Vibrator Sub Reducing Friction in Deviated Wells
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Solution Overview
Problem
The difficulty in lowering a bottom hole assembly into oil or gas wells, particularly in horizontal or deviated sections, due to friction with the well bore, which can cause the assembly to become stuck and the tubing to buckle, and the limitations of well tractors in low-strength reservoirs and high costs.
Innovation Solution
A vibrator tool with a cylindrical body, motor, and non-linear shaft that vibrates to reduce friction by amplifying contact between the tool and the well bore, or a gear with an off-center weight to induce vibration, allowing the bottom hole assembly to be effectively pushed through deviated sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a well tractor is used to propel the bottom hole assembly, then the assembly can be pushed through horizontal or deviated portions of the well, but the tractor may fail to provide sufficient traction in low-strength reservoirs and the tool is expensive
Solution Approach 1:
The patent applies mechanical vibration through a vibrator tool that generates high-frequency vibrations to reduce friction between the bottom hole assembly and the well bore. The vibrator includes a rotor with unbalanced weights that create vibrational forces, allowing the assembly to move through deviated sections without requiring a well tractor. This vibration-based approach provides reliable movement in low-strength reservoirs where traditional mechanical propulsion fails.
2Ease of operation
If a well tractor is used to propel the bottom hole assembly, then the assembly can be pushed through horizontal or deviated portions of the well, but the tubing may buckle when the assembly becomes stuck
Solution Approach 1:
The vibrator tool generates continuous high-frequency vibrations that prevent the bottom hole assembly from stopping or becoming stuck in deviated sections. By maintaining constant vibrational motion, the assembly keeps moving smoothly through the well bore, preventing the tubing from buckling that would occur if the assembly halted during propulsion.
3Speed
If the bottom hole assembly is pushed through horizontal or deviated portions of the well using tubing, then the assembly can reach the bottom of the well, but friction between the assembly and well bore walls causes the assembly to stop progressing
Solution Approach 1:
The vibrator tool generates high-frequency vibrations that reduce friction between the bottom hole assembly and the well bore walls. The vibrations create a kind of vibrational lubrication effect, allowing the assembly to maintain progress speed by preventing direct contact and sticking points along the well bore path.
4Ease of operation
If a well tractor is used, then the bottom hole assembly can be propelled through deviated sections, but the tool is expensive and few companies produce them
Solution Approach 1:
The vibrator tool is a simpler, more readily manufacturable device compared to expensive well tractors. It uses standard motor and bearing components that can be produced by many companies, increasing availability and reducing cost. The vibrator's straightforward design with a rotor, bearing, and housing allows for easier manufacturing and wider producer support.
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 vibrator tool reduces friction between the bottom hole assembly and the well bore, enabling continued progress even in low-strength reservoirs and reducing the need for expensive well tractors, thus facilitating the insertion of logging equipment into the well.
Implementation Method 1
a non-linear shaft attached to the motor so that as the motor turns the non-linear shaft, the non-linear shaft extends outwardly from the motor within the substantially cylindrical body. The vibrator tool further includes a bearing attached to the shaft a distance from the motor so that the bearing rotates as the non-linear shaft turns, the bearing contacting portions of the inner surface of the cylindrical body as the non-linear shaft turns, thereby vibrating the substantially cylindrical body
Implementation Method 2
a substantially circular gear that rotates radially and that is driven by the motor. The vibrator tool further includes a weight attached to the gear at a position off-center relative to the center of the gear, so that when the gear rotates the off-center attachment of the weight causes the motor and the cylindrical body to vibrate
Data Source
AI summary
A vibrator tool for use in inserting a bottom hole assembly into a wellbore. The vibrator tool includes a substantially cylindrical body, a motor within the substantially cylindrical body, and a non-linear shaft attached to the motor so that the motor turns the non-linear shaft. The non-linear shaft extends outwardly from the motor within the substantially cylindrical body. The vibrator tool further includes a bearing attached to the shaft a predetermined distance from the motor so that the bearing rotates as the non-linear shaft turns. The bearing contacts portions of the inner surface of the cylindrical body as the non-linear shaft turns, thereby vibrating the substantially cylindrical body.