渭北地区小曲率半径定向煤层气井优化设计及应用
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摘要
鄂尔多斯盆地东缘渭北地区传统定向煤层气井面临抽油杆偏磨、压裂改造效果差、单井产量低等技术瓶颈,通过对该地区煤层地质特点的深入剖析和评价,提出了适合渭北煤层气老井改造的小曲率半径定向井布井方案。在考虑排水采气等煤层气井的特殊条件下,建立了小曲率半径定向井轨迹优化设计模型,并进行了配套定向钻井工具优选。研究结果表明:通过集成应用分段压裂改造技术,小曲率半径定向井纵向上可开采3号、5号、11号三层煤,横向上可在主力11号煤层形成有效的压裂缝网,单井控制面积与常规定向井相比提高37.76%,产气量提高25%;从煤层气排采工艺角度出发,若井口能够产生1.5 MPa稳定套压,沉没度可满足常规杆式泵正常排采作业要求;小曲率半径定向井最优造斜率为11.5°/30 m,需配置1.55°及以上单弯螺杆钻具组合进行定向施工,且139.7 mm套管能够顺利下入。
The traditional directional wells in Weibei area, eastern Ordos gas field are faced with the technical bottleneck of eccentric wear of sucker rod, poor effect of fracturing reconstruction and low production of single well. Through in-depth analysis and evaluation on the characteristics of coal geology of the area, small radius directional well drilling scheme suitable for Weibei coal seam gas wells transformation was put forward. Considering the special conditions of CBM wells such as drainage and gas recovery, the optimal design model of small radius directional well trajectory was established, and the optimization of directional drilling tools was also carried out. The results show that through the integrated application of staged fracturing technique, directional wells with small curvature radius could use seams 3, 5 and 11 vertically, an effective pressure fracture network could be formed in the main coal seam 11 horizontally, controlled area of single well increased by 37.76% and gas production increased by 25% compared to conventional directional wells; From the point of view of CBM drainage technology, submergence depth could meet the requirements of normal discharge operation of conventional rod pump if the wellhead produced stable casing pressure of 1.5 MPa; The optimal slope of small curvature radius directional well was 11.5°/30 m, and it is necessary to configure directional drilling with single curve screw drill assembly of 1.55 degree or more, and the 139.7 mm casing can be tripped in smoothly.
The traditional directional wells in Weibei area, eastern Ordos gas field are faced with the technical bottleneck of eccentric wear of sucker rod, poor effect of fracturing reconstruction and low production of single well. Through in-depth analysis and evaluation on the characteristics of coal geology of the area, small radius directional well drilling scheme suitable for Weibei coal seam gas wells transformation was put forward. Considering the special conditions of CBM wells such as drainage and gas recovery, the optimal design model of small radius directional well trajectory was established, and the optimization of directional drilling tools was also carried out. The results show that through the integrated application of staged fracturing technique, directional wells with small curvature radius could use seams 3, 5 and 11 vertically, an effective pressure fracture network could be formed in the main coal seam 11 horizontally, controlled area of single well increased by 37.76% and gas production increased by 25% compared to conventional directional wells; From the point of view of CBM drainage technology, submergence depth could meet the requirements of normal discharge operation of conventional rod pump if the wellhead produced stable casing pressure of 1.5 MPa; The optimal slope of small curvature radius directional well was 11.5°/30 m, and it is necessary to configure directional drilling with single curve screw drill assembly of 1.55 degree or more, and the 139.7 mm casing can be tripped in smoothly.
引文
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[3]王西民.煤层气丛式井钻进工艺[J].煤炭技术,2009,28(2):130–131.WANG Ximin.Drilling technology of CBM cluster wells[J].Coal Technology,2009,28(2):130–131.
[4]乔磊,申瑞臣,黄洪春,等.沁水盆地南部低成本煤层气钻井完井技术[J].石油勘探与开发,2008,35(4):482–486.QIAO Lei,SHEN Ruichen,HUANG Hongchun,et al.Research on low-cost CBM drilling and completion technology in southern Qinshui basin[J].Petroleum Exploration and Development,2008,35(4):482–486.
[5]邓钧耀,张毅,纪元,等.鄂尔多斯盆地东缘煤层气钻井实践与认识[J].煤田地质与勘探,2017,45(2):157–162.DENG Junyao,ZHANG Yi,JI Yuan,et al.Practice and understanding of CBM drilling in the eastern margin of Ordos basin[J].Coal Geology&Exploration,2017,45(2):157–162.
[6]邱勇凯.渭北地区煤层气储层物性特征及控制机理[D].北京:中国地质大学(北京),2015.
[7]薛光武,刘鸿福,要惠芳,等.渭北盆地韩城开发区煤层气储层特征分析[J].太原理工大学学报,2012,43(2):185–189.XUE Guangwu,LIU Hongfu,YAO Huifang,et al.Characteristics of CBM reservoirs in Hancheng development zone,Weibei basin[J].Journal of Taiyuan University of Technology,2012,43(2):185–189.
[8]饶孟余,江舒华.煤层气井排采技术分析[J].中国煤层气,2010,7(1):22–25.RAO Mengyu,JIANG Shuhua.Analysis of coalbed methane well extraction technology[J].China Coalbed Methane,2010,7(1):22–25.
[9]张胜杰,汪旭伟.利用修正的三点定圆法计算单弯螺杆造斜率及其应用[J].内蒙古石油化工,2015,41(1):35–36.ZHANG Shengjie,WANG Xuwei.Calculation of draft-making rate of single-bend screw and its application by modified three-point fixed circle method[J].Inner Mongolia Petrochemical Industry,2015,41(1):35–36.
[10]刘修善.导向钻具几何造斜率的实用计算方法[J].天然气工业,2005,25(11):50–52.LIU Xiushan.Practical calculation method of geometrical production slope of guided drill[J].Journal of Gas Industries,2005,25(11):50–52.
[11]冯东海.水平井固井关键技术探讨及应用分析[J].西部探矿工程,2017,29(7):92–95.FENG Donghai.Discussion and application of key techniques for cementing of horizontal wells[J].Journal of Western Exploration,2017,29(7):92–95.
[12]杨决算,梁勇,高大勇,等.鲁迈拉定向井钻井设计优化与应用[J].探矿工程(岩土钻掘工程),2016,43(11):32–35.YANG Juesuan,LIANG Yong,GAO Dayong,et al.Optimization and application of drilling design in the Rumaila directional wells[J].Exploration Engineering(Rock&Soil Drilling and Tunneling),2016,43(11):32–35.