CO₂ capture and sequestration - A solution for enhanced recoveries of unconventional gasses and liquids

Abstract

The consequences of increase in CO₂ concentration in atmosphere are well known to scientists, politicians and policy makers. These effects can be foreseen in near future, bringing a serious concern and responsibility to the research community to find efficient and potential solutions to deal with it. Furthermore, use of fossils to fulfill the extensive energy requirements worldwide is majorly responsible for rapidly rising CO₂ levels. Therefore, CO₂ capture in unconventional reservoirs by injection and displacement of oil and gas either in supercritical state or liquid state is a potential method to permanently capture a significant volume of CO₂. In larger picture, this strategy can substantially contribute in the mitigation of global warning. This review presents some useful aspects of CO₂ sequestration in unconventional reservoirs i.e. in form of gas hydrates, shale reservoirs and in coalbeds. Here we explain in-depth mechanisms involved in gas production, adsorption/desorption, diffusion, gas migration and expansion/shrinkage in a given matrix. The review also includes the pathways involved in displacement of oil and gas by CO₂, challenges involved in this process and how enhanced recovery of oil and gas can be achieved. This process solves the following challenges worldwide (i) rising levels of CO₂, (ii) continuous rise in energy demand (iii) replacement of limited conventional resources (iv) worldwide distribution of unconventional reservoirs (v) eliminating the geopolitical conflicts with minimal harmful effects towards environmental and human health. This review presents collective information about the parameters responsible for enhanced oil and gas recovery.