Coring Tool Stabilizer Reduces Rotational Eccentricity
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Solution Overview
Problem
Coring tools often produce core samples with reduced accuracy due to rotational eccentricity and premature lodging, leading to contamination and incomplete fluid capture, which affects the representation of earth formation characteristics.
Innovation Solution
The implementation of stabilizers connected to the coring tool's outer barrel, which remain rotationally stationary relative to the earth formation, reducing eccentric rotation and lateral vibrations, and a sponge material lining the inner barrel to absorb fluids, ensuring accurate fluid capture and sample representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coring tool rotates the coring bit to cut the core sample, then the core sample can be procured and advanced through the borehole, but rotational eccentricity causes the core sample diameter to deviate from the intended diameter and reduces measurement accuracy
Solution Approach 1:
The stabilizer assembly acts as a counterbalancing mechanism that offsets the rotational eccentricity of the coring bit. By positioning the stabilizer blades to contact the borehole wall opposite to the direction of maximum eccentricity, the system creates a counteracting force that maintains the intended core sample diameter and reduces rotational deviation during drilling operations.
Solution Approach 2:
The invention addresses the rotational eccentricity problem by introducing a stabilizer assembly that operates in a different dimensional plane. Rather than trying to correct the coring bit rotation directly, the stabilizer blades contact the borehole wall at strategic positions to constrain the coring tool's rotational path, effectively adding a radial constraint dimension to control the core sample diameter.
2Productivity
If the coring tool advances rapidly to increase productivity, then more core samples can be procured per unit time, but lateral vibrations increase causing premature lodging and contamination
Solution Approach 1:
The stabilizer assembly provides beforehand cushioning by pre-positioning the stabilizer blades to contact the borehole wall before significant lateral vibrations can develop. This proactive stabilization creates a damping effect that absorbs vibrational energy and prevents the buildup of lateral movements that would otherwise cause premature lodging and contamination of the core sample.
Solution Approach 2:
The stabilizer blades act as an intermediary element between the coring tool and the borehole wall. They mediate the interaction by providing a stable contact interface that reduces lateral vibrations and prevents direct transmission of vibrational energy to the core sample, thereby maintaining core sample integrity during rapid advancement.
3Ease of operation
If the inner barrel remains open during coring to receive the core sample, then the core sample can be collected, but contaminants from the borehole environment can enter and contaminate the core sample
Solution Approach 1:
The system performs preliminary action by positioning the stabilizer assembly to ensure stable, centered rotation of the coring tool before the core sample is fully received into the inner barrel. This preliminary stabilization prevents lateral movements that would otherwise cause the core sample to shift and become contaminated during the collection process.
4Speed
If the coring bit rotates with high speed to increase cutting efficiency, then more material can be removed per unit time, but rotational eccentricity increases causing the core sample to deviate from the intended diameter
Solution Approach 1:
The stabilizer assembly functions as a counterbalancing mechanism that offsets the increased rotational eccentricity caused by high-speed coring bit rotation. By contacting the borehole wall at strategic positions, the stabilizer blades create counteracting forces that maintain the intended core sample diameter even during high-speed operations.
Solution Approach 2:
The stabilizer assembly provides dynamic stabilization that adapts to the varying rotational conditions of the coring bit. As the coring bit rotates at different speeds, the stabilizer blades automatically adjust their contact pressure and positioning to maintain optimal stabilization, ensuring consistent core sample diameter across varying operational speeds.
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 accuracy of core samples by maintaining the intended diameter and reducing contamination, allowing for a more precise representation of earth formation characteristics and efficient fluid capture.
Implementation Method 1
A sponge material may line an inner surface of the inner barrel and may be configured to absorb a fluid from the core sample.
Data Source
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AI summary
Coring tools configured to procure core samples of earth formations may include a coring bit comprising a cutting structure configured to cut a core sample and an outer barrel connected to the coring bit. The outer barrel may be configured to apply axial and rotational force to the coring bit. An inner barrel may be located within the outer barrel and may be configured to receive a core sample within the inner barrel. A sponge material may line an inner surface of the inner barrel and may be configured to absorb a fluid from the core sample. A stabilizer may be connected to the outer barrel. At least one blade of the stabilizer may be rotatable with respect to the outer barrel and may be configured to remain at least substantially rotationally stationary relative to the earth formation during coring.