Weight-on-bit self-adjusting drill bit with pulsed jet mechanism
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Solution Overview
Problem
Existing weight-on-bit self-adjusting drill bits face challenges in achieving optimal rate of penetration (ROP) due to inability to automatically adjust the distribution of weight on bit, leading to reduced service life and efficiency, especially in interlayer strata.
Innovation Solution
A pulsed jet type weight-on-bit self-adjusting drill bit is designed with a pulsating impact generating mechanism that modulates drilling fluid flow to create a pulsed jet, applying periodic axial downward force on the pilot bit, thereby automatically adjusting the weight distribution and reducing chip hold down effect, enhancing rock breaking efficiency and ROP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a special tool is mounted above the drill bit to release stratum stress based on hydraulic energy, then rock stress can be released in advance, but consumption of drilling fluid energy increases and the safety and reliability of the special tools are compromised
Solution Approach 1:
The patent combines the stress release function with the drill bit itself by integrating a pilot bit and reaming bit into a single combined bit structure. This eliminates the need for separate special tools mounted above the drill bit, thereby reducing drilling fluid energy consumption while maintaining the rock stress release function. The combined bit integrates rock breaking and stress release capabilities in one unit.
Solution Approach 2:
The combined bit serves multiple functions simultaneously: it breaks rock, releases stratum stress, and controls weight distribution. The pilot bit and reaming bit work together to achieve both rock fragmentation and stress relief, making the drill bit a multi-functional tool that eliminates the need for additional specialized equipment.
2Productivity
If the contact shape between the drill bit and the bottom hole is changed to release stratum stress, then the stress of the formation at the bottom hole can be reduced, but the pilot bit is prone to collapse or increased wear due to inability to automatically adjust the distribution of the weight on bit
Solution Approach 1:
The patent introduces a dynamic weight adjustment mechanism using springs and movable connecting pieces that allow the pilot bit and reaming bit to automatically adjust their weight distribution during drilling. This dynamic adjustment capability enables the pilot bit to adapt to varying drilling conditions, preventing collapse and excessive wear by optimizing the weight distribution in real-time.
Solution Approach 2:
The patent changes the weight distribution parameter between the pilot bit and reaming bit through mechanical means (springs and movable connecting pieces). By adjusting the weight-on-bit parameter dynamically, the system optimizes the drilling performance and reliability of the pilot bit while maintaining effective stress release.
3Device complexity
If the pilot bit and reaming bit are used without automatic weight adjustment, then the structure remains simple, but the weight distribution cannot be optimized leading to reduced service life and drilling efficiency
Solution Approach 1:
The patent incorporates dynamic adjustment mechanisms (springs and movable connecting pieces) that automatically adjust weight distribution during drilling operations. These mechanisms add minimal structural complexity while significantly improving drilling efficiency by optimizing the weight-on-bit in real-time based on drilling conditions.
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 solution improves rock breaking efficiency, extends drill bit service life, and increases ROP by automatically distributing weight on the pilot and reaming bits, while maintaining a simple structure and compatibility with various strata types, including interlayer strata.
Implementation Method 1
a pulsating impact generating mechanism provided inside the joint for modulating a drilling fluid to form a pulsed jet at a reaming bit nozzle and a pilot bit nozzle respectively and generating a periodic axial downward impulsive force
Implementation Method 2
modulating a drilling fluid to form a pulsed jet at a reaming bit nozzle and a pilot bit nozzle respectively and generating a periodic axial downward impulsive force which periodically impacts on the pilot bit during the modulation of the drilling fluid, thereby reducing chip hold down effect
Data Source
AI summary
A weight-on-bit self-adjusting drill bit includes a reaming bit, a WOB adjusting element, a transmission mechanism and a pilot bit and a pulsating impact generating mechanism; the pulsating impact generating mechanism includes a centralizing element, a driving element, a rotating element and a throttling element which are placed and connected successively, the centralizing element, the driving element and the rotating element are connected successively, the throttling element is in clearance fit with the rotating element, both of the centralizing element and the throttling element are respectively provided with a flow-through passage for the drilling fluid to flow through, the driving element drives the rotating element to rotate, the rotating element rotates relative to the flow-through passage on the throttling element.