Continuous Anti-Agglomerant LDHI Application For Deepwater Subsea Tieback: A Study on Water Quality and Low Water Cut Scenarios

摘要

This paper details the continuous field application of an anti-agglomerant low dosage hydrate inhibitor (AA-LDHI) for a deepwater Gulf of Mexico subsea tieback with an unconventional projected production profile. Due to pump limitations and projected production, as well as methanol-in-crude contamination issues, thermodynamic hydrate inhibition was not suitable for this new well. The chemical was first qualified by rocking cell performance tests, followed by a rigorous topsides trial on the host platform simulating AA injection into the expected water production. AA injection began less than 24 hours after the well was brought online using methanol. Several lessons were learned regarding the application of AA at low water cuts. The chemical has been successfully applied for more than one year with no significant effects on water quality or hydrate events including during shut-ins.rnThis paper will provide the feasibility for continuous application of AA from early field life without water quality issues when reliance on methanol, a thermodynamic hydrate inhibitor, wasn't viable. Field and lab data will be presented to support the case for continuous application of AA chemical without the traditional water quality issues associated with LDHIs. Field data will also reveal important discoveries regarding the application of AA at low water cuts (<1%). The discovery of the behavior of AA at lower water cuts is a significant contribution to the industry. Chemical phase partitioning must be considered in an oil-dominated system.