Two-Stage Drill Bit for Deeper Cuts at Lower Torque
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Solution Overview
Problem
Conventional drag bits used for drilling in earth formations are limited by the torque and weight that can be applied, restricting the depth of cut due to safety concerns, leading to inefficient material removal.
Innovation Solution
A drill bit design incorporating a rolling cutting element followed by fixed cutting elements, where the rolling element degrades the formation material and the fixed element removes the degraded material, allowing for a two-stage process that enhances cutting depth and rate while reducing torque and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drag bits use fixed cutting elements to scrape and fracture rock, then material removal is achieved, but the depth of cut is limited by torque and weight constraints
Solution Approach 1:
The cutting elements are segmented into two distinct stages: rolling cutting elements that degrade the formation material, and fixed cutting elements that remove the degraded material. This segmentation allows each stage to perform its specific function optimally, enabling greater depth of cut without exceeding torque and weight constraints.
Solution Approach 2:
The rolling cutting elements perform preliminary degradation of the formation material before the fixed cutting elements remove it. This preliminary action softens and breaks down the rock structure, reducing the force required by subsequent fixed cutting elements and enabling deeper cuts within safe operating limits.
2Productivity
If fixed cutting elements are used to fracture rock, then material removal occurs, but wear and damage to the drill bit increases
Solution Approach 1:
By dividing the cutting function into two stages with different element types, the wear and damage are distributed differently. The rolling elements experience different wear mechanisms than fixed elements, and both can be optimized for their specific roles, extending overall bit life while maintaining high material removal rates.
Solution Approach 2:
The invention changes the operational parameters of cutting elements by introducing rolling motion in addition to fixed dragging. This parameter change reduces the mechanical stress and wear on individual cutting elements, thereby improving drill bit reliability and reducing damage while maintaining productivity.
3Length of moving object
If torque and weight applied to the bit are increased to improve depth of cut, then cutting depth increases, but safe operating conditions are compromised
Solution Approach 1:
The rolling cutting elements perform preliminary degradation that reduces the strength and cohesion of the formation material. This preliminary action enables fixed cutting elements to achieve greater depth of cut at lower applied torques and weights, maintaining safe operating conditions while increasing cutting depth.
Solution Approach 2:
By changing from purely fixed cutting to a two-stage rolling and fixed cutting system, the force parameters required for cutting are reduced. The rolling elements prepare the material in a way that requires less force for removal, enabling deeper cuts within safe torque and weight limits.
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 two-stage drill bit achieves higher drilling rates with reduced torque and weight-on-bit, minimizing damage to the drill bit and improving material removal efficiency in challenging formations.
Implementation Method 1
a rolling cutting element positioned on the outward surface; and a fixed cutting element positioned with a fixed cutting profile at least partially rotationally overlapping with a rolling cutting profile of the rolling cutting element
Implementation Method 2
a fixed cutting element positioned with a fixed cutting profile at least partially rotationally overlapping with a rolling cutting profile of the rolling cutting element
Data Source
AI summary
A device may include a bit body with a rotational axis in a longitudinal direction. A device may include at least one blade coupled to the bit body with an outward surface. A device may include a rolling cutting element positioned on the outward surface. A device may include a fixed cutting element positioned with a fixed cutting profile at least partially rotationally overlapping with a rolling cutting profile of the rolling cutting element.