Coring Bit Sleeve for Drilling Fluid Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional core barrel assemblies are prone to damaging core samples due to exposure to high-velocity drilling fluid, leading to fluid invasion and contamination, which compromises the integrity of the core and renders subsequent analysis unreliable, especially in unconsolidated formations.
Innovation Solution
A core bit design featuring a sleeve that separates face discharge channels and throat discharge channels, optimizing hydraulic losses to divert more drilling fluid through face discharge channels and reduce exposure of the core to drilling fluid, thereby minimizing fluid invasion and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If drilling fluid is circulated through the core barrel assembly to lubricate and cool the cutting structure, then the cutting structure is properly lubricated and cooled, but the core is exposed to high-velocity drilling fluid causing fluid invasion and contamination
Solution Approach 1:
The core barrel assembly is segmented into distinct flow zones: an upper annular region for coolant delivery to the cutting structure, and a lower region isolated from the core by a core shoe. This segmentation allows drilling fluid to cool the bit without directly contacting the core, resolving the contradiction between cooling requirements and core protection.
Solution Approach 2:
The core shoe acts as an intermediary barrier between the drilling fluid flow and the core. It redirects the high-velocity drilling fluid away from the core while allowing the core to pass through its central opening, thereby protecting the core from fluid invasion while maintaining the cooling function.
2Productivity
If drilling fluid velocity is increased to improve cuttings removal, then cuttings removal efficiency is improved, but core exposure to high-velocity fluid increases causing damage and contamination
Solution Approach 1:
The annular region is segmented into an upper portion for high-velocity cuttings removal and a lower portion protected from direct fluid impact. The core shoe creates this segmentation, allowing high velocity where needed for productivity while protecting the core from harmful effects.
Solution Approach 2:
The core shoe serves as a mediator that allows high-velocity drilling fluid to pass through for effective cuttings removal while redirecting the flow to bypass the core, thus maintaining productivity without compromising core integrity.
3Ease of operation
If a narrow annulus is provided between core bit inside diameter and core shoe outside diameter, then the core bit can rotate freely, but drilling fluid flows into the narrow annulus increasing velocity and core exposure
Solution Approach 1:
The core shoe acts as an intermediary that manages the narrow annulus flow path. It allows the annulus to exist for bit rotation while configuring its geometry to redirect fluid flow away from the core, thus maintaining operational ease while controlling fluid velocity and exposure.
Solution Approach 2:
The narrow annulus has different flow characteristics at different locations: near the bit face where rotation is needed, and further up where the core shoe redirects flow away from the core. This local differentiation allows rotation functionality while minimizing harmful fluid velocity in the core exposure zone.
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 design effectively reduces the velocity and amount of drilling fluid contacting the core, enhancing core quality and reliability of formation characterization by minimizing fluid invasion and contamination.
Implementation Method 1
optimizing hydraulic losses to divert more drilling fluid through face discharge channels
Data Source
AI summary
A coring bit for use on a coring tool for extracting a sample of subterranean formation from a wellbore includes a bit body having a cavity, wherein a throat portion of the cavity extends into the bit body from a face of the bit body. The coring bit includes a sleeve disposed within the cavity of the bit body, the sleeve configured to separate a face discharge channel and a throat discharge channel. The face discharge channel is located radially outward of the sleeve and the throat discharge channel is located radially inward of the sleeve. A method of repairing a such a coring bit includes removing the sleeve from the cavity of a bit body.