New Progress of the Offshore Thermal Recovery Technologies in Bohai Bay, China

Abstract

Abstract There is abundant heavy oil resource in Bohai Oilfield and good development performance of the pilot area has been acquired by using thermal recovery technology. In recent years, a series of researches and field pilots have been conducted and great progress has been achieved on several aspects. For HSE, a high-temperature safety control system was developed, which consists of downhole safety valve, cable packer, vent valve, and heat compensator. The overall temperature and pressure resistance value could reach as high as 350°C and 21MPa, respectively. With the development of the high temperature safety control tools and the progress of the high temperature electric submersible pump lifting technique, the integrated tubing with functions of both steam injection and oil production was designed and developed which could be applied for the 250°C cyclic steam and flue gas stimulation. The application of this integrated tubing could greatly decrease production cost by avoiding unwanted well workover. For treatment of gas channeling, the comprehensive treatment technology which consists of the injection parameters optimization, multi-well cyclic stimulation, and the chemical blocking method was formed based on the experiments, reservoir simulation, and field pilots. Besides, 50t/h steam generator that is suitable for offshore thermal recovery was designed and developed, and the related matching technologies such as nitrogen generation, sea water desalination, artificial lifting, viscosity reduction in wellbore were all studied. The design of the overall development program produced by huff and puff for an unexploited oilfield are carrying out. Great progress and breakthrough of the offshore thermal recovery technologies in Bohai Oilfield have been achieved in recent years, which will provide powerful technical support for the high efficiency development of the heavy oil resource in Bohai Bay.