Rupture Cutters with High Penetration Utility

Abstract

A cutting element design that includes a base portion designed to be brazed, pressed or otherwise attached into a drill bit or reaming tool where the design of the cutting element is such that forward drilling force is concentrated in a small area to improve piercement of and / or impingement into the rock to enhance shear and rupture when the element is rotated into the rock on a drill bit. The cutting element is further enabled by the use of a thick, unitary hardened surface coating on an everted working surface to dissipate heat.

Description

FIELD[0001]This invention relates generally to cutting elements used in drill bits in the oil, gas and mining industries having fixed cutters or inserts with ultrahard cutting surfaces and edges made from materials such as diamond, polycrystalline diamond (PDC) or other ultrahard material bonded to or built with an attaching substrate portion, and particularly to fixed cutters or inserts in which the working surface of the cutting element is designed to comprise a small area of impingement or piercement into the rock to enhance shear and rupture when the cutter or insert is rotated into the rock on a drill bit.BACKGROUND OF THE INVENTION[0002]Rotary drill bits with no rotating or otherwise moving components are typically referred to as “drag” bits or “fixed cutter” bits. These drill bits utilize cutters (sometimes referred to as cutter elements, cutting elements, inserts or compacts) attached to the bit body, with the bit body essentially serving as the carrier for the cutters. Trad...

AI Technical Summary

Benefits of technology

The present invention is about improving the process of drilling through rock formations by balancing the need to remove the rock effectively while shearing away other parts of the formation without increasing the risk of damage to the drill string. This is accomplished by using piercing cutters and planar or semi-planar cutting elements in conjunction with a cylindrical solid that acts as a mounting base with a projection on its surface to reduce contact area with the rock and improve penetration. The invention also allows for variations in the shape of the tapered working surface, such as plows, chisels, teardrops, and extra-planar variations of standard PDC cutters. These variations all use a thick, unitary, everted PDC or similar coating to efficiently dissipate heat.

Problems solved by technology

Although the weight of a drill string typically results in sufficient penetration by each of the cutting elements to allow some level of shearing, the design of the standard PDC cutter, being planar, results in shearing not because the cutter is able to cut into the rock formation but simply because the weight of the drill string causes some amount of the cutter to contact the rock formation, the rotational motion of which as part of the drill bit results in some level of shearing of rock formation during operation.

The design of conventional cutters combined with limitations thereof as to back rake angles suitable for use therewith, do not allow for the optimization of shearing AND penetration.

It has not, however, been accomplished in the field where conical cutters have been designed to optimize both shearing and penetration.

It is not feasible to counter the limitations of typical PDC cutters merely by substituting cutters capable of piercing the rock formation more effectively.

Cutters capable of piercing the rock formation too substantially are subject to breaking.

Either the individual cutters may break or the shock and vibration induced in the drill string during operation by aggressive cutters may cause other elements of the drill string to fail.

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