Modelling carbon dioxide storage within closed structures in the UK Bunter Sandstone Formation

Abstract

The Bunter Sandstone Formation in the UK Southern North Sea has the potential to become an important CO 2 storage unit if carbon dioxide capture and storage becomes a widely deployed option for the mitigation of greenhouse gases. A detailed geological model of a region of the Bunter Sandstone consisting of four domed structural closures was created using existing seismic, well log and core data. Compositional simulation of CO 2 injection was performed to estimate the storage capacity of domes within the system. The injection was constrained by both pressure and CO 2 migration criteria, and the storage efficiencies of the domes (volume of stored CO 2 divided by the pore volume of the dome) were calculated when injection ceased. A sensitivity study evaluated the effect of varying the total aquifer volume, reservoir heterogeneity and injection well location. A wide range of storage efficiency values were obtained across the different simulation cases, ranging from 4% (closed dome) to 33% (homogeneous model). Intra-reservoir heterogeneity, specifically in the form of continuous low permeability layers has an important effect on storage capacity in dome-like structures, because it increases the tendency for CO 2 to migrate laterally from the storage complex via structural spill points.

Seismic monitoring of CO2 plume growth, evolution and migration in a heterogeneous reservoir: Role, impact and importance of patchy saturation

“…The model used in this study is an adaptation from Williams et al, (2013), representing part of the Triassic Bunter Sandstone Formation in the UK sector of the North Sea (Fig. 2).…”

Optimization of CO2 Storage in Saline Aquifers using the Raven Software

“…The initial properties of Bunter formation which are used in geological model are summarized in Table 1. The detailed model of reservoir properties and characteristics of the formation are provided in Williams et al [8]. …”

“…The data are shown in Tables 2 and 3. In addition, because there is no specific value for fracture gradient, the fracture pressure of 0.018 Mpa/m was chosen from paper published by William et al [8] and this vale will be used as criterion for maximum allowable pressure in injector and observation wells.…”

“…Consequently, a small amount of CO 2 migrates throughout the dome A ( Table 5). The second reason is that, it could be due to the effect of permeability because Bunter formations are very heterogeneous [8].…”

Pressure constraints on the CO 2 storage capacity of the saline water-bearing parts of the Bunter Sandstone Formation in the UK Southern North Sea

“…The capillary seal potential of the Solling Claystone in the Netherlands P15-14 well to gas is about 4.7 MPa at a depth of 3140 m (Spain & Conrad 1997). Both the fracture and the capillary sealing pressures could easily be exceeded during CO 2 injection (Heinemann et al 2012;Williams et al 2013), necessitating the requirement for careful pressure control.…”