Claims
- 1. A two stage bit enabling enhanced penetration rates comprising:
a body defining a proximal end adapted for connection to a drilling string and a distal end, where said distal end defines a pilot and an intermediate reamer section; where said pilot includes a first cutter face defining a given diameter D; where said reamer section includes a second cutter face defining a given diameter R where R>D; and where the first and second cutter faces include upsets where each upset defines an upper and a lower portion where said upper portion is provided with a series of cutting elements and said lower portion is provided with a surface adapted to extend to gauge into substantially non-cutting contact with the formation.
- 2. The two stage bit of claim 1 where said lower portion includes a gauge pad which extends to gauge.
- 3. The two stage bit of claim 1 where said cutting elements are formed of polycrystalline diamond.
- 4. An anti-whirl two stage bit comprising:
a body defining a proximal end adapted to be connected to a drilling string and a distal end, where said distal end defines a pilot and a reamer section; where said pilot includes a cutting face having a first diameter where said cutting face is comprised of two or more cutting blades defining proximal and distal surfaces; where said reamer includes a cutting face having a second diameter where said cutting face is comprised of two or more cutting blades defining proximal and distal surfaces; where the first diameter is less than said second diameter; and where cutting elements are disposed on the distal surfaces of said cutting blades and where said proximal surfaces are adapted to slidably engage the formation during rotation of the bit.
- 5. The bit of claim 4 where the proximal surfaces extend to gauge.
- 6. The bit of claim 5 where the proximal surface define at least one gauge pad.
REFERENCE TO PROVISIONAL APPLICATION
[0001] Pursuant to 35 U.S.C. §119(e), this application derives from a provisional application for the same invention filed on May 28, 1998, Provisional Ser. No. 60/088,010.
Provisional Applications (1)
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Number |
Date |
Country |
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60088010 |
May 1998 |
US |