Anti-channeling methods for coalbed methane production using L-type horizontal wells

Authors

LIU Zhan, CBM Branch Company, PetroChina Huabei Oilfield Company, Changzhi 046000, ChinaFollow
ZHANG Qunxia, CBM Branch Company, PetroChina Huabei Oilfield Company, Changzhi 046000, China
GENG Yuxin, CBM Branch Company, PetroChina Huabei Oilfield Company, Changzhi 046000, China
LUO Dan, CBM Branch Company, PetroChina Huabei Oilfield Company, Changzhi 046000, China
WANG Minggang, CBM Branch Company, PetroChina Huabei Oilfield Company, Changzhi 046000, China

Abstract

Coalbed methane (CBM) production using L-type horizontal wells can yield stable single-well production of up to above 8 000 m³/d. However, due to the lack of sand settling pockets, L-type horizontal wells fail to achieve gas-water separation under the action of gravity. Consequently, gas channeling from tubing is prone to occur, significantly decreasing pumping efficiency and restricting further drainage and pressure reduction. By optimizing the lifting process for production in the early stage, the gas channeling from tubing has been somewhat alleviated. However, the anti-channeling effects remain unsatisfactory in low-fluid-pressure and high-yield gas wells. This study examined L-type horizontal wells in the Fanzhuang-Zhengzhuang block within the Qinshui Basin. Based on the changing patterns of gas and water in 56 wells subjected to gas channeling from tubing, this study established evaluation indicators for gas channeling severity. Using grey relational analysis, this study identified dominant factors influencing gas channeling from tubing, determining the causes. Furthermore, this study proposed two methods for preventing and controlling gas channeling from tubing to optimize the production system. Key findings are as follows: (1) The annular liquid column height in the wellbore is proved to be the prerequisite for gas channeling from tubing. Gas channeling from tubing can occur suddenly with a decrease in the liquid column height. Liquid column heights above 75 m suggest the absence of gas channeling or the occurrence of mild/moderate gas channeling primarily at the outlet, while those below 75 m are predominantly associated with severe gas channeling. Moreover, gas channeling severity increases exponentially with a decrease in the liquid column height. (2) The gas-liquid ratio is identified as a critical factor affecting gas channeling severity, which increases logarithmically with the former. Gas-liquid ratios below 30 suggest mild/moderate gas channeling primarily, whereas those above 30 are principally associated with severe gas channeling. (3) The pressure-controlled drainage method, by remaining constant high casing pressure, can effectively enhance the liquid holdup of the two-phase flow near the pump inlet. The production-controlled drainage method, by controlling the daily gas production, can reduce the gas-liquid ratio near the pump inlet to below 30. Both methods, which can effectively alleviate the gas channeling from tubing, combined with the anti-channeling lifting process for production, can jointly eliminate gas channeling from tubing.

Keywords

coalbed methane(CBM), L-type horizontal well, gas channeling from tubing, liquid column height, gas-liquid ratio, Fanzhuang-Zhengzhuang block, Qinshui Basin

DOI

10.12363/issn.1001-1986.23.10.0660

Recommended Citation

LIU Zhan, ZHANG Qunxia, GENG Yuxin, et al. (2024) "Anti-channeling methods for coalbed methane production using L-type horizontal wells," Coal Geology & Exploration: Vol. 52: Iss. 5, Article 9.
DOI: 10.12363/issn.1001-1986.23.10.0660
Available at: https://cge.researchcommons.org/journal/vol52/iss5/9

Reference

[1] 孟庆春，左银卿，周叡，等. 沁水盆地南部煤层气水平井井型优化及应用[J]. 中国煤层气，2010，7(6)：15−19.

MENG Qingchun，ZUO Yinqing，ZHOU Rui，et al. Optimization and application of horizontal CBM well in south of Qinshui Basin[J]. China Coalbed Methane，2010，7(6)：15−19.

[2] 贾慧敏，胡秋嘉，樊彬，等. 沁水盆地郑庄区块北部煤层气直井低产原因及高效开发技术[J]. 煤田地质与勘探，2021，49(2)：34−42.

JIA Huimin，HU Qiujia，FAN Bin，et al. Causes for low CBM production of vertical wells and efficient development technology in northern Zhengzhuang Block in Qinshui Basin[J]. Coal Geology & Exploration，2021，49(2)：34−42.

[3] 田江，霸振，陈志鑫，等. 沁水煤层气田L型水平井防窜气技术研究[J]. 中国煤层气，2017，14(6)：21−23.

TIAN Jiang，BA Zhen，CHEN Zhixin，et al. Research on L-type horizontal well anti-channeling technology in Qinshui coalbed methane field[J]. China Coalbed Methane，2017，14(6)：21−23.

