页岩气解吸方法研究进展

Research Progress on the Desorption Methods of Shale Gas

页岩含气量评价对页岩气资源预测、储量计算、勘探开发规划具有重要的意义。解吸法是页岩含气量评价中应用非常广泛的一种直接测量方法。页岩气的解吸方法主要沿用了煤层气的技术,将岩心或岩屑封装于解吸罐后,测定解吸气和残留气,计算损失气,3部分的总和即页岩储层的含气量。经过多年的发展,解吸装置在不断改进,解吸数据分析方法一直在优化。目前已经发展了USBM法、多项式法、Smith-Williams法、下降曲线法、Amoco法等多种解吸数据处理方法。在实际应用中,温度等环境因素、损失时间、采用的拟合方法以及解吸装置本身都会对解吸结果产生明显的影响。由于页岩气的扩散机制和解吸过程与煤层气存在一定差异,简单沿用煤层气的方法与技术评价页岩含气量,可能存在明显的误差。未来的研究将致力于改进解吸装置,发展符合页岩气体解吸机理的数学模型,规范解吸方法,建立相关行业标准。

The evaluation of shale gas content has a great significance on resource prediction,reserve calculation,and exploration and development planning.Desorption method is one of the methods which is widely applied to the evaluation of shale gas content.The present shale gas desorption method has mainly followed coalbed methane technologies.After the core or cutting shale sample is sealed in the desorption canister,desorbed gas and residual gas are measured,and the lost gas is fitted using the measured data.Their sum is the total gas content.After years of development,desorption apparatuses as well as data analytical methods have been improved continuously.USBM method,polynomial method,Smith-Williams method,decline curve method and Amoco method have been successively developed to analyze desorption process.In actual applications,temperature and other environmental factors,lost time,fitting method and desorption apparatuses will influence the result of desorption.Due to the differences in diffusion mechanism and desorption process between shale gas and coalbed methane,evaluation of shale gas content based on methods from coalbed methane may lead to a significant error.Future research will target to improve desorption apparatuses,develop shale gas desorption models,standardize desorption methods as well as set up a relevant industry standard.