Magnetorheological Drill String Damper Using Remnant Magnetization
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Solution Overview
Problem
Existing MR fluid damping systems for drill strings require significant electrical energy to maintain magnetic fields, leading to inefficient damping and high energy costs, particularly when operating at low damping levels due to residual magnetization issues in valve components.
Innovation Solution
The system employs an MR valve with components made from materials that retain a high remnant magnetization, allowing for efficient damping using residual magnetic fields, reducing the need for continuous electrical power by using a demagnetization cycle and sensors to manage remnant magnetization levels, and incorporating a battery pack for power, eliminating the need for turbine alternators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MR valves use low carbon steel or martensitic stainless steel components, then the valve can be manufactured with standard materials, but the remnant magnetization reduces the minimum damping level and compromises performance
Solution Approach 1:
The patent applies composite materials by combining ferritic stainless steel (providing high remnant magnetization) with other materials in the valve construction. This composite approach allows the valve to achieve both high damping performance through enhanced remnant magnetization and manufacturability through using established stainless steel fabrication processes.
Solution Approach 2:
The patent changes the magnetic parameter of the valve components by selecting ferritic stainless steel with specific magnetic properties (high remnant magnetization). This parameter change transforms the valve from one that requires continuous power to maintain damping to one that maintains damping through remnant magnetization alone, eliminating the technical contradiction between performance and manufacturability.
2Reliability
If continuous electrical power is supplied to maintain magnetic field in MR valves, then damping can be maintained, but energy consumption increases significantly
Solution Approach 1:
The patent applies self-service by designing the valve to maintain its own magnetic field through remnant magnetization of the ferritic stainless steel components without requiring continuous external power. The valve serves itself by retaining magnetic properties after initial magnetization, eliminating the need for continuous electrical energy input while maintaining damping consistency.
Solution Approach 2:
The patent uses periodic action by applying electrical power only intermittently to initially magnetize the ferritic stainless steel components or to adjust damping levels, rather than continuous power supply. This periodic magnetization approach allows the valve to maintain damping through remnant magnetization between power applications, significantly reducing energy consumption while maintaining reliability.
3Reliability
If shock subs are used to isolate up-hole portions from vibration, then up-hole components are protected, but down-hole vibration increases including at the drill bit
Solution Approach 1:
The patent applies local quality by placing the MR valve specifically at the down-hole location near the drill bit rather than using a shock sub at the up-hole position. This localized placement allows the damping action to occur precisely where vibration affects the drill bit performance, protecting both up-hole and down-hole components while eliminating the harmful effect of increased down-hole vibration associated with shock subs.
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 approach enables effective damping across a range of operating conditions with reduced electrical energy consumption, increasing drill bit penetration rates, extending component lifespan, and maintaining contact with the drilling surface, while being more compact and efficient than traditional shock subs.
Implementation Method 1
The viscosity of MR fluid can be varied in a down-hole environment by energizing coils in the valve that create a magnetic field to which the MR fluid is subjected.
Implementation Method 2
energizing coils in the valve that create a magnetic field to which the MR fluid is subjected
Implementation Method 3
The shafts in such embodiments have been made of 410 stainless steel, which can have a relative magnetic permeability of 750 Gauss and a coercivity of 6 to 36 Oe. Unfortunately, the inventors have found that the minimum level of damping achievable using such MR valves is compromised by the fact that energizing the coil can result in a low level of permanent magnetization of the valve components.
Data Source
AI summary
A system for damping vibration in a drill string can include a magnetorheological fluid valve assembly having a supply of a magnetorheological fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil for inducing a magnetic field that alters the resistance of the magnetorheological fluid to flow between the first and second chambers, thereby increasing the damping provided by the valve. A remnant magnetic field is induced in one or more components of the magnetorheological fluid valve during operation that can be used to provide the magnetic field for operating the valve so as to eliminate the need to energize the coils during operation except temporarily when changing the amount of damping required, thereby eliminating the need for a turbine alternator power the magnetorheological fluid valve. A demagnetization cycle can be used to reduce the remnant magnetic field when necessary.