Quasi-static analysis of the dynamic effect of a jack-up rig's work load during safe drilling operation

Severe sea environment is a major disadvantage affecting the safety of jack-up rig operation in offshore drilling. In recent years, more than 20 rigs sank or were severely damaged due to hurricanes (typhoons) in foreign countries. Since few researches have been conducted in China on the jack-up rig safety under extreme environmental conditions, domestic operation adopts relatively conservative practices. With limited rig resources at home, the imbalance continuously grows between the supply and demand. In view of this, a quasi-static analysis of dynamic effect was conducted through calculating parameters born by the jack-up rig including inertia force, self-load, and such environmental loads as wind, wave and current. In addition, other main structures and parameters were calibrated, including legs, lifting/locking systems and hulls, as well as pre-loading performance, spudcan loading capacity, overturning resistance, and maximum elastic deformation. Moreover, JU2000E jack-up rig, the current mainstream rig, was taken as an example for calibrating and calculating relevant environmental parameters. This technology has been tested in over 100 applications in the jack-up rig operation market in the coastal area at home and abroad. According to the results, the quasi-static analysis is simple in process and accurate in evaluation, and the rig operation safety is improved with a satisfactory effect. Therefore, this technology can benefit and promote the rig operation safety and acceleration of developing and utilizing subsea oil and gas resources.