论文部分内容阅读
通过分析煤层气的气相及液相吸附特点,论证了煤层气的吸附服从液相吸附规律,讨论了地层原始条件下煤层气的解吸过程,发现其是由气相与液相解吸复合而成的,建立了描述煤层气复合解吸的数学模型.复合解吸受气相解吸、液相解吸以及煤层含水饱和度控制,并存在相转换解吸模式,计算出煤层气复合解吸的静态及动态曲线.研究结果表明:静态曲线表明当煤层含水饱和度由100%减少至60%时,复合解吸量较气相解吸量多36.48%;动态曲线表明在煤层气解吸初期,相转换解吸气量比例为74%;而在解吸晚期相转换解吸气量比例下降至4%.复合解吸同样满足Langmuir规律;早期解吸气的主要来源是由于相转换解吸且解吸量会出现台阶式变化;而在解吸晚期,则主要由气相解吸模式控制,煤层产出气的主要来源是气相解吸和液相解吸.
By analyzing the characteristics of gas phase and liquid phase adsorption of CBM, the adsorption law of CBM is proved to follow the law of liquid phase adsorption. The desorption process of CBM under the original formation conditions is discussed. It is found that the gas is desorbed from the gas phase by liquid phase. A mathematical model describing the compound desorption of coalbed methane was established.The composite desorption was controlled by gas phase desorption, liquid desorption and coal seam water saturation control, and the phase transition desorption mode existed to calculate the static and dynamic curves of compound desorption of coalbed methane.The results show that: The static curves show that when the water saturation of coal seam decreases from 100% to 60%, the amount of composite desorption is 36.48% more than that of gas phase desorption. The dynamic curve shows that the proportion of phase transfer desorption gas is 74% in the initial stage of desorption of coalbed methane, The ratio of phase transfer desorption decreased to 4% .The composite desorption also satisfies the Langmuir law.The main source of the early desorption gas is due to the phase transition desorption and step-by-step desorption amount, while in the late desorption phase, it is mainly controlled by the gas phase desorption mode The main sources of coalbed gas production are gas desorption and liquid desorption.