Offshore and Marine: Challenging Offshore Installation Tactics and First Float Over Installation Accomplishment in Cheleken Field

Abstract The Caspian Sea is the largest landlocked sea between Asia and Europe with its own pros and cons. The enormous reserves in Caspian has created great opportunities for Oil and Gas operators and their partners (Service and EPIC Contractors). The design and installation of offshore structures have been always inspiring for structural designers and naval architects. In the past decade, various installations have been successfully completed using different techniques based on the availability of marine vessels & cost dynamics. This paper provides insights about challenging techniques used for various installations including Topside float over keeping focus on Safety, various technical aspects and cost effectiveness right from detailed engineering to installation phase. Considering availability of marine heavy lift vessels in the region and their day rates considering the constraints with the Volga-Don Canal size, the following methods/Designs were developed and implemented: The jacket was divided into two parts (lower and upper). Each portion weighing approximately 400 mt (metric ton) were installed one above the other with locator mechanism to maintain lower CAPEX. This was mainly due to non-availability of heavy lift vessels.Similarly for another project, during detailed engineering phase an "Intermediate Support Frame" was introduced by adjusting jacket and deck module height."Hydra-Lok connection technology" was used for pile sleeve strong connectivity. This was mainly to avoid any welding and grouting requirement.For the float over, unique LMU (Leg Mating Unit) were fabricated in Caspian and Transportation barge was assembled in Caspian region with capacity to launch 4,000 mt jackets and install 6,000 mt topsides. These customized installation techniques have helped in achieving required timely project completion and thus meeting production targets. For other conventional installations, available crane barges with smaller lifting capacity were used for facilities/ modules installations. This paper further addresses the technical issues and challenges emphasising intricacy and effectiveness of the technology used. The development of novel systems described in 1, 2 & 3 above are most suitable for Caspian region, with more focus on float over installation systems as well. The achievements till date has paved ways for future optimised and safer designs and float over method has added a feather in Cheleken area resulting in early completions of projects at reduced CAPEX.