摘要
基于页岩气"源藏合一"的成藏模式——天然气源自页岩有机质(固态、液态)吸附、溶解及黏土矿物吸附的机制以及微裂缝、裂缝、页岩孔隙中的游离气成藏的认识,以四川盆地下二叠统为研究对象和实例,论证了同为烃源岩的碳酸盐岩(富含有机质的局限—开阔海台地相等的细结构—生物泥粒、泥粒—泥质灰岩、泥灰岩等)也应该具有天然气成藏的前景和可能。研究区下二叠统碳酸盐岩烃源岩发育,在栖霞组(P1q)和茅口组(P1m)都有分布;依据厚度较大、有机质丰度较高、有机质类型佳、有机质成熟度适中、埋藏较浅等特征,论证了其具备形成烃源岩气的有利条件及其勘探前景,并对埋深在2 000m左右的川东高陡构造区、川南泸州印支期古隆起区、川西南威远构造区进行了类比评估。最后,建议对泸州印支期古隆起区展开试探(可选择已钻井的P1m1、P1q1先行),待取得突破后,再扩大至威远构造区及川东高陡构造区。
Based on the understanding of the indigenous accumulation patterns of shale gas,i.e.generated from organic matters(in solid and liquid states) in shales and stored indigenously in the adsorbed state on organic matters and clay particles,in the dissolution state in liquids,or in a free state in microfracture,fracture and lamellation,this paper first discusses the possibility and the prospect of gas accumulation in another kind of source rock,i.e.organic rich carbonates of restricted open marine facies such as packstone,argillaceous limestone and marl,by taking the Lower Permian in the Sichuan Basin as an example.Source rocks are well developed in the Lower Permian carbonates in the study area such as the Qixia Formation(P 1 q) and the Maokou Formation(P 1 m).They are characterized by great thickness,high TOCvalues,good kerogen types,moderate organic maturity and shallow burial depth,all of which are favorable for source-rock gas accumulation.In this basin,the high-steep structural zone in the east,the Indosinian Luzhou uplift zone in the south and Weiyuan structural zone in the southwest with a burial depth of about 2000mare evaluated analogically.It is proposed to perform trial exploration first in the Indosinian Luzhou uplift zone(such as the drilled wells in P 1 m 1 and P 1 q1).After a breakthrough is obtained there,gas exploration will be then extended to other structural zones like the Weiyuan and other highsteep structures in West Sichuan Basin.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2012年第11期4-9,111-112,共6页
Natural Gas Industry
关键词
页岩气
吸附
游离
有机质
裂缝(岩石)
碳酸盐岩
烃源岩气
成藏模式
四川盆地
早二叠世
shale gas,adsorption,free,organic matter,fracture(geology),carbonates,source-rock gas accumulation pattern,Sichuan Basin,Early Permian
