Dissolvable Ballast Attachment for Downhole Robots
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Solution Overview
Problem
Untethered devices in oil and gas applications face issues such as wellbore cluttering due to accumulation of attachment plates, heat damage from exothermic ballast weight reactions, unpredictable buoyancy regain times, and potential immobilization from muddy aggregates formed by dissolving ballast byproducts.
Innovation Solution
The use of a dissolvable ballast weight with an attachment plate and dissolvable attachment elements, where at least one attachment element is designed to dissolve and release the ballast from the plate, allowing the untethered device to change buoyancy and move uphole without excessive heat exposure or cluttering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional attachment plate is used for ballast weight, then the ballast can be securely attached to the tool, but the attachment plate accumulates at the bottomhole region causing wellbore cluttering
Solution Approach 1:
The patent extracts the harmful accumulation problem by making the attachment plate dissolvable, allowing it to break down and disappear after serving its purpose of securing the ballast weight during descent
Solution Approach 2:
The attachment plate is designed to be discarded after use by dissolving in the downhole environment, eliminating the need for recovery operations and preventing wellbore cluttering while maintaining secure ballast attachment during the operational phase
2Reliability
If the ballast weight is exposed and dissolves, then the tool can regain buoyancy, but the exothermic reaction produces heat that can damage other components
Solution Approach 1:
The patent segments the ballast weight into multiple smaller weights distributed around the tool, which reduces the concentration of exothermic reaction heat at any single location and allows better heat dissipation while still achieving the required buoyancy change
Solution Approach 2:
The patent introduces a sacrificial layer between the ballast weight and the tool components, which absorbs or shields the heat generated during ballast dissolution, protecting sensitive tool components from thermal damage while allowing the buoyancy regain function to proceed
3Reliability
If the ballast volume is increased to ensure sufficient buoyancy regain, then the buoyancy recovery is more reliable, but the dissolution time becomes unpredictable and longer
Solution Approach 1:
The patent divides the total ballast weight into multiple smaller units, which increases the total surface area available for dissolution without increasing the overall volume significantly, thereby reducing dissolution time while maintaining sufficient buoyancy recovery capability
Solution Approach 2:
The patent modifies the physical parameters of the ballast weights, such as surface area to volume ratio, material composition, or surface treatment, to optimize the dissolution rate and make the dissolution time more predictable and controllable while ensuring adequate buoyancy regain
4Object-generated harmful factors
If the ballast weight is made dissolvable to prevent cluttering, then wellbore operations are improved, but muddy aggregates can form and immobilize the tool
Solution Approach 1:
The patent extracts the problematic aggregate-forming byproducts by using alternative dissolvable materials that do not produce muddy aggregates, or by designing the dissolution process to produce soluble or easily dispersible products that do not immobilize the tool
Solution Approach 2:
The patent employs composite material structures for the ballast weight, combining dissolvable materials with release agents or surface treatments that prevent aggregate formation and ensure smooth dissolution without tool immobilization, while still achieving clutter-free wellbore operations
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
This solution prevents wellbore clutter, reduces the risk of heat damage, ensures predictable buoyancy regain, and avoids immobilization due to muddy aggregates, thereby enhancing the operational efficiency and safety of untethered devices in wellbore operations.
Implementation Method 1
heat produced by the highly exothermic reaction undergone by the exposed ballast weight
Implementation Method 2
dissolving an attachment element to release the dissolvable ballast from the attachment plate
Implementation Method 3
reduce a density of untethered device for allowing the untethered device to float back upward to the surface
Data Source
AI summary
An untethered device includes a tool and a ballast weight. The ballast weight includes an attachment plate that is securable to the tool, a dissolvable ballast, and attachment elements that secure the dissolvable ballast to the attachment plate. At least one of the attachment elements is dissolvable to release the dissolvable ballast from the attachment plate.