Flow Assurance Challenges - FPSO Based Development of MA Deep Water Field

Abstract

AbstractMA (D-26) field in KG DWN 98/3 (KG D6) block is located on East Coast of India, about 60 km away from the Onshore Terminal (OT). This is India’s first deep water oil and gas field developed and being operated by Reliance Industries Limited (RIL). The water depth in this field varies from 1100m to 1400m. This field was put on production through FPSO in September 2008 and production was gradually ramped up to 35,000 BOPD and 8.5 MMSCMD gas.MA field had major flow assurance challenges of hydrate formation, wax and scale deposition and slug flow. This paper describes the strategy adopted to address the flow assurance challenges and the lessons learnt from practical field experiences related to three distinct areas of MA field operations:Field start up and production from wells through the subsea manifold and risers.Changeover of gas injector well into a producer.Gas export from FPSO to Onshore terminal.The initial startup of the field highlights the importance of having a suitable fluid in the production tubing to minimize the J-T effect across the subsea choke to prevent hydrate formation. Startup of a well also posed slug handling challenge which was mitigated by using topside chokes and adequate slug handling capacity of separators. The hydrate management strategy developed for successfully managing the shutdown and start ups within the available cool down period of 4-5 hours for MA field is discussed.Changeover of gas injector into gas producer had its challenge of understanding the well bore temperature dynamics. Continuous injection of methanol at the well head of the changeover well was resulting in carryover of methanol in the crude oil/gas at the FPSO which called for a relook at the hydrate management strategy.Comparison of the options of flowing the dehydrated gas in trunk pipe line containing pre commissioning fluid (MEG-Water) vis a vis vacuum drying of the trunk pipeline for gas export from FPSO to Onshore Terminal is discussed and the field experience is presented.