Platform Re-Design for CO2 Re-injection: Process and Safety Engineering Challenges

Abstract

Abstract There has recently been Conceptual and FEED studies to convert existing hydrocarbon producing facilities to CO2 injection. Often the most cost effective option for CO2 injection is when combined with enhanced hydrocarbon recovery. This new operation, however, increases levels of risk; the additional CO2 gives rise to a new asphyxiate hazard, while the increased CO2 in the Process stream brings its own production and safety trade-offs. This paper addresses these hazards and the conundrum of optimising production and safety. Presented herein is an integrated Process and Safety Engineering approach to control the risks and develop a decision making framework to allow confidence for the safe design of future CO2 injection Projects. INTRODUCTION In recent years, it has been recognised that the threat of climate change, due to the emission of greenhouse gases, particularly carbon dioxide (CO2) is one of the key environmental concerns facing modern society. It is recognised that carbon Capture and Storage (CCS) is one of the most effective means of preventing carbon discharge, with many sites in the UK identified for this technology. Furthermore, recent research by Edinburgh University, sponsored by the Scottish Government, indicates that this technology may outstrip oil and gas in the importance to UK economy. This paper attempts to show that there is only a small step from rhetoric to implementation. The developments at the Power Station phase of CCS are recognised (ref 1) but it is the detail of the other phases that is missing: In particular the carbon reception facilities and the injection and storage and, if applicable, the miscible flood which is one of the forms of extended oil recovery (EOR) available from CO2 injection. This paper offers detail to these latter phases, from the key development questions f robustness of business case through to detailed technical requirements and the management of any potential show stoppers. PHASES OF CCS DEVELOPMENT There are three phases of concept development and selection processes: Onshore: The generation of 'carbon free' electricity through either the construction of a gas reformer and new turbines to run on hydrogen or by the addition of post combustion carbon capture equipment, as detailed in reference 1 and in the current trails at Longannet. Transportation: The pressurisation and transportation of the captured CO2 through an existing pipeline to an offshore oil and gas platform.