Helical Hardbanding for Drill String Wear and Cuttings Removal
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Solution Overview
Problem
Conventional hardbanding methods on drill string components create obstacles for cuttings to reach the surface during drilling, leading to increased wear and erosion due to trapped cuttings, which reduces the effective life of the components and requires additional repair costs.
Innovation Solution
A helical band of hardbanding material with a helix angle of 5 degrees or more and spaced coils 18 mm or more apart is applied around the tubular component, using a non-magnetic Ni-based matrix with 40-80 wt.% spherical or macrocrystalline tungsten carbide, to act as an auger and facilitate the bypass of abrasive particles, reducing wear and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hardband is applied around the entire circumference of a tubular component, then wear protection of the component is improved, but cuttings removal efficiency deteriorates due to obstacles formed by the hardband
Solution Approach 1:
The continuous circumferential hardband is segmented into discrete helical coils with spacing between them. This segmentation allows drilling fluid and cuttings to pass through the gaps between coils, eliminating the obstacle effect while maintaining wear protection on the component surface.
Solution Approach 2:
The hardband geometry is transformed from a planar circumferential ring to a three-dimensional helical structure wrapping around the component. This dimensional change creates longitudinal pathways for cuttings removal while providing distributed wear protection along the component length.
2Power
If the drill string is pulled to one side of the hole during directional drilling, then gravity assistance for drilling is improved, but cuttings become trapped on the leading edge of the hardband causing increased wear
Solution Approach 1:
The helical coil segmentation creates multiple bypass pathways around the component, allowing cuttings to flow through the gaps rather than being trapped on the leading edge, even when the drill string is gravity-assisted to one side of the hole.
Solution Approach 2:
The helical configuration converts the potential harmful effect of cuttings accumulation into a beneficial auger-like flow pattern that actively transports cuttings upward through the drilled hole, reducing residence time and wear.
3Loss of time
If cuttings residence time in a specific area is increased, then drilling time for back reaming is extended, but wear and erosion damage to the component is intensified
Solution Approach 1:
The helical coil structure with spacing creates accelerated flow pathways that rush cuttings through the protected area, minimizing residence time and reducing the opportunity for wear and erosion damage to occur.
Solution Approach 2:
The helical geometry converts the stationary hardband into a dynamic flow-guiding structure that actively reduces cuttings residence time, transforming the potential harm of prolonged exposure into a protective flow acceleration effect.
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 helical band design reduces the residence time of cuttings, minimizing damage to the drill string components and extending their useful life by allowing abrasive particles to pass quickly, thus protecting a greater surface area and reducing maintenance costs.
Implementation Method 1
The patterned hardbanding design will enable the sand grains to preferentially take an alternate path through the non-contact areas due to the hydrodynamic forces
Implementation Method 2
a single bead spiral made by laser welding techniques
Data Source
AI summary
A method of hardbanding a tubular component. The method involves placing a helical band of hardbanding material forming spaced coils around an exterior wear surface of a body of the tubular component. The helical band has a helix angle of not less than 5 degrees relative to a longitudinal axis of the tubular component and the spacing between the coils is a minimum of 18 mm.