Offshore Early Production Platform Proposal to Overcome Caspian Sea Constraints

Abstract This paper highlights the constraints for installation of early production facilities in the Caspian Sea region due to land-locked geography and non-availability of suitable marine construction vessels. Additionally, high risk for investment exists in the offshore Turkmenistan fields due to the concern of marginal field reservoirs. To address the concern, a removable jacket concept is provided that can be constructed and installed quickly and relocated at other locations in case of commercially unviable well flow rate. This paper proposes a minimum structure to drill and appraise two oil wells without installing a full-fledged structural jacket and deck. The jacket will be connected to the seabed by temporary skirt piles. In case of a positive drilling outcome, the jacket will be piled and a deck with minimum topside facilities will be installed. A flexible pipeline will also be installed to connect with the nearest subsea/onshore tie-in point to carry out prolonged well testing (for months) and subsequent production operation. The existing and the new decks will be joined offshore. The conceptual design has a provision for four future wells. Numerical studies show that the skirt-piled structure at 30m water depth can withstand up to 1-year return period environmental loads. The final structure after installing the permanent piles can withstand 100-year environments loads. Structural design is performed using API RP2A working stress design method. The results show the adequacy of the structure and prove that the investment risk can be considerably reduced by carrying out appraisal drilling before installing the full production facilities.