煤层气开发中的层间矛盾问题--以柳林地区为例

Interlayer contradiction problem in coalbed methane development: a case study in Liulin area

直井分层压裂及合层排采能有效降低煤层气勘探开发成本,提高煤层气产能,但层间矛盾的干扰制约了这一排采工艺的推广。借鉴常规油气层间矛盾问题相关理论,首次提出并总结了煤层气开发中层间矛盾的概念、特点和影响因素。通过分析柳林地区典型井产能曲线特征,剖析了该区层间矛盾的特征和原因。结果表明:柳林地区合层排采太原组煤层(8号+9号)和合层排采山西组与太原组煤层(3号+4号+5号与8号+9号)时,层间矛盾问题严重;引起该层间矛盾的原因有煤层物性特征和煤层顶底板水文地质条件因素,其中8号煤层顶板水文地质条件是引发该区层间矛盾的主要因素。

The implement of separate layer fracturing and multiple layers drainage for vertical CBM wells is an ef- fective method to reduce costs of exploration and development, and to increase productivity. Based on theories of conventional reservoirs, the concept, characteristics and influence factors of interlayer contradiction in CBM de- velopment are firstly proposed and summarized. Features of typical production curves in Liulin area are analyzed, and characteristics and reasons of interlayer contradiction and development suggestions are given. The result shows that the interlayer contradiction is serious when coal seams（No.8＋9） in Taiyuan Formation and seams （No.3＋4＋5） in Shanxi Formation are drained. Property characteristics of coal seams and hydrogeological conditions of roof and floor are two factors for interlayer contradiction in the area, of which the later is the main factor.