An Experimental Subsea Production Station
Authors: Chateau Georges M. 
Published: December 2007

An experimental subsea production station was installed in 200ft of water offshore the Republic of Gabon. This paper describes installation of the three major elements - Grondin production platform, support vessel Anguille, and the subsea unit. Operation of the station resulted in the development of advanced systems and equipment for deep-water production.

Introduction

Elf Aquitaine has initiated a research program for producing offshore oil in deep water in virtually any location producing offshore oil in deep water in virtually any location in the world. Pilot operations are planned. The first pilot in the series is an experimental subsea station off the Republic of Gabon (Fig. 1). This station is located on the northeast extension of the Grondin Field, 4,920 ft from the fixed production platform complex, in 200 ft of water.The experimental station will be used for developing production from the Grondin Northeast extension. The production from the Grondin Northeast extension. The station includes three producing wells - one vertical well and two deviated wells.During 1976, the sea-floor station was installed and the vertical well was drilled and completed. Operations from the barge Anguille, a support vessel constructed for the station, were begun to connect control circuits and production lines. Production from the well began in production lines. Production from the well began in Dec. 1976.During 1977-78, two deviated wells were drilled and completed. Production continued after the experimental programs began. programs began. The Societe Nationale Elf Aquitaine (Production), abbreviated as SNEA(P), has over-all responsibility for the project. A subsidiary, Elf Gabon, operates the field. An project. A subsidiary, Elf Gabon, operates the field. An Elf research engineering group located in Pau, France, assisted by SNEA(P) services and several contractors, is responsible for conception, engineering, and project coordination. Project decision centers are located in Pau, Paris, and Port Gentil. The scope of the project is Paris, and Port Gentil. The scope of the project is international, using the combined knowledge of companies located in France, Gabon, Europe, and the U.S.

Description of Station

The Grondin Northeast experimental subsea production station (Fig. 2) has three major elements:the subsea installation,the Grondin production platform, andthe support vessel Anguille.

The subsea installation includes wellheads (equipped with control systems and production piping) for delivering produced production piping) for delivering produced hydrocarbons to the Grondin production platform. The subsea station is linked to production facilities on the Grondin platform by remote-control lines and flowlines. platform by remote-control lines and flowlines. Wellhead functions are controlled remotely from the platform. Production from wells flows to the platform through two Production from wells flows to the platform through two subsea flowlines. Installation, connection, and maintenance on Ne subsea station are conducted from the Anguille.

The Subsea Installation Template for Subsea Wellheads

The subsea production wellheads (Fig. 3) are mounted on a template constructed of 16-in. pipe. The template is 75 x 22 x 5 ft and weighs 40 tons. The template is designed to receive manifold structures, production equipment, and three production wellheads. Construction includes five identical well slots. The first slot is occupied by a control system module.

JPT

P. 1641