Pulse Generator for Viscous Fluids in Wellbore Sealing
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Solution Overview
Problem
Current wellbore plugging and abandonment (P&A) operations are complex, costly, and require multiple trips into the wellbore, involving complex tools that are slow to deploy and require expert personnel, with existing tools unable to effectively pulse high viscosity fluids like cement for efficient sealing.
Innovation Solution
A downhole tool assembly that performs cleaning, perforating, and cementing operations in a single trip using a plugging tool capable of generating low frequency, high amplitude pulses of high viscosity fluids, such as cement slurry, for improved injectivity and penetration, along with a wash tool for enhanced perforation cleaning and cement bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple separate tools are used for cleaning, perforating, and cementing operations, then each operation can be performed with specialized equipment, but the overall process requires multiple trips into the wellbore, increasing time and operational complexity
Solution Approach 1:
The patent combines multiple separate tools (cleaning tool, perforating tool, cementing tool) into a single integrated downhole tool assembly. This merging allows all operations to be performed in one trip into the wellbore, directly resolving the contradiction by improving productivity while managing device complexity through functional integration.
Solution Approach 2:
The downhole tool assembly is designed with multi-functional capabilities, where a single tool assembly can perform cleaning, perforating, and cementing operations. This universality eliminates the need for multiple specialized tools and trips, thereby improving productivity while the modular design keeps complexity manageable.
2Reliability
If conventional cementing methods are used for high viscosity fluids, then the equipment is simpler, but the injectivity and penetration of cement into tight spaces is insufficient
Solution Approach 1:
The patent implements a pulse generation mechanism that creates periodic pressure fluctuations during cement injection. This periodic action enhances the injectivity and penetration of high viscosity cement into tight spaces by overcoming resistance through repeated pressure cycles, thereby improving seal integrity while the mechanism remains integrated into the tool assembly.
Solution Approach 2:
The pulse generation mechanism changes the pressure parameters during cement injection, creating high-frequency pressure fluctuations that improve fluid penetration. This parameter change approach enables effective injection of high viscosity fluids without requiring overly complex external equipment, balancing reliability improvement with manageable device complexity.
3Productivity
If multiple separate operations are performed sequentially, then each operation can be optimized independently, but the overall process time and cost increase significantly
Solution Approach 1:
By merging cleaning, perforating, and cementing operations into a single tool assembly that can execute all functions in one deployment, the patent eliminates the time losses associated with removing and replacing tools between operations. This directly addresses the contradiction by improving operational speed while reducing total process time.
Solution Approach 2:
The integrated tool assembly enables continuous execution of operations without interruption or tool replacement. The cleaning, perforating, and cementing functions can be performed sequentially without breaking the operational continuity, thereby improving productivity while minimizing time loss compared to multiple separate trips.
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 enables faster, cost-effective wellbore sealing with reduced need for expert personnel, as the tool assembly can deploy and operate more efficiently, providing better seal integrity by effectively injecting cement into tight spaces within the wellbore.
Implementation Method 1
The plunger assembly is designed to generate pulses in a high viscosity fluid by moving the plunger assembly in a downhole direction to obstruct a flow of the high viscosity fluid, thereby generating a water hammer wave
Implementation Method 2
The pressure wave opens a pressure activated sleeve to allow the pulses to pass through a discharge sub having a plurality of cement ports
Data Source
AI summary
A plugging tool includes an elongated inner housing allowing a first fluid to flow through a hollow interior of the inner housing, a retractable plunger positioned within the inner housing and operable to obstruct the flow of the first fluid into a discharge chamber and resume the flow of the first fluid into the discharge chamber based on a pressure exerted by the first fluid on the retractable plunger, and at least one pressure release valve (PRV) operable to open and release at least a portion of the first fluid from the inner housing based on a pressure exerted by the first fluid on the at least one PRV, wherein operation of the retractable plunger and the at least one PRV generates pulses of the first fluid used to deposit a sealing plug at a target interval of a wellbore.