Flexible Shaft Coring Bit for In-Drilling Sampling
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Solution Overview
Problem
Conventional coring methods for oil and gas exploration require frequent removal of drilling tools from the wellbore, making them time-consuming and costly, especially in challenging environments like high-angle, horizontal, and deep-water wells, and are ineffective in unstable boreholes.
Innovation Solution
A bottom hole assembly with a core sampling tool that includes a motor-driven coring bit system allowing for in-drilling core sampling without removing the drilling tool, featuring a flexible drilling shaft, sealing door, and rotatable actuator to collect and store core samples within the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional coring methods are used, then core samples can be collected, but the drilling tool must be removed multiple times which increases time and cost
Solution Approach 1:
The patent combines the coring function with the drilling tool by integrating a coring bit into the drill string. This allows the drilling tool to perform both drilling and coring operations without requiring removal or replacement, thereby eliminating the time loss associated with bit replacement while maintaining core sampling capability.
Solution Approach 2:
The drill string is designed to serve multiple functions: it can drill the wellbore and also collect core samples when the coring bit is engaged. This multi-functionality eliminates the need for separate coring operations and reduces the number of trips to the wellbore, improving productivity while reducing time loss.
2Productivity
If wireline sidewall coring tools are used, then sidewall core samples can be obtained, but the drilling assembly must be removed which increases time and cost
Solution Approach 1:
The patent merges the sidewall coring capability into the drilling assembly by incorporating a coring bit that can be engaged from the drill string. This eliminates the need to remove the drilling assembly for sidewall coring operations, as the coring bit can be deployed and retrieved through the drill string, thereby reducing time loss while maintaining coring efficiency.
3Productivity
If conventional coring or wireline sidewall coring is used in highly deviated or horizontal wells, then core samples can be collected, but the operation becomes very difficult and costly
Solution Approach 1:
The patent employs a flexible drilling shaft that can dynamically adapt to the wellbore configuration. This flexible shaft allows the coring bit to reach the sidewall even in highly deviated or horizontal wells where rigid conventional tools cannot effectively operate. The flexibility enables the tool to navigate complex wellbore paths while maintaining coring capability, thereby improving ease of operation in challenging well geometries.
4Productivity
If conventional coring tools are used in unstable boreholes with washouts, then core samples can be collected, but the tools cannot effectively capture core samples
Solution Approach 1:
The patent uses a flexible drilling shaft that can adapt to unstable borehole conditions. This flexible shaft maintains contact with the wellbore wall even in washout zones where rigid tools fail. The flexibility allows the coring system to navigate and stabilize in unstable environments, enabling reliable core sample collection where conventional rigid tools cannot effectively operate.
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
Enables efficient and cost-effective core sampling during drilling operations, reducing time and flow restrictions, and allowing sampling in deviated and unstable wells, including those with borehole washouts.
Implementation Method 1
a flexible drilling shaft extending between and coupled to the motor and the coring bit
Implementation Method 2
the coring bit configured to rotate to deposit a core sample within the core storage container
Data Source
AI summary
A system includes a bottom hole assembly and a core sampling tool. The bottom hole assembly includes a housing and a drill bit coupled to the housing. The core sampling tool includes a first compartment positioned within the housing, the first compartment including a motor; a second compartment positioned within the housing and radially spaced apart from the first compartment, the second compartment including a coring bit; and a flexible drilling shaft extending between and coupled to the motor and the coring bit.