沁水盆地南部煤层气井支撑剂回流原因分析及治理措施探讨

Reason Analysis and Control Measures of Proppant Backflow for CBM Wells in South Qinshui Basin

煤层气井需要通过压裂措施改造储层,压裂过程中普遍使用石英砂作为支撑剂。在排采过程中会发生支撑剂回流,导致卡泵、砂埋管柱等生产现象发生,影响了排采连续性。为了防止排采过程中发生支撑剂回流现象,分析统计了樊庄区块近5年来的检泵原因,发现支撑剂回流的主要发生在排水段、控压产气段和稳产段,总结了三个阶段气水产出规律及支撑剂回流的原因。提出了使用低密度支撑剂、在近井地带形成遮挡层、合理控制排采强度、使用防砂泵等措施应对支撑剂回流的影响。该类措施有效减少了樊庄区块支撑剂回流现象,可以在其他同类区块推广应用。

CBM wells need to transform reservoir by fracturing measures,and the quartz sand are usually used as proppant in the process of fracturing. However,during the drainage process,the backflow of proppant will occur and result in the stuck pump and burial of pipe string,which affect the continuous drainage of gas. In order to prevent the proppant backflow occurred in the drainage process,the paper analyzes the reasons of pump inspection during recent five years in Fanzhuang Block,and figures out that the proppant backflow mainly occurred during the periods of water drainage,pressure control and gas production,and stable production. It summarizes the rules of water and gas drainage and the reasons of proppant backflow in the three periods. It also proposes that measures could be taken to prevent the influence of proppant backflow,inlduing to use low density proppant,form barrier near wellbore,and control the intensity of production,and apply sand control pump. These control measures have reduced the situation of proppant backflow in Fanzhuang Block,and can be promoted in other similar blocks.