Buckling-Resistant Sucker Rod Using Steel Sleeve
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Solution Overview
Problem
Sucker rods in oil well pumping systems, particularly those made of carbon fiber and fiberglass, are prone to buckling and failure due to compression, limiting their use to shallower depths and increasing failures with the advent of deviated well drilling techniques, which cause frictional drag and destructive buckling.
Innovation Solution
A buckling-resistant sucker rod assembly where the rod is maintained in tension by a surrounding sleeve that absorbs compressive forces, allowing the use of lightweight materials like carbon fiber and fiberglass throughout the well, including deeper depths, by positioning a sleeve with a clamshell spacer between fittings to distribute compressive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If carbon fiber or fiberglass rods are used to reduce weight, then the pumping unit can lift a lighter load, but the rods become prone to buckling under compression
Solution Approach 1:
The invention combines carbon fiber or fiberglass rod with a steel sleeve to create a composite structure. The rod provides light weight and tensile strength, while the steel sleeve provides compressive strength and buckling resistance. This composite approach allows the rod to benefit from both materials' properties simultaneously.
Solution Approach 2:
The steel sleeve acts as an intermediary element that transfers compressive loads away from the carbon fiber or fiberglass rod. The sleeve absorbs the compressive forces that would otherwise cause buckling, allowing the lightweight rod to maintain its structural integrity while reducing overall weight.
2Reliability
If steel rods are used to prevent buckling, then the rods can withstand compression, but the pumping unit must lift a heavier load
Solution Approach 1:
Instead of using solid steel rods, the invention uses a composite structure with a steel sleeve surrounding a lightweight rod. This reduces the overall weight while maintaining buckling resistance, as only the sleeve needs to provide compressive strength rather than the entire rod structure.
Solution Approach 2:
The steel sleeve is positioned specifically where compressive forces are most likely to cause buckling, providing localized reinforcement only where needed. This allows the majority of the rod structure to remain lightweight while still preventing buckling at critical locations.
3Reliability
If fiberglass and carbon fiber rods are restricted to shallower depths, then rod destruction is reduced, but the usefulness of these materials is limited
Solution Approach 1:
The steel sleeve enables carbon fiber and fiberglass rods to be used at greater depths by providing the necessary compressive strength. This composite construction removes the depth limitation, allowing these lightweight materials to be used throughout the entire rod string from surface to bottom hole.
Solution Approach 2:
The steel sleeve acts as a protective intermediary that allows carbon fiber and fiberglass rods to withstand the harsh compressive conditions at greater depths. This enables the lightweight materials to be used in environments where they would previously have been too vulnerable to buckling.
4Productivity
If deviated well drilling is used to reach bottom hole location, then multi-well pad drilling efficiency is improved, but frictional drag causes rods to go into compression and buckle
Solution Approach 1:
The steel sleeve serves as a mediator that protects the lightweight rod from the harmful effects of frictional drag and compression caused by deviated well drilling. It absorbs these compressive forces, allowing the rod to maintain structural integrity even in deviated well configurations.
Solution Approach 2:
The composite structure of lightweight rod plus steel sleeve provides both the weight reduction needed for efficient pumping and the compressive strength required to withstand the additional frictional forces generated by deviated well drilling.
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 solution effectively prevents buckling of sucker rods, enabling their use at all depths and reducing downtime due to breakage, thereby enhancing the efficiency and longevity of oil well operations.
Implementation Method 1
the sleeve, or the combination of the sleeve and its extension, can absorb all compressive forces transmitted through the fittings, while the rod remains in a condition of tension
Implementation Method 2
the rod itself is held in tension between opposing fittings
Data Source
AI summary
A Buckling-resistant Sucker Rod for well pumps. The present invention comprises a sucker rod assembly in which the rod itself is held in tension between opposing fittings, and in which a sleeve surrounds the rod, occupying the space between the fittings. In one version, the buckling-resistant rod is assembled such that the end fittings are placed under tension prior to the installation of the sleeve, In another version, the sleeve is designed to be extendable until it places the rod segment under tension by pressing outwardly on the end fittings. Thus, the sleeve, or the combination of the sleeve and its extension, can absorb all compressive forces transmitted through the fittings, while the rod remains in a condition of tension. The invention enhances the efficiency of oil well operation, by using light-weight sucker rods, while minimizing down time due to breakage of the rods.