A numerical modelling study to support design of an in-situ CO2 injection test facility using horizontal injection well in a shallow-depth coal seam. (September 2022)

• Record Type: Journal Article
• Authors: Masum, Shakil A.; Chen, Min; Hosking, Lee J.; Stańczyk, Kamil; Kapusta, Krzysztof; Thomas, Hywel R.
• Is Part Of: International journal of greenhouse gas control. Volume 119(2022)
• Publication Date: 2022-09
• Subjects: CO2-storage -- Swelling -- Injectivity -- Modelling -- Dual porosity -- Horizontal well; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2022.103725
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: Adsorption induced matrix swelling reduces coal permeability and CO2 injectivity. Coal-CO2 contact length greatly influences swelling and permeability behaviour. CO2 storage via vertical injection wells suffer significantly due to smaller contact. Simulations predict sustained injection and safe CO2 storage via horizontal wells. Benefits of enlarging coal-CO2 contact exploited to design in-situ gas injection test. Abstract: Previous projects on CO2 storage in coal often reported the challenges associated with coal swelling and swelling-induced loss of gas injectivity. Since coal seams are typically thin, commonly used vertical wells only intersect a target reservoir over a small contact area, placing constraints on CO2 injectivity in addition to those resulting from coal swelling. This leaves the storage reservoirs largely under-utilized and, therefore, questions the viability of this technology. To address the challenges/limitations of the current practice, a novel in-situ CO2 injection test is planned using horizontal injection wells in Mikolow, Poland. This paper presents the pre-operational simulation studies conducted to assist the design and operation of the in-situ test. An existing dual-porosity model that is built on a coupled thermo-hydro-chemical-mechanical (THCM) modelling framework is employed in this study. Sensitivity of the model parameters and validity of the model are tested. Several simulation scenarios are developed in reference to the selected test site for various horizontal well configurations and gas injection conditions. From the results and analyses, it is evident that by varying the coal-CO2 contact area via the length of the horizontal injection well, as well as the operating conditions including fixed pressure, and fixed rate injection scenarios, the targeted amount (between 1 to 10 tonnes) of CO2 can be injected into the seam without significant loss of permeability or injectivity, yielding sustained gas injection. Moreover, the spread of CO2 is predicted to be contained within the model domain suggesting no significant concern of spread exceeding the test area.