海陆过渡相地层有机质纳米孔成因及地质意义——以鄂尔多斯盆地东部山西组为例  

Genesis and geological significance of organic matter nanopores in transitionalfacie strata:a case study of the Shanxi Formation in eastern Ordos basin

作　　者：刘洪林[1,2,3] 邹辰 梅珏 张介辉 李晓波 LIU Honglin;ZOU Chen;MEI Jue;ZHANG Jiehui;LI Xiaobo(Research Institute Petroleum Exp.&Dev.,Petrochina,Beijing 100083,China;PetroChina Key Laboratory for Unconventional Oil and Gas,Beijing 100083,China;National Energy Shale Gas Research and Development(Experiment)Center,Langfang,Hebei 065007,China;Zhejiang Oilfield,Petrochina Company Limited,Hangzhou,Zhejiang 310023,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油非常规油气重点实验室,北京100083 [3]国家能源页岩气研发(实验)中心,河北廊坊065007 [4]中国石油浙江油田分公司,浙江杭州310023

出　　处：《地质学报》2022年第7期2562-2572,共11页Acta Geologica Sinica

基　　金：中国石油集团公司重大现场试验“深层页岩气有效开采关键技术攻关与试验”(编号2019F-31);中国石油科技开发项目“页岩气提高储量动用程度技术研究”(编号KT2021-11-02)资助成果。

摘　　要：海陆过渡相煤系地层已经发现丰富的非常规天然气资源。本文以鄂尔多斯盆地东部山西组煤系地层为例,通过开展微观特征分析及物理模拟实验,查明山西组主要孔隙类型为有机质孔隙、残余原生孔隙、不稳定矿物溶蚀孔、黏土矿物层间孔,认为黏土矿物层间孔和有机质纳米孔隙是页岩储集空间与常规砂岩储层的显著区别;山西组煤系地层广泛发育的有机质纳米孔,经过模拟实验认为形成于早期液态烃裂解气,随着原油沥青化,气泡被固化在沥青条带中形成纳米孔隙;集中发生在晚侏罗世至早白垩世末的异常热事件控制了裂解气生成的强度和范围,在此过程中沥青化产生的有机质纳米孔大幅度提高煤系地层非常规气储集空间和资源丰度。这一认识对于深入了解山西组煤系地层孔隙结构特征及非常规油气地质评价选区具有重要意义。Abundant unconventional natural gas resources have been found in coal measures deposited transitional facies in the Carboniferous-Permian strata.In this paper,the author has undertaken microscopic investigations and physical simulation experiments on Shanxi Formation in Ordos basin.The results indicate that the main pore types of the Shanxi Formation include organic matter pore,residual primary pore,unstable mineral dissolution pore and clay mineral interlayer pore.Interlayer pores of clay minerals and nanopores of organic matter are significant differences between shale and conventional sandstone reservoirs.Nanopores of organic matter are widely developed in coal measure strata of the Shanxi Formation.Through simulation experiments,it is believed that the formation process of nanopores is closely related to the cracking gas of early formed liquid hydrocarbon in strata.With the asphaltation of crude oil,bubbles solidified in asphalt strips and converted nanopores.From Late Jurassic to the end of Early Cretaceous,abnormal thermal events which controlled the generation intensity and scope of pyrolysis gas occurred widely in Ordos basin.During the process of asphalting,lots of organic matter nanopores formed,which greatly improved the resource abundance of unconventional gas in coal measures.This knowledge from the experiments could improve the understanding of the pore structure characteristics in coal measures and be helpful for the selection of unconventional oil and gas prospecting area in the Shanxi Formation.

关 键 词：鄂尔多斯盆地 石炭-二叠系 煤系 非常规天然气 异常热事件 

分 类 号：P618.13[天文地球—矿床学]