Well Flow Rate Measurement via Pump Motor Driver
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Solution Overview
Problem
Conventional methods for measuring fluid flow in subterranean wells are costly, unreliable, and lack accuracy, particularly in rod pump systems where valve leaks introduce errors and require expensive surface or downhole metering equipment, and periodic measurements are insufficient for real-time monitoring.
Innovation Solution
A system that measures the changing liquid level in the wellbore over time to calculate flow rates, accounting for pump leakage and reservoir inflow, using electronic or sonic signaling devices to determine annular flow rates and pump performance without the need for additional hardware or central monitoring stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated surface meters are used to measure well flow rate, then measurement accuracy is improved, but equipment cost increases significantly
Solution Approach 1:
The invention extracts the measurement function from expensive dedicated surface meters or downhole meters and relocates it to the existing pump motor driver electronics. By utilizing the existing power cable and control system infrastructure, the patent eliminates the need for separate metering devices while achieving accurate flow rate measurement through monitoring pump motor electrical characteristics and correlating them with production data.
Solution Approach 2:
The pump motor driver system is made multi-functional by enabling it to perform both its primary function of controlling pump motor operation and the secondary function of measuring flow rate. The existing electronics are utilized to measure electrical parameters, calculate pump input power, and determine production rates, thereby eliminating the need for dedicated measurement equipment.
2Measurement precision
If downhole meters are installed inside the well, then flow rate measurement is achieved, but equipment cost and installation complexity increase
Solution Approach 1:
The measurement function is extracted from downhole equipment and relocated to surface-level pump motor driver electronics. This eliminates the need for expensive downhole-compatible packaging, connectivity infrastructure, and specialized installation procedures while maintaining accurate measurement capability through electrical parameter monitoring at the surface.
Solution Approach 2:
The existing pump motor driver system serves itself by using its own electrical measurements and control data to determine flow rate. The system leverages its existing sensors, power measurements, and operational data to calculate production rates without requiring external measurement equipment or additional downhole instrumentation.
3Ease of operation
If pump performance curves are used to determine flow rate, then measurement approach is simplified, but accuracy decreases due to pump degradation
Solution Approach 1:
The system implements continuous feedback by monitoring actual pump motor electrical parameters (current, power, efficiency) and using this real-time data to calculate flow rate. This ongoing measurement approach allows the system to adapt to pump degradation, changing fluid properties, and varying operating conditions, maintaining accuracy without relying on static performance curves that become obsolete over time.
4Device complexity
If periodic flow measurements are conducted, then equipment cost is reduced, but real-time monitoring capability is lost
Solution Approach 1:
The system enables continuous measurement of flow rate by continuously monitoring pump motor electrical parameters and operational status. Rather than conducting periodic measurements, the system provides ongoing real-time data on production rates, allowing for immediate detection of changes in pump performance, fluid properties, or reservoir conditions while utilizing the existing pump motor driver infrastructure.
Data Source
AI summary
The present invention discloses an improved system for measurement of the liquid flow rate and totalized liquid production of a producing well. In the method of the present invention, liquid production rate in a pumping well is determined by calculation based upon wellbore geometry and continuously monitoring the depth of the fluid level within the wellbore. It is applicable to any pump lifted well where it is possible to shut the pump off periodically. Accuracy is enhanced with this method by properly accounting for pump leakage and where pump leakage is either known or can be estimated within reasonable limits or where it is measured during the pump shut off cycle.