煤系碳酸盐岩天然气勘探前景初探--以华北太原组为例  

Preliminary study on exploration prospect of carbonate gas in coal measures:a case study of Taiyuan Formation in North China

作　　者：王瑞瑞 傅雪海[1,2] 张宝鑫[1,2] 冯嘉楠 李伟松 WANG Ruirui;FU Xuehai;ZHANG Baoxin;FENG Jia’nan;LI Weisong(Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,Ministry of Education of China,Xuzhou 221008,China;School of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221116,China;Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;Sichuan Province Coalfield Geological Bureau One Hundred Forty-one Team,Deyang 618000,China;Shaanxi Geology and Mining Group Co.,Ltd.,Xi’an 710054,China)

机构地区：[1]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]中国地质科学院地质研究所自然资源部深地动力学重点实验室,北京100037 [4]四川省煤田地质局一四一队,四川德阳618000 [5]陕西地矿集团有限公司,陕西西安710054

出　　处：《煤炭科学技术》2021年第12期138-149,共12页Coal Science and Technology

基　　金：江苏省自然科学基金青年基金资助项目(BK20180665);中国博士后科学基金资助项目(2019M652014);自然资源部深地动力学重点实验室开放基金。

摘　　要：煤系碳酸盐岩天然气的勘探前景是值得探究的重要问题,以华北太原组为例进行初步研究分析。太原组是华北最有利的生烃岩系之一,煤层之上发育多套灰岩。近年来,丰富的太原组碳酸盐岩天然气资源在山西霍西煤田被发现,该发现可为今后煤系碳酸盐岩天然气的勘探提供启示。首先剖析了霍西煤田太原组碳酸盐岩气藏实例,其次对太原组灰岩的空间展布规律、太原组烃源岩和热演化程度、灰岩储层发育、盖层、圈闭、运移和保存条件进行了总结。研究认为,太原组煤层-灰岩沉积组合与其上的多套泥岩和煤层可以组成生储盖组合,而储层的近烃源岩优势使得煤系气易于在太原组灰岩中聚集。从太原组煤和灰岩厚度分布特点来看,北部煤层厚而灰岩薄,南部煤层薄而灰岩厚。从烃源岩角度来看,太原组煤层和暗色泥岩是优质的烃源岩,而中等变质程度的煤有利于游离的煤成气的形成。从储集空间来看,华北许多地区太原组灰岩普遍具有较好的岩溶和裂隙储集空间发育。从封盖条件看,太原组灰岩层上覆的泥岩可作为良好的盖层。因此,太原组具有煤系碳酸盐岩气藏形成所需的物质基础。此外,华北太原组煤系碳酸盐岩气藏的形成需要多个地质要素在时间与空间上相互匹配。煤系碳酸盐岩储集空间和圈闭的发育是气藏得以形成的前提,晚期成藏是气藏能否形成的关键。华北主要含煤盆地均广泛发育圈闭,而盆地新生代总体伸展背景下的局部隆升以及现今煤矿采动导致的储层压力降低都可能有利于煤系气向煤系碳酸盐岩储集空间中运移和聚集。The exploration potential of carbonate gas in coal measures is still rarely studied.A case study of Taiyuan Formation is presented here.The Taiyuan Formation is one of the most favorable hydrocarbon-generating deposits in North China,and several limestone layers a-bove the coals are well-developed in this formation.In recent years,Taiyuan Formation limestone gas is discovered in Huoxi Coalfield in the North China Block.This discovery can provide us in the future with significant inspiration in the exploration of carbonate gas in the coal measures.In this study,the case of Taiyuan Formation limestone gas was initially analyzed.Then,the distribution of limestone layers of Taiyuan Formation,source rocks and their thermal evolution,reservoir space of the limestone,cap rocks,trap development,migration and preservation conditions are summarized.The preliminary understandings are as follows.The coals,limestones in Taiyuan Formation and over-lying mudstones can make up source-reservoir-cap assemblages.As the limestones are close to the coals,gas in the coal measures can be easily accumulated in the limestone layers.As for the thickness of coals and limestones in Taiyuan Formation,the northern part of North China is characterized by thick coals and overlying thin limestones,while the south part by thick limestone and underlying thin coals.The coals and dark mudstones in Taiyuan Formation are premium source rocks,and coals of moderate metamorphism are in favor of the forma-tion of free gas.Karst and fissures acting as the reservoir space are well developed in the limestone layers in Taiyuan Formation.The overly-ing mudstones can work as good cap rocks.Thus,the Taiyuan Formation has the material fundament for the formation of carbonate gas reser-voir in coal measures.Besides,the formation of the carbonate gas pool in coal measures needs good matching of geological factors.The de-velopment of reservoir space and trap widely occurring in the coal-bearing basins in North China is the prerequisite,while the late-stage gas accum

关 键 词：煤系碳酸盐岩 天然气 太原组 霍西煤田 华北板块 

分 类 号：TE122[石油与天然气工程—油气勘探]