Research On Punching And Separating Composite PDC Bit And Tool Technology

At present, it is difficult to adapt to drill in deep complex and hard drilling formations for using cnventional bit in the oil and gas wells. PDC cutters could hardly cut into the rock with badly worn in hard formations and high plasticity tight formations. Because of the disadvantage of being easy to fail and low energy efficiency benefits for impact cutters, it lets be low efficiency of rock breaking, and be narrow rock scope for impact-rotary bit. Compared to the pneumatic impactor, hydraulic impactor has better adaptability in deep and complex and hard drilling formation.The impact-scrape separately composite PDC bit is a new type of rock breaking tool, its way of breaking rock combing the advantages and features of PDC bit which has excellent cutting, continuous scratching with continuous breaking by impact of impact-rotary bit. The new composite tool can effectively improve the efficiency of rock breaking while slowing the rate of wear of the cutting teeth, extend the life of PDC cutter, and be one of effective ways to solve the problems with low drilling efficiency in deep complex and hard drilling formationsThis article focus on the technology research with impact-scrape separately composite PDC bit and the related tools. The main research work includes:1. Based on the research of structural features and rock-breaking mechanism and failure modes of conventional air hammer drill bit and PDC bit, studying on the structural features and rock breaking mechanism of new bit.2. Conducting the research of design theory and methods of impact-scrape separately composite PDC bit, including:designing the cutting structure principle of composite bit, design methods of runaway structure and limit runaway structural, etc.3. Conducting the research of impact cutting structure, specifically including: circumferential position matching design of impactor head, the density design of impact cutters, and the spatial position of coordination design between the fixed cutters and impat cutters etc.4. Carrying out the research of structure selection and design of matching tools (namely hydraulic impactor), specifically including:proposing design scheme of dydraulic impactor of hammer assembled restrictor ring, carrying out the research of the movement theory foundation of matching hydraulic impactor, establishing dynamic model and numerical simulation program to analyze the hydraulic and structural parameters affecting working performance of the hydraulic impactor.5. According to the setting formation parameters, the product design case is completed including a composite PDC bit.The composite bit breaks rock based on scraping and supplemented by impact, and has good potential which breaks rock drilling in the hard formations. In this paper, the results of basic research for new composite tool will provide technical support and important reference for the prototype manufacturing and processing, product promotion and application.