寺河井田穿煤柱下组煤煤层气水平井钻井技术研究  

Drilling technology of CBM horizontal wells through coal pillar lower coal group in Sihe minefield

作　　者：苏善博 张培河[1,2] 李林 降文萍 王正喜 SU Shanbo;ZHANG Peihe;LI Lin;JIANG Wenping;WANG Zhengxi(China Coal Research Institute,Beijing 100013,China;Xi’an Research Institute(Group)of China Coal Technology and Engineering Corp.,Xi’an 710076,China)

机构地区：[1]煤炭科学研究总院,北京100013 [2]中煤科工西安研究院(集团)有限公司,陕西西安710076

出　　处：《煤炭工程》2023年第3期78-83,共6页Coal Engineering

基　　金：山西省科技重大专项项目(20201102001);中煤科工集团西安研究院有限公司科技创新基金(2020XAYJS09)。

摘　　要：下组煤煤层气超前预抽已成为煤矿区煤与煤层气共采的重要任务。以寺河井田为例,通过分析3号煤层采动卸压后下伏岩层应力分布、裂隙演化及渗透率变化规律,研究了通过地面抽采下煤组煤层气降低瓦斯含量的可行性,开展了下组煤地面煤层气抽采井位部署方法、钻井技术工艺及关键排采技术等研究。结果表明:下组煤15号煤层渗透率增加约2.20倍,有利于15号煤层进行地面煤层气预抽;根据煤层气开发工程要求,按照地面井下综合分析的方法,优化部署了穿煤柱下组煤水平井煤层气抽采井位,设计了三开钻井井身结构,优化了井眼轨迹设计及钻井轨迹控制技术,研究了不同钻井层段的钻井液体系、裂隙发育段堵漏及分级固井工艺等钻井技术;为有效减少L型水平井排采中管柱磨阻,采用“大井扶斜正+双保接箍防偏磨+导向器降扭矩”工艺。所实施的穿煤柱下组煤水平井,最高日产气量9522 m^(3),14个月内累计产气量220万m^(3),产气效果理想,证明了技术工艺的可行性。Pre-extraction of CBM from the lower coal group has become an important task for coal and CBM co-mining.Taking Sihe Mine as an example,the stress distribution,fracture evolution and permeability change of the underlying strata of No.3 coal seam after mining pressure relief were analyzed.The feasibility of reducing gas content by surface extraction of CBM from the lower coal group was studied,and research on the deployment method of surface extraction CBM wells from the lower coal group,drilling techniques and drainage key technologies were carried out.The results showed that the permeability in No.15 lower coal group was increased by about 2.20 times,which is beneficial to the surface CBM advanced extraction of No.15 coal seam.According to the requirements of CBM development project,based on the method of comprehensive analysis of surface wells,the deployment of CBM extraction wells in the horizontal wells of the lower coal group through the coal pillar was optimized,the structure of the three section drilling well body was conceived,the design of borehole trajectory and drilling trajectory control technology was evaluated,and drilling technologies such as drilling fluid system,leak plugging and graded cementing process of fracture development section for different drilling layers was investigated.In order to effectively reduce the wear resistance of the string in the drainage of L-shaped horizontal wells,the technology of“well buttoning positive+two-way protection rod collar prevention eccentric wear+guider torque reduction”was adopted.The maximum daily gas output of the horizontal well through coal pillar of the lower coal group was 9522 m^(3),and the cumulative gas output is 2.2million m^(3) within 14 months,the gas production effect was ideal.

关 键 词：采动卸压 下组煤 煤层气 水平井 钻井技术 

分 类 号：TD713[矿业工程—矿井通风与安全]