Composite drill applicable to middle Yangtze Cambrian system shale gas exploitation

Abstract

The invention discloses a composite drill applicable to middle Yangtze Cambrian system shale gas exploitation. The composite drill comprises a drill body, the inside of the drill body is provided with a flushing cavity, the front end of the body is provided with a cutting part, the top of the cutting part protrudes outward to form an arc top face, the cutting part is prominently provided with three evenly distributed main cutting blades, the main cutting blades extend to the arc top face and are converged at the arc top face, the portions, located at the gaps of the converging part of the cutting blades, of the arc top face are provided with three nozzles, the nozzles are communicated with the flushing cavity inside the drill body, the cutting part is further provided with a shaft neck part, the shaft neck part is provided with an opening, the opening is communicated with the flushing cavity, the top end of the shaft neck part is connected with a spherical sub cutting face in a clamping mode, and several particle-shaped subsidiary cutting blades are inlaid on the sub cutting face. According to the composite drill applicable to the middle Yangtze Cambrian system shale gas exploitation, the advantages of a PDC drill and a roller bit are combined, the hole drilling efficiency is improved, the application range of the drill is expanded at the same time, the cost is lowered, and the composite drill is applicable to the middle Yangtze Cambrian system shale gas exploitation.

Description

technical field [0001] The invention relates to the field of drilling tools, in particular to a composite drill bit suitable for the exploitation of Cambrian shale gas in the Middle Yangtze. Background technique [0002] Polycrystalline Diamond Compact (Polycrystalline Diamond Compact) drill, referred to as PDC drill. It is formed by using polycrystalline diamond (thin disc shape) to make a small cutting block and inserting it or sintering it on the bit body, which is suitable for soft to medium hard formations. [0003] At the beginning of the last century, the roller cone bit replaced the scraper bit in hard abrasive formations, but the disadvantage of this kind of bit in drilling shale and other plastic rock formations is mainly that the bottom hole mud bag is caused by the compression effect, and with the drilling depth and With the increase of the bottom hole pressure and the specific gravity of the mud, the mud bag phenomenon will be more serious. In order to solve t...

AI Technical Summary

Problems solved by technology

However, in hard and abrasive formations and complex directional drilling operations, due to performance limitations, PDC bits cannot replace roller cone bits

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