四川盆地桐湾期古隆起震旦系储层沥青特征与天然气聚集机制  

Asphalt features and gas accumulation mechanism of Sinian reservoirs in the Tongwan Palaeo-uplift,Sichuan Basin

作　　者：李伟[1] 胡国艺[1] 周进高[1] 

机构地区：[1]中国石油勘探开发研究院

出　　处：《天然气工业》2015年第6期14-23,共10页Natural Gas Industry

摘　　要：四川盆地桐湾期古隆起震旦系近期获得了天然气勘探的新突破,但是对其天然气成藏机理的认识还存在着较多的争议。该古隆起震旦系储层普遍发育沥青,使得据沥青的发育规律来研究其古油藏与气藏的关系成为一种可能。为此,开展了针对该区震旦系储层沥青发育特征与规律的研究。结果表明:①古隆起震旦系储层沥青主要发育于四川盆地重要热液事件之后,即著名的二叠纪中晚期的峨眉地裂作用之后;②沥青的分布主要与印支期—燕山期古构造所控制的古油藏有关,这一时期的古构造高部位沥青含量较丰富;③桐湾期古隆起震旦系大规模的油气聚集发生于印支期—燕山期,形成了乐山—资阳古油藏与高石梯—磨溪—广安古油藏,这些古油藏主体部位原油的裂解控制了现今天然气藏的发育;④震旦系储层沥青的发育不仅反映灯影组古油藏的油气主要来自下寒武统烃源岩,而且还证明震旦系储层中聚集的天然气应为震旦系古油藏裂解晚期阶段的产物;⑤四川盆地印支期—燕山期震旦系的古构造是其古油藏发育的有利地区,寻找这一时期震旦系油气大规模聚集的区带,对开拓震旦系天然气勘探新领域具有重要的意义。Breakthroughs have been made in natural gas exploration in Sinian reservoirs in the Tongwan Palaeo-uplift, Sichuan Basin, recently. However, there are disputes with regard to the genetic mechanisms of natural gas reservoirs. The development law of asphalts in the Sinian reservoirs may play an extremely important role in the study of the relationships between palaeo oil and gas reservoirs. Accordingly, researches were conducted on the features and development patterns of asphalts in the Sinian reservoirs in this ar ca. The following research results were obtained. （1） Asphalts in the Sinian reservoirs were developed after the important hydrothermal event in the Sichuan Basin, namely the well-known E＇mei Fissure in the mid-late Permian Period. （2） Distribution of asphalts is related to palaeo oil reservoirs under the control of palaeo-struetures of Indosinian-Yanshan Period, when the palaeo-structures contained high content of asphalts in high positions of the palaeo uplift. （3） Large-scale oil and gas accumulations in the Sinian reservoirs occurred in the Indosinian-Yanshan Period to generate the Leshan-Ziyang and Gaoshiti Moxi-Guang＇an palaeo oil reservoirs. Cracking of crude oil in the major parts of these palaeo oil reservoirs controlled the development of the present natural gas reservoirs. （4） The development of asphalts in the Sinian reservoirs indicates that hydrocarbons in the Dengying Formation originated from Cambrian source rocks and natural gas accumulated in the Sinian reservoirs are products of late-stage cracking of the Sinian reservoirs. （5） The Sinian palaeo-structures of Indosinian-Yanshan Period in the Siehuan Basin are favorable regions for the development of the Sinian reservoirs, where discoveries and exploration practices will play an important role in the era of Sinian natural gas development in China.

关 键 词：四川盆地 桐湾期古隆起 震旦纪 储集层 沥青 热液作用 印支期—燕山期 古构造 古油藏 天然气聚集 

分 类 号：P618.13[天文地球—矿床学]