自然降压开采和注气开采煤层气的效果评价

EVALUATION OF EFFECTS ON THE EXPLOITATION OF COALBED METHANE BY THE NATURAL DECOMPRESSION AND INJECTION GAS

依据吸附平衡理论,向煤层中注气可加快吸附煤层气解吸速度,从而可以提高煤层气采气速率和回收率。本文推导了自然降压开采和注气开采煤层气时最大理论回收量和回收率的计算公式,利用这些公式可以评价注气效果和选择注气种类。根据这些公式和统计资料计算出我国煤层气在自然降压开采时最大理论回收率为44％,而注CO2和N2开采时最大理论回收率分别为76％和54％。

In the light of the adsorption equilibrium theory, adsorption velocity of adsorbing coalbed methane may be speeded up by injection gas into the coalbed, and the rate of exploitation of methane and the rate of recovery may be lifted. The paper educes calculation formula of the largest theory recovery amount and the rate of recovery when exploitation of methane by the natural decompression and injection gas. By means of these formulas effect can be evaluated, and sorts of injection gas may be selected. It is calculated out on the basis of these formula and statistics datum that the largest theory rate of recovery of methane in our country is 44% when the nature decompression exploitation, but the largest theory rate of recovery is 76% and 54% separately when injection CO2 and N2.