Bottom-Hole Dynamic Coring Assembly Analysis Using The Finite Element Method And Deviation Control Research Of Chinese Continental Scientific Drilling No.1 Well

Chinese Continental Scientific Drilling No.1 Well-CCSD-1 Well has strict technique request to deviation and azimuthal angle's excursion, because the bigger angle of deviation, the harder drilling operation, and the greater risk. Besides this, gneiss encountered in drilling process has remarkable anisotropy. And steep attitude of rock formation has strong building angle character, which leads to hole inclination easily. Therefore, how to achieve wellbore trajectory control in drilling process is a difficult problem of engineering construction.Chinese Continental Scientific Drilling Project developed a complete set of diamond coring system used in large diameter, hard rock and deep hole, which includes bit, underreamer, PDM and hydraulic hammer. This system originated in the world has outlived trial in inclement condition of well drilling, and attained successful application. And the system can improve drilling efficiency and round footage, and obvious effect in inclination prevention and decreasing hole angle. Using of PDM can reduce power consumption, drilling tools' wearing and influence to borehole wall, and also decrease occur of hole trouble. Using of hydraulic hammer can increase drilling efficiency and round footage, and is in favor of lightening inclination. Using of single action double barreled coring tools can heighten core taking efficiency and degree of completion. The development success of this system is an important breakthrough of coredrilling exploration technique.The nonlinear static mechanics model of bottom-hole dynamic coring assembly in CCSD-1 Well is founded in this paper firstly. Configuration of bottom-hole assembly(BHA), boundary conditions and different kinds of external loads are considered in this model. In boundary condition treatment of upper end imagination section, it is suggested that drilling tools under neutral point is regarded as subject investigated, making the problem simplified properly and small effect to computational accuracy. Comprehensively considered of geometrical and contact nonlinearity, the nonlinear static mechanics model is a double nonlinear static mechanics model, which has complex loads, rather big structural changes, and uncertain boundary conditions. And static analysis of BHA is come down to geometrical and contact nonlinear problem, and can...