Oil and gas field development
Santos Basin, offshore Brazil
Shell Brasil (50%), Ecopetrol (30%) and Total (20%)
Gato do Mato is an oil and gas field located at a water depth of about 2,000m in the Santos Basin, approximately 200km offshore of Rio de Janeiro, Brazil.
The field is operated by Shell Brasil, which holds a 50% stake. Other stakeholders in the consortium include Ecopetrol, which holds a 30% interest, and Total, which holds the remaining 20%.
Ecopetrol joined the consortium by acquiring a 30% stake in the project, including two neighbouring blocks, BM-S-54 and South of Gato do Mato, from Shell Brasil in October 2019.
The licence for the BM-S-54 block was obtained under Brazil’s National Petroleum Agency’s (ANP) seventh pre-salt bidding round in 2005, while that of the South of Gato do Mato block was obtained under a production sharing contract in the second bidding round in 2017.
Location, geology and production
The Gato do Mato discovery covers blocks BM-S-54 and South of Gato do Mato, situated in the pre-salt layers of the Santos Basin. The entire region is located at a water depth ranging between 1,720m and 2,050m.
The prospect contains light to very light hydrocarbons in Aptian microbial carbonate reservoirs, sealed by a thick layer of evaporites.
Peak production from the field is estimated to be 70,000 barrels of oil equivalent per day (boepd).
Discovery and appraisal details
The Gato do Mato oil and gas field was explored through a three-well drilling campaign in the two blocks in 2019. The drilling campaign began in June 2019 using Constellation’s sixth-generation drillship Brava Star.
The drilling activities were supported by the Sikorsky S-92 aircraft, based out of Jacarepagua airport.
The oil and gas discovery was found to contain light hydrocarbons, with 41°API and gas-oil ratio (GOR) ranging between 2,500 standard cubic feet per barrel (scf/bbl) and 4,000scf/bbl. The presence of contaminants, such as carbon dioxide and hydrogen sulphide in the hydrocarbons, was found to be low.
The Gato do Mato-4 appraisal well was successfully drilled in the first half of 2020. Seismic studies were also conducted in the field.
Gato do Mato development details
The Gato do Mato oil and gas discovery will be developed through ten wells, including four oil producers, four gas injectors and two water injectors wells.
The wells will be tied back to a floating production and storage offloading (FPSO) unit, which will have a production capacity of 90,000 barrels a day.
The FPSO is scheduled to arrive in the Santos Basin in 2023.
BW Offshore received a limited notice to proceed (LNTP), worth up to $50m, for early-stage engineering and supplier reservations for an FPSO for the Gato do Mato project in May 2022.
BW Offshore subcontracted Saipem to provide early-stage engineering services for the supply of the FPSO unit in June 2022.
Shell and its partners are also expected to award a lease and operate contract, including the engineering, procurement, construction and installation (EPCI) of the FPSO, to the Saipem-BW Offshore consortium, upon completion of the LNTP, with expected delivery in 2026.
The 18-year FPSO lease and operate contract will have an option for a seven-year extension.
Constellation and Halliburton provided integrated drilling services and equipment for the project.
CHC Brazil, a subsidiary of CHC Helicopter, supported the exploration and appraisal activities through helicopter services in the Gato do Mato field area.