煤层气井气水两相流产气通道导流能力分析  

Analysis of variable fracture flow conductivity of gas production channel at stage of CBM well air-water two-phase flow

作　　者：张芬娜[1] 李明忠[1] 綦耀光[1] 朱洪迎 陈波[1] 孟尚志 

机构地区：[1]中国石油大学(华东)机电学院,山东青岛266580 [2]中联煤层气有限公司,北京100108

出　　处：《辽宁工程技术大学学报（自然科学版）》2016年第4期347-352,共6页Journal of Liaoning Technical University (Natural Science)

基　　金：国家自然科学基金项目(51174224);国家科技重大专项项目(2011ZX05062-004);青岛市博士后资助项目(T1402021)

摘　　要：为分析煤层气井产能,基于煤层气井压裂后地层液渗流和管流模型,建立了气水两相流阶段下变裂缝变流量产气通道导流能力模型,并对排采阶段影响导流能力的因素进行了分析,提出了持液率是影响气水两相流阶段导流能力的重要因素.该模型为煤层气井产能的分析提供了重要依据.当持液率等于1时,该模型为单相水流阶段导流能力模型;当持液率等于0时,该模型为单相气体流动阶段导流能力模型;当计算模型中裂缝宽度变化函数为常数时,即为恒裂缝宽度导流能力模型;分析结果表明:煤层气井在气水两相流阶段其产气通道导流能力受持液率的影响,随着持液率增加,导流能力增加;气水两相流中水所占的比例越大其导流能力越大,即单相水流阶段比单相气体流动阶段产气通道的导流能力大,一方面煤层气的解吸产出使产气通道内持液率降低,产气通道的导流能力降低;另一方面煤层气的解吸产出时煤基质收缩,产气通道增大,其导流能力增加.故煤层气定量排采中可以设计合理的产气量使产气通道达到最佳的导流能力,以优化煤层气的排采制度.This paper established the diverting capacity modal of gas production tunnel of variable fracture and flow at the stage of air-water two-phase flow,and analyzed the factors which effected on diverting capacity at the stage of drainage, on the basis of percolation and conduit flow model in Fracture Stimulation of CBM Wells. The modal provided importance basis for the analysis of productivity of CBM wells. When liquid holdup was equal to 1,the modal was transformed to the diverting capacity modal at the stage of single-phase water. When liquid holdup was equal to 0,the modal was transformed to the diverting capacity modal at the stage of single-phase air. When variation function of fracture width was constant,the diverting capacity modal of gas production tunnel of fracture width was constant. These showed liquid holdup effected on the diverting capacity of gas production tunnel at stage air-water two-phase flow. The diverting capacity will be increased as liquid holdup increases. The greater proportion of water,the larger the diverting capacity. The diverting capacity modal of gas production tunnel at the stage of single-phase water was larger than that at the stage of single-phase air. Unstable drainage changed fluid phase in gas production tunnel. The change of fluid phase led to the change of diverting capacity. Continue and smooth decompression favored slow adjustment of CBM diverting capacity. It prevented damage due to the fluid phase sensitive which was caused by rapid decrease of diverting capacity from the stage of single-phase water to the stage of single-phase air.

关 键 词：煤层气井 气水两相流 变裂宽 导流能力 产气通道 

分 类 号：P618.11[天文地球—矿床学]