different lithology source rocks, basinal simulation of gas-generating amount in the individual geohistory period, combined with the geologic factors of reservoir lithology, diagenesis evolution and fluid inclusion, etc. The results show that the coal measure strata of Lower Jurassic in this basin are far better than the mudstone in each index, being dominated gas source of the tight sandstone reservoir, starting gas generation from the Late Jurassic to Early Cretaceous and entering into peak value when the matu- rity is greater than 1.1%. Controlled by fast deep burial process and diagenetic compaction, the tightening time of the strata is in Late Juras- sic. So, such a source-reservoir assemblage relation of the first sand-tightening and later gas-generating is favorable for large-scale develop- ment of tight sandstone gas reservoir dominated by vertical accumulation near gas-generating center in Tuha basin. Also, influenced by Hi- malayan movement, there exist two types of tight sandstone gas reservoirs in this area, one is the transitional, and the other is the typical.

关 键 词：吐哈盆地 致密砂岩气藏 煤岩 生气强度 储集层演化 成藏模式 

分 类 号：TE112.43[石油与天然气工程—油气勘探]