Case Study: The Importance of Integrated Flow Assurance Modelling for Carbon Capture and Storage CCS Project

A gas field located offshore Malaysia will be developed with carbon capture technology which will recover the remaining amount of hydrocarbon from CO2 rich permeate stream and subsequently concentrate the amount of CO2 to higher purity. The separated high concentration CO2 will be compressed, transported to storage site and injected to store the CO2 safely in a sub-surface geological formation which is a depleted gas field. One of the key success criteria for the CCS development is to be able to inject the CO2 to the reservoir for permanent storage from early to end of injection life. Typically, the battery limit of interface between the subsurface and surface engineer is the surface ITHP whereby the initial prediction was based on stand-alone sub-surface well modelling. A validation exercise was conducted using surface well modelling, including a sensitivity of three main Equation of State (EOS) being considered i.e., GERG-2008, PR 1978 and Advanced PR 1978, to allow the range of pressure drop to be translated to the ITHP number to be quantified. It is acknowledged that impurities within the CO2 stream have strong effect on phase behaviour and physical property predictions. The CO2 composition under study is >95mol% with a mixture of impurities. In addition, ambient temperature has also been found to influence pressure drop prediction. A similar approach is extended for pipeline study. Subsequently, the result provides a clear picture to develop a basis for facility design pressure. The integrated approach of flow assurance between wells and pipeline is important as this was found to affect the CO2 source pressure and design of the surface facility. This paper explains how the study was conducted during conceptual engineering stage and can serve as a reference to other CCS projects.