Formation and removal of hydrate plugs -- Field trial at Tommeliten

This paper describes experimental results from the study on hydrate plug formation and removal. Fields tests were carried out at the Tommeliten Gamma Field in 1994. The observations from the field experiments raised a number of questions which were later tested in the laboratory. Laboratory experiments on the formation and melting of plugs are still ongoing. The paper gives an overview of the field trial observations and briefly summarizes some of the laboratory results retained. The hydrate experiments were performed at the Tommeliten Gamma field in the North Sea. Tommeliten is located west of Ekofisk and is tied back to the Edda platform through three 11.5 km flowlines; two 9-inch production lines and one 6-inch test/service line. The field experiments were carried out using the 6-inch test/service line. Hydrate plugs were formed in the line as well as topside on Edda. Hydrates were formed under various conditions; clogging at continuous flow conditions, as well as re-start after shut-in both in a pressurized line and in a depressurized system. Depressurization, methanol injection and heating were applied in order to melt the plugs. The laboratory experiments were performed using a flow simulator as well as a rig specifically designed to study meltingmore » of hydrate plugs.« less