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Abstract Hydrate formation becoming a common problem in a deepwater wells especially with colder temperature well. Due to extreme cold temperature near seabed and reaction between pressure and temperature with the present of gas, hydrate can form anytime in a short period of time. The common method that has been practiced on the past in removing the hydrate is by pumping an exothermic chemical due to inability of mechanical intervention behind CTGL string. With a certain chemical ratio and volume, these solutions can create more than 100degC liquid temperature at surface. With the good heat carrying capacity, this fluid is pumped into the well and eventually break the hydrate blockage. Hydrates formation evolves with time potentially due to an aging well and becoming more complex to remove it where in colder wells wax presence need to be considered. The blockage percentage becoming higher or composition of hydrate become undefinable potentially combination with other substance, i.e. wax thus need more exothermic chemical to break it and eventually reach to insufficiency and becoming uneconomical. This chemical is extremely expensive, need long lead time to procure, need proper storage in tanks after decanting which lead to logistics issues to mobilize onsite and high-risk exposure during handling it offshore. Due to these key challenges, optimization has been considered and implemented by pumping heated diesel as a substitution of exothermic chemical. On well architecture, it is equipped with 1.25" OD coiled tubing gas lift (CTGL), extending from CTGL hanger sit in profile at wellhead to circa 1500m inside production riser and ended 300m below the mudline. CTGL is installed to assist the well production improvement. Hydrates normally formed from 1200m at seabed upward in the annuli between CTGL and production tubing. Heat in the diesel is generated via circulating diesel system between the triplex pumping unit and holding tank. Due to looping lineup mechanism, temperature in the diesel will rise after few cycles of circulation. The orifice effect with high back circulating pressure increases the diesel temperature few degC until it can reach up to 60degC at pump discharge. Once the stabilized temperature established, heated diesel diverted and pump into the CTGL down into the well. At some point with certain amount of diesel pumped, heat equilibrium temperature is achieved across inside the CTGL and transfer it to hydrates regime or blockage zone outside. The pumping of heated diesel is continued for 5 to 6 days until contact time is sufficient to start melting the hydrate blockage, then the signed of increment of the SITHP indicates some communication has been established with the downhole with hydrate slowly breaking & melting. When this occurred, another batch of diesel is pumped from the backside through hydrocarbon flow path and eventually break the hydrates bridge inside the annuli. More than 2000bbls of heated diesel pumped into the well with no sign of formation damage to the reservoir. Even it took more days, about USD0.5 million cost saving per well is realized due to diesel cost is cheaper and recoverable. Diesel is also easier to source and has a reasonable flash point, making it much handier to handle. The risks are also low when dealing with diesel, even when handling it in large volumes. This exercise proved that heated diesel does help in breaking the hydrate even the generated temperature is not as high as exothermic chemical. Well production back online and reinstated after idling for many months. However, maintaining a constant diesel temperature with minimal heat dissipation toward the end of the CTGL remained a major challenge. This paper presents the development and field application of a heated diesel approach pumped through an existing coiled tubing gas lift (CTGL) system as an alternative hydrate remediation method. Leveraging diesel's availability, favorable heat-carrying capacity, reasonable flash point, and recoverability, sustained heat was safely delivered to hydrate-prone zones without mechanical intervention. Field results demonstrated consistent hydrate removal, zero safety incidents, no formation damage, and full restoration of well productivity to approximately 700 BOPD per well. Although requiring a longer operational duration, the method achieved cost savings of up to USD 3.7 million per well compared to pumping exothermic chemical or the usage of conventional HWU-based interventions, positioning heated diesel as a reliable and cost-effective solution for deepwater hydrate management.