贵州织金煤层气非储层水平井开发技术研究

Research on Non-reservoir Horizontal Well Development Technology of Zhijin Coalbed Methane Reservoir in Guizhou Province

直井开发煤层气钻井和压裂成本高,控制面积小,单井产气量低;煤层内水平井钻进难度大,风险高,薄煤层中井眼轨迹控制难度大,钻井液有害固相对储层伤害严重,采收率低。基于此,分析贵州织金区块煤系地质构造,提出在煤系地层内稳定的非储层内布水平井,通过压裂造缝沟通水平井上下煤层同时开发多层煤层的新思路。与常规开发方式相比,非储层内水平井具有钻井风险小、储层伤害小、单井产量高的优点,同时还可以开发煤系致密气和页岩气,提高非常规天然气利用率。研究非储层内水平井开发贵州织金煤层气技术,为解决贵州煤系地层煤层多而薄、层间距小等特性煤层气开发难题以及综合利用煤系气提供新的方式。

Drilling and fracturing come to high cost for vertical well in coalbed methane development with small control area and low production rate of single well; while for horizontal wells in coal seam, drilling is difficult with high risk and well bore trajectory control is difficult in thin coal seam, the harmful solid in drilling fluid has serious reservoir damage and the recovery factor is low. Based on the above, this paper analyzes the geological structure of coal measures in Zhijin block of Guizhou and puts forward a new way that horizontal wells are laid in stable non-reservoir of coal measure strata to get through the coal seams above and under the horizontal wells by hydraulic fracturing for multi coal seams development at the same time. Compared with the conventional development mode, the horizontal wells in non-reservoir have the advantages of small drilling risk, light reservoir damage and high production of single well; and at the same time, coal measure tight gas and shale gas can be developed to improve utilization ratio of unconventional gas. The research on the development technology of Guizhou Zhijin coalbed methane in non-reservoir with horizontal wells provides new way to solve the difficult development of coalbed methane in Guizhou coal measures strata with the characteristics of many thin coal seams and small interlayer spaces as well as the utilization of coal measures gas.