Importance of Surface-Subsurface Integration in CCS System Design

Abstract The main objective of this study is to investigate the impact of subsurface conditions on surface networks and vice-versa to highlight correlated challenges and establish best-practice guidelines to be taken into consideration for carbon dioxide (CO2) injection networks to optimize surface and subsurface operations. This study involved CO2 transport and injection well modelling for a variety of surface and subsurface conditions. This includes the simulation of onshore and offshore transport conditions as well as injection into depleted reservoirs and saline aquifers. Steady state and transient operations were performed on the injection well to investigate the surface and subsurface challenges associated with CO2 phase behavior in the system. In this work, an integrated CO2 transport and injection network was modelled for various operating scenarios during the life cycle of a CCS project. The challenges encountered in the entire system including Joule-Thomson (JT) cooling, hydrate formation and multiphase flow are highlighted with field case studies presented. In the context of Carbon Capture, and Storage (CCS) projects, it is essential for CO2 injection wells to meet projected CO2 injection rates for both economic as well as regulatory requirements. The regulatory consequences could be significant, with the operator potentially held responsible for carbon credits until adequate well capacity is attained. There are several subsurface and surface conditions which impact the performance of either the surface and subsurface operations and these operational scenarios are discussed in an integrated study so that the entire CCS system can be optimized to meet transport and injection requirements.