A method for use in designing rotary drill bits comprises determining locations in which cutters are to be provided, determining likely wear rates for cutters positioned at those locations, and using the likely wear rates to chose between relatively high and relatively low wear rate cutters for each location. The cutters all have substantially the same impact toughness.
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Patent Application No. 60/234,075 filed Sep. 20, 2000, and from U.S. Provisional Patent Application No. 60/281,054 filed Apr. 2, 2001.
A fixed cutter drill bit and a method for designing a fixed cutter drill bit includes simulating the fixed cutter drill bit drilling in an earth formation. A performance characteristic of the simulated fixed cutter drill bit is determined. A side rake angle distribution of the cutters is adjusted at least along a cone region of a blade of the fixed cutter drill bit to change the performance characteristic of the fixed cutter drill bit.
A method for simulating a drilling tool assembly having a drill string and a drill bit. The method includes simulating a dynamic response of the drill string; simulating a dynamic response of the drill bit; and resolving the dynamic response of the drill string and the dynamic response of the drill bit into a dynamic response of the drilling tool assembly.
One aspect of the instant disclosure relates to a subterranean drilling assembly comprising a subterranean drill bit and a sub apparatus coupled to the drill bit. Further, the sub apparatus may include at least one cooling system configured to cool at least a portion of the drill bit. For example, the sub apparatus may include at least one cooling system comprising a plurality of refrigeration coils or at least one thermoelectric device. In another embodiment a subterranean drill bit may include at least one cooling system positioned at least partially within the subterranean drill bit. Also, a sub apparatus or subterranean drill bit may be configured to cool drilling fluid communicated through at least one bore of a subterranean drill bit and avoiding cooling drilling fluid communicated through at least another bore of the subterranean drill bit. Methods of operating a subterranean drill bit are disclosed.
Griffin, Nigel, et al78.1081-1.3-29 Disclosed is a method for manufacturing a polycrystalline diamond or diamond-like element with greatly improved wear resistance without loss of impact strength. These elements are formed with a binder-catalyzing material in a high-temperature, high-pressure (HTHP) process. The PCD element has a body with a plurality of bonded diamond or diamond-like crystals forming a continuous diamond matrix that has a diamond volume density greater than 85%. Interstices among the diamond crystals form a continuous interstitial matrix containing a catalyzing material. The diamond matrix table is formed and integrally bonded with a metallic substrate containing the catalyzing material during the HTHP process. The diamond matrix body has a working surface, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material. Typically, less than about 70% of the body of the diamond matrix table is free of the catalyzing material.
The present invention provides a method of making an earth boring drill bit having a superhard polycrystalline diamond or diamond-like element with greatly improved resistance to thermal degradation without loss of impact strength. Collectively called PCD elements, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure process. The PCD element has a plurality of partially bonded diamond or diamond-like crystals forming at least one continuous diamond matrix, and the interstices among the diamond crystals forming at least one continuous interstitial matrix containing a catalyzing material. The element has a working surface and a body, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material.
