气藏开发过程中渗流可逆性研究

储层气体渗流能力是决定气井产量和气田经济效益的重要因素。为此，提出了气藏开发过程中渗流可逆性的概念，并分析了渗流可逆性的影响因素，指出储层条件(储层介质类型、渗透率和非均质性)、地层水（边底水和层间水）、外来工作液、反凝析、应力敏感、出砂、硫沉积和结蜡是气藏开发中影响渗透率可逆性的主要因素。通过定义渗透率降低指数和渗透率恢复指数进行了各单因素的可逆性评价，随后采用模糊数学方法对气藏开发过程中渗流可逆性进行了综合评价，确定了可逆性评价因素集和评语集，并根据各因素对渗透率可逆性的影响程度，采用层次分析法确定了各评价因素的权重。基于上述分析建立了渗流可逆性评价方法，并对克拉2气田的渗流可逆性进行了实例评价，其结果显示克拉2气田渗流可逆性程度较高。

REVERSIBILITY OF GAS FLOW THROUGH POROUS MEDIA DURING THE RECOVERY PROCESS

The capacity of gas flowing through porous formation is a key factor affecting single well production and economic benefit of the gas field. In this paper, the concept of flow reversibility during the recovery of gas reservoirs was put forward with analysis of relevant factors, which mainly included reservoir conditions (type of the reservoir media, permeability and heterogeneity), formation water (edge, bottom and interlayer water), added operating fluids, retrograde condensation, stress sensitivity, sanding, sulphide deposit and paraffin deposit, etc. Reversibility analysis was conducted for individual factor based on the definition of permeability reduction index and recovery index. Moreover, comprehensive analysis has been done for reversibility of gas flowing through the porous media during the recovery of gas reservoirs by fuzzy mathematics. Collections of affecting factors and analyzing comments were also resulted. In addition, based on their reacting levels on permeability reversibility, weight of the affecting factors was identified through the analytical hierarchy process. As result of the study, an analyzing method of permeability reversibility was established and practiced by the application in Kela-2 gas field.