基于测井信息的煤层顶板水平井抽采煤层气技术  

The coal seam roof strata-in horizontal well CBM gas drainage technology based on logging information

作　　者：巩泽文 贾建称 许耀波 石娟 GONG Zewen;JIA Jiancheng;XU Yaobo;SHI Juan(China Coal Research Institute,Beijing 100013,China;Xi'an Research Institute of China Coal Technology and Engineering Group Corporation,Xi'an,Shaanxi 710077,China)

机构地区：[1]煤炭科学研究总院 [2]中煤科工集团西安研究院有限公司

出　　处：《天然气工业》2021年第2期83-91,共9页Natural Gas Industry

基　　金：国家自然科学基金项目“碎软煤层顶板水平井穿层压裂裂缝扩展机理及形态控制研究”(编号:51874349);国家科技重大专项“碎软煤层煤层气分段压裂水平井抽采技术”(编号:2016ZX05045002-004)。

摘　　要：碎软煤层顶板水平井煤层气抽采技术目前尚处于发展初期,卡钻塌孔、加砂困难等问题频发,严重影响了煤层气的开发效果。为了提高碎软煤层水平井的成孔率和煤体改造效率、强化顶板水平井抽采工艺,以沁水盆地晋城矿区赵庄井田3号煤层为研究对象,综合利用井田测井信息,提出了一套基于测井信息的顶板水平井煤层气开发优化技术:利用声波测井资料,引入形变系数建立煤系有效应力测井解释公式,修正组合弹簧模型,解释井田X-01V井地应力,并通过井壁应力场分析,结合摩尔库伦理论和拉伸屈服准则,建立了X-01H井井壁稳定评价方法,得到X-01H井水平段安全钻井密度窗口介于1.15~1.81 g/cm^(3);完钻后利用随钻自然伽马数据,绘制X-01H井水平段泥质含量曲线和X-01H水平段与目标煤层相对位置曲线,优选泥质含量小于50%和井眼轨迹距离煤层小于1 m的位置,优化第3压裂段至第6压裂段射孔位置。现场应用效果表明,X-01H井水平段钻井周期为8 d,加砂完成率达110%,目前已累计产气168×10^(4)m^(3),日产气量最高达11000 m^(3)。结论认为,所建立的基于声波测井信息的井壁稳定评价方法+“双曲线”射孔位置优选法,对于指导碎软煤层顶板水平井煤层气开发具有良好的效果。The CBM drainage technology in horizontal well drilling in roof strata close to the broken and soft coal seams is still at its early stage.Such problems like sticking drill,hole collapse and difficulty in sand fracturing occur frequently,which affects the CBM gas development efficiency.In order to improve the pore forming rate of horizontal wells in roof strata close to the broken-soft coal seams and coal body transformation efficiency as well as to strengthen the roof horizontal-well drainage technology,we made a case study of the No.3 coal seam of the Zhaozhuang wellfield in the Jincheng of the Qinshui Basin.Through comprehensive utilization of wellfield logging data,we presented a set of CBM development optimization technology with horizontal well drilling in roof strata close to the broken-soft coal seams based on logging data.By using acoustic logging data and introducing deformation coefficient,we established the effective stress logging interpretation formula of coal measures,and modified the combined spring model to interpret the ground stress of Well X-01V.Then,according to the analysis of wellbore stress field,we integrated with the Mohr–Coulomb theory and tensile yield criterion to set up the wellbore stability evaluation method of Well X-01H,the safe drilling density window of which was obtained as 1.15–1.81 g/cm3.We plotted the mud content curves and relative position curves of Well X-01H horizontal sections and target coal seam according to the while-drilling natural gamma data.Finally,we optimized the perforation location of fracturing sections from 3rd to 6th while the shale content was less than 50%and the distance between well trace and coal seam was less than 1 m.After applying this technology during field operation 8 days later in the horizontal sections of Well X-01H,we achieved 168×10^(4)m^(3)coal seam gas in total with 110%as the completion rate of sand addition,and the highest daily production rate was up to 11000 m^(3).In conclusion,the established evaluation methodology of wellbore

关 键 词：碎软低渗透煤层 声波测井 地应力 顶板水平井 安全密度窗口 泥质含量 射孔优化 煤层气开发 沁水盆地 

分 类 号：TE37[石油与天然气工程—油气田开发工程]