The Study Of PDC Drilling Bit For Interbedded Formation With Gravel

PDC bit is used widely in the artesian well. Based on the research of PDC bit design at home and abroad, combining with the characteristics of the interbedded formation with gravel, the research about method of PDC bit design and manufacture is made.This paper systematically investigated the design principle of cutting structure and hydraulic structure for PDC bits. The geometry characteristics of cutting structure is studied. And it systematically studied the adaptability between the crest shape of bit and geologic strata. In research of the theory and methods of arranging design, the design process of embryo body blade PDC drilling bit is described. It puts forward the jet nozzle mechanism and the principle of nozzle combinations. The Fluent CFD software is used to analyze the flow scene of the nozzle.In this article, the wear mechanism of PDC drilling bit in the interbedded formation with gravel is analyzed. According to the situation of the area of North Ordos, a suitable four-blade embryo body PDC drilling bit is designed. Combined with mixed cutting structure and shallow cone profile, the PDC bit's cutter is spirally arranged. And the nozzles is unsymmetrical arranged. Diamond impregnated tungsten carbide is used as secondary cutter. Then the three-dimensional entity model of the PDC drilling bit is established using the Pro-E software.The soft mould is used to manufacture the PDC bit body, and the temperature of sintering and welding process is automatic controlled. The polishing BD cutters are choose. The properties of material of the PDC bit are tested. Field test result shows that the penetration rate increase and the service life of the bit extend in comparison with the existing bits. The bits meet the design demand.