Zinc Project: Integration Land Testing Of The Subsea Control System

Abstract

ABSTRACT Integration land testing of the Zinc subsea control system was a vital step in the preparation of the overall production system for successful operation after installation. The testing was done using all control system, umbilical, manifold, tree, and pigging valve assembly equipment in the exact configuration to be used during operations to the highest degree possible. This paper describes the various tests included in the program, giving results of each test, and pointing out the problems that were encountered and dealt with. OVERVIEW OF INTEGRATION LAND TEST PROGRAM Prior to installation of the Zinc Subsea Production System template in December 1992, all components which interface with the template were rigorously tested during an eight month Integration Land Test program. Since Zinc is a diverless system designed for 1,500 foot water depth, the goal of the program was to verify proper fit and function of all components under conditions simulating remote installation and operation. An important feature of the testing was the participation of operations personnel as an integral part of the test team. The scope of the program included:Trials of template, flowline, and umbilical installation ProceduresRemoval and replacement of components which can be retrieved to the surface for maintenance such as subsea control pods, the pigging valve assembly, and the production manifoldFit testing of subsea tree components on template and manifold interfacesVerification of Remote Operated Vehicle (ROV) access and operation of ROV-conveyed tools at all locations where ROV intervention is requiredSystematic demonstration and verification of all functions and operating characteristics of the control system which enables remote operation of the Zinc subsea system. Factory Acceptance Testing (FAT) of individual components to ensure compliance with dimensional and functional specifications was performed at contractor manufacturing locations before delivery to the Land Test site. The thorough FAT program was a key to minimizing the duration and enhancing the success of the Integration Lanci Testing Program. Wherever possible, the Land Test program duration was further minimized by incorporating integration tests which did not require access to the template (such as operation of subsea tree functions by the installation/workover control system) into the off-site acceptance test programs. The site selected for land testing was the fabrication yard where the template and manifold were built. Most of the integration tests performed during the program took place inside a deck assembly building and were therefore unaffected by weather. Two overhead cranes were available to assist with movement of components and test equipment around the template. A temporary clean morn facility was erected inside the building for preparation and testing of control system components requiring protection from the ongoing construction activities in adjacent bays of the assembly building. This paper focuses on the considerable portion of the Integration Land Test program associated with the subsea control system and its interface with other subsea equipment such as trees and the pigging valve assembly. This portion of the program included fit and function testing, a series of integration tests with the other subsea equipment operated by the control system, and testing of all the running tools needed for control system maintenance.