Phase 1 development of the Garoupa Field, offshore the state of Rio de Janeiro, Brazil, involves the use of a unique system for control of the subsea production equipment. The project is an ambitious one, directed by a special engineering group set up within the Petrobras Department of Exploration and Production. Nine subsea dry completions and one subsea dry manifold center house the underwater production equipment in approximately 150 meter water depth. A storage and processing' tanker is permanently moored to an articulated production tower located 800 meters from the manifold center. The control system operates all of the subsea equipment at the wells and in the manifold center from a control room located on the tanker.
The Garoupa Field subsea electro-hydraulic control system is the first underwater production system to use microprocessors and minicomputers in both the subsea locations and in the tanker control room. This technology represents a major advance in the application of modern electronics to underwater oil and gas production control systems. It is particularly applicable to both wet and dry early subsea production systems (those brought into production before platforms are available). Design considerations are presented describing the use of redundant electronic and hydraulic subsystems to achieve high, long-term reliability. The paper discusses the overall electro-hydraulic system and describes the development, design and testing of the equipment. Results of the exhaustive dry land testing program are included in the discussion.
The background of the Phase 1 Garoupa Field Development Project has been described previously (reference 1) but will be summarized here for completeness.
Petrobras, in 1975, formed a special engineering task force (ASCAM) within the Department of Exploration and Production (DEXPRO) to develop and produce the resources of the Garoupa Field. This area is located approximately 50 miles offshore the state of Rio de Janeiro, Brasil, at a water depth of about 150 meters.
The field development was planned in three stages:
Phase 1 - produce 9 exploratory and field delineation wells as quickly as possible to help ease Brazil?s energy shortage problem
Phase 2 - build a permanent production system
Phase 3 - expand the facilities and lay pipelines to shore
Petrobras elected to manage the Phase 1 project directly within the ASCAM organization in Rio, integrating and coordinating the efforts of many Brazilian and foreign companies. A great deal of effort was expended by both ASCAM and the various suppliers in coordinating the subsystem interfaces in view of the language barriers and large geographical distances involved.
Cameron Iron Works, Inc., Cameron Control Systems, based in Houston was selected to supply the control system to operate the subsea production equipment from the production tanker control room. An engineering review committee was created by ASCAM to write the control system specifications and to periodically review and modify the specifications as required during the engineering design and early manufacturing stages. This committee consisted of engineering representatives from Petrobras ASCAM, Cameron Control Systems and Lockheed Petroleum Services, Ltd. Lockheed was chosen to supply the subsea, dry, one-atmosphere chambers.
