title: Minimising hydrogen sulphide generation during steam assisted production of heavy oil.
abstract: The majority of global petroleum is in the form of highly viscous heavy oil. Traditionally heavy oil in sands at shallow depths is accessed by large scale mining activities. Recently steam has been used to allow heavy oil extraction with greatly reduced surface disturbance. However, in situ thermal recovery processes can generate hydrogen sulphide, high levels of which are toxic to humans and corrosive to equipment. Avoiding hydrogen sulphide production is the best possible mitigation strategy. Here we use laboratory aquathermolysis to reproduce conditions that may be experienced during thermal extraction. The results indicate that hydrogen sulphide generation occurs within a specific temperature and pressure window and corresponds to chemical and physical changes in the oil. Asphaltenes are identified as the major source of sulphur. Our findings reveal that for high sulphur heavy oils, the generation of hydrogen sulphide during steam assisted thermal recovery is minimal if temperature and pressure are maintained within specific criteria. This strict pressure and temperature dependence of hydrogen sulphide release can allow access to the world's most voluminous oil deposits without generating excessive amounts of this unwanted gas product.
authors: Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, UK.
authors: Wren
authors: W
authors: Montgomery
authors: Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, UK.
authors: Mark A
authors: MA
authors: Sephton
authors: Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, UK.
authors: Jonathan S
authors: JS
authors: Watson
authors: Heavy Oil Technology Flagship, BP Canada Energy Group ULC, 240 4th Ave SW, Calgary T2G 0N3, Canada.
authors: Huang
authors: H
authors: Zeng
authors: Heavy Oil Technology Flagship, BP America Production Co, 501 Westlake Park Boulevard, Houston, TX 77079, USA.
authors: Andrew C
authors: AC
authors: Rees