DLC Multi-Layer Friction Reducing Tape for Drill Strings
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Solution Overview
Problem
In subterranean rotary drilling, particularly in directional drilling, excessive friction between the drill stem assembly and well casing or borehole leads to increased torque and drag, limiting the depth and reach of wells due to the abrasive wear caused by metal-on-metal contact, which existing solutions like hardfacing and lubricants fail to adequately address without compromising durability or introducing environmental concerns.
Innovation Solution
A multi-layer friction reducing tape comprising a foil layer, an under layer, an adhesion promoting layer, and a functional layer with fullerene-based or diamond-like-carbon (DLC) materials, applied in a patterned design to reduce friction and wear while maintaining mechanical integrity, is used to coat drill strings and other equipment, thereby reducing friction and wear without degrading the casing or drill string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hardfacing or lubricants are used to reduce friction, then friction and wear are reduced, but durability or environmental safety is compromised
Solution Approach 1:
The patent applies a multi-layer composite coating system consisting of a base layer, intermediate layer, and functional layer. The base layer provides adhesion to the drill stem assembly, the intermediate layer serves as a transition zone, and the functional layer contains diamond-like carbon particles embedded in a binder matrix to provide low friction and wear resistance. This composite structure resolves the contradiction by integrating multiple material properties into a single coating system that simultaneously ensures durability through the base layer and low friction through the functional layer.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the coating layers, particularly the functional layer which contains diamond-like carbon particles with specific size distributions (0.1-10 microns) and binder material composition. By controlling particle size, concentration, and binder properties, the coating achieves optimal balance between wear resistance and low friction characteristics, resolving the contradiction between reducing friction and maintaining durability.
2Strength
If metal-on-metal contact is used for drilling, then structural strength is maintained, but abrasive wear increases and drilling depth is limited
Solution Approach 1:
The patent applies the low friction and wear-resistant functional layer specifically to the outer surface of the drill stem assembly that contacts the borehole and casing, while maintaining the original metal structure and strength of the drill stem itself. The coating is applied locally to the contact surfaces, providing wear protection without compromising the structural integrity of the underlying metal components.
3Power
If conventional coatings are applied to reduce friction, then torque and drag are reduced, but the coatings degrade the casing or drill string
Solution Approach 1:
The patent divides the coating into distinct functional segments: a base layer for adhesion, an intermediate layer for transition and protection, and a functional layer for friction reduction. The base layer is specifically designed to bond to the drill stem assembly without degrading it, while the functional layer provides low friction. This segmentation allows each layer to perform its specific function while protecting the underlying structures from degradation.
Solution Approach 2:
The intermediate layer acts as a mediator between the base layer and the functional layer, and between the coating system and the drill stem assembly. This intermediate layer provides a gradual transition in material properties, ensuring good adhesion while protecting the drill stem and casing from direct contact with the functional layer materials, thus preventing degradation of the underlying structures.
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 multi-layer tape significantly reduces friction and wear, enabling deeper and longer drilling operations with reduced parasitic torque and stick-slip vibrations, while maintaining the durability and mechanical integrity of the drill string and casing, thus enhancing drilling efficiency and equipment longevity.
Implementation Method 1
a functional layer that includes a fullerene based composite, a diamond based material, diamond-like-carbon (DLC), or combinations thereof
Implementation Method 2
an adhesion promoting layer contiguous with a surface of the under layer
Data Source
AI summary
A multi-layer friction reducing tape, including: a foil layer including a metal, polymer, or hybrid-metal-polymer; an under layer disposed on the foil layer; an adhesion promoting layer contiguous with a surface of the under layer; a functional layer that includes a fullerene based composite, a diamond based material, diamond-like-carbon (DLC), or combinations thereof, wherein the functional layer is contiguous with a surface of the adhesion promoting layer; and a tape, including an adhesive layer and a backing material, wherein the adhesive layer is attached to a surface of the foil layer opposite the under layer.