关键词: 高煤阶煤层气藏, 低煤阶煤层气藏, 储层物性, 成藏机理, 模拟实验

Abstract:

The differences of reservoir physical properties, including the porosity, permeability, fracture, adsorption/desorption characteristics, and the generation mechanism of characteristic differences between the low-rank and high-rank coal-bed methane (CBM) were discussed by using the SEM, FY-II CBM formation simulation system and the thermal alteration simulation. It is proved that the high-rank CBM reservoir is characterized by low porosity and permeability, strong adsorption volume and slower comparison desorption speed. The low-rank CBM reservoir is characterized by high porosity and permeability, weak adsorption volume and faster comparison desorption speed. It is also proved that the differences between molecular constitution, physical structure and micro-lithofabric of coal are the key factors for generating the differences of reservoir physical property. So, it is easier to develop the low-rank CBM reservoir. The structure thermal event can improve the physical property of high-rank CBM reservoir and is favorable for the development of high-rank CBM reservoirs.

Key words: high-rank coal-bed methane reservoir, low-rank coal-bed methane reservoir, reservoir physical property, reservoir-generation mechanism, simulation experiment