Hybrid Drill Bit Stabilizer Pads for Off-Center Running
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Solution Overview
Problem
Existing earth-boring drill bits, whether rolling-cutter or fixed-cutter, face challenges in achieving stable running during drilling operations, leading to potential off-center running and premature failure of cutting elements.
Innovation Solution
A hybrid earth-boring bit design featuring a combination of fixed blades and rolling cutters, with stabilizer pads extending radially outward to the gage surface, ensuring contact with the borehole sidewall and distributing load evenly to maintain stability, thereby preventing off-center running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rolling cutters are used to engage and disintegrate formation material, then drilling capability is improved, but stable running is compromised leading to off-center operation
Solution Approach 1:
The patent combines rolling cutters and fixed blades into a hybrid bit design. The rolling cutters (cones or buttons with cutting elements) provide formation breaking capability, while the fixed blades with stabilizer pads maintain stable running by contacting the borehole wall. This merging of two different cutting mechanisms resolves the contradiction between drilling capability and stable running.
2Stability of the object's composition
If fixed blades with stabilizer pads are added to improve stable running, then stable running is improved, but device complexity increases
Solution Approach 1:
The fixed blades in the hybrid bit serve multiple functions: they act as cutting elements that engage the formation and as stabilizer pads that contact the borehole wall to maintain stable running. This multi-functionality reduces the need for separate stabilizer components, thereby limiting the increase in device complexity while still improving stable running.
3Productivity
If rolling cutters are designed to extend to the center of the bit, then formation cutting efficiency is improved, but stable running deteriorates
Solution Approach 1:
The patent applies local quality by having rolling cutters positioned at specific locations (not necessarily extending to the center) and fixed blades with stabilizer pads positioned at the periphery. The rolling cutters are concentrated where formation cutting is needed, while the fixed blades are positioned where stabilization is needed (at the borehole wall interface), optimizing both functions locally rather than uniformly across the entire bit.
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 hybrid bit design enhances drilling stability, reducing the risk of damage to cutting elements and prolonging bit lifespan by ensuring consistent, centered operation.
Implementation Method 1
The rolling cutters are provided with cutting elements or teeth that are forced to penetrate and gouge the bottom of the borehole by weight from the drillstring. Engagement between the diamond cutting elements and the borehole bottom and sides shears or scrapes material from the formation, instead of using a crushing action as is employed by rolling-cutter bits.
Implementation Method 2
The cuttings from the bottom and sides of the borehole are washed away by drilling fluid that is pumped down from the surface through the hollow, rotating drillstring, and are carried in suspension in the drilling fluid to the surface.
Data Source
AI summary
A bit body is configured at its upper extent for connection into a drillstring. At least one fixed blade extends downwardly from the bit body, and has a radially outermost gage surface. A plurality of fixed cutting elements is secured to the fixed blade, preferably in a row at its rotationally leading edge. At least one bit leg is secured to the bit body and a rolling cutter is mounted for rotation on the bit leg. At least one stabilizer pad is disposed between the bit leg and the fixed blade, the stabilizer pad extending radially outward to substantially the gage surface. The radially outermost gage surface of each blade can extend axially downward parallel to the bit axis or angled (non-parallel), spirally or helically, relative to the bit axis.