Dual Axial Pressure Gauge Assembly for Formation Tester
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Solution Overview
Problem
Accurate and precise measurement of fluid pressure in borehole environments is challenging due to contamination and the need for redundant measurements to ensure reliable reservoir production data, particularly in formation testing systems where contamination from drilling fluids can affect sample integrity.
Innovation Solution
A dual axially aligned pressure gauge assembly with parallel major axes is used in formation tester tools, providing redundant pressure measurements by exposing both gauges to the same fluid pressure, which reduces shut-in fluid volumes and minimizes errors from hydrostatic differences, and allows for rapid thermal stabilization with a cooperating heater assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pressure gauge is used, then the device complexity is reduced, but the reliability and measurement precision are compromised due to potential gauge malfunction and lack of redundant data
Solution Approach 1:
The patent employs identical pressure gauges configured in parallel within the same assembly, creating redundant copies that can independently measure pressure. This redundancy ensures that if one gauge malfunctions, the other can still provide valid measurements, thereby improving reliability without requiring complex additional systems.
Solution Approach 2:
Multiple pressure gauges are merged into a single integrated assembly that shares common hydraulic connections and structural support. This combining approach provides redundant measurements while maintaining a unified, manageable structure that does not excessively increase device complexity.
2Measurement precision
If pressure gauges are positioned axially aligned with parallel major axes, then the shut-in fluid volumes are reduced and hydrostatic differences are minimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies that pressure gauges be positioned with parallel major axes rather than collinear alignment, creating an asymmetric arrangement that reduces the shut-in fluid volume and eliminates hydrostatic head differences. This asymmetric configuration improves measurement precision by ensuring both gauges experience identical pressure conditions.
Solution Approach 2:
The axial alignment with parallel axes ensures that both pressure gauges are at the same potential level regarding fluid pressure exposure, eliminating hydrostatic differences that would otherwise affect measurement accuracy. This equipotential arrangement allows both gauges to measure the same pressure point accurately.
3Reliability
If dual pressure gauge assemblies are used, then redundant measurements are provided to identify malfunctions, but the device complexity and initial setup time increase
Solution Approach 1:
The patent uses identical pressure gauge assemblies that can be interchanged and configured the same way, simplifying the complexity management. The redundancy is achieved through copying rather than through complex different systems, making the added complexity more manageable and the reliability benefit more achievable.
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 dual pressure gauge assembly ensures accurate and reliable fluid pressure measurements by identifying gauge malfunctions and minimizing systematic errors, enabling real-time data collection and reducing operational downtime, while allowing for quick calibration and deployment across multiple wells.
Implementation Method 1
The low mass of the gauges and a cooperating heater assembly allow the pressure gauges to rapidly thermally stabilize with changing temperatures in the well borehole
Implementation Method 2
a pressure gauge assembly can be hydraulically coupled to a probe flow line to measure formation pressure at the probe
Data Source
AI summary
A system for measuring pressure in a well borehole using two pressure sensing gauges that are exposed to an area of common pressure. Pressure measurements are made with preferably two pressure gauge assemblies each containing a single pressure sensing gauge. The two pressure gauge assemblies are removably disposed within a receptacle or “pocket” in the outer surface of a wall of a formation tester tool section. When disposed or “side loaded” in the pocket, the gauges within the pair of assemblies are axially aligned and positioned in a plane that is normal to the radius of the formation tester tool section. Both pressure sensing gauges can be connected to respond to the same fluid pressure originating from a probe or port section of a formation tester tool. By disposing the pressure gauge assemblies in a receptacle or “pocket” in the outer surface or wall of a formation tester tool section, the pressure sensing gauges are exposed to wellbore fluids. Pressure sensing gauges are selected to have low mass. The low mass of the gauges and a cooperating heater assembly allow the pressure gauges to rapidly thermally stabilize with changing temperatures in the wellbore.