Installation of Conductor Supported Platform CSP at X Field

Abstract

This technical paper presents the offshore installation execution work of Conductor Supported Platforms (CSP) at ‘X’ field. The knowledge sharing was based on the successful installation of three (3) numbers of CSP for ‘X’ development project. The platforms were installed at approximately of 70m water depth and encountered technical challenges during offshore execution. ‘X’ field is located about approximately 45km North West of Miri, Sarawak. The CSPs were installed by Derrick Barge (DB) via double blocks crane upending method for the substructures and conventional lifting method for the topsides. The CSP was designed for 70 meters water depth with four (4) numbers of vertical legs, four (4) numbers of skirt piles, and one (1) number of pin pile. The weight of the topside was about 600MT, meanwhile the substructure was about 1100MT respectively. These CSPs marked as a pioneer in the installation of its kinds at 70m water depth in COMPANY. The concept required high accuracy of detailed offshore installation engineering. This configuration however had caused some challenges during installation. Among the major challenges were issues on the pin-pile verticality, substructure levelness and upending activities via double blocks crane upending method. The effective strategies were adopted to improve the on-bottom stability by installing pin pile prior to substructure set down. The pin pile was installed by utilizing Subsea Fast Frame (SFF), in order to achieve pin pile's verticality. The crucial part during pin pile installation was to ensure meeting the verticality accuracy and minimum tolerance may high potentially impact the substructure install ability and meeting level requirement. However, due to a big annulus gap at pin pile sleeve of the substructure had caused prolong in levelling operation. In order to improve subsequent platforms levelling operations, a set of centralizers were introduced and installed after confirming the pin pile verticality result, in order to reduce the annulus gap. Despite all the challenges aforementioned, the installation of CSPs were completed successfully and most importantly with Zero Lost Time Injury (LTI).