Drag Bit Blade Geometry for Clogging Prevention
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Solution Overview
Problem
Conventional drag bits face efficiency issues when drilling through materials like shale, as they tend to clog due to sticky clay formation, which narrows channels and reduces the rate of penetration by allowing new material to pass through.
Innovation Solution
The design incorporates a blade geometry with rotationally offset inner and outer cutters, along with dual channel and nozzle configurations, to effectively flush and remove cuttings, reducing clogging and maintaining low channel pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional drag bits are used to drill through shale materials, then the bit can fail the rock and advance the borehole, but the channels become clogged with sticky clay material reducing the rate of penetration
Solution Approach 1:
The bit is divided into multiple blades with distinct leading edges, where each blade has inner and outer cutters positioned at different radial locations. This segmentation allows material to be failed at multiple points and directs it into channels more effectively, preventing clogging and maintaining flushing efficiency while advancing the borehole through shale materials.
2Object-generated harmful factors
If the bit fails clay material at the borewall, then the material is removed from the formation, but the clay absorbs fluid and forms sticky ribbons that cling to the bit surface narrowing the channels
Solution Approach 1:
The invention extracts the harmful clay material from the channel flow path by positioning cutters to fail material away from the channel entrance and using blade geometry to direct cuttings into the channel more effectively. This prevents clay ribbons from forming and clinging to the bit surface, maintaining channel width and material evacuation efficiency.
Solution Approach 2:
The blade geometry acts as an intermediary between the cutters and the channel, mediating the flow of cuttings. The blade shape and positioning guide the failed material into the channel in a controlled manner, preventing direct contact between sticky clay ribbons and the channel surfaces where they would adhere and cause clogging.
3Strength
If channels are narrowed by clay accumulation, then the bit structure remains intact, but new material cannot pass through the channels efficiently limiting penetration rate
Solution Approach 1:
The invention performs preliminary action by positioning cutters and shaping blades in advance to prevent clay material from entering the channels in a clogging state. The cutters are positioned to fail material at optimal locations and the blade geometry is designed beforehand to direct cuttings into channels in a manner that prevents ribbon formation and adhesion, maintaining both structural integrity and high material processing volume.
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
This configuration enhances the rate of penetration by preventing clogging and maintaining efficient evacuation of cuttings, thereby improving drilling efficiency through materials that form sticky clays.
Implementation Method 1
A pump circulates drilling fluid through the drill pipe and out of the drill bit flushing rock cuttings from the bit and transporting them back up the borehole
Implementation Method 2
A pump circulates drilling fluid through the drill pipe and out of the drill bit flushing rock cuttings from the bit and transporting them back up the borehole
Implementation Method 3
Each blade supports a plurality of discrete cutters that contact, shear and/or crush the rock formation in the borehole as the bit rotates to advance the borehole
Implementation Method 4
Each blade supports a plurality of discrete cutters that contact, shear and/or crush the rock formation in the borehole as the bit rotates to advance the borehole
Implementation Method 5
The PCD table provides improved wear resistance, as compared to the softer, tougher tungsten carbide substrate that supports the diamond during drilling
Data Source
AI summary
A drag bit includes a blade extending from the bit body and supporting inner cutters proximate the longitudinal axis and outer cutters spaced from the longitudinal axis. The inner cutters are rotationally offset from the outer cutters. During operation the inner cutters deposit cut material in a channel that is contiguous with a channel that receives material cut by the outer cutters. The cutters and the contiguous channels flush agglomerating material from the slots.