Perforated Shock Absorber for Drillpipe Conveyance
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Solution Overview
Problem
Existing logging tools with large diameters or transverse dimensions cannot be conveyed inside drillpipe, exposing them to harsh downhole conditions and risking damage, which can lead to costly delays and environmental hazards.
Innovation Solution
A shock absorber comprising plastically deformable perforated members and rigid spacer members that absorb impact energy and allow controlled deformation, enabling the deployment of large-diameter logging toolstring elements while protecting them from damage during conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large-diameter logging toolstring elements are conveyed inside drillpipe, then protection from harsh downhole conditions is improved, but the internal diameter of drillpipe is insufficient to accommodate them
Solution Approach 1:
The shock absorber is divided into multiple perforated members (first, second, third, and fourth members) arranged in series, each contributing to the overall energy absorption capability. This segmentation allows the shock absorber to achieve greater total deformation capacity while maintaining a compact structure that can fit within drillpipe dimensions.
Solution Approach 2:
The shock absorber is designed to be nested within the drillpipe during conveyance, with the perforated members and spacers arranged to minimize the overall diameter. The hollow configuration of each perforated member allows for nested arrangement, enabling the entire shock absorber assembly to fit within the limited internal diameter of the drillpipe while still providing adequate protection.
2Ease of operation
If shock absorber allows large-diameter toolstring elements to protrude from drillpipe, then ease of deployment is improved, but exposure to harsh downhole conditions increases
Solution Approach 1:
The shock absorber is pre-installed within the drillpipe before conveyance to the logging location. This preliminary placement ensures that when the toolstring elements are deployed by protruding from the drillpipe, the shock absorber is already in position to provide immediate impact energy attenuation, enabling safe and easy deployment while minimizing exposure time to harsh conditions.
3Reliability
If shock absorber undergoes plastic deformation to attenuate impact energy, then impact protection is improved, but structural integrity may be compromised
Solution Approach 1:
The shock absorber features localized deformation zones in the perforated members where plastic deformation is intended to occur. The spacers are strategically positioned to create controlled deformation regions between them, allowing impact energy to be absorbed in specific locations while maintaining the overall structural integrity of the shock absorber assembly.
Solution Approach 2:
The shock absorber employs a composite structure combining perforated members made of plastically deformable material with rigid spacer members. This composite design allows the deformable portions to absorb impact energy through plastic deformation while the rigid spacers maintain structural integrity and prevent complete collapse of the assembly.
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 shock absorber effectively attenuates impact energy, prevents damage to logging tools, and allows for the safe conveyance of large-diameter toolstring elements, reducing the risk of delays and environmental incidents.
Implementation Method 1
an elongate, hollow member defined by a series of mutually aligned, plastically deformable perforated members... on compression of the shock absorber the perforated members deform plastically
Implementation Method 2
capable of acting between the toolstring and the landing surface to attenuate impact energy arising on movement of the toolstring to the extended position
Data Source
AI summary
A shock absorber (29) for downhole use comprises an elongate, hollow member defined by a series of mutually aligned, plastically deformable perforated members (38) having aligned perforations that define the hollowness of the elongate, hollow member that are spaced from one another in the direction of elongation by respective relatively rigid spacer members (39) that are secured to the perforated members. The elements of each pair of perforated members (38) of the series are so spaced from one another by one or more of the spacer members (39) such that on compression of the shock absorber (29) the perforated members (38) deform plastically to a lesser extent in regions at which the spacer members (39) are secured than at other regions. The arrangement of the perforated members (38) and the spacer members (39) causes compression to occur substantially parallel to the length of the shock absorber (29).