Submerged Production System - A Final Report

ABSTRACT The offshore pilot test of Exxon's Submerged Production System (SPS) has reached a successful conclusion. This pilot test encompassed the entire spectrum of SPS equipment, spanning from the well completion intervals to, but not including, common surface processing and storage facilities. Since the SPS is designed to meet all the life cycle needs of a subsea field, one of the objectives of' the pilot test was to evaluate both the techniques and the equipment used to install, operate, and maintain a prototype version of the SPS. The equipment under test was designed for use in water depths up to 2000 feet, but with minor modifications it is capable of operating in significantly greater depths. Evaluation of pilot test results has shown that the deep water installation techniques are practicable and that the deep water maintenance machinery is competent to repair any failures likely to occur in an operating system. One of the most significant problems in conducting the pilot test was achieving adequate quality control during equipment manufacture. The test results have demonstrated that, with relatively minor modifications, the SPS is suitable for commercial application. INTRODUCTION The purpose of the submerged production system (SPS) is to provide a means of producing offshore fields in water depths beyond the practical capability of bottom-founded, surface-penetrating structures. The SPS is an integrated suite of equipment designed to satisfy the life cycle requirements for producing a subsea field from developmental drilling through field abandonment. This integrated suite of equipment spans from the completion interval of the wells to transfer of the produced fluid into a common carrier pipeline or shuttle tanker. The prototype version of the SPS used for the pilot test included at least one representative piece of every type of ocean floor equipment required for a commercial application. The subject of this paper is a discussion of SPS capabilities from both a functional and maintenance viewpoint followed by a description of the offshore pilot test performed to validate the SPS concept. The pilot test description covers the prototype SPS equipment, test objection Yes, conduct of test, and, finally, conclusions that were made following an evaluation of test results. SPS FUNCTIONAL CAPABILITIES The SPS is a full capability production system. Figure 1 depicts the system's most general equipment configuration. The template unit shown on the sea floor is the major component of the system. The fluids produced by the wells and gathered by the template unit are routed via pipelines and an articulated production riser to a surface processing facility for storage and disposal. The drillship shown on Figure 1 is used both for installing the template and for drilling the development wells. Among the design requirements that apply to all SPS equipment are that they be simple, highly reliable, and have a long life expectancy. One of the most salient characteristics of the SPS is that it eliminates the need to expose personnel to the ocean floor environment during installation, operation, maintenance, and (at field abandonment) recovery of the subsea equipment.