Hydrates Management in Deep Water Field with Lower Temperatures Reservoirs- Challenges and Lessons Learnt

Abstract Hydrate formation is a major challenge in production from deep water fields especially in reservoirs with higher pressure and lower reservoir temperatures. Partial or total hydrate blockages usually occur after shutdown in pipeline, downstream of choke or upstream plants is most common and can be handled by hydrate inhibitors. Hydrate formation in down hole tubing near the gravel pack completion of the well is unusual. Due to the intricacies of subsea production systems, challenges in well completions and vastness and complexities of Deepwater fields present challenges and envisaged hydrate management strategies might not be as effective as planned in exceptional cases. ONGC Eastern Offshore Asset consists of deep water brown and green fields with subsea well completions. A deep water gas field of Eastern Offshore Asset ONGC with reservoir temperature less than 40°C is one such exceptional case and has faced unique hydrate issues which is hydrate formation in the lower completion of the well during production. This has caused flow assurance and operational challenges in the well along with production decline. This paper is intended to discuss the various hydrate control methods and strategies that have been evaluated and implemented during the project's design and Factors for failure of implemented hydrate management in down hole were analyzed and various approaches that have been taken in mitigation of hydrate in the well. It will be beneficial to be shared across the fraternities of the lesson learnt in the mitigation strategies which will be discussed in detail throughout the article based on case study from subsea deep water Y field development.