Open Access

ARTICLE

A Feasibility Study of Using Geothermal Energy to Enhance Natural Gas Production from Offshore Gas Hydrate Reservoirs by CO₂ Swapping

Md Nahin Mahmood^*, Boyun Guo

Department of Petroleum Engineering, University of Louisiana at Lafayette, Lafayette, 70504, USA

* Corresponding Author: Md Nahin Mahmood. Email:

(This article belongs to the Special Issue: Advances in Geothermal Energy)

Energy Engineering 2023, 120(12), 2707-2720. https://doi.org/10.32604/ee.2023.042996

Received 19 June 2023; Accepted 18 September 2023; Issue published 29 November 2023

Abstract

The energy industry faces a significant challenge in extracting natural gas from offshore natural gas hydrate (NGH) reservoirs, primarily due to the low productivity of wells and the high operational costs involved. The present study offers an assessment of the feasibility of utilizing geothermal energy to augment the production of natural gas from offshore gas hydrate reservoirs through the implementation of the methane-CO₂ swapping technique. The present study expands the research scope of the authors beyond their previous publication, which exclusively examined the generation of methane from marine gas hydrates. Specifically, the current investigation explores the feasibility of utilizing the void spaces created by the extracted methane in the hydrate reservoir for carbon dioxide storage. Analytical models were employed to forecast the heat transfer from a geothermal zone to an NGH reservoir. A study was conducted utilizing data obtained from a reservoir situated in the Shenhu region of the Northern South China Sea. The findings of the model indicate that the implementation of geothermal heating can lead to a substantial enhancement in the productivity of wells located in heated reservoirs during CO₂ swapping procedures. The non-linear relationship between the temperature of the heated reservoir and the rate of fold increase has been observed. It is anticipated that the fold of increase will surpass 5 when the gas hydrate reservoir undergoes a temperature rise from 6°C to 16°C. The mathematical models utilized in this study did not incorporate the impact of heat convection resulting from CO₂ flow into the gas reservoir. This factor has the potential to enhance well productivity. The mathematical models’ deviation assumptions may cause over-prediction of well productivity in geothermal-stimulated reservoirs. Additional research is required to examine the impacts of temperature drawdown, heat convection resulting from depressurization, heat-induced gas pressure increment, and the presence of free gas in the formation containing hydrates. The process of CH₄-CO₂ swapping, which has been investigated, involves the utilization of geothermal stimulation. This method is highly encouraging as it enables the efficient injection of CO₂ into gas hydrate reservoirs, resulting in the permanent sequestration of CO₂ in a solid state. Additional research is warranted to examine the rate of mass transfer of CO₂ within reservoirs of gas hydrates.

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