Pressure and production decline laws of low-permeability gas wells and their influential factors

Production performance and decline laws of gas wells in low-permeability gas reservoirs are affected by multiple factors, so distinguishing the influential laws of each factor is significant to predict the production performance of gas wells and guide the efficient development of gas fields.The factors influencing pressure and production decline laws of low-permeability wells are divided into two types (i.e., static reservoir factors and dynamic production factors) based on the development concept of constant-production pressure dropping in the early stage of gas reservoir production and constant-pressure production decreasing in the late stage.Then, the influential laws were comprehensively analyzed by means of numerical simulation.It is indicated that pressure decline law of gas wells in the early stage of production is mainly affected by gas well controlled reserves, production proration and water production and that in the late stage is mainly dominated by seepage capacity, multi-well interference and water production.Static reservoir factors are prerequisite to the development potential of gas reservoirs, and dynamic production factors can be optimized or adjusted by means of rational methods so that gas wells will be in the best production state.In the actual production, static and dynamic factors shall be combined.It is necessary to describe the dynamic production factors in detail according to the gas field development target so as to provide the guidance for production system adjustment and verify the accuracy of gas reservoir understanding.