Journal of CO2 Utilization ( IF 7.7 ) Pub Date : 2018-09-27 , DOI: 10.1016/j.jcou.2018.09.013 Jialin Shi , Guofei Shen , Hongyu Zhao , Nannan Sun , Xuehang Song , Yintong Guo , Wei Wei , Yuhan Sun
Using CO2 as a shale fracturing fluid was proposed recently as an alternative to H2O fracturing, one of its advantages is enhanced recovery of CH4, which is based on the competitive adsorption of CO2 and CH4 on shales. Therefore, investigations on gas adsorption in shales are of great importance. Recent researches evidenced that organic matter (OM) in shale is the major control on its adsorption behavior, but in some cases, mineral components (MC) may also play a role. Herein, we focus on the alteration of porosity due to the presence of OM-MC interface and their influence on gas adsorption, these cannot be simply attributed to either OM or MC as frequently reported in the previous publications. In this context, OM from a shale sample was purified following reported methodology, while a universal procedure for extraction of MC was established. Further studies on the porosity and adsorption behavior were carried out on OM, MC, and shale, which were then compared with a hypothetic mixture (HM) from OM and MC bearing the same composition of shale. For the first time, we demonstrate experimentally the profound effect of porosity at the OM-MC interface on gas adsorption of shales particularly at temperatures more relevant to reservoir conditions. The current work deepened the understanding on gas adsorption of shale, and thus shed meaningful lights on related areas such as gas-in-place (GIP) estimation, CO2 sequestration in shales, and particularly the utilization of CO2 for enhanced shale gas recovery.
中文翻译:
有机质和矿物成分的界面处的孔隙度显着促进了页岩气的吸附
最近有人提出使用CO 2作为页岩压裂液替代H 2 O压裂的方法之一,其优点之一是提高了CH 4的回收率,这是基于CO 2和CH 4的竞争性吸附。在页岩上。因此,研究页岩中的气体吸附非常重要。最近的研究表明,页岩中的有机物(OM)是对其吸附行为的主要控制因素,但在某些情况下,矿物成分(MC)也可能起一定作用。在这里,我们主要关注由于OM-MC界面的存在及其对气体吸附的影响而引起的孔隙度的变化,这些不能简单地归因于先前出版物中经常报道的OM或MC。在这种情况下,按照报道的方法从页岩样品中纯化OM,同时建立了提取MC的通用程序。对OM,MC和页岩进行了孔隙率和吸附行为的进一步研究,然后将其与来自OM和MC且具有相同页岩成分的假想混合物(HM)进行了比较。首次,我们通过实验证明了OM-MC界面孔隙率对页岩气吸附的深远影响,特别是在与储层条件更为相关的温度下。当前的工作加深了对页岩气吸附的理解,从而为相关领域(如就地气(GIP)估算,CO)提供了有意义的启示。2隔离页岩,特别是利用CO 2增强页岩气的回收率。