Project X Complex Transportation & Installation Campaign; Strategies & Scheduling for Greater Cost Effectiveness Conference Paper uri icon

abstract

  • Abstract This paper discusses on the methods of the installation of platforms, pipelines and subsea fiber optic cable including its challenges the subsequent mitigations. The knowledge is based on the successful installations of Project X Gas Development Project consist of a CPP, flare tower & riser platform, 28" × 81km pipeline from CPP to riser platform and 8km CPP to nearby platform of subsea fiber optic cable. The methodology applied in the installation of the CPP jacket is via reverse launch and self upending method. The CPP topside is installed via longitudinal floatover method. The rest of the jackets, topside and other structures was lifted and installed by main work barge. The pipeline was installed via typical S-lay pipeline installation utilizing automatic welding system for the pipelaying and stalk-on of risers at both sides of the platform. The inspection is using Automatic Ultrasonic Testing (AUT) complete with the Engineering Criticality Assessment (ECA) and precomm activities were performed as well. The subsea fiber optic cable has been laid and post trenching was performed to bury the cable. There are multiple approaches that a company can take to reduce the schedule and ultimately reduce the cost of offshore installation. For platform installation for example for this project is on the self upending method for jacket installation whereby less main work barge cranage capacity can be used to upend the structure underwater. The flare tower and riser platform jacket were installed using a double block upending method as the HLV crane is equipped with split block configuration on the main hoist. This reduces the duration as it eliminates the flooding and buoyancy requirement including reduction in lifting points. Furthermore, floatover installation with integrated topside design significantly reduces the duration of offshore installation including the need to have high cranage capacity to lift the topside. For pipeline installation, stalk-on of risers reduces the need to flood to pipeline prior to riser installation and eliminates a weak point of subsea flange connection for this gas pipeline. Furthermore, an overall study of the pipeline in flooded and operational condition can reduce the numbers of concrete mattress installation required to meet the design requirement. For subsea fiber optic cable, a post trenching machine that is less sensitive to weather ie. that can perform the work during monsoon, can further improve the schedule of the offshore installation. The overall schedule was improved by 20% and subsequently the cost implicated is reduced as well. The diverless platforms installation including reverse launch self upending method for jacket installation and longitudinal floatover topside installation are the few novel approaches in the project.

publication date

  • 2024

start page

  • D021S011R005