Anti-Agglomerant Hydrate Inhibitors for Prevention of Hydrate Plugs in Deepwater Systems

Abstract

Abstract Anti-agglomerant low dosage hydrate inhibitors (LDHI’s) give operators an additional tool for controlling hydrates in their systems. In contrast to kinetic and thermodynamic hydrate inhibitors, anti-agglomerant LDHI’s inhibit hydrate plugging, rather than hydrate formation. Thus anti-agglomerant LDHI’s allow hydrates to form but keep the particles small and well dispersed. Fluid viscosity remains low, allowing the hydrates to be transported along with the produced fluids. Emulsification of the produced fluids is not necessary; in fact, anti-agglomerant LDHI’s have aided in demulsifying several black oil emulsions. In the laboratory, anti-agglomerant LDHI’s have been shown to be effective up to 40 °F below the hydrate formation temperature, at pressures up to 7000 psi, and for shut-ins up to two weeks in duration. In addition, extensive laboratory testing and formulation work have been performed to ensure that the anti-agglomerant LDHI’s are compatible with system metals, elastomers, and treatment chemicals, and that the products will not plug umbilicals nor cause upsets in surface facilities. After a comprehensive laboratory evaluation, an anti-agglomerant LDHI was selected for field testing in a deepwater, Gulf of Mexico oil well. The product protected the system throughout the 1.5 month trial, including two brief shut-ins. This paper presents the results of the laboratory and field tests.