Operating Capability of Big-foot Jack-up in China's Offshore

摘要

There are some offshore oilfields that have comparatively low shearrnstrength cohesive soils in China, which means very deep penetration forrnmost of the jack-ups. To develop these fields more efficiently, a kind ofrnbig-foot jack-up is introduced. A larger spudcan may result inrnshallower penetration but larger extraction resistance, which may makernthe jack-ups difficult to pull out. To evaluate the operating capability ofrnthe big-foot jack-up, both the penetration and extraction capability at allrnwell sites of offshore China are calculated. It is shown that largerrnspudcans enable the rig to penetrate much shallower in soft soils, andrnthe possibility of punch-through in all fields is reduced too. To improvernthe extraction capability of the rig, the jetting system is redesignedrnbased on finite element simulation and lab experiment. By investigatingrnthe structural strength with environmental data, it can be concluded thatrnbig-foot rig could be operated at most of China's offshore fields inrnmoderate weather.