CFD MODELING FOR THE TOTAL EP ANGOLA PAZFLOR SUBSEA FIELD COLD SPOT MANAGEMENT PLAN

摘要

The PAZFLOR field is located in Block 17, deep offshore Angola, and is one of the largest offshore/subsea development operated by TOTAL E&P Angola (TEPA). As part of the SURF package scope of work, flow assurance analyses had to be performed to verify the global thermal integrity and operability of the subsea architecture. In particular, a cold spot management study was carried out to ensure that adequate insulation was implemented on all the SURF equipment to achieve the project specified thermal performances. The purpose of the cold spot management plan is to complete the general Flow Assurance study mainly using OLGA software by performing a detailed flow and thermal analyses, using dedicated CFD simulations, for each subsea singularities identified as potentially creating a local cold or hot spot Hot spots could lead to an accelerated ageing of some of the equipment materials, whereas cold spot could lead to a quicker cooldown time than required creating a local risk of wax or hydrate plug formation. The Pazflor SURF cold spot management plan has combined detailed CFD modeling and full scale thermal testing to validate the equipment insulation design and check via a validated simulation the exact thermal behavior under subsea conditions. An extensive amount of subsea elements have been studied such as Rigid Pipe-in-Pipe (PIP) waterstops, flexible IPB riser, pipeline In line Tee structure piping and valves, Field Joint Coating with anode pad, flexible end-fittings and thermal insulation covers amongst other things. This paper will detail the CFD simulations performed, present the comparison between the simulation results and the full scale thermal tests and draw conclusions on the benefit of such cold spot analyses for future projects.