Sucker-Rod Pump Efficiency Estimation Using Finite-Difference Algorithm
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Solution Overview
Problem
Existing methods for controlling and estimating the efficiency of sucker-rod pumps in the oil and gas industry are prone to errors due to the elasticity of the sucker-rod string and viscous damping effects, leading to inaccurate measurements of downhole pump operations and pump fillage, which can result in mechanical damage and inefficient fluid production.
Innovation Solution
A method that calculates pump efficiency directly from surface load and displacement data using a finite-difference algorithm to determine the minimum and maximum strokes and transfer point, eliminating the need for a downhole dynamometer card and reducing processing requirements, allowing for precise estimates of pump fillage and fluid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If surface dynamometer cards are used to control sucker-rod pumping systems, then automation and monitoring are improved, but measurement precision deteriorates due to elasticity of the sucker-rod string and viscous damping effects
Solution Approach 1:
The patent uses a mathematical model as an intermediary to translate surface measurements into accurate downhole pump performance data. The model accounts for sucker-rod elasticity and viscous damping effects, acting as a mediator between the surface dynamometer card and the actual downhole pump conditions, thereby preserving measurement precision while maintaining automation.
Solution Approach 2:
The patent replaces direct mechanical measurement at downhole with a computational approach. Instead of using complex mechanical sensors downhole, it substitutes a mathematical model that processes surface measurements to derive accurate downhole pump stroke and fillage information, eliminating the need for complex downhole mechanical measurement systems.
2Measurement precision
If downhole dynamometer cards are used to improve measurement accuracy, then pump efficiency estimation is improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent extracts the essential measurement information needed for pump efficiency estimation from complex downhole dynamometer card data. By using a mathematical model that processes only the necessary surface measurements, it extracts the critical fillage and stroke information without requiring the full complexity of downhole dynamometer systems.
Solution Approach 2:
The patent creates a mathematical copy or representation of downhole pump conditions based on surface measurements. Instead of physically measuring downhole parameters directly, it generates a computational model that replicates downhole pump stroke and fillage behavior, providing accurate efficiency estimation without physical downhole sensors.
3Reliability
If pump operations are continuously monitored to prevent pump-off conditions, then reliability is improved, but energy consumption increases
Solution Approach 1:
The system uses the existing surface dynamometer card data that is already being collected for other purposes. By processing this existing data through a mathematical model, the system provides pump-off detection and reliability monitoring without requiring additional sensors or increasing measurement frequency, thereby avoiding extra energy consumption while maintaining reliability.
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 approach provides accurate and reliable estimates of pump efficiency and fluid production, reducing the risk of mechanical damage and operational inefficiencies, while enabling automated control of pumping units to prevent pump-off conditions and detect tubing leaks.
Implementation Method 1
the elasticity of the sucker-rod string and viscous damping effects among other operating conditions
Implementation Method 2
the elasticity of the sucker-rod string and viscous damping effects among other operating conditions
Data Source
AI summary
The present invention provides highly accurate methods for directly calculating pump fillage which avoid the need and expense of a pump dynamometer card and subsequent calculations.