Reverse nozzle drill bit

Abstract

A drill bit design that employs reverse flow nozzles through which a portion of the drilling fluid is diverted. This reverse or upward flow of drilling fluid creates a condition by which the extraction of drilling sludge (combination of drilling fluid and drilling cuttings) in the cutting area of the drill bit is more efficient and has a greater amount of flow than designs of prior art. This increased flow has the effect of more efficiently removing damaging cuttings away from the drill cutters, lubricating the drill cutters more efficiently, and cooling the drill cutters more efficiently. The end result is increased drilling uptime, increased drilling speed, and less frequent drill bit catastrophic failures.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of priority of U.S. Provisional Patent Application No. 60 / 864,819 filed Nov. 8, 2006, which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates generally to well drilling technology. More particularly, to drill bits used for drilling oil wells and other similar drilling operations.BACKGROUND OF THE INVENTION[0003]The technology of drilling oil wells and other similar drilling operations such as for natural gas or water or other similar boring operations is affected by the design of the drill bit itself. Specifically, it is very expensive to lease and operate drilling rigs so reduced downtime, increased drill bit operating life, and drilling speed (rate of penetration or ROP) are favorable attributes. Additionally, drill bits may be leased due to their relatively high cost. However, if a drilling operation damages the drill bit in a catastrophic m...

AI Technical Summary

Benefits of technology

[0017]The present invention provides a drill bit having a reverse nozzle, directing a portion of the cutting fluid in a generally upward direction. It may be applied to newly fabricated rotary drilling bit, or as a retro-active modification to any rotary drilling bit, casing milling or junk milling device (thereafter referred to as drill bit or drill bits) which serves to ameliorate the drill bit's performance through the inclusion of one or more upwardly directed jet nozzles at an angle (preferably between about 45° and about 90° from the horizontal axis of the drill bit body) and diversion of a percentage (preferably about 15% up to about 25%) of the hydraulic drilling fluid flow up the hole (in a direction opposite the downward flow through the cutting face of the drill bit). This diversion enhances drilling performance by creating a region of relatively reduced pressure or “venturi” to promote and increase the efficiency of the removal of cuttings thereby improving the drill bit's ability to contact fresh formation. Several other enhancements, include but are not necessarily limited to, contributing to generally extending the drill bit's operating life, increasing drilling rate per hour (rate of penetration or ROP), increasing downwards weight applied to the cutting structure against the formation or medium being drilled, and enhancing the hole cleaning above the drill bit to avoid being stuck in the debris generated by the drilling action.

[0018]It is an object of the present invention to obviate or mitigate at least one disadvantage of previous drill bit designs.

[0036]All but a small percentage of drill bits in service maybe modified to take advantage of this invention. Preferably, less than about one quarter (about 25%) of the total fluid volume flow delivered to the drill bit is diverted through the reverse flow nozzle. The remaining fluid is powerful enough in terms of rate of flow and volume to maintain drilling performance without significant negative impact.

Problems solved by technology

Additionally, drill bits may be leased due to their relatively high cost.

However, if a drilling operation damages the drill bit in a catastrophic manner, the client is responsible for the replacement cost of the drill bit.

Though this is common practice, the extraction process of the drilling sludge from the drill bit cutting face is not ideal.

Therefore, when a portion of the drilled media remains in the drilling area, successive cutters in the drill bit sequence are presented with cutting media obstructions to pulverize instead of efficiently performing the next portion of cutting deeper into the media to progress the drilling operation.

This leads to excessive and premature dulling of the drill bit cutters and can lead to catastrophic failures.

The removal of cuttings is particularly important when considering the drill bit's progress or “penetration rate” is detrimentally affected when the drilling operation is regrinding cuttings rather than attacking new formation.

However, the confined space immediately below and around the drill bit body, at times restricts the free flow and therefore the removal of previously cut debris.

The result is that the bit's efficiency referred to in terms of unit depth drilled per unit time (e.g. feet or meters per hour) suffers while the bit wastes energy regrinding the cuttings rather than being exposed to new or fresh rock formation.

Furthermore, by the time cuttings generated at the bit are cleared away, pulverized and finally transported in the fluid stream to the surface, they may be of a state which renders them relatively difficult to analyze geologically.

This action results from a “cushion” of trapped fluid under the bit which is unable to escape rapidly enough.

This “hydraulicking” or “piston effect” can drastically impact drill bit performance and could transmit a false signal to the operator that the drill bit is prematurely worn out or damaged possibly beyond repair.

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