Abstract When deep-water subsea production is shut in for long periods, measures are normally taken to prevent the formation of hydrate blockages in the flowline network. One common inhibition method is to inject methanol into the jumpers, manifold headers, and well bores. This paper presents the result of experiments that were conducted to investigate the distribution of inhibitor injected into a static (no production flow) header or bore that contains oil, water, and gas. The test results were used to help develop a more effective header design and also to shape operating guidelines for inhibiting after shut-in. A test facility was constructed to test various header configurations and production conditions. Tests were conducted to investigate the effect of varying the water cut, gas volume fraction, header inclination angle from horizontal, and the oil density. Experiments also examined the distribution of methanol injected into a vertical well bore. Results are presented that show the dispersal of oil, water, and gas in the header after shut-in and after injecting inhibitor into the header. In all test cases, uninhibited water remained in the header after methanol injection and no protection was provided against hydrate formation. Either the methanol never came into contact with the water or the diffusion in the static system was so small that the methanol and the water remained segregated. Test results also show that the maximum amount of inhibitor present in the header after methanol injection depends upon the oil density, header geometry, and the amount of gas trapped in the header. These results can be used to determine the maximum amount of inhibitor that needs to be pumped to inhibit a shut-in header section. Given the apparent failure of methanol to disperse in such a way as to inhibit water, further tests were run to examine why this common practice of methanol inhibition is successful. These experiments gave some explanation for the success of this procedure and yielded insights to the timing of chemical injection.