天然气工业2023，Vol.43Issue(12)：1-13,13.DOI:10.3787/j.issn.1000-0976.2023.12.001
四川盆地中西部区域性超压特征与天然气大规模聚集的关系
Relationship between regional overpressure characteristics and large-scale natural gas accumulation in the central and western Sichuan Basin
摘要
Abstract
Over the past two decades,large and super large gas fields have been discovered in the Sichuan Basin,but there are different opinions on the mechanism of large-scale natural gas accumulation,especially on how formation overpressure effectively promotes the formation of large gas fields,which has become an important research focus for geologists.Based on the measured formation pressure and drilling fluid density,this paper calculates and analyzes formation pressure coefficient and apparent formation pressure coefficient,and then combined with the geological conditions of natural gas accumulation and the development laws of gas reservoirs,discusses the basic characteristics of overpressure systems in the key areas in the central and western Sichuan Basin and their relationship with natural gas enrichment.And the following research results are obtained.First,overpressure is common in most areas of the Sichuan Basin except the piedmont fracture zone in the central and western Sichuan Basin and the Himalayan uplift fracture zone in the southwest,and the thickness of the overpressure formation ranges from 4 000 m to 8 000 m.Second,due to the widespread existence of overpressure,the regional direct cap rocks of large-scale natural gas accumulation become vague and unimportant,making it possible to form large-scale,large-area and multi-layer lithologic gas reservoirs.Third,the development of thick overpressure layers and faults within them promotes the large-scale accumulation of natural gas in multiple layers and multiple zones in the areas with abundant gas sources and relatively stable structures.In conclusion,the formation of thick layers overpressure in the relatively stable tectonic areas in the central and western Sichuan Basin is the important mechanism for the large-scale accumulation of natural gas in multiple layers and multiple zones.The regions with relatively low pressure coefficients in the interior of thick overpressure layers and strata below them are the most favorable for the formation of large gas reservoirs.关键词
四川盆地中西部/区域性超压/超压强度/超压层/超压封存/天然气大规模聚集Key words
Central and western Sichuan Basin/Regional overpressure/Overpressure strength/Overpressure layer/Overpressure storage/Large-scale natural gas accumulation引用本文复制引用
李伟,谢武仁,王雪珂..四川盆地中西部区域性超压特征与天然气大规模聚集的关系[J].天然气工业,2023,43(12):1-13,13.基金项目
中国石油天然气股份有限公司重大科技攻关项目"叠合盆地中下组合叠加地质构造与成因机制研究"(编号:2023ZZ0202). （编号:2023ZZ0202）
