Drilling stabilizer

Abstract

A stabilizer used to centralize drill pipe in the drilling of wells, such as oil and gas wells, having a replaceable member with a contoured outer surface and specifically designed flow paths.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]NoneFEDERALLY SPONSORED RESEARCH[0002]Not ApplicableSEQUENCE LISTING OF PROGRAM[0003]Not ApplicableBACKGROUND OF INVENTION[0004]1. Field of Invention[0005]This invention relates to an apparatus utilized to stabilize and centralize drill pipe and / or other tubular goods during the drilling of wells, such as oil and gas wells. More particularly, this invention pertains to a drilling stabilizer having a removable stabilizing member having a contoured outer surface and at least one flow path.[0006]2. Description of Related Art[0007]During the drilling of wells, such as oil and gas wells, a drill bit is typically located at the distal end of a length of drill pipe known as a “drill string,” and rotated to penetrate into the earth's crust. The drill string generally comprises a number of individual joints of drill pipe and / or down hole tools joined end-to-end to form a continuous length of pipe. In many cases, the outer diameter of the drill bi...

AI Technical Summary

Benefits of technology

[0016]In the preferred embodiment, the stabilizer of the present invention comprises a tubular body member. Said body member can be incorporated into a drill string; in the preferred embodiment, said body member has threaded connections for this purpose. A centralizing member having a central bore is received on the outer surface of said tubular member and secured in place. The tubular body member has threads on its outer surface terminating at a shoulder. The centralizing member has matching threads on the inner surface of its central bore, thereby permitting the centralizing member to be threaded onto the tubular body member and tightened against the shoulder of the tubular body member.

[0017]In this manner, the centralizing member is replaceable. As a result, when a different ring gauge is required, the centralizing member may be exchanged without removing tubular body member from the drill string. Safety and efficiency are improved by eliminating the need to remove the tubular body member from the drill string. Because only the centralizing members, and not the entire stabilizer assemblies, must be maintained in inventory, transportation costs, storage costs and space requirements are greatly reduced.

[0018]In the preferred embodiment, the centralizing member is machined from a single piece of stock, thereby eliminating the need for welding. The outer surface of the centralizing member has a generally convex shape. Such shape minimizes the contact surface between the stabilizer and the inner wall of the well bore or casing. As such, rotational and axial drag is reduced compared to prior art stabilizers. Further, because the stabilizer of the present invention passes through bends and “doglegs” in well bores, the risk of the centralizing member becoming stuck to the inner surface of a well bore is eliminated. Axial slots are formed in the outer surface of the centralizing member to allow for the passage of mud and drill cuttings. Such axial slots are designed to optimize the flow of mud, and balling up of chips is reduced or eliminated.

Problems solved by technology

When drilling in open hole, the drill string may be forced against the wall of the well bore by the pressurized drilling mud with sufficient force that the drill string and down hole tools become stuck and cannot be withdrawn from the well.

During drilling operations, drill strings are frequently loaded in torsion and compression, thereby making such drill strings subject to buckling.

In addition to other problems, such drag can prevent weight from being transferred to a down hole drill bit.

However, space on drilling rigs is usually limited, especially on offshore drilling rigs.

Therefore, maintaining a large inventory of stabilizers is both expensive and inefficient.

Elongate stabilizer blades of the existing art create significant resistance to rotation and to axial “sliding” of the drill string, thereby reducing the efficiency of the drilling process.

Elongate stabilizer blades are also subject to becoming stuck against the wall of a well bore.

Moreover, drill cuttings generated during the drilling operation tend to “ball up” between the blades of the stabilizer as they are carried up the annulus, thereby restricting the flow of mud up the annulus.

Prior art welded stabilizer blades also present various problems.

The welding process can be expensive and requires heat treatment procedures which, if done improperly, may reduce the integrity of the tubular body member.

Further, welded members must be inspected periodically using an approved method of non-destructive testing; such inspection can be expensive and must be performed by highly trained personnel.

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