Submerged Production System - A Final Report

Abstract

The offshore pilot test of a submerged production system (SPS) encompassedthe entire spectreum of SPS equipment, which was designed for use in waterdepths to 2,000 ft. Results show that deepwater installation techniques arepracticable, deepwater maintenance machinery is competent to repair anoperating system, with some modifications, the SPS is suitable for commercialapplication. Introduction The purpose of the submerged production system (SPS) is to provide a meansof producing offshore fields in water depths beyond the practical capability ofbottom-founded, surface-penetrating structures. The SPS is an integrated suiteof equipment designed to satisfy the life-cycle requirements for producing asubsea field from developmental drilling through field abandonment. Thisintegrated suite of equipment spans from the completion interval of the wellsto the transfer of produced fluid into a common-carrier pipeline or shuttletanker. The prototype version of the SPS used for the pilot test included atleast one representative piece of every type of oceanfloor equipment requiredfor a commercial application. The subject of this paper is a discussion of SPScapabilities from both functional and maintenance viewpoints followed by adescription of the offshore pilot test performed to validate the SPS concept.The pilot test description covers the prototype SPS equipment, test objectives, conduct of prototype SPS equipment, test objectives, conduct of the test, and, finally, conclusions that were made following an evaluation of testresults. SPS Functional Capabilities The SPS is a full-capability production system. Fig. 1 depicts the system'smost general equipment configuration. The template unit shown on the seaflooris the major component of the system. The fluids produced by the wells andgathered by the template produced by the wells and gathered by the templateunit are routed via pipelines and an articulated production riser to a surfaceprocessing facility for production riser to a surface processing facility forstorage and disposal. The drillship shown in Fig. 1 is used both for installingthe template and for drilling the development wells. Among the designrequirements that apply to all SPS equipment are that they be simply, highlyreliable, and have a long life expectancy. One of the most salientcharacteristics of the SPS is that it eliminates the need to expose personnelto the ocean-floor environment during personnel to the ocean-floor environmentduring installation, operation, maintenance, and (at field abandonment)recovery of the subsea equipment. Surface-controlled, electrohydraulic, supervisory control equipment is used to control and monitor the ocean-floorequipment remotely. On command from the surface, hydraulic power is switched tooperate valve actuators and diverter actuators in the manifold. Allflow-control valves - such as downhole safety valves, master valves, wingvalves, and pipeline block valves - are fail-safe closed and pipeline blockvalves - are fail-safe closed and require the presence of hydraulic pressure toremain open. The monitoring capability provides sufficient information to (1)determine the performance of a well, (2) generate appropriate workoverprograms, and (3) troubleshoot an equipment malfunction in preparation formaintenance. An automatic, fail-safe preparation for maintenance. An automatic, fail-safe safety system monitors the manifold and the control equipment. If anoperating parameter exceeds its preset limit, a preplanned course of action ispreset limit, a preplanned course of action is initiated automatically toreturn the equipment to a safe operating condition, usually to shut in all orpart of the wells. JPT P. 899