Speaker
Description
Low natural gas recovery factors from shale reservoirs have stimulated interest in Enhanced Shale Gas Recovery (ESGR) using CO$_2$ injection. This process seeks to exploit the preferential adsorption of CO$_2$ in shale’s nanometric pores, so as to enhance desorption of CH$_4$ and to promote geological sequestration of CO$_2$. To facilitate the design of this process, an integrated experimental and modelling workflow was developed and deployed on shale samples from the Longmaxi (China), Marcellus (USA) and Bowland (UK) formations to achieve the following: (i) high-resolution textural characterisation, (ii) supercritical adsorption measurements with CO$_2$ and CH$_4$, and (iii) their description by a novel mathematical model that predicts adsorption in chemically and morphologically heterogeneous materials. The results show that CO$_2$ adsorbs more than CH$_4$ at all pressures (2–3 times) and that both adsorption capacities and textural properties are strongly influenced by the shale mineralogy. The model developed in this work is based on the lattice Density Functional Theory and describes adsorption systems featuring both slit and cylindrical pores and accounts for the presence of energetically distinct organic- and clay-rich pore surfaces. The workflow was calibrated on three model adsorbents (micro/mesoporous carbon [1] and source clays [2]) that have been used in this study as surrogates for the organic- and clay-rich fractions of shale, respectively. As such, the model is used in a predictive fashion to describe supercritical adsorption, only requiring knowledge of the shale’s composition. The adsorption data have been used as input to an equilibrium-based ESGR proxy reservoir model, which uses the concept of Pressure Swing Adsorption, and was deployed to demonstrate that a cyclic CO$_2$ injection operation, including three stages (Injection/Soak/Production), may be required to achieve sufficient recovery and secure CO$_2$ storage [3]. The results indicate that competitive adsorption and partial pressure both influence enhanced recovery and reveal a trade-off between CH$_4$ production and CO$_2$ sequestration. The practical workflow presented in this work can be used to quantify accurately the Gas-in-Place and CO$_2$ storage potential of shale reservoirs at subsurface conditions and design an optimal CO$_2$-ESGR process.
References
[1] H. Ansari, L. Joss, J. Hwang, JPM. Trusler, G. Maitland, R. Pini, Microporous and Mesoporous Materials. 308 (2020) 110537.
[2] J. Hwang, R. Pini, Environmental Science & Technology. 53 (2019) 11588–11596.
[3] H. Ansari, E. Rietmann, L. Joss, JPM. Trusler, G. Maitland, R. Pini, Fuel. 301 (2021) 121014.
| Participation | In person |
|---|---|
| Country | United Kingdom |
| MDPI Energies Student Poster Award | No, do not submit my presenation for the student posters award. |
| Time Block Preference | Time Block B (14:00-17:00 CET) |
| Acceptance of the Terms & Conditions | Click here to agree |
