PDC Variable Diameter Drilling Bit Mechanical Characteristics And Structural Design

The exploration of Daqing Oil Field mine indicates that massive oil gases still reserve in thedeep place of oil field in certain areas. in order to develop this part of energy, therefore mustcarry on well drilling work in original old well aperture foundation. because the majority of oilwells of daqing oil field use drive pipe of 5 12", its diameter isф123.7mm, If drillingoperations on the basis, its next level of drive pipes diameter will be smaller, will make the laterperiod development of the oil field inconvenient inevitably . Therefore develop one kind of PDCvariable diameter drilling bit under small well aperture condition to meet the well drilling needof daqing oil field which changes the diameter of drill bit, which has the extremely significantapplication value to expand the oil field production. This article is one research work, whichaims at Daqing Oil Field old well reformation.Aiming at the problem existing in Reamer bit in current day, this article refers to theregulation of well drilling handbook, combines the design method of reamer bit that has had atpresent and Daqing Oil Field's concrete geological condition, puts forward one kind of PDCvariable diameter drilling bit under small well aperture condition, and analyses and researcheshydraulics characteristic of PDC variable diameter drilling bit, nozzle hole bottom flow field, theeffects of the dent shape on the mechanics characteristic of the drilling bit and so on .Water conservancy structure of PDC variable diameter drilling bit is referred to the workingperformance and the length of the service time of the drilling bit. In view of this situation,establish the calculating procedure of hydraulic parameter of PDC variable diameter drilling bit,the procedure chooses different computation module based on the flow pattern of the fluid, andcomputation module has good parameter input surface, can meet basic needs of hydraulicscomputation, and apply FLUENT computation hydromechanics software to carry on nozzle holebottom flow field simulation of the nozzle of PDC variable diameter drilling bit, put forwardreasonable nozzle form, structural style of chip removing flute and the distributing regulation offluid field of drilling fluid. And carry on analysis of the PDC variable diameter drilling bit fluidfield including intensity, pressure, speed and so on. Integrate liquid mechanics parametercalculating procedure. Propose suitable hydraulics parameter.Finally, pay more attention to the discussion of the crown shape design of PDC variablediameter drilling bit, radical distribution of cutting dent, and circumferential distribution ofcutting dent and rake angle of cutting dent and the design of angle of yaw. And on the basis oftheoretical calculation and design of experience, we have proposed rational scheme of PDCvariable diameter drilling bit.