Drill Bit Jack Element for Hard Formation Stability
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Solution Overview
Problem
Drill bits often suffer damage due to harsh underground conditions, such as bit whirl and excessive weight-on-bit in hard formations, leading to costly and time-consuming replacements, as existing solutions do not effectively manage these issues in real-time.
Innovation Solution
A drill bit design featuring a jack element coaxial with the axis of rotation, extending within a conical region, which shares the weight-on-bit load and limits penetration in hard formations by jacking the bit, thereby reducing cutter damage and stabilizing the bit against whirl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If weight on bit is increased to maintain high penetration rates in hard formations, then penetration rate is improved, but cutter damage and bit whirl increase
Solution Approach 1:
The jack element serves as an intermediary component between the bit body and formation. It has a larger contact area than cutters, distributing weight on bit across a broader surface. This mediation allows the system to maintain high penetration rates while reducing the concentrated stress that causes cutter damage in hard formations.
2Productivity
If weight on bit is increased to drill through hard formations, then penetration rate is improved, but bit whirl increases causing instability
Solution Approach 1:
The jack element acts as a stabilizing intermediary by providing a broad contact surface with the formation. This distribution of weight on bit reduces the concentrated forces that trigger bit whirl, thereby maintaining bit stability even at higher penetration rates in hard formations.
Solution Approach 2:
The jack element performs preliminary action by engaging the formation before the cutters. Its larger contact area预先 distributes the weight on bit, preventing the concentrated loading that leads to bit whirl before the cutters engage the formation.
3Productivity
If conventional drill bits are used in hard formations, then drilling can proceed, but unexpected hard formations cause sudden cutter damage before weight adjustment
Solution Approach 1:
The jack element provides beforehand cushioning by absorbing and distributing weight on bit through its large contact area. This cushioning effect protects cutters from sudden impact loads when encountering unexpected hard formations, allowing drilling to continue without catastrophic cutter failure.
4Ease of repair
If entire downhole tool string is removed to replace damaged drill bits, then bit replacement can be performed, but time and cost increase significantly
Solution Approach 1:
The jack element is designed as a replaceable segment of the drill bit assembly. When worn or damaged, only the jack element needs to be replaced rather than the entire tool string. This segmentation enables maintenance of the high-contact-area protective function while significantly reducing replacement time and cost.
Data Source
AI summary
A drill bit has an axis of rotation and a working face with a plurality of blades extending outwardly from a bit body. The blades form, in part, an inverted conical region, and a plurality of cutters with a cutting surface is arrayed along the blades. A jack element is coaxial with the axis of rotation and extends within the inverted conical region within a range defined by the cutting surface of at least one cutter.