川东石炭系尖灭带天然气聚集特征与勘探潜力  

Characteristics and Exploration Potential of Natural Gas Accumulations in Carboniferous Pinchout Belts in East Sichuan

作　　者：李伟[1] 张志杰[1] 汪洋[2] 张朝军[1] 

机构地区：[1]中国石油勘探开发研究院 [2]中国石油西南油气田公司

出　　处：《中国石油勘探》2015年第2期9-17,共9页China Petroleum Exploration

基　　金：中国石油勘探与生产分公司前期项目"四川盆地石炭系油气地质综合研究与有利区带优选"(2008D-0704-04)

摘　　要：四川盆地东部大面积发育石炭系尖灭带,这些尖灭带储层的非均质性强,形成了复杂的天然气聚集规律。通过近期的研究与勘探实践,认为川东石炭系黄龙组地层尖灭带受地层、岩性、构造、断裂等因素的控制,主要发育岩性—构造复合气藏、构造—岩性—地层复合气藏、岩性气藏。这些气藏受构造特征的影响,在褶皱强烈的地区形成以岩性—构造复合为主的天然气聚集模式,在宽缓斜坡区形成以岩性—地层为主的复合天然气聚集模式;认为地层尖灭带岩性气藏,由于其储层薄,不仅气藏规模小、个数多、常发育异常高压与异常超高压,展示出局部岩性封闭性极强的特征,其储层致密带的发育为构造围斜区大面积岩性圈闭的形成创造了有利条件;认为川东还存在广安—重庆石炭系西南部尖灭带、明月峡—涪陵北石炭系南部尖灭带、梁平古隆起东侧石炭系尖灭带及开县—马槽坝石炭系东北部尖灭带等4个有利勘探领域,这些区带不仅是川东石炭系以岩性—地层为主的复合圈闭的有利发育区,而且也是未来石炭系天然气勘探的重要新类型。Carboniferous pinchout belts developed in a large area in the eastern part of Sichuan Basin. The reservoirs of these pinchout belts are strongly heterogeneous, leading to a complex natural gas accumulation law. It is concluded that the stratigraphic pinchout belts of Carboniferous Huanglong Formation in East Sichuan are controlled by a series of factors, such as strata, lithologic characters, structural and fault, with development of lithologic-structural compound gas reservoirs, structural-lithologic-stratigraphic compound gas reservoirs and lithologic gas reservoirs. In the strongly folded areas, natural gas is accumulated mainly in a lithologic-structural compound pattern because these gas reservoirs are influenced by structural characteristics. In the wide and gentle slope areas, natural gas is accumulated mainly in a lithologic-stratigraphic compound pattern. It is also assumed that the lithologic gas reservoirs of stratigraphic pinchout belts are not only small-scale and numerous but also abnormally high and ultra abnormally high in pressure, showing the characteristic of strong regional lithologic closure. Development of compact belts of reservoirs creates the favorable conditions for large-area lithologic closure of the structural enclosing slope zones. It is concluded that four favorable exploration areas exist in East Sichuan – the Guang'an-Chongqing Carboniferous southwestern pinchout belt, the Mingyuexia-Peilingbei Carboniferous southern pinchout belt, the Carboniferous pinchout belt east of Liangping palaeo-uplift, and the Kaixian-Macaoba Carboniferous northeastern pinchout belt. These belts are not only the favorable development areas of Carboniferous lithologic-stratigraphic compound traps in East Sichuan but also the important new types of Carboniferous natural gas exploration in the future.

关 键 词：四川盆地 石炭系 黄龙组 地层尖灭带 天然气聚集 气藏类型 岩性气藏 岩性—构造复合气藏 构造—岩性—地层复合气藏 天然气聚集模式 勘探潜力 

分 类 号：P618.13[天文地球—矿床学]