Lacq Carbon-Capture and -Sequestration Pilot

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 157157, ’The Lacq CCS Pilot, a First,’ by Jacques Monne, SPE, Total, prepared for the 2012 SPE/APPEA International Conference on Health, Safety, and Environment in Oil and Gas Exploration and Production, Perth, Australia, 11-13 September. The paper has not been peer reviewed. Carbon capture and sequestration (CCS) holds promise for use on an industrial scale. Total has been involved in CO2 injection and geological storage for more than 15 years, in Canada (Weyburn oil field) for enhanced oil recovery and in Norway (Sleipner and Snohvit fields) for aquifer storage. In 2006, the company decided to set up an experiment for CO2 capture, transportation, and injection in a depleted gas reservoir. The pilot is in the Lacq basin in southwestern France, 800 km from Paris, and has been on stream since January 2010. Introduction This CCS project entailed converting an existing air/fuel-gas combustion boiler into an oxygen/fuel-gas combustion (oxy-combustion) boiler using oxygen delivered by an air-separation unit (ASU) to obtain more-efficient combustion and a more-concentrated flue-gas-CO2 stream. The 30-MW oxy-combustion boiler can deliver up to 38 t/h of steam to the high-pressure steam network of the Lacq sour-gas-production and -treatment plant. After quenching the flue-gas stream, the rich CO2 stream is compressed to 27 barg, dried, and transported in gaseous phase by use of existing pipelines to a depleted gas field, 29 km away, where it is injected into the deep Rousse reservoir. Over a 3½-year period, up to 90 000 t of CO22 could be injected. The main objectives in this experiment were: To demonstrate the technical feasibility and reliability of an integrated chain comprising steam production and CO2 capture, transportation, and injection into a depleted gas reservoir. To acquire operating experience and data to scale up the oxy-combustion technology from pilot scale (30 MW) to industrial scale (200 MW) while reducing costs. To develop on-site monitoring methods and technologies to serve future onshore storage-monitoring programs that will be larger in scale, longer in term, and economically and technically viable (i.e., microseismic and environmental monitoring). Technical Description The CCS pilot installation, shown in Fig. 1, consists of an ASU, an oxy-combustion boiler, a direct-cooling contactor, a CO2 compressor, a dryer system, a transportation pipeline, and an injection site (i.e., compressor, injection well, reservoir, and a subsurface-seismic network). ASU. A dedicated ASU, the oxygen-production unit, was installed on the Lacq gas-treatment complex to produce 240 t/d of low-pressure oxygen (1.8 bara) at 95 to 99.5 vol% purity. Only 99.5% pure oxygen is used to feed the oxy-combustion boiler. The nitrogen rejected by the ASU is partially used for regenerating the dryer system.