Welltracker Retrieval via Dissolvable Weight in Low-Pressure Wells
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Solution Overview
Problem
In low-pressure wells, there is insufficient pressure to lift a welltracker back to the surface using buoyancy, making retrieval challenging.
Innovation Solution
A system comprising a Christmas tree with a master valve and a sensor deployment capsule, which includes a cylindrical housing with a removable cap screw, a drain valve, and a pressure gauge, allows for the deployment and retrieval of a welltracker. The welltracker has a dissolvable weight that dissolves at a well fluid pressure threshold, enabling retrieval back into the cylindrical housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If buoyancy is used to lift the welltracker to surface, then retrieval is simplified, but in low pressure wells there is insufficient pressure to lift the welltracker
Solution Approach 1:
The patent changes the physical-chemical state of the weight material by dissolving it in response to pressure or temperature changes downhole. This transforms the weight from a permanent obstacle to a temporary condition that can be eliminated, allowing the welltracker to become buoyant and retrieve itself without requiring high well pressure
Solution Approach 2:
The weight material undergoes a phase transition or chemical transformation when exposed to downhole pressure or temperature conditions. This phase change causes the weight to dissolve or detach, fundamentally altering the mass balance and enabling natural buoyancy retrieval without requiring complex mechanical retrieval systems
2Ease of operation
If a dissolvable weight is used to enable retrieval, then low pressure well retrieval becomes possible, but the device complexity increases
Solution Approach 1:
The capsule system performs multiple functions: it protects the welltracker during deployment, provides a controlled environment for the dissolvable weight mechanism, manages pressure differentials, and facilitates both deployment and retrieval operations. This multi-functionality consolidates what would otherwise require separate systems into a single integrated unit
Solution Approach 2:
The capsule acts as an intermediary between the welltracker and the well environment. It contains the dissolvable weight mechanism and mediates the interaction between the welltracker and downhole conditions, simplifying the overall system by isolating the complexity within a contained subsystem rather than requiring complex modifications to the welltracker itself
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 enables efficient deployment and retrieval of welltrackers in low-pressure wells by utilizing a dissolvable weight and pressure management systems, reducing the need for complex wireline or slickline operations.
Implementation Method 1
a dissolvable weight configured to dissolve at a well fluid pressure threshold for retrieving the welltracker to the cylindrical housing
Implementation Method 2
there may not be enough pressure to lift the welltracker up to surface using buoyancy
Data Source
AI summary
A system and method for deploying and retrieving a welltracker in a well include coupling a Christmas tree to the well, coupling a sensor deployment capsule to the Christmas tree, inserting and storing the welltracker into the cylindrical housing via a removable cap screw, and deploying the welltracker through the Christmas tree and into the well. The system and method further include dissolving a dissolvable weight on the welltracker at a well fluid pressure threshold, retrieving the welltracker to the cylindrical housing, bleeding off trapped pressure in the cylindrical housing from retrieval, via the drain valve, through the pressure transfer line, and controlling pressure in the sensor deployment capsule via the pressure gauge. The sensor deployment capsule includes a cylindrical housing including a removable cap screw, a drain valve coupled to the cylindrical housing and a pressure transfer line, and a pressure gauge coupled to the removable cap screw.