Drilling Rig Fluid Outflow Measurement Using Vertical Stack Height
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Solution Overview
Problem
Existing outflow measurement systems on drilling rigs suffer from poor sensitivity and accuracy, especially at low flow levels, due to the dissipation of subtle flow changes throughout the return flow line, making it difficult to detect minor changes in fluid influxes or losses, which can lead to undetectable anomalies that may threaten life and property.
Innovation Solution
A novel fluid outflow measurement system that combines a flow sensor at the return flow line with a fluid height sensor at the vertical stack or bell nipple section of the drilling rig, utilizing a flow computer to integrate readings from both sensors, enhancing sensitivity and accuracy across the entire flow range from zero to maximum flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow sensors are installed on the partially-filled return flow line, then the system can measure fluid flow, but sensitivity to subtle flow changes deteriorates due to dissipation throughout the return flow line
Solution Approach 1:
The patent combines two measurement locations: a flow sensor on the return flow line and a fluid level sensor at the vertical stack or bell nipple section. By merging these measurements in the flow computer, the system achieves both flow measurement capability and high detection sensitivity, resolving the contradiction between measurement capability and reliability.
2Device complexity
If only flow line mounted sensors are used, then the measurement system is simple, but sensitivity to subtle flow changes deteriorates
Solution Approach 1:
The patent adds a vertical dimension to the measurement system by placing a fluid level sensor at the vertical stack or bell nipple section, rather than only using horizontal flow line sensors. This dimensional change enables detection of subtle flow changes through fluid level variations, significantly improving reliability while maintaining reasonable system complexity.
3Ease of manufacture
If measurements are taken at the return flow line, then the system can operate with simple sensor placement, but accuracy at low flow levels deteriorates
Solution Approach 1:
The patent introduces the fluid level at the vertical stack or bell nipple section as an intermediary measurement point. This intermediary provides a more sensitive indication of low flow conditions than direct flow line measurements, improving low flow measurement accuracy while keeping sensor installation straightforward.
Data Source
AI summary
A fluid outflow measurement system and a method are disclosed for fluid flow determination that measures and determines fluid flow and retains consistent high-sensitivity and high-accuracy performance throughout the measurement range of zero flow to maximum flow. The fluid outflow measurement system and method adds a fluid height measurement from a sensor mounted on the vertical stack or bell nipple section of a drilling rig. The vertical stack or bell nipple section is a location where a change of flow, manifested by a change in fluid height, is more detectable and makes the overall flow more sensitive throughout zero to maximum flow range, especially at low flows (resulting in better curve shape definitions of flow back signatures) and to subtle flow changes due to micro influxes or losses.