川西坳陷新场气田沙二段气藏储层物性与渗流特征

为了分析新场气田沙二段气藏不同砂组之间产能差异较大的原因,本文利用物性分析和气水两相渗流实验,对覆压渗透率和气水两相渗流特征进行了评价和研究。结果表明,常规岩心物性证实主力层和难采层砂组渗透率平均值基本接近,但在覆压条件下,主力层和难采层渗透率差异明显;黏土矿物含量越高且产状越复杂,喉道越细小,喉道闭合越大,渗透率降低幅度越大,应力敏感性越强。难采层气相相对渗透率最大值低,临界含水饱和度高,水相上升快且相对渗透率最大值比主力层高。在开发过程中,难采层气井见水早,产水量比主力层大,井底积液、水锁伤害比主力层严重。

Reservoir physical properties and seepage characteristics of the second member of Shahejie formation in Xinchang gas field,western Sichuan depression

To analyze the reasons for the large difference of productivity between different sand groups in the second member of Shahejie formation in Xinchang gas field, by means of physical property analysis and gaswater two-phase seepage experiment, the study and evaluation on the overburden permeability and gas-water two-phase seepage characteristics have been carried out. The results show that the average permeability of the sand group in the main layer and the difficult production layer is basically close to each other by conventional core physical properties. While under the condition of overburden pressure, the permeability difference is obvious. The higher the clay mineral content and the more complex the occurrence, the smaller the throat, the larger the throat closure, the greater the permeability reduction and the stronger stress sensitivity is. The maximum relative permeability of gas phase is low, the critical water saturation is high, the water phase rises rapidly and the maximum relative permeability is higher than that of the main formation. In the process of development, the water breakthrough of gas wells in the difficult production layer is earlier, the water production is larger than that of the main layer, and the bottom hole effusion and water lock damage are more serious than those of the main layer.