煤田地质与勘探2024，Vol.52Issue(5)：77-87,11.DOI:10.12363/issn.1001-1986.23.10.0660
煤层气L型水平井防窜气排采控制方法研究
Anti-channeling methods for coalbed methane production using L-type horizontal wells
摘要
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-chan-neling effects remain unsatisfactory in low-fluid-pressure and high-yield gas wells.This study examined L-type hori-zontal 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 channel-ing 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 chan-neling 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 pre-dominantly associated with severe gas channeling.Moreover,gas channeling severity increases exponentially with a de-crease in the liquid column height.(2)The gas-liquid ratio is identified as a critical factor affecting gas channeling sever-ity,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 re-duce the gas-liquid ratio near the pump inlet to below 30.Both methods,which can effectively alleviate the gas channel-ing from tubing,combined with the anti-channeling lifting process for production,can jointly eliminate gas channeling from tubing.关键词
煤层气/L型水平井/油管窜气/液柱高度/气液比/樊庄-郑庄区块/沁水盆地Key words
coalbed methane(CBM)/L-type horizontal well/gas channeling from tubing/liquid column height/gas-liquid ratio/Fanzhuang-Zhengzhuang block/Qinshui Basin分类
能源科技引用本文复制引用
刘展,张群霞,耿宇欣,罗丹,王铭刚..煤层气L型水平井防窜气排采控制方法研究[J].煤田地质与勘探,2024,52(5):77-87,11.基金项目
中国石油华北油田公司山西煤层气勘探开发分公司科技项目(2023-Ⅰ-14) （2023-Ⅰ-14）
