贵州省对江南井田地面煤层气抽采经济可行性研究

FEASIBILITY STUDY ON SURFACE EXTRACTION OF DUIJIANGNAN COAL FIELD CBM IN GUIZHOU PROVINCE

贵州省对江南井田煤层发育多,瓦斯含量高,煤层气资源量大,煤与瓦斯突出危险性高。采用体积法计算贵州省对江南井田主要可采煤层煤层气资源量,在评估前期抽采试验井效果的基础上,进行对江南井田煤层气抽采项目设计,并采用折现现金流量法对项目进行经济评价。研究结果表明:对江南井田资源潜力较好,资源量为31.05×10^(8) m^(3),资源丰度为1.56×10^(8) m^(3)/km^(2),是一个中型储量规模、中等丰度的煤层气田;煤层气井单井产气量高,最高可达1803.94 m^(3)/d,累计排采10年,综合抽采率为31.26%~32.54%,主采煤层M78含气量可降至8.0~13.5 m^(3)/t,抽采效果显著;开发项目经济评价各项指标良好,税后财务内部收益率为8.22%,略大于行业基准收益率,税后财务净现值91.42万元,大于0,税后投资回收期6.98年,略小于基准投资回收期,地面煤层气开发经济上可行。

Duijiangnan coal field in Guizhou province holds lots of coal beds with high content of methane,meaning abundant CBM resources,but high outbreak risk of CBM.This paper uses the volume method to estimate the CBM resources of minable coal beds,based on the prior extraction test.Extraction project is designed,and feasibility study is conducted by means of depreciated cash flow.Duijiangnan coal field is a medium sized CBM field with a resources potential of 31.05×10^(8) m^(3) and resources concentration of 1.56×10^(8) m^(3)/km^(2).Single well gains high production,up to 1803.94 m^(3)/d,and comprehensive extraction rate is 31.26%-32.54%with a mining life of ten years.CMB content of the major coal bed M78 may decrease to 8.0-13.5 m^(3)/t,with economic extraction.This development project has good economic indexes with intern return rate of 8.22% after tax,a bit over the basic return rate.Net present value after tax is 914.2 thousand Yuan,with a payback period of 6.98 years,less than the basic payback period.It is proved to be a feasible project.