4Subsea (Norway)

Abstract In recent years, various operating companies have been working on the processes of "Simplification, Standardization, Automation, Digitalization, and Optimization in several elements". To achieve this, there are tremendous subsea technology developments going on all over the world in many areas such as; design in terms of size and weight, improvement in reliability, advanced materials, flow assurance, digital tools, real time condition monitoring and control, installation and operation. The development of Subsea technology continues to be an important part of subsea field development projects to reduce the life cycle costs, increase recovery, provide solution to long tieback problems and challenges. PETRONAS ("the Company") is pursuing an Upstream Life Cycle Cost (CAPEX/OPEX) reduction approach under the Facilities of Future (FOF) program and mission called "Subsea Factory". The FOF target is to reduce Upstream life cycle cost by 40% starting from 2025 and Subsea Factory is one of the enablers to contribute to the reduction. There are four primary technologies focused on Subsea Factory: Subsea Separation, Subsea Multiphase Pump, Water Injection and Subsea Storage. The Subsea Multiphase Pump is one of the prioritized technologies for Subsea Factory to contribute to a 40% reduction. Subsea multiphase pump technology has great potential to reduce the CAPEX/OPEX and increase oil recovery, but due to the high equipment cost, huge topside space requirement, reliability and operating issues become very challenging and limit its application to operating companies. The Company collaborates with FASTsubsea AS on a Joint Industry Project to develop and qualify "the World first All Electric & Topside-less Subsea Multiphase Pump Technology". The uniqueness about this technology compared to commonly installed subsea pump is that it requires much less topside space as there is no need for variable speed drives or barrier fluid hydraulic power units. This paper describes the qualification and application of All-electric & Topside-less subsea multiphase pump technology in the Company - Subsea Factory mission, including: pain point with conventional subsea multiphase pumpthe Joint Industrial Project initiative with respect to technology development to pilot test to maturityimplementation of this technology and value creation in upcoming field development projectthe case study and potential of this technology for the Company future field development project

Abstract The cylindrical FPSO is now in operation at three offshore oilfields, on in Brazil and two in the UK Central North Sea. It is furthermore selected for a field development in the harsh and sub-arctic Norwegian Barents Sea. Full scale monitoring of motions on units in operation has verified predictions, confirming very favorable motions when compared to shipshape FPSOs and even semi submersibles. In 2009, a study was awarded by a major oil company to investigate the feasibility of applying Steel Catenary Risers (SCR) with a cylindrical FPSO at a location with deep water and very harsh environment. Results from the initial analysis proved feasibility and associated model testing has allowed calibration of first order and second order analysis methods and particularily have lead to a better understanding of second order and heave coupled pitch motion effects. Adaptation of the cyclindrical hull to improve its characteristics as a host platform for steel catenary risers has been the incentive for the case study outlined in this paper. Platform and riser optimisation should be field specific, but the results presented for a very harsh environment, demonstrate the feasibility of steel catenary risers with a cylindrical FPSO at any location, worldwide. In this paper, the focus is on demonstrating how a cylindrical FPSO/SCR design spiral can progress towards meeting the challenges of a harsh environment with competitive hull/riser combinations. Introduction The cyclindrical FPSO/SCR challenge is to provide an SCR hang-off location with motions, as follows, even in very harsh environments.The maximum downwards vertical velocity in 100-year design conditions should be less than 2,4 m/s (1,9m/s in 100 year conditions is achieved)The long term distribution of all motions at the riser hang-off shall provide a robust SCR fatigue life (achieved with low amplitude heave RAO within Tp range with high % occurrence)Angular motion should stay within a range of +/- 25 degrees at hang-off (achieved 18,1 degres)Horizontal offsets envelope within 2,5% of waterdepth in 100 year conditions with intact mooring (achieved 2,3%) A cylindrical FPSO with SCR hang-off in a moonpool is demonstrated to meet the above criteria with margins, even for very harsh environments. The Cylindrical FPSO is arranged so that the SCR hang-off is located very close to the centre of the FPSO, within a moonpool, and thus the predominantly heave induced vertical motion at the riser hang-off meets SCR hang-off motion targets. Mooring systems are developed to meet the offset criteria. The case study responses are reported for a 16" gas export riser, based on API standard seamless pipe dimensions with 5 mm corrosion protection coating, resulting in an "OD/weight submerged" ratio with 148 kg/m3 contents of 3,0 m2/tonne. Equivalent 123/4" and 103/4" production SCRs with contents 800 kg/m3 and high insulation are outlined for benchmarking.