Well design considerations for CO2 injection at Prelude

• Main Author: Haugstad, Stig Bjoeran
• Format: Master Thesis
• Language: English
• Published: University of Stavanger, Norway 2011
• Subjects: petroleumsteknologi; boreteknologi; Snøhvit
• Online Access: http://hdl.handle.net/11250/183610

Master's thesis in Petroleum engineering The global economy is set to grow four-fold by 2050, promising economic benefits and a higher standard of living for millions. At the same time the global community is uniting in an effort to combat global warming. Achieving both goals will require energy to be harvested from sustainable resources. Australia, producing most of its electricity from coal, can achieve this through a switch to natural gas, in which it has a large resource base. However, most natural gas resources contain a portion CO2 which will cause large emissions. Geo-sequestration is recognized as safe mean of control and through implementation of both; a double environmental benefit can be achieved. Prelude is a gas condensate field located in Western Australia, operated by Shell Development Australia. The field is planned to be developed as a floating LNG facility. Containing 9% CO2 it will give significant emission. The sensitivity of the emissions has prompted Shell to look at reduction measures. One such measure is re-injection into the reservoir in which the CO2 originated. There is currently much focus on deep saline formation as these offers the largest theoretical storage potential. However, injecting into existing gas fields offer significant advantages through proven capacity and sealing structure, limiting the leak risk to wells penetrating the cap rock. CO2 injection is not new to the industry and have been used for EOR since the 1970’s. However, injection at Prelude is more complex in two aspects: • The pressure and temperature is much higher than the current experience with CO2 injection. • The well is located subsea in a remote location. To date there is only one operational subsea CO2 injector, Snøhvit, and injection generally commences at shallower depth than what is the case at Prelude. Well design at Prelude is thus pushing the envelope and it is necessary to investigate the significance. Challenges and gaps were identified through investigating the current body of knowledge and by ...