Abstract: In view of the workover characteristics of offshore platform, the pilot laboratory evaluation and subsequent field application of workover unplugging and cleaning technology have been conducted for selecting the platform suitable for offshore operation. In this technology, thermo chemical washing is dominated, combined with the assistant fluids for well washing and the preflushing fluid. With the large amount of heat and gas produced by the thermo chemical reactions, this technology can effectively remove the organic plugs from the wellbore and the reservoir, and especially can increase the output of the oil well and shorten the recovery period of the well.