物理模拟技术在煤层气成藏研究中的应用

APPLICATION OF PHYSICAL SIMULATION TECHNIQUE IN STUDYING COALBED METHANE RESERVOIR FORMATION

煤层气作为一种非常规天然气,其运聚机制和气藏模式与常规天然气均不相同,这些都直接制约了 我国煤层气产业化的进程。利用高温、高压岩心测试分析技术为基础,充分考虑煤层气的吸附解吸特性,嫁接常规 天然气成藏模拟技术,建立了国际上第一台煤层气成藏模拟具有重要科学意义。煤层气成藏模拟装置能模拟煤层 气储层的温压特征,探索煤层气运聚机制,特别是煤层气藏是如何保存的,煤层气如何运聚的,煤层气藏压力系统 是如何变化的。模拟技术充分考虑煤层气保存条件、煤层气运聚规律、水文地质条件开展了卓有成效的模拟工作, 在沁水高煤阶区域和吐哈低煤阶区域开展对比模拟,取得了以物性变化二元论为代表的一批新成果,查清了渗透 性和水文地质条件对高低煤阶煤层气的控制作用。

As an unconventional natural gas, caolbed methane is different from conventional gas in migration/accumulation mechanisms and reservoiring pattern. All of these restrain directly the course of coalbed methane industralization. On the basis of core test and analysis techniques at high-temperaturr and high-pressure the first coalbed methane reservoiring simulation device in the world was set up with the aid of the conventional gas reservoiring simula tion techniques and fully in consideration of the adsorption/desorption properties of coalbed methane. Such a device can simulate the temperature/pressure characteristics in coalbed methane reservoir and probe the migration/accumulation mechanisms of coalbed methane, i. e. the preservation of coalbed methane reservoir, the migration and accumulation of coalbed methane and the change in coalbed methane reservoir pressure system. The preservation conditions and migration/accumulation laws of coalbed methane and the regional hydrogeological conditions were fully considered in the simulations. The comparative simulation works were carried ot for the high coal rank areas in Qinshui Basin and the low coal rank areas in Tuha Basin. A lot of new achievements of taking the dualism of petrophysical change as the representative were obtained and the control effects of permeability and hydrogeological condifions on high/low rank coalbed methane were found out finally.