Microwave-Aided In-Situ Combustion Generates Hydrogen From Kerogen-Bearing Reservoirs

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 231484, “In-Situ Hydrogen Generation from Kerogen-Bearing Reservoirs Using Microwave-Assisted In-Situ Combustion,” by Hao Ye, Zinah W. Albabawat, SPE, and Ahmet B. Demir, SPE, Texas A&M University, et al. The paper has not been peer-reviewed. _ This study investigates the potential for in-situ hydrogen generation from hydrocarbons using in situ combustion, with particular emphasis on the role of kerogen content and heating mode. Hydrogen is a promising low-carbon energy carrier; however, conventional hydrogen production methods are energy-intensive and face significant challenges related to storage and transportation. This study investigates the potential for in-situ hydrogen generation from hydrocarbons using in-situ combustion (ISC), with particular emphasis on the role of kerogen content and heating mode. The objective is to evaluate whether hydrocarbon reservoirs can function as integrated subsurface hydrogen generation systems while minimizing surface energy input and storage requirements. Materials and Method One kerogen-rich and one kerogen-poor rock sample from the Bakken were used in this study, representing a source rock and a reservoir (pay-zone) rock, respectively. Before the combustion experiments aimed at hydrogen generation, the organic content and thermal behavior of both samples were characterized using thermogravimetric analysis coupled with differential scanning calorimetry. Two conventional ISC experiments were performed to establish a baseline for hydrogen generation from Bakken crude oil. In Experiment E1, kerogen-rich rock (approximately equal to 23-wt% kerogen) was blended with Bakken crude oil (46.6 °API) and Bakken formation brine at a 50:50 volumetric oil/brine ratio. Experiment E2 was conducted under identical conditions using kerogen-poor rock containing approximately 1.2- wt% organic content. Ten combustion experiments were conducted in this study. Following the conventional ISC tests, Experiments E3 and E4 repeated the same rock/fluid combinations as E1 and E2, respectively, but used microwave-assisted combustion. Microwave-assisted experiments were conducted using a modified microwave oven. The microwave cavity was customized to allow continuous air injection and controlled venting of effluent gases through a sealed quartz reaction system. Temperature profiles were monitored using type-K thermocouples positioned at 1-in. intervals along the tube.