Drilling device and process

Abstract

A plurality of cutting faces is attached sequentially at a distal end of a drill string. The forward most cutting face that is distal to the top of the hole is exposed and used for drilling until worn to a point of inefficiency. The forward most or distal cutting face is then detached, exposing the next cutting face in the sequence. Detachment of the forward most cutting face is performed by remote actuation at the top of the drill string and/or outside the hole. A new cutting face is provided without the necessity of removing the drill string. The detachment process is repeated as long as drilling is continued and cutting faces remain.

Description

[0001]This application is a continuation-in-part of Application No. 13 / 918,414 filed June 14, 2013, which claims the benefit of PCT Application No.: PCT / US13 / 45943, filed June 14, 2013 and U.S. Provisional Application No. 61 / 659,677 filed June 14, 2012.FIELD OF THE INVENTION[0002]This invention relates to drilling of holes in the earth and is more specifically related to a device and method for changing drill cutting faces of drill strings for use while the drill string is in situ in the hole.BACKGROUND OF THE INVENTION[0003]Drilling for oil and gas involves a drill bit at the end of hundreds of lengths of pipe, collectively referred to as the drill string. The drill bit is attached to the lowest section of pipe of the drill string and is rotated by the drill string to cut or drill into the earth. Each time the drill bit has drilled the length of the pipe, the drilling stops and another pipe section is attached to the pipe so that drilling can continue. Each pipe section is conventi...

AI Technical Summary

Benefits of technology

[0009]A preferred embodiment of the present invention is a drill bit comprising a plurality of sequentially nested cutting disks or faces. Each cutting face is removably attached to the drill bit and contains an explosive charge and a control which can selectively activate to disintegrate the cutting face. In accordance with a preferred embodiment of the method of this invention, a drill bit having a plurality of sequentially nested cutting faces is attached to the distal end of a drill string. The forward most cutting face is used for drilling until worn to a point of inefficiency. The forward most cutting face is then detached, exposing the next cutting face in sequence. Detachment of the forward most cutting face is performed by withdrawing the drill string a short distance from the bottom of the wellbore and then separating the most distal cutting face from the mandrel by remote controlled actuation. After the forward-most cutting face is detached, it is disintegrated by activating an internally contained explosive charge from the top of the drill string and / or outside the hole. A new cutting face is exposed without the necessity of removing the drill string. The drill string is then lowered to the bottom of the hole. High pressure drilling mud then flushes the worn cutting face fragments away from the bottom of the bore hole and up and around the pipe of the drill string. After the fragments begin to migrate upwardly and away from the bottom of the bore hole, which generally takes only a few minutes, downward pressure is applied to the drill string, and the attached drill bit system. Rotation of the drill string resumes, which resumes the drilling process. This method allows a new cutting face to be exposed for use without pulling the entire drill string from the hole. The process may be repeated as long as an unused cutting face is available in the sequence. The number of cutting faces that may be sequentially positioned or stacked for use may be from 2 to 6 or even more.

Problems solved by technology

Drill bits are subject to wear, and wear out during the drilling process.

Unfortunately, changing bits requires removing the entire drill string from the hole to access the old bit so that it can be replaced.

A lost day of drilling to replace bits once or twice a week is very expensive.

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