XWI with Gorgon project operated by Chevron expands stage by stage!

Jansz Io one of the fields which has been imaged by seismic technology S-Cube XWITM is part of the Gorgon Gas Project. 

This is one of the world’s largest natural gas projects with an annual LNG production capacity of 15.6 million tonnes located at Barrow Island in Western Australia. It marks the first use of subsea compression technology outside Norway and with a ‘digital twin’ being developed it will allow long-term predictive maintenance and performance optimization strategy, reducing the need for intervention and lower operating costs. 

In 2018-19, the Gorgon gas project was Australia’s highest greenhouse gas emitting project releasing almost 9 million tonnes of CO2 equivalent. With standard industry practice, most of the gas fields around the world separate their CO2 from the process and release it into the atmosphere. The increase in carbon dioxide concentration causes air temperature to rise, and thus more water vapour evaporates into the atmosphere amplifying greenhouse heating. 

The Australian government on terms of mutual benefit and in anticipation of a carbon tax has initiated Gorgon operator Chevron to start the country’s first CO2 sequestration project and bury 40% of its carbon emissions to minimise the environmental footprint on the island when CO2 is separated. 

The project is now developing the world's largest carbon capture and storage (CCS) plant involving design, construction and operation facilities at two gas fields, Jansz-lo which contains an average of less than one percent of naturally occurring reservoir CO2 while the Gorgon field contains approximately around 14%. Around 80% of this reservoir CO2 from CO2 rich natural gas fields is separated by an absorber & stripper system and amine-based solvent from the inlet gas at liquified natural gas (LNG) processing plant before the gas is processed, liquefied & fed to the plant. If CO2 remained in the natural gas stream during the liquefaction process, then when natural gas is cooled (to -162 C) into a liquid, CO2 would freeze into a solid.

The captured CO2 is then re-injected into three drill centres with total 9 injection wells at more than 2 km into the deep onshore Dupuy formation beneath the sandstone reservoirs at Barrow island via 7 km pipeline. 3.3 to 4 million tonnes per year of reservoir CO2 is planned to be injected which will abate 40% emission from the Gorgon Project. the impact of this storage will be comparable to all the rooftop solar installed in Australia collectively which save 6.2 million tonnes of carbon dioxide per year. Moreover, in terms of net present value, the project is expected to add $1 trillion to the national gross domestic product (GDP) and continue to be an important pillar for Austrian economy for years to come.

With a project lifespan of about 40 years, 120 million tonnes of CO2 will be stored in total. The entire project cost is more than $80 billion but was initially expected to be $55 billion. Chevron increased the cost mainly due to labour shortages, logistics challenges and the strength of the Australian dollar. Cost of just the injection project is around $2.5 billion. The government of Australia has accepted liability for the Gorgon CCS project and under Low Emission Technology Development Fund (LETDF), the government has contributed $60 million to the capital cost of this project as half of the increase in countries GHG emissions in 2018 were due to Gorgon gas project. Chevron (47.3%) mainly operates the project on behalf of the other five joint venture partners of the Australian subsidiaries of Chevron: ExxonMobil (25%), Shell (25%), Osaka Gas (1.25%), Tokyo Gas (1%), and JERA (0.417%).

The CCS project construction was started in September 2009 and was expected to start CO2 injection from 2016. But due to extra moisture content in the pipeline and injection site facilities, which could cause corrosion, the injection was delayed for two years. Some modification to equipment and changes in operating procedures were carried out to avoid water condensing in the gas stream which helped to initiate the CCS project in August 2019 and is anticipated to have a full capacity injection rate of 130 kg per second, 10 thousand tonnes per day by 2020. Due to the technical difficulties, the project failed to inject 10 to 12 million tonnes of CO2 over a period of more than three years of delay to work in full capacity, which is greater than emissions from domestic airline industry annually. If required to offset these emissions, Gorgon will have to pay more than $100 million. However, under the safeguard mechanism to assume CCS is not operating, Gorgon will not face any penalty right now but will have to account for its excess emissions over a five-year rolling period. Chevron will have to show its emission management report to the western Austrian government in July 2021 before Gorgon’s fist five year period expires. With the market rate of approximately $15 a tonne for Australian carbon credit, Chevron will have to pay in millions of dollars to offset their emissions.

Managing Director AI Williams of Chevron Australia said: “We are monitoring system performance and plan to safely ramp up injection volumes over the coming months as we bring online processing facilities.” With an increase in the number of injection or monitoring wells, the injection capacity can be increased to further save millions of dollars in emission penalty. The latest innovations in XWI optimisation solution which automatically infers sound velocity maps from seismic data provides clearer images of deeper structures in the earth's interior can lead to greater drilling success for its users in complex wells. These new methods are driven by the emergence of leading-edge artificial intelligence (AI) and machine learning (ML) capabilities, combined with affordable massive cloud computing systems. Similar implementation of the technology has been proven by S-Cube by aiding the discovery of a major hydrocarbon-bearing formation in Guyana with Tullow Oil in 2019. More can be read here. 

The Department of Mines Industry Regulation and Safety (DMIRS) is monitoring the performance of the project with two reservoir surveillance wells &  seismic surveys present for an ongoing monitoring program. 

Australia was the world’s largest carbon emitter per capita with emission of 558.4 million tonnes of CO2 equivalent in 2018. Emissions were up by 0.7% from the previous year mainly due to increased LNG exports. Thus with the development of the Gorgon project, a legacy would be created in reliable energy supply, environmental management, innovative technology and expertise. Further, an upgrade of existing subsea petroleum infrastructure for Gorgon stage 2 is planned by Chevron with new wells and subsea facilities to maintain gas supply.