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 above 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 overlying 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 formation of free gas.Karst and fissures acting as the reservoir space are well developed in the limestone layers in Taiyuan Formation.The overlying mudstones can work as good cap rocks.Thus，the Taiyuan Formation has the material fundament for the formation of carbonate gas reservoir in coal measures.Besides，the formation of the carbonate gas pool in coal measures needs good matching of geological factors.The development of reservoir space and trap widely occurring in the coal-bearing basins in North China is the prerequisite，while the late-stage gas accumulations are the key.The local uplift in a regional extensional background in the basins，as well as the mining activities accompanied by decreasing reservoir pressure，are helpful to the migration and accumulation of the coal measures gas to the carbonate reservoir.

0 引言

1 霍西煤田实例及启示

2 太原组空间展布规律

3 太原组烃源岩和热演化程度

4 太原组灰岩储集空间

5 盖层条件

6 圈闭、运移和保存条件

7 结论