Dual Flexible Bag Fluid Level Sensor for Wellbore Moisture Isolation
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Solution Overview
Problem
Existing fluid level monitoring systems in wellbores are prone to inaccuracies and longevity issues due to moisture sensitivity of pressure sensors, which require physical contact with the fluid for measurement.
Innovation Solution
A fluid level sensing system utilizing a dual flexible bag assembly where a first flexible bag responds to pressure changes within a wellbore, and a second flexible bag applies a controlled vacuum to exert a compressive reference pressure, allowing for accurate fluid level monitoring without direct physical contact with the pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is placed directly in contact with gas in the wellbore to sense pressure, then pressure measurement is achieved, but the pressure sensor is exposed to moisture that affects its longevity and accuracy
Solution Approach 1:
A flexible bag is introduced as an intermediary element between the pressure sensor and the wellbore gas. The bag transmits pressure changes to the sensor while physically isolating the sensor from moisture and contaminants in the gas, thus resolving the contradiction between measurement accuracy and sensor longevity
Solution Approach 2:
The flexible bag acts as a thin film barrier that allows pressure transmission while blocking direct contact between the pressure sensor and the wellbore environment. This flexible membrane solution protects the sensor from moisture exposure while maintaining pressure sensing capability
2Ease of operation
If a bellows is used to physically change dimensions and move an indicator to show fluid level, then visual indication is provided, but the device requires physical contact with the fluid and has movable parts that may fail
Solution Approach 1:
The patent replaces the mechanical bellows-indicator system with an electronic pressure sensor that converts pressure changes into electrical signals. This substitution eliminates movable mechanical parts while maintaining the ability to detect and indicate fluid level changes, thereby improving reliability
Solution Approach 2:
The flexible bag serves as an intermediary that transmits pressure changes from the fluid to the sensor without requiring direct fluid contact with the sensing element. This resolves the contradiction by enabling detection capability while eliminating the need for movable mechanical indicators
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 system provides reliable and accurate real-time fluid level monitoring, protecting the pressure sensor from moisture and over-pressurization, enabling effective fluid collection optimization in wellbores.
Implementation Method 1
A portion of one of the first and second flexible bags communicates with the first bore and is responsive to a change in pressure within the first bore caused by a changing fluid level in the well
Implementation Method 2
The upper and lower housings cooperate to define an interior area which houses a first flexible bag and a second flexible bag
Implementation Method 3
A portion of the other one of the first and second flexible bags is in communication with the second bore and is isolated from the first bore, and configured to exert a reference pressure on the one of the first and second flexible bags
Implementation Method 4
configured to exert a reference pressure on the one of the first and second flexible bags
Implementation Method 5
A sensing subsystem may be included which is responsive to expanding and contracting movement of the first and second flexible bags, for generating a signal indicative of a change in a level of the fluid in the well
Data Source
AI summary
The present disclosure relates to a fluid level sensing system for sensing a fluid level in a well. The system has an upper housing in communication with a lower housing, with the lower housing having a first bore in communication with a fluid in the well, and a second bore isolated from the first bore and in communication with at least one of a vacuum gauge or an external vacuum source. The upper and lower housings house a first flexible bag and a second flexible bag, with the first bag housed within the second bag. A portion of the first bag communicates with the first bore and is responsive to a change in pressure within the first bore caused by a changing fluid level in the well. A portion of the second bag communicates with the second bore and exerts a reference pressure on the first bag. A sensing subsystem senses expanding and contracting movement of the bags and generates a signal indicative of a change in a level of the fluid in the well.