Study On The BHA Motion States Of Vertical Drilling System

Vertical drilling technology can achieve bottom hole actively preventing and correctingwell deviation to maintain the borehole wall vertical, improve the penetration rate, and reducethe drilling cost. Currently, the new district and deep zone oil and gas development are facinga major problem that is preventing the well deviation and drill fast in the formation, such asthe high-steep structure and large inclination angle formation. Vertical drilling system caneffectively solve the problem of the well deviation, increase the drilling speed, reduce thedrilling cost and complete the exploration and development successfully. For enhancing thevertical drilling system application effect, study on the BHA motion states of vertical drillingsystem has a great significance.Based on a large number of domestic and abroad literature research, summarized thepresent situation and developing direction of the drilling technology. Give a brief introductionof the strapdown auto-vertical drilling system, including its structure and working principle.Present a mathematical model of the vertical drilling system, called planar disc model. On thebasement of this model, analyzed the forces, derived the solutions of acceleration equations.Then imitated the motion states and analyzed the influence factors. Also present a torsionmodel of the vertical drilling system, analyzed the torques, simulated the motion states andstudied the factors, affecting the motion states of the bottom hole drilling tools.Strapdown vertical drilling system is independently researched by the DrillingTechnology Research Institute of Shengli Oil Field, finished the field test in some wells,achieved good results and got field test data. Based on the field test data, processedpreliminary and analyzed the data, extracted the characteristic parameters which can reflectthe motion states of the BHA-triaxial acceleration data and triaxial magnetic flux data. Basedon the extracted characteristic parameters, established the BHA motion states judging methodon the basement of the Z-axis acceleration data by programming calculation. Using origin8.0data analysis software for the X-axis magnetic flux frequency analysis, established the BHAmotion states judging method. On the basement of the X-axis and Y-axis magnetic flux data,calculated the speed of the BHA and established the motion states judging method. Based on the field data analysis, established the vertical drilling system motion states judging methods.