Flow Sensing Device with Static Seals for Drilling Fluid Measurement
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Solution Overview
Problem
Conventional flow meters in the oil and gas industry face accuracy issues due to decreased sensitivity from drilling fluid interference and viscosity-dependent sensitivity, leading to inaccurate mud flow rate measurements, which can impact safety and alarm triggering.
Innovation Solution
A system with a flow sensing device featuring a straight arm design and static seals, located within a high-pressure zone, reduces the need for dynamic seals, minimizing pressure differential-induced seal drag and viscosity effects, using an incompressible backing fluid and a Hall effect sensor array enclosed within the conduit to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dynamic seals are used to allow coupling movement, then the flow sensing device can move relative to the mount, but fluid leaks past the seal and increases resistance to motion
Solution Approach 1:
Instead of placing the coupling in a low-pressure zone outside the conduit (conventional approach), the patent inverts the approach by locating the coupling within the high-pressure zone inside the conduit. This inversion eliminates the pressure differential across the seal, preventing fluid leakage and reducing seal drag while still allowing flow sensing device movement.
Solution Approach 2:
The patent introduces an incompressible backing fluid (grease) as an intermediary substance between the coupling and the seal. This backing fluid fills the space around the coupling and transmits pressure uniformly, preventing drilling fluid from forcing its way into the bearing and reducing seal drag on the coupling.
2Speed
If dynamic seals are used to permit coupling movement, then the flow sensing device can respond to fluid flow, but seal drag increases with pressure
Solution Approach 1:
The patent inverts the conventional pressure zone arrangement by placing the coupling within the high-pressure zone rather than outside it. This eliminates the pressure differential that causes seal drag to increase with pressure, allowing the flow sensing device to respond quickly to fluid flow without increasing resistance to motion.
Solution Approach 2:
The incompressible backing fluid acts as a mediator that distributes pressure uniformly around the coupling, preventing concentrated seal drag forces. This allows the coupling to move freely in response to fluid flow while maintaining reliable sealing.
3Ease of manufacture
If the coupling is located outside the conduit in a low-pressure zone, then sealing is easier, but pressure differential forces fluid into bearings and increases seal drag
Solution Approach 1:
The patent inverts the conventional approach by locating the coupling inside the conduit in the high-pressure zone rather than outside in the low-pressure zone. This inversion eliminates the pressure differential that forces fluid into bearings, protecting the bearing arrangement while still allowing for effective sealing using static seals at the conduit interface.
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 more accurate and reliable fluid flow measurements, reducing errors caused by viscosity and improving sensitivity to fluid height changes, while shielding sensitive components from hazardous environments.
Implementation Method 1
The sensor array comprises a plurality of Hall effect sensors
Data Source
AI summary
There is described a system for measuring fluid flow within a conduit. The system comprises a conduit for conveying a fluid, a mount attached to the conduit which may define a high-pressure zone in an interior of the conduit and a low-pressure zone in an exterior of the conduit, and a flow sensing device attached to the mount and configured to move relative to the mount in response to flow of the fluid within the conduit. The flow sensing device is attached to the mount via a coupling which may be located within the high-pressure zone. The system further includes a sensor configured to measure movement of the flow sensing device. The flow sensing device may comprise a paddle and a straight arm extending from the paddle to the coupling.