Upgrade of Spar Topsides with Comprehensive Facilities Sand Management System

A Deepwater field located offshore Sabah, East Malaysia, in average water depth of approximately 1300m and operated by Murphy Sabah Oil Co., Ltd features a spar dry tree unit and multiple subsea hub tie-backs to an FPSO. In early 2011, several of the wells on the spar began producing fines which affected production. In order to maximize production, Murphy Sabah initiated three separate actions to control the fines. The long term solution was to re-complete the affected wells with enhanced sand control on the lower completions, such as open hole gravel pack and cased hole frac packs. The short term solutions consisted of installing a topsides sand management system on the spar to remove solids at the wellhead prior to the choke, and installation of sand sparging equipment on the FPSO separators to remove build up of sand that was produced by the subsea wells and any sand that passed the spar wellhead desanders. This paper focuses on the spar topsides sand management system that is unique in its size and scope. It includes ten wellhead desanders, common slurry transport system, dewatering and bagging station, and skip removal to process up to 10 tons per day of sand. Current work is underway to upgrade the system even further with an integrated sand cleaning system and overboard discharge of the solids, which will be a first for Malaysian waters. The separation system is integrated into the wellbay with dedicated wellhead desander and accumulator units on each of ten wells which are designed to remove sand upstream of the choke. The first wellhead desander and the sand handling system were commissioned in October 2011 and a total of six desanders were on line by April 2012. Upgrading the spar with topsides sand management has effectively controlled the production of sand and maximized hydrocarbon production during the period between the advent of sand and long-term control by upgraded lower completions. A detailed process review of the sand management system is provided along with system integration timeline, solids analysis, and lessons learned.