Segmented Reaming Tool Nose for Bore Hole Drillout
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Solution Overview
Problem
Existing methods fail to consistently achieve a cylindrically drilled bore hole with the intended diameter and without deviations when running casing or liner into a predrilled bore hole, due to factors like formation irregularities and out-of-tolerance drill bits.
Innovation Solution
A reaming tool with a tubular body, a concave nose portion, and spirally configured blades equipped with superabrasive cutting elements and tungsten carbide layers, designed to enlarge the bore hole by facilitating drillout from the center to the side wall, ensuring complete removal of material and optimal reaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reaming tool with a solid nose portion is used to enlarge the bore hole, then the reaming capability is improved, but the drillout process becomes more difficult and time-consuming
Solution Approach 1:
The nose portion is segmented into multiple thin-walled sections instead of being a solid structure. This segmentation allows the drill bit to more easily penetrate and remove the nose material during the drillout process, significantly reducing drillout time while preserving the reaming functionality of the blades.
Solution Approach 2:
Different parts of the reaming tool have different structural properties optimized for their specific functions. The nose portion has thin walls to facilitate easy drillout, while the blades maintain sufficient thickness and strength to perform the reaming operation effectively. This local differentiation of structural quality resolves the contradiction between reaming capability and drillout ease.
2Ease of manufacture
If the nose portion walls are made thin to facilitate drillout, then the drillout process is easier, but the structural strength during reaming operation is reduced
Solution Approach 1:
The nose is divided into multiple thin-walled segments that can be easily removed during drillout. The segmented structure provides sufficient structural integrity during reaming operations while allowing for easy removal later, as each segment can be independently drilled out without requiring excessive force.
Solution Approach 2:
The thin-walled nose structure is designed in advance to be easily removable by a drill bit. The preliminary design of the nose geometry and wall thickness ensures that the drillout operation can be performed quickly and easily without compromising the reaming function, as the nose is intended to be removed before the reaming blades are deployed.
3Device complexity
If conventional drill bits are used to drill the bore hole, then the drilling process is simple, but the bore hole cylindricity and diameter accuracy are compromised due to formation irregularities
Solution Approach 1:
The reaming blades are positioned to engage the formation before the main drilling operation completes, performing a preliminary reaming action that establishes the correct bore hole diameter and cylindricity. This preliminary reaming ensures that even if conventional drill bits are used, the final bore hole dimensions and shape meet the required specifications.
Solution Approach 2:
The reaming blades change the physical parameters of the bore hole by cutting and enlarging it to the precise target diameter and shape. This parameter change from the initially drilled hole to the final reamed hole ensures cylindricity and dimensional accuracy, compensating for any deviations caused by using simple conventional drill bits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The reaming tool effectively enlarges the bore hole to the intended diameter, ensuring the casing or liner can be run to its full extent, with the cutting elements and tungsten carbide layers enabling efficient and complete reaming without leaving large segments of material behind.
Implementation Method 1
cutting structure for enlarging, also termed 'reaming,' of a bore hole through contact with the side wall thereof
Data Source
AI summary
A reaming tool includes a tubular body having a nose portion with a concave center. A plurality of blades defining junk slots therebetween extend axially behind the nose portion and taper outwardly from the exterior of the tubular body. Rotationally leading edges of the blades carry a plurality of cutting elements from the axially leading ends. Selected surfaces and edges of the blades bear tungsten carbide, which may comprise crushed tungsten carbide. The shell of the nose is configured to ensure drillout from the centerline thereof toward the side wall of the tubular body. A method of drilling out a reaming tool is also disclosed.