Offset Spoke Spider for Downhole Drilling Fluid Flow
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Solution Overview
Problem
Designing spiders for downhole drilling tools that balance strength, stability, and fluid flow requirements is challenging, especially under extreme conditions, as existing spiders often compromise on either strength or flow rate.
Innovation Solution
The spider design features axially and circumferentially offset spokes to create separate flow areas, allowing for thicker, more robust components while maintaining or exceeding the minimum required flow rate, with configurations such as two or four spokes in each row, and varying offset angles to optimize stability and fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spider components are designed to provide sufficient strength and stability to withstand drilling conditions, then the structural strength is improved, but the flow area is reduced which limits the fluid flow rate
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional single-plane spoke arrangement to a multi-row axially offset spoke configuration. This three-dimensional arrangement creates multiple flow paths through the spider structure, increasing the effective flow area without compromising structural strength. The axial offset between rows allows drilling fluid to flow through multiple levels, effectively adding a dimensional aspect to the flow path that resolves the contradiction between strength and flow rate.
Solution Approach 2:
The spider structure is segmented into multiple rows of spokes that are axially offset from each other. This segmentation creates distinct flow channels between and among the rows, allowing drilling fluid to pass through multiple pathways simultaneously. The segmentation of the spoke arrangement into discrete rows with offset positioning enables the structure to maintain strength while providing sufficient cumulative flow area to meet minimum flow rate requirements.
2Reliability
If thicker spokes are used to increase strength and stability, then the spider can withstand extreme drilling conditions, but the flow area is blocked reducing fluid flow rate
Solution Approach 1:
By arranging spokes in multiple axially offset rows, the invention creates flow paths that extend in the axial dimension rather than being confined to a single transverse plane. This allows the use of thicker spokes for reliability while maintaining adequate flow area, as the fluid can pass through the gaps between rows in addition to the spaces between individual spokes within each row.
Solution Approach 2:
The multi-row spoke structure creates a nested arrangement where flow paths are formed both within individual rows and between adjacent rows. The axial offset creates a nested three-dimensional flow channel system that allows fluid to navigate through the robust spoke structure without being completely blocked by the thicker components needed for reliability.
3Stability of the object's composition
If more spokes are added to increase structural stability, then the spider can better withstand drilling conditions, but the flow area is reduced
Solution Approach 1:
The invention resolves this contradiction by distributing spokes across multiple axially offset rows rather than concentrating them in a single plane. This dimensional distribution allows the addition of more spokes for enhanced stability while maintaining flow area, as the axial spacing creates additional flow channels that would not be available in a single-plane configuration.
Solution Approach 2:
Segmenting the spoke arrangement into multiple rows creates discrete flow channels between each row. This segmentation allows the total number of spokes to be increased for stability while the segmented arrangement ensures that flow area is preserved through the creation of multiple pathways, preventing any single row from completely blocking the flow.
Data Source
AI summary
A spider for a downhole tool, comprises: an inner rim; an outer rim; and at least two spokes extending radially between and connected to the inner and outer rims. The spider can be selected from a group consisting of grounding spiders, landing spiders, and centralizers. The at least two spokes comprise a first spoke in a first row and a second spoke in a second row that is axially offset from the first row; the second spoke can be circumferentially offset from the first spoke. The second row can be at a drilling fluid inlet end of the spider, and the first row can be at a drilling fluid outlet end of the spider. Each row defines a transverse plane having a flow area that is sufficient for drilling fluid flowing through the spider to at least meet a minimum target flow rate under specified operating conditions.