Linear Motor Hoisting for Top Drive Cable Wear Reduction
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Solution Overview
Problem
The excessive wear of flexible lines in hoisting systems of drilling rigs due to multi-layer spooling and increased tension causes a decrease in operational life, leading to cuts and abrasions, and stress on the lines.
Innovation Solution
The implementation of a hoisting system utilizing linear electric motors with stators and rotors connected via flexible lines, allowing for precise control and reduction of wear by generating magnetic fields to raise and lower the top drive, thereby minimizing the mechanical stress on the lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drawworks with drum and flexible line is used for hoisting, then the top drive can be raised and lowered, but the flexible line experiences excessive wear and reduced operational life
Solution Approach 1:
The patent replaces the traditional mechanical drawworks system with a linear motor system that uses electromagnetic force to directly lift and lower the top drive. This eliminates the flexible line entirely, substituting electromagnetic propulsion for mechanical cable-based hoisting, thereby resolving the wear and operational life issues.
Solution Approach 2:
The invention extracts and removes the flexible line from the hoisting system. By eliminating this component that suffers from wear, the system achieves improved reliability without the harmful effects of cable degradation, cuts, and abrasions associated with traditional drawworks.
2Ease of operation
If multi-layer spooling of flexible line around drum is used, then hoisting function is achieved, but cuts and abrasions are imparted to the flexible line
Solution Approach 1:
The linear motor system replaces the mechanical spooling action with electromagnetic force. The motor directly propels the top drive vertically without requiring any flexible line to be spooled around a drum, thereby eliminating the source of cuts and abrasions while maintaining full hoisting capability.
Solution Approach 2:
By removing the flexible line and drum spooling mechanism from the system, the invention eliminates the harmful interaction between multiple layers of line forcing against each other during spooling operations.
3Ease of operation
If traditional drawworks system with multiple sheaves is used, then top drive movement is controlled, but tension and stress increase on the flexible line
Solution Approach 1:
The linear motor replaces the mechanical advantage system of multiple sheaves and flexible line with direct electromagnetic force application. This provides precise control of top drive movement through electromagnetic field modulation while eliminating the cumulative tension and stress that would be distributed across multiple line segments in a traditional block and tackle system.
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 solution extends the operational life of flexible lines by reducing wear and stress, enhancing the efficiency and reliability of drilling operations by using linear electric motors to manage the movement of the top drive.
Implementation Method 1
The stator may be operable to generate magnetic fields operable to move the rotor relative to the stator to raise and lower the top drive
Data Source
AI summary
Systems and methods for hoisting a top drive of a drilling rig. An example system includes a hoisting system having a linear electric motor operable to raise and lower the top drive. An example method includes commencing operation of a processing device to cause operation of the linear electric motor to raise and lower the top drive. The linear electric motor may have a stator connected to and extending vertically along a mast of the drilling rig, and a rotor connected to the top drive and operable to move relative to the stator. The rotor may be connected to the top drive via one or more flexible lines.