This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 32705, “Mero Field: Subsea Development Challenges,” by Leonidio Buk Jr., Rafael M. Pereira, and Claudio J.G.M. Valença, Petrobras, et al. The paper has not been peer reviewed. Copyright 2024 Offshore Technology Conference.
The complete paper presents the technological achievements in the subsea scope of the Mero field development. Mero is the third-largest presalt field and the first developed under a production sharing contract (PSC). The paper details the subsea system development for the Mero field that was recognized with the Distinguished Achievement Award by OTC Brazil and how Mero early production system (EPS) operation influenced the final configuration for all Mero projects. The paper also presents the technical challenges that had to be overcome to initiate production successfully.
The Libra block is approximately 180 km from Rio de Janeiro in ultradeep water of the Santos Basin varying from 1700 to 2400 m, under a presalt layer. The prospect area is close to 1500 km2. The reservoir fluid has a gas/oil ratio (GOR) of 440 sm3/sm3 and CO2 content in gas varying from 40 to 45% in volume. These conditions carry many challenges that must be overcome to develop the subsea production system.
Four years after the signing of the PSC in November 2017, a Libra extended well test (EWT) produced the block’s first oil with the floating production, storage, and offloading (FPSO) vessel Pioneiro de Libra declaring northwest block-portion commerciality. The asset was thence named Mero Field. From that point, the Libra EWT became known as the EPS, continuing foreseen planned tests in the field and interconnecting the FPSO to different producer and injection wells to gather valuable reservoir information to drive block development. In April 2022, Mero 1, the first permanent project in the Mero field, began production with FPSO Guanabara.
To explore, derisk, and optimize the development concept of the large Mero field, the Libra Consortium launched an EWT campaign using the Pioneiro da Libra as it moved between different locations in the field. This FPSO vessel connected to one or two production wells and one injection well in each location. The development concept used flexible lines and thermoplastic umbilicals. The FPSO started operation in 2017. At the time of writing, the FPSO has performed three EWTs combining different production and injection wells.
By 2025, the Mero field will have four additional FPSO vessels besides Pioneiro de Libra. The first is Guanabara, which began producing in April of 2022 in the Mero 1 area. The second is Sepetiba, which will begin operations in the Mero 2 project area, followed by Marechal Duque de Caxias in Mero 3, and Alexandre de Gusmão in Mero 4 (Fig. 1).
