Critical Review on Carbon Dioxide Sequestration Potentiality in Methane Hydrate Reservoirs via CO<sub>2</sub>–CH<sub>4</sub> Exchange: Experiments, Simulations, and Pilot Test Applications
Grant Charles Mwakipunda, Elieneza Nicodemus Abelly, Melckzedeck Michael Mgimba, Mbega Ramadhani Ngata, Edwin E. Nyakilla, Long Yu
Abstract
Many researchers have investigated the potential of methane hydrate reservoirs (MHRs) for carbon dioxide (CO 2 ) sequestration and methane (CH 4 ) production through the CO 2 –CH 4 replacement method. This technique is not yet commercially implemented due to various limitations, especially economic reasons. This study investigated recent advancements in MHRs potentiality for CO 2 sequestration through CO 2 or mixed gas exchange injection while recovering CH 4 . From the experiments, modeling, and simulations, and one pilot test conducted, it was found that there is a great potentiality of sequestrating CO 2 in MHRs while recovering CH 4 . In addition, it was revealed that to produce more CH 4, the nitrogen/hydrogen (N 2 /H 2 ) mole fraction in the injector gas stream should be more significant than that in CO 2, while to sequestrate more CO 2, the CO 2 mole fraction in the injector gas stream should be greater than the N 2 /H 2 mole fraction. The CO 2 –mixture gases mole fraction ratio recommended from one successful pilot test conducted was 23:77 (CO 2 /N 2 ), which revealed that approximately 60% of injected CO 2 was sequestrated with 855 × 10 3 standard cubic feet of CH 4 produced. The challenges identified in this review will urge researchers to explore suitable technologies to conduct more pilot tests and pave the way toward entire field operations on CO 2 sequestration in MHRs toward decarbonization.