Porous String Wellbore Pressure Gauge Cemented Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wellbore pressure measurement technologies face challenges in accurately measuring formation pressure without establishing a fluid connection, as they are prone to damage, clogging, and sediment deposition, which affects the responsiveness and accuracy of the measurements.
Innovation Solution
A wellbore formation pressure gauge system that includes a housing with a pressure sensor, an oil-filled chamber, and a porous string extending from a pressure permeable filter port, allowing hydrostatic connectivity through the cement, which increases the contact area and responsiveness of pressure measurements, and a compensation mechanism to account for temperature-induced pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure gauge is permanently cemented in place outside of a wellbore conduit, then the measurement reliability is improved, but the responsiveness and accuracy of pressure measurements deteriorates due to cement isolation
Solution Approach 1:
The patent employs a porous string made of porous material that allows formation fluid to percolate through it while being embedded in cement. This porous structure enables pressure measurements to be taken through the cement barrier without requiring direct fluid connection, thus maintaining measurement reliability while improving responsiveness and accuracy by allowing pressure transmission through the porous medium.
2Reliability
If a diaphragm is used to isolate the sensor from the surrounding fluid, then the sensor protection is improved, but the contact area required increases making the diaphragm more vulnerable to damage
Solution Approach 1:
The patent extracts the diaphragm component from the pressure gauge system entirely. Instead of using a diaphragm to isolate the sensor, the invention uses a porous string that allows direct pressure transmission from the formation through the cement to the sensor, eliminating the need for a diaphragm and its associated vulnerabilities while maintaining sensor protection through the porous medium.
3Reliability
If buffer tubes are used to isolate the sensor from shock and vibration, then the sensor durability is improved, but the device complexity increases and buffer tubes may clog up with time
Solution Approach 1:
The patent removes buffer tubes and complex isolation systems from the pressure gauge. The porous string inherently provides shock and vibration isolation while maintaining pressure transmission capability, eliminating the need for separate buffer tube components and reducing overall device complexity while preventing clogging issues.
4Speed
If the pressure gauge housing is open to the environment, then the pressure transfer efficiency is improved, but sediment deposition in the housing increases inhibiting bellows movement
Solution Approach 1:
The patent uses a porous string with filtered pores that allow pressure transmission while blocking sediments and contaminants from entering the housing. This porous barrier maintains pressure transfer efficiency by allowing fluid pressure to pass through while preventing sediment deposition that would inhibit bellows movement or contaminate the internal environment.
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 real-time, accurate formation pressure measurements by enhancing the contact area and pressure transfer efficiency through the cement, while the compensation mechanism minimizes thermally induced errors, resulting in improved responsiveness and reliability.
Implementation Method 1
the string is arranged to transfer said formation fluid in its longitudinal direction when it is embedded in said cement to allow said formation pressure to act on said pressure transfer means via hydrostatic connectivity in said cement and in said string
Implementation Method 2
a pressure permeable filter port through a wall of said housing, wherein said pressure permeable filter port is in hydrostatic connectivity with said first oil filled chamber
Data Source
AI summary
A method for in-situ determination of a wellbore formation pressure through a layer of cement, the method includes detecting an output pressure signal from a pressure sensor disposed in a housing in the cement outside a wellbore casing; detecting a first temperature signal from a first temperature sensor disposed in the housing; and calculating a temperature compensated output pressure signal based on the output pressure signal and the first temperature signal.