Details

Autor(en) / Beteiligte

• Fu, Pengcheng
• Ju, Xin
• Huang, Jixiang
• Settgast, Randolph R.
• Liu, Fang
• Morris, Joseph P.

Titel

Thermo‐poroelastic responses of a pressure‐driven fracture in a carbon storage reservoir and the implications for injectivity and caprock integrity

Ist Teil von

• International journal for numerical and analytical methods in geomechanics, 2021-04, Vol.45 (6), p.719-737

Ort / Verlag

Bognor Regis: Wiley Subscription Services, Inc

Erscheinungsjahr

2021

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• CO2 injection into a reservoir with marginal permeability (≲ 10−14 m2) could induce pressure high enough to fracture the reservoir rock and/or caprock. A pressure‐driven fracture can immensely enhance the injectivity and would not compromise the integrity of the overall storage complex as long as the fracture is contained vertically. Conventional models for geologic carbon storage simply treat fractures as high‐permeability conduits, ignoring coupled interactions between the fluids, the fracture, the reservoir, and caprock. We employ a high‐fidelity model coupling multiphase flow, heat transport, poroelasticity, thermal contraction, as well as fracture mechanics to study thermo‐poroelastic responses of a pressure‐driven fracture in a carbon storage reservoir. We found that poroelasticity dictates that to maintain an open fracture in the reservoir rock requires a continuous and significant increase of pressure, potentially exceeding the fracturing pressure for the caprock. A closed‐form equation is derived to conservatively compute the pressure increase. Although cooling in the near‐well region could reduce the fracture‐opening pressure, the fracture propagation pressure is still dictated by processes in the far‐field rock unaffected by the cooling. This discrepancy causes a high net pressure near the injection well and could further drive the fracture into the caprock. However, while such fracturing is likely, we demonstrate that in many instances we can expect it to be contained.