Client: DEO Petroleum Location: UK Continental Shelf Conducting a concept screening study for a sour reservoir.Xodus Group’s integrated team of specialists shortlist development options prior to concept selection for the Perth oil field. ChallengeDEO Petroleum proposed to develop the Perth oil field located in a water depth of 140m, approximately 6.5km southwest of the existing Tartan production platform in the UK North Sea. The area also included significant existing processing facilities and pipeline infrastructure. Xodus Group was asked to perform a screening study to identify and evaluate a range of development options for concept selection and to provide information which could be used to communicate with partners and regulatory authorities. Economic viability, environmental impact and safety of operations were identified as the main areas of concern. The Perth reservoir fluid is sour, with high levels of both Hydrogen Sulfide (H2S) (0.65mol%) and Carbon Dioxide (CO2) (36mol%) posing challenges for material selection and topsides facilities. H2S is toxic by inhalation and can be fatal at atmospheric conditions as low as 500ppm. Our experts also needed to take into account other fields likely to have high H2S concentrations, which could be produced via the Perth facility in the future, and the nearby Tartan field which produced sour crude but at much lower levels. Assignment scopeOur integrated team provided a complete development solution including: Flow assurance Subsea architecture Oil export option selection Greenfield and brownfield substructure analysis Materials and corrosion Qualitative risk and safety assessment Environmental sensitivity analysis Cost estimates. Results Successful execution of 1,850 man-hour study Through close collaboration with DEO Petroleum, 12 options were narrowed down to three preferred candidates High levels of H2S required environmental and risk analysis, including H2S leak dispersion simulations Capital Expenditure (CAPEX) costs were developed using an in-house estimating tool (for module / equipment design, purchase, fabrication, installation and commissioning) and QUE$TOR cost software.