A new desorption-induced permeability dynamic model and its application in primary coalbed methane recovery
A new desorption-induced permeability dynamic model and its application in primary coalbed methane recovery
复制标题
一种新的解吸诱导渗透率动态模型及其在煤层气原生开采中的应用
DOI：
10.1007/s13202-021-01393-x
复制
发表时间：
2021
影响因子：
2.2
通讯作者：
Guo Dan
中科院分区：
文献类型：
--
作者：
Zhang Xianmin;Zhang Bin;Zhang Jiyuan;Deng Ze;Guo Dan
在煤层气脱水开采过程中，由于受到基质收缩和应力效应的影响，煤岩渗透率表现出十分独特的特征。基于煤岩火柴杆几何形状和单轴应变条件的假设，提出了一种新的煤岩渗透率动态理论模型。与以往的P&M和S&D模型不同的是，我们的模型将气体吸附还原应变与煤固体表面能的变化联系起来。该模型的优点之一是它不需要将吸附减少的应变作为必要的输入，因此消除了相关的费力和昂贵的实验室测量。该模型通过拟合两组公共数据进行了验证，并与观测数据显示出良好的匹配。结果还表明，我们的模型具有更好的性能在预测渗透率动态比P&M和S&D模型。此外，利用灰色关联理论对输入参数对渗透率动态的影响进行了敏感性分析，发现初始孔隙度和储层温度对渗透率动态的影响最为显著。最后，将该模型应用于数值模拟器，并成功地应用于某开发区的产气率和产水率的历史拟合。
In the process of dewatering and recovery of coalbed methane, coal permeability exhibits a quite unique feature due to the interference of matrix shrinkage and stress effects. A new theoretical dynamic model was proposed for coal permeability based on the assumptions of matchstick geometry of the coal and uniaxial strain condition. Distinct from previous models such as P&M and S&D models, our model relates the gas-sorption-reduced strain to the change of surface energy of coal solids. One of the advantages of this model is that it does not require the sorption-reduced strain as an essential input, and therefore eliminates the related laborious and expensive laboratory measurement. The model was validated by fitting it to two sets of public data and shows an excellent match with the observed data. The results also indicate that our model has a better performance in predicting the permeability dynamics than P&M and S&D models. Additionally, a sensitivity analysis of the effect of input parameters on permeability dynamics was conducted by gray-relation theory, and the initial porosity and reservoir temperature are demonstrated to exert a most distinguished effect on the permeability dynamics. Finally, the proposed model was incorporated into a numerical simulator and successfully applied to conduct a history match of the gas and water production rate in a developed territory.