[4] 张莹，韦乃详，刘姝祺，等. 泵外防气装置沉降部分数值模拟[J]. 科学技术与工程，2010，10(29)：7259−7262.

ZHANG Ying，WEI Naixiang，LIU Shuqi，et al. Simulating the numerical of subsidence section of the pump external defense installment[J]. Science Technology and Engineering，2010，10(29)：7259−7262.

[5] 崔金榜，孙泽良，朱庆忠，等. 煤层气无杆泵举升配套关键技术[R]. 长治：中国石油山西煤层气勘探开发分公司，2013.

[6] 原红超，安玉敏，张慧，等. 煤层气L型水平井无杆泵油水分离装置研发与应用[J]. 中国煤层气，2020，17(5)：28−30.

YUAN Hongchao，AN Yumin，ZHANG Hui，et al. Development and application of oil-water separation unit for rodless pump drainage technology in L-type horizontal well for coalbed methane[J]. China Coalbed Methane，2020，17(5)：28−30.

[7] 蔡华. 无杆举升工艺在煤层气井的适应性研究[J]. 中国煤层气，2021，18(5)：29−32.

CAI Hua. Adaptability research of rodless lifting technology in CBM wells[J]. China Coalbed Methane，2021，18(5)：29−32.

[8] 张鹏，王相春，封从军，等. 基于多因素的煤储层气水两相非稳态流入动态评价方法及应用[J]. 天然气地球科学，2023，34(9)：1641−1651.

ZHANG Peng，WANG Xiangchun，FENG Congjun，et al. Evaluation method and application of gas-water two-phase unsteady inflow performance of coal reservoir based on multiple factors[J]. Natural Gas Geoscience，2023，34(9)：1641−1651.

[9] SUN Zheng，SHI Juntai，WU Keliu，et al. Novel optimization method for production strategy of coal-bed methane well：Implication from gas-water two-phase version productivity equations[J]. Journal of Petroleum Science and Engineering，2019，176：632−639.

[10] SONG Hongwei，GUO Haimin，XU Sihui. Analysis of gas and liquid two-phase slug flow production logging interpretation model in near horizontal shale gas wells[J]. Open Journal of Yangtze Oil and Gas，2019，4(2)：100−112.

[11] SHU Yong，SANG Shuxun，ZHOU Xiaozhi，et al. A coupled hydraulic–mechanical model with two-phase flow for fracturing development of undersaturated coalbed me-thane reservoirs considering permeability velocity-sensitive damage[J]. Natural Resources Research，2023，32(5)：2053−2076.

[12] 韩悦，李梦杰. 垂直管内两相流流型的实验研究[J]. 当代化工，2016，45(8)：1697−1699.

HAN Yue，LI Mengjie. Experimental study on two phase flow pattern in vertical tube[J]. Contemporary Chemical Industry，2016，45(8)：1697−1699.

[13] 窦金宝. 气井井筒气液两相流动特性及临界携液模型研究[D]. 西安：西安石油大学，2020.

DOU Jinbao. Subject：A study of gas-liquid two-phase flow characteristics and critical liquid carrying model in wellbore[D]. Xi’an：Xi’an Shiyou University，2020.

[14] 杨通. 水平管内低含液率气液两相流流动特性数值模拟[D]. 西安：西安石油大学，2022.

YANG Tong. Numerical simulation of flow characteristics of gas-liquid two-phase flow with low liquid content in horizontal pipe[D]. Xi’an：Xi’an Shiyou University，2022.

[15] 董银涛. 煤层气直井井筒流动模型研究[D]. 北京：中国石油大学(北京)，2017.

DONG Yintao. Study on wellbore flow model of coalbed methane vertical wells[D]. Beijing：China University of Petroleum (Beijing)，2017.

[16] 黄思婧，侯大力，强贤宇，等. 致密砂岩气藏压裂直井气水两相产能评价新方法[J]. 非常规油气，2023，10(6)：68−74.

HUANG Sijing，HOU Dali，QIANG Xianyu，et al. A new method for evaluating the gas-water two-phase productivity of fractured straight wells in tight sandstone gas reservoirs[J]. Unconventional Oil & Gas，2023，10(6)：68−74.

[17] 罗程程，吴宁，王华，等. 水平气井气液两相管流压降预测[J]. 深圳大学学报(理工版)，2022，39(5)：567−575.

LUO Chengcheng，WU Ning，WANG Hua，et al. Pressure gradient prediction of gas-liquid two-phase pipe flow in horizontal gas wells[J]. Journal of Shenzhen University (Science and Engineering)，2022，39(5)：567−575.

[18] 刘羽珊. 高气液比倾斜管道气液两相瞬态流变化规律及携液研究[D]. 荆州：长江大学，2021.

