致密砂岩气藏产水机理及其对渗流能力的影响

致密砂岩气藏具有低孔、低渗，储层物性差，非均质性强等地质特征，在岩性构造背景下，气水关系复杂，地层中气水赋存状态多样。烃类充注成藏时，很难将地层中的水完全驱替出来，会有部分滞留水残存在地层中。对于不存在边底水、层间水等自由水的致密砂岩气藏，储层中的可动水是气井产水的主要来源。气井见水将严重影响气井的产能和泄流半径，导致井底压力和产量迅速下降，生产压差和废弃压力显著增加，缩短了气井生产周期。为此，调研了国内外学者对致密砂岩储层可动水赋存状态和产出机理、可动水产出规律及控制因素、可动水对储层渗流能力影响等多方面的研究方法及成果，在分析和总结目前研究成果的基础上，针对致密砂岩气藏开发过程中的产水问题及其对开发的影响，提出了下一步的研究方向及改进建议，以期改善致密砂岩气藏的开发效果，提高最终采出程度。

Water production mechanism of tight sandstone gas reservoir and its influence on percolation capacity

Tight sandstone gas reservoirs have low-porosity, low-permeability, poor reservoir properties and strong heterogeneity. Under the gentle structure background, the gas-water relationship is complex, and the occurrence of water in the stratum is diverse. When hydrocarbons fill into stratum, it’s difficult to displace the water completely, some of the water remained. For some tight sandstone gas reservoirs where there is no free water, the movable water in the formation is the main source of water production. Water appears in the gas well will seriously affect the productivity and discharge radius of gas wells, leading to a rapid decline in bottom hole pressure and production, increasing production pressure difference and waste pressure significantly, shortening the life cycle about gas well and reducing the final recovery of gas reservoirs. This paper investigates the research of scholars at domestic and foreign, including occurrence and outputs mechanism of movable water, production rules and controlling factors of movable water, influence of movable water on reservoir percolation capacity. According to the understanding of the current research results, the next research direction and suggestions for improvement of production measures are proposed to improve the development effect of tight sandstone gas reservoirs and the final recovery.