贵州省煤层气(瓦斯)开发适用性技术分析

Analysis of suitable development technology of CBM(gas) in Guizhou

近年来在煤层气勘探开发实践中遇到诸多技术瓶颈,针对其中关键技术适用性开发问题,基于贵州地区煤储层呈薄煤层群赋存且构造复杂的地质背景,结合贵州地区煤层气成功开发、利用案例,提出了适用于贵州复杂地质条件下的煤层气开发及利用技术。贵州地区不同薄煤层群可根据实际间距情况采用光套管合层压裂、可捞式桥塞分段压裂等技术,煤层松软地区要加强防煤粉压裂技术及缝内转向技术的综合利用;松软低透煤层群应优选首采层,采动卸压后瓦斯抽采效果较好,同时加强定向长钻孔"以孔代巷"、松软煤层全程下套管、低透煤层CO2相变致裂或水力割缝等技术的综合应用,实践证明可有效增强瓦斯抽采效果。

In recent years,technical bottlenecks have been encountered in the practice of CBM exploration and development in Guizhou Province,selecting suitable development technology is one of the key issues.Based on the background that CBM exists in thin coal seams and geological structures are complicated in Guizhou,combined with successful development and utilization of CBM,the CBM development and utilization technology suitable for complex geological conditions in Guizhou was put forward.Air drilling is recommended for drilling in Guizhou,according to different distance of thin seams,such as optical casing composite fracturing and salvageable bridge plug fracturing can be used.Comprehensive utilization of anti-pulverized coal fracturing technology and in-fracture steering technology should be strengthened in soft coal seams;First mining seam should be optimized for soft and low permeability coal seam group,CBM drainage effect is better after mining pressure relief.At the same time,the integral application of the techniques such as directional long borehole,"replacing roadway with hole",casing in whole soft coal seams,fracturing of low permeability coal seams by CO2 phase transition and hydraulic cutting should be enhanced.It is proved that the effect of gas extraction can be effectively enhanced.