LIU Yushan. Study on variation law of gas-liquid two-phase transient flow and liquid carrying in inclined pipeline with high gas-liquid ratio[D]. Jingzhou：Yangtze University，2021.

[19] 李紫晗，刘宇沛，张滨海，等. 临兴区块致密气井动态携液规律研究[J]. 非常规油气，2021，8(2)：80−87.

LI Zihan，LIU Yupei，ZHANG Binhai，et al. Study on dynamic liquid carrying law of tight gas wells in Linxing Block[J]. Unconventional Oil & Gas，2021，8(2)：80−87.

[20] LUO Chengcheng，CAO Yufeng，LIU Yonghui，et al. Experimental and modeling investigation on gas-liquid two-phase flow in horizontal gas wells[J]. Journal of Energy Resources Technology，2023，145(1)：013102.

[21] 胡秋嘉，贾慧敏，祁空军，等. 高煤阶煤层气井单相流段流压精细控制方法：以沁水盆地樊庄—郑庄区块为例[J]. 天然气工业，2018，38(9)：76−81.

HU Qiujia，JIA Huimin，QI Kongjun，et al. A fine control method of flowing pressure in single-phase flow section of high-rank CBM gas development wells：A case study from the Fanzhuang–Zhengzhuang Block in the Qinshui Basin[J]. Natural Gas Industry，2018，38(9)：76−81.

[22] 郑俊德，张洪亮. 油气田开发与开采：2版[M]. 北京：石油工业出版社，1997.

[23] 秦朝葵，高顶云. 天然气体积修正系数的计算方法[J]. 同济大学学报(自然科学版)，2004，32(1)：27−30.

QIN Chaokui，GAO Dingyun. Calculation of volume-correction coefficient of natural gas[J]. Journal of Tongji University，2004，32(1)：27−30.

[24] 白利娜，曾家瑶，高为. 基于灰色关联分析的盘关向斜煤层气有利井区优选[J]. 煤炭科学技术，2019，47(4)：169−173.

BAI Lina，ZENG Jiayao，GAO Wei. Optimization of favorable well for CBM based on grey correlation analysis in Panguan syncline[J]. Coal Science and Technology，2019，47(4)：169−173.

[25] 崔立伟，孙彦高，刘征. 煤层气井井筒流动状态研究[J]. 煤炭技术，2013，32(2)：82−84.

CUI Liwei，SUN Yangao，LIU Zheng. Study on shaft flow state of coalbed methane well[J]. Coal Technology，2013，32(2)：82−84.

[26] 胡秋嘉，毛崇昊，石斌，等. 沁水盆地南部高煤阶煤层气井“变速排采−低恒套压” 管控方法[J]. 煤炭学报，2019，44(6)：1795−1803.

HU Qiujia，MAO Chonghao，SHI Bin，et al. “Variable speed drainage-low casing pressure” control method of high rank CBM wells in South Qinshui Basin[J]. Journal of China Coal Society，2019，44(6)：1795−1803.

[27] 韩胜华，刘利梅，秦守栋，等. 电动潜油螺杆泵技术及应用[J]. 油气田地面工程，2009，28(4)：41.

HAN Shenghua，LIU Limei，QIN Shoudong，et al. Technology and application of electric submersible screw pump[J]. Oil-Gasfield Surface Engineering，2009，28(4)：41.

[28] 刘展，张雷，蒋轲，等. 煤层气多分支水平井产能影响因素及增产稳产对策：以鄂尔多斯盆地三交区块为例[J]. 天然气工业，2018，38(增刊1)：65−69.

LIU Zhan，ZHANG Lei，JIANG Ke，et al. Influencing factors of productivity of multi-branch horizontal wells in coalbed methane and countermeasures for increasing and stabilizing production：Taking Sanjiao Block in Ordos Basin as an example[J]. Natural Gas Industry，2018，38(Sup.1)：65−69.

[29] 李媛，郭大立，康芸玮. 融合注意力机制的煤层气产量动态预测[J]. 科学技术与工程，2023，23(2)：550−557.

LI Yuan，GUO Dali，KANG Yunwei. Dynamic prediction of coalbed methane production with attention mechanisms[J]. Science Technology and Engineering，2023，23(2)：550−557.

[30] 翟雨阳，胡爱梅，王芝银等. 韩城地区煤层气井合理动液面高度控制方法探讨[C]//中国煤炭学会煤层气专业委员会，中国石油学会石油地质专业委员会. 2011年煤层气学术研讨会论文集. 北京：地质出版社，2011：5.

[31] 李金平，潘军，李勇等. 基于流动物质平衡理论的煤层气井定量化排采新方法[J]. 天然气工业，2023，43(6)：87−95.

LI Jinping，PAN Jun，LI Yong，et al. A new CBM well quantitative production method based on the flow material balance theory[J]. Natural Gas Industry，2023，43(6)：87−95.