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为了探讨煤层气井排采控制指标,以沁水盆地南部高阶煤为研究对象,基于气-水相对渗透率试验和渗流物理仿真模拟,探讨了宏观与微观渗流网络中气-水相对渗透率变化机制,并进一步阐述了煤储层气、水产出过程。结果表明,宏观裂隙气-水相渗曲线分为气-水同流区和纯气流动区;微观孔裂隙气-水相渗曲线分为单相水流区、气-水同流区和纯气流动区。煤储层流体产出过程可归纳为开发初期宏观裂隙中水带气的过程,微观孔裂隙中水的单相流动阶段,气相饱和度上升阶段,气驱水的过程,气的单相流动阶段,以及宏观裂隙中气的单相流动阶段。其中,微观孔裂隙中气驱水的过程是高产气井稳定产液的关键,而游离气产出则是煤层压力整体下降的基础。
In order to explore the control index of CBM well drainage, taking the high-rank coal in southern Qinshui Basin as the research object, the relative permeability-permeability changes in macro and micro seepage networks were discussed based on the test of gas-water relative permeability and the simulation of seepage flow Mechanism, and further elaborated coal reservoir gas, aquatic products process. The results show that the macroscopic fissure gas-water permeability curve is divided into gas-water concentric zone and pure gas flow zone. The microscopic pore fissure gas-water permeability curve is divided into single-phase water flow zone, gas-water co-flow zone and pure gas Flow area. The process of fluid production in coal reservoirs can be summarized as the process of water vapor in the macroscopic fissures at the initial stage of development, the single-phase flow of water in the micro-pore fissures, the rising phase of gas saturation, the process of gas flooding and the single phase flow of gas , And the single-phase flow of gas in the macro-fracture. Among them, the process of gas-driven water in the fracture of micro-pores is the key to stabilize liquid production in high production gas wells, while the output of free gas is the basis of the overall decline of coal seam pressure.