Santos Basin, Brazil
Petrobras (65%), BG Group (25%), Galp Energia (ten percent)
Iara oil field is situated in the Santos Basin, about 230km off the coast of Rio de Janeiro. The light oil field lies in a water depth of 2,230m and is located near the Tupi field.
The Iara field is operated by Petrobras and is owned by a consortium comprising Petrobras (42.5%), Total (22.5%), Shell Brasil Petróleo (25%) and Petrogal Brasil (10%).
First oil from the Iara oil field was achieved in November 2019.
Discovery of the Brazilian field
The Iara oil field was discovered by Petrobras in August 2008. Discovery well 1-BRSA-618-RJS (1-RJS-656) was drilled by the Noble Paul Wolff semi-submersible rig.
The well is located in the smaller area of Block BM-S-11. A light oil sampling gathered by conducting a cable test in reservoirs at a depth of 5,600m established the discovery.
Samples gathered from carbonate reservoirs of high quality settled under the salt layer at a depth of 5,045m confirmed the discovery.
Block BM-S-11 also includes a larger exploratory area known as Tupi. The Tupi field is estimated to hold five to eight billion barrels of light oil and natural gas.
Reserves at the Iara oil field
The formation tests confirmed that the Iara area is estimated to hold recoverable reserves of three to four billion barrels of oil and natural gas. The exploratory potential was proved by formation tests realising the light oil of approximately 28º API.
Development of the Santos Basin-based oil field
Formation tests realising the light oil of approximately 28º API confirmed that the Iara field’s exploratory potential is three to four billion barrels of oil and natural gas in recoverable reserves.
The Iara field was developed under the Iara Evaluation Plan implemented in Block BM-S-11. Drilling on the Iara Horst well (3-BRSA-891A-RJS) was successfully completed in March 2011.
An extension to one of the exploratory wells encountered good quality oil (28˚ API) in a dense reservoir. The well was drilled at a water depth of 2,279m. Initial outcomes of the well have shown superior reservoir features in comparison with the original discovery well.
Petrobras completed the drilling of exploratory well 3-BRSA-1032-RJS (3-RJS-697) in April 2012. The well, also referred to as Iara Oeste, is located at a water depth of 2,150m. It was drilled to a total depth of 6,050m.
The fourth well, 3-RJS-706 (3-BRSA-1132-RJS), was drilled at a water depth of 2,197m in the Iara area in March 2013. The cable samples gathered from the well confirmed the presence of 28º API oil in high quality carbonate reservoirs.
Petrobras discovered good quality oil in the Transfer of Rights area known as Entorno de Iara in May 2013. The area is located in the Santos Basin pre-salt region. Well 1-BRSA-1146-RJS (1-RJS-711) lies at a water depth of 2,266m. The productivity of the reservoirs in this area was evaluated through a formation test and the drilling of an additional well under the Mandatory Exploratory Programme of the Transfer of Rights Agreement.
The consortium carried out development activities in the Iara area according to the Evaluation Plan sanctioned by the Brazilian National Petroleum, Natural Gas and Biofuels Agency (ANP).
Contractors involved with the Iara oil field’s development
Aker Solutions signed an agreement with Petrobras in April 2010 to supply 40 subsea trees for the Iara and Guará fields. The scope of the $300m contract included the supply of 40 vertical subsea trees for 2,500m water depth, subsea control systems and 17 complete tool sets through 2014. The Iara field includes 26 trees.
The field development partners placed Engineering, Procurement and Construction (EPC) contracts worth $3.5bn with Engevix Engenharia for eight hulls for the Floating Production, Storage and Offloading (FPSO) vessels to be used in blocks BM-S-11 and BM-S-9.
Six vessels were allocated to block BM-S-11, including Tupi, Iracema and Iara discoveries, The remainder were dedicated to block BM-S-9, which comprises of the Guará and Carioca discoveries.
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