Patent ID: 8047296
Filing Date: 2011-11-01
Classification: C09K,E21B,Y10T

Abstract:
1. A method for transitioning from introducing both a thermodynamic hydrate inhibitor (THI) and a kinetic hydrate inhibitor (KHI) in a hydrate-susceptible pipeline to introducing only a KHI in the hydrate-susceptible pipeline, in a system comprising at least a first hydrocarbon production pipeline leg from a first wellhead to a joint on the hydrate-susceptible pipeline and a second hydrocarbon production pipeline leg from a second wellhead to the same or different joint on the hydrate-susceptible pipeline at a joint, the method comprising: injecting a first amount of THI into both the first and second hydrocarbon production pipeline legs; injecting a first amount of KHI into both the first and second hydrocarbon production pipeline legs; increasing the amount of THI injecting into the first hydrocarbon production pipeline leg to a second amount of THI that is at least twice that of the first amount of THI while ceasing injecting THI into the second hydrocarbon production pipeline leg; increasing the amount of KHI injecting into the second hydrocarbon production pipeline leg to a second amount of KHI that is at least twice that of the first amount of KHI while reducing the amount of THI injecting into the first hydrocarbon production pipeline leg slowly at a rate effective to not cause hydrate formation in the hydrate-susceptible pipeline until the amount of THI injected is zero; and reducing the amount of KHI injected into both hydrocarbon production pipeline legs until a relatively constant amount is reached that prevents hydrate formation in the hydrate-susceptible pipeline.