Downhole Milling Tool Cooling and Debris Flushing
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Solution Overview
Problem
Existing methods fail to effectively dissipate heat and remove cuttings and shavings generated during the milling of fluid isolation barriers in well operations, which can lead to equipment damage and operational inefficiencies.
Innovation Solution
The use of a milling tool comprising a motor, gear box, pump, and mill bit, where a centrifugal or progressive cavity pump generates fluid flow to dissipate heat and remove cuttings and shavings by designating clearances and screens to prevent solids from entering the housing, operating within a wide range of downhole conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If milling is performed to remove stuck fluid isolation valves, then operational access is improved, but heat generation and debris accumulation occur
Solution Approach 1:
The patent employs a centrifugal pump to generate fluid flow that passes through the milling tool, motor, and gear box. This hydraulic system removes heat generated during milling operations by circulating fluid through the components, preventing thermal damage while enabling continuous operation for accessing formation sections.
Solution Approach 2:
The patent introduces fluid as an intermediary medium that serves multiple functions: cooling the motor and mill bit, carrying away cuttings and shavings, and lubricating moving parts. This intermediary fluid resolves the contradiction by absorbing heat and debris without interfering with the milling process itself.
2Ease of operation
If milling is performed to remove stuck fluid isolation valves, then operational access is improved, but cuttings and shavings accumulate
Solution Approach 1:
The centrifugal pump generates continuous fluid flow that carries cuttings and shavings away from the milling site. The fluid trajectory is designed to pass through the mill bit and gear box area, effectively transporting debris to the surface or collection point, thus preventing accumulation that could interfere with milling operations.
Solution Approach 2:
The patent converts the harmful effect of cuttings accumulation into a beneficial flushing action. The fluid flow, which could be considered waste, is utilized to transport debris away from critical components, turning a potential problem into a useful debris removal mechanism that maintains operational efficiency.
3Temperature
If pump flow rate is increased to improve heat removal, then heat dissipation is improved, but device complexity increases
Solution Approach 1:
The centrifugal pump is designed to perform multiple functions simultaneously: cooling the motor and mill bit, carrying away cuttings and shavings, and providing lubrication to moving parts. This multi-functionality reduces the need for separate systems, thereby limiting the increase in device complexity while achieving effective heat dissipation through optimized fluid flow rates.
Solution Approach 2:
The patent merges the cooling function, debris removal function, and lubrication function into a single integrated fluid flow system driven by one pump. By combining these functions, the system avoids the complexity of multiple independent systems while achieving effective heat dissipation through carefully controlled flow rates that satisfy all functional requirements.
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 system efficiently removes heat, cuttings, and shavings, ensuring the longevity of equipment and maintaining operational efficiency during the milling process.
Implementation Method 1
the pump generates flow past the motor and the mill bit to at least partially remove generated heat
Implementation Method 2
the pump generates flow past the mill bit to at least partially remove generated heat, cuttings, and shaving
Data Source
AI summary
In the drilling of oil and gas wells, some fluid isolation valves may be stuck in a closed position and may need to be milled out. Provided are methods and systems to dissipate heat and remove cuttings and shavings generated during milling of these fluid isolation barrier. The methods may include conveying a milling tool into a borehole, wherein the milling tool comprises a motor, a gear box coupled to the motor; a pump coupled to the gear box, and a mill bit coupled to the pump, milling a fluid isolation barrier positioned in the borehole using the milling tool, wherein heat is generated at the mill bit and by the motor during the milling of the fluid isolation barrier, and removing at least a portion of the heat by pumping fluid past the motor and the mill bit using the pump.