Production Subsea Installations Control And Supervision Electronic Systems Development

Abstract

ABSTRACT This paper intends to present not only a supervision and control subsea electronic system development history in the PETROBRAS Production Department, but also their architecture, basic characteristics and offshore operational results. The aimed projects are: MUXCOM: The MUXCOM project, conducted by PETROBRÁS and BRASNOR, a PETROBRÁs affiliate company in Norway, has developed an electro-hydraulic multiplexed control system, which has been installed at Bonito-n production wel1 in Campos Basin, Brazi1, and is under uninterrupted operation since November/1990. SESCO: As a MUXCOM evolution, it was developed by PETROBRAS a second Supervision and Control Electronic System (SESCO " Sistema EletrÔnico de Supervisao e Controle) for application at "OCTOS-1OOO, a subsea production template-manifold, composed by seven "X-mas trees" and also developed by PETROBRÁS. The communication between the surface unit and the seven subsea units is done trough a two-wire network. The subsea units power supply is done by the communication signal, itself. The system is also able to be integrated to the P1atform Central Supervision and Control Station (ECOS), what permits the OCTOS-1OOOoperation from the rig main control console. MUXCOM PROJECT The MUXCOM (Multiplexed Control and Monitoring) projects was part of PETROBRÁS "Deep Water Capability Program"(PROCAP) and its main objective was the identification of critical points and cost allocation of a subsea control system designed to operate at 1000 m water depth. The program should also provide the basis for a control system more suitable for the Brazilian scenario. Reliability is the most important requirement when dealing with subsea production control systems, but some other points 1ike versatility and cost efficacy are important as well. The project development was based on wel1 tested standard components with good field records in order to reduce cost and failures risk and, therefore, extensive testing at component 1evel was not required. However, a 1ot of tests were carried out to ensure that al1 of them could work together in the proposed configuration and submitted to 100 bar external pressure. Special attention was paid to some critical components 1ike hydraulic and electrical connectors and solenoids valves. MUXCOM'S ELECTRONICS During the MUXCOM project conceptual development phase, a market survey was carried out to verify the feasibility of introducing a market available electronics into the system and so reducing the cost and time of developing it by ourselves. It was concluded, after sane inquiries, that there was no electronic package available in the market able to fulfill our requirements and to fit the project budget. It was also considered that the effort that should be spent in order to modify and to adapt the market available electronic system to our application would be almost so high as developing a brand new and dedicated one. Therefore, it was decided to go into a dedicated electronic system development from scratch.