低渗气井压力和产量递减规律及其影响因素

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

影响低渗气藏气井生产动态及递减规律的因素众多,区别各类因素的影响规律对预测气田生产动态、指导气田合理高效开发具有重要意义。将低渗气井压力和产量递减规律影响因素分为储层静态因素和生产动态因素两大类,结合实际气藏生产早期定产降压、后期定压降产的开发路线,分别研究了气井定产降压阶段压力递减特征及定压降产阶段产能递减特征,并基于数值模拟手段对其影响规律进行了综合分析。结果表明:气井生产早期压力递减规律主要受气井控制储量、配产、产水等因素影响;生产后期产量递减规律主要受渗流能力、井间干扰、产水等因素影响。同时,储层静态因素是气藏开发潜力的先决条件,而生产动态因素则往往可以通过合理的方法进行优化或调整以使气井达到最好的生产状态,在实际生产中需要做到"动静结合",根据气田的开发目标对各生产动态因素进行详细描述,指导调整生产制度或验证气藏认识的准确性。

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.