Early last century, the cone drill bit instead of the scraper in hard abrasive formations application, but this drill drill shale and other shortcomings in the plastic formation is mainly caused by pressure downhole mud pack holding role, and with drilling depth and bottomhole pressure and increase the proportion of mud, mud pack phenomenon will be more serious. To solve this problem, over the years various manufacturers cone drill bits made various improvements, but with little success. Taking into account the fixed cutter blade or drill bit in this regard less affected, people began to try a combination of two kinds of drill bits. With the popularization and application of PDC bits and PDC cutter technology to improve fixed cutter PDC drill bit in a variety of formations gradually replace cone bit. But in the hard, abrasive formations and complex directional drilling operations, due to the performance, PDC drill bit can not replace cone bit. In order to play the advantages of roller cone and PDC drill bits, our company has recently developed an integrated roller cone and PDC bit of a new generation of composite drill. We are launching composite drill There are two designs, one is the small size twice wing, double-cone bit, the other is slightly larger size of Mito wing, tricone bit, Based on these drill four knives wings and six blades PDC drill bit, and vice blades and short positions were replaced cone size. Thus, the center position of the borehole is located on the surgeon wing PDC cutter complete break rocks, and the peripheral portion of the borehole drilling completed by the cutter cutters and blades and on the peripheral portion of the wellbore rock breaking more difficult, rock breaking effect depends cone and blades and mating.