摘要
为客观评估地面井压裂抽采和衰竭期井下接替抽采效果,通过综合运用现场实测和数值模拟的方法,对影响地面井压裂抽采和井下接替抽采效果的主要因素进行了研究。结果表明,研究区最大水平主应力在9.27~15.38 MPa,最小水平主应力在5.51~8.54 MPa,垂直应力在9.58~14.96 MPa,属于典型的以自重应力为主的应力场。煤层气井水力压裂裂缝形态以垂直缝为主,水平裂缝方向在垂直于最大主应力方向发生压剪破坏,在垂直于最小主应力方向发生拉破坏。本文选择具有代表性的地面压裂抽采井作为研究对象,将地面井压裂抽采时期划分为增产期、稳产期和衰竭期,并优选出了活性水+氮气伴注的地面井压裂工艺,实现了27口改造井累计产气931万m^(3)。通过井下现场实测,发现井下接替钻孔实现了单孔纯流量达到0.012~0.028 m^(3)/min,同期地面井衰竭期井抽采纯量平均为0.081 m^(3)/min,井下3~7个接替钻孔抽采纯量与地面井衰竭期相同,达到同样的抽采效果,说明地面压裂井抽采取得了良好效果、井下接替抽采衔接良好。
In order to evaluate the drainage effectiveness of the on-land fracturing drainage and succeeded underground drainage for the exhaustion of the on-land wells,on site measuring and numerical modeling were carried out.As the results,key parameters and important factors that may influence the drainage of on-land wells and succeeded underground drainage holes were analyzed.The results showed that the maximum horizontal principal stress was between 9.27 and 15.38 MPa,the minimum horizontal principal stress was between 5.51 and 8.54 MPa,and the vertical stress between 9.58 and 14.96 MPa,which was a typical stress field dominated by self-weight stress.The fracture pattern of coal-bed gas well hydraulic fracturing was mainly vertical fracture,the horizontal fracture direction was vertical to the direction of the maximum principal stress,and the tension fracture direction was vertical to the direction of the minimum principal stress.On the basis of these understandings,27 on-land wells were selected for the strengthen drainage test.The wells were grouped into three stages of increasing yielding,stable yielding,and exhaustion,then the technique of activated water accompanying with nitrogen injection was implemented,leading to an accumulated drainage output for 9.31 million m^(3).The underground measure showed that the succeeded underground drainage holes got drainage flow rate of 0.012~0.028 m^(3)/min,while the on-land well achieved 0.081m^(3)/min at the same time.Three to seven underground drainage holes could succeed one on-land well in the exhaustion stage successfully.The result showed that the fracturing drainage and succeeded test achieved an approving effectiveness.
作者
崔宝库
何健
周建伟
汪开旺
Cui Baoku;He Jian;Zhou Jianwei;Wang Kaiwang(Methane Research Institute of Shanxi Lu’an Group Corporation Ltd.,Xiangyuan 046204,China;Methane Control Research center of Yuwu Coal Corporation Ltd.,Shanxi Lu’an Group,Changzhi Tunliu 046100,China;State Key Lab of Coal and Coalbed Methane Co-Mining,Jincheng 048000,China;China Coal Technology&Engineering Group Shenyang Research Institute,Fushun 113122,China;State Key Laboratory of Coal Mine Safety Technology,Fushun 113122,China)
出处
《煤炭与化工》
CAS
2021年第4期103-107,共5页
Coal and Chemical Industry
基金
“十三五”国家科技重大专项(2016ZX05067006-001)。
关键词
地面井压裂
抽采效果
衰竭期
接替抽采
裂隙分布规律
fracturing drainage
drainage effectiveness
stage of exhaustion
succeeded drainage
fracture distribution
