Downhole Flow Metering in ESPs Using Pressure Differential
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Solution Overview
Problem
Current electrical submersible pumping systems (ESPs) face challenges in accurately measuring flow rates when wells produce below bubble point pressure, as surface meters are inaccurate due to liberated gas, and replacing them with multi-phase meters is costly.
Innovation Solution
A cost-effective single-phase flow meter is integrated into ESP monitoring tools by adding pressure sensing means below the ESP, utilizing existing ESP monitoring tool and power cable for data transmission, allowing real-time flow rate monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface single phase meters are used to measure flow rate, then the measurement is accurate under normal conditions, but the measurement becomes inaccurate when wells produce below bubble point pressure due to liberated gas
Solution Approach 1:
Instead of attempting to measure flow rate at the surface where gas liberation causes measurement errors, the invention inverts the measurement location to downhole at the ESP where intake pressure remains above bubble point pressure. This ensures single-phase fluid conditions for accurate measurement while avoiding the gas interference problem at surface.
Solution Approach 2:
The invention introduces an intermediary measurement system (pressure differential sensors and flow meter) installed at the ESP that acts as a mediator between the wellbore fluid and surface measurement equipment. This intermediary system measures flow under controlled single-phase conditions and transmits data to surface, eliminating the need for complex multi-phase metering at surface.
2Measurement precision
If multi-phase meters are installed at surface to measure flow rate accurately under all conditions, then measurement accuracy is maintained, but the cost increases by tens of thousands of dollars per well
Solution Approach 1:
The invention replaces expensive multi-phase metering systems with a more economical downhole measurement system using standard pressure differential sensors and existing ESP infrastructure. This cost-effective approach achieves accurate single-phase measurement without requiring costly multi-phase meter technology.
Solution Approach 2:
The invention makes the existing ESP system serve multiple functions: it continues to provide pumping while also serving as the measurement platform through integrated pressure sensors and flow metering capability. This eliminates the need for separate expensive surface multi-phase metering equipment.
3Measurement precision
If downhole flow measurement is implemented using additional sensors and equipment, then accurate flow rate data is obtained, but the device complexity and cost increase
Solution Approach 1:
The invention merges the flow measurement function with the existing ESP monitoring system by integrating pressure differential sensors and flow metering capability into the ESP's existing electrical and mechanical structure. This consolidation avoids adding separate complex measurement systems while achieving accurate downhole flow measurement.
Solution Approach 2:
The ESP system serves itself by utilizing its existing power cable for data transmission and its structural components as part of the measurement system. The downhole flow meter leverages the ESP's existing infrastructure rather than requiring entirely separate measurement equipment, reducing overall system complexity.
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 solution provides accurate and cost-effective flow rate measurement, extending the life of ESPs by leveraging existing infrastructure for data transmission, enhancing operational performance and reducing the need for expensive multi-phase meter replacements.
Implementation Method 1
an upper pipe section with an outer diameter, the upper pipe section having an upper pressure sensing means and a lower pipe section with an outer diameter smaller than the outer diameter of the upper pipe section, the lower pipe section having a lower pressure sensing means
Data Source
AI summary
An apparatus for metering fluid in a subterranean well includes an electric submersible pump having a motor, a seal section and a pump assembly and a metering assembly. The metering assembly includes an upper pipe section with an outer diameter, the upper pipe section having an upper pressure sensing means, and a lower pipe section with an outer diameter smaller than the outer diameter of the upper pipe section, the lower pipe section having a lower pressure sensing means. A power cable is in electronic communication with the electric submersible pump and with the metering assembly.