Pump Flow Rate Calculation via Pressure Change
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Solution Overview
Problem
Existing automated pump control systems for oil wells are inadequate when multiple wells produce fluids that accumulate in a single production tank, particularly when flow lined, as they fail to accurately adjust pump rotations per minute to match fluid flow rates effectively.
Innovation Solution
A method to determine the flow rate of a pump by calculating the volume capacity, starting pressure, and pressure change over time, allowing for the optimization of pump efficiency by adjusting the pump speed based on derived flow rates, using a controller and pressure sensor to maintain flow rates within an optimal range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a control system based on production tank fluid level rise rate is used, then pump rotation can be matched to fluid flow rate, but it cannot be used when multiple wells produce fluids that accumulate in a single production tank including flow lined wells
Solution Approach 1:
The patent introduces a flow line as an intermediary component with known volume capacity between the pump and production tank. By measuring pressure changes in this flow line and converting them to volume changes using the known capacity, the system can accurately determine pump flow rates without directly measuring fluid level rise in the production tank, thus enabling accurate measurement in multi-well configurations.
2Productivity
If pump speed is increased to match higher fluid flow rates, then productivity increases, but pump efficiency decreases when operating outside the optimum efficiency range
Solution Approach 1:
The patent implements a feedback control system that continuously monitors pressure changes in the flow line, calculates the actual flow rate, and uses this information to adjust pump speed. The controller compares the calculated flow rate with the optimum efficiency range and adjusts pump rotations per minute accordingly, ensuring the pump operates within the efficient range while maintaining required productivity.
Solution Approach 2:
The patent makes the pump speed dynamic rather than fixed, allowing it to adjust in real-time based on calculated flow rates. The system continuously modifies pump operations to maintain optimal efficiency across varying production conditions, transitioning from static to dynamic control to optimize both productivity and energy efficiency.
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
This method enhances pump efficiency by adjusting pump speed according to calculated flow rates, ensuring optimal performance across varying fluid flow conditions, and provides diagnostic indications for potential issues like intermittent pressure rises.
Implementation Method 1
monitoring pressure in the flow line to determine a time interval required to reach the target pressure
Implementation Method 2
The calculations are based upon the fact that a change in pressure equals a change in volume ΔP=ΔV in a closed system
Data Source
AI summary
A method of determining a flow rate of a pump involves determining a volume capacity for a flow line carrying produced fluids from the pump, determining a starting pressure for the flow line and setting an arbitrary target pressure for the purpose of testing. The test is initiated by preventing flow in the flow line while continuing to operate the pump and monitoring pressure in the flow line to determine a time interval required to reach the target pressure. The method then involves performing calculations to determine flow rate using the volume capacity, the starting pressure, the change in pressure over the time interval required to reach the target pressure. The flow rate is equivalent to ΔV divided by a change in time ΔT. The method is preferably used as part of a manual or automated pump control strategy to keep the pump operating within flow rate ranges that provide optimum pump efficiency.