Gas Flowrate Estimation Using Downstream Temperature and Empirical Correlations
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Solution Overview
Problem
Current methods for gas flowrate calculations and well production allocations in oil and gas wells lack accuracy and reliability, requiring frequent well modeling and relying heavily on unreliable flowrate measurements from Venturi meters.
Innovation Solution
A computer-implemented method using empirical correlations based on choke size and downstream temperature to estimate gas flowrates, combining measured rates from Venturi meters with calculated rates, thereby reducing the need for well modeling and enhancing accuracy and reliability of production data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Venturi meters are used to measure flowrate, then flowrate measurement is obtained, but the measurements are unreliable and lack accuracy
Solution Approach 1:
The patent introduces an intermediary calculation method that uses downstream temperature measurements and empirical correlations as a mediator between the unreliable Venturi meter readings and the actual flowrate. This intermediary approach provides an alternative calculation path that compensates for the unreliability of direct Venturi meter measurements.
Solution Approach 2:
The patent changes the measurement parameters from relying solely on pressure differential (Venturi meter principle) to incorporating downstream temperature as an additional parameter. By using temperature-based empirical correlations, the system achieves more reliable flowrate estimates that are less susceptible to the limitations of traditional pressure-based measurement.
2Measurement precision
If well modeling is performed frequently to estimate gas rates, then estimation accuracy can be improved, but the complexity and time consumption increase
Solution Approach 1:
The patent replaces complex, time-consuming well modeling with simpler, faster empirical correlations that can be applied continuously. These simplified calculation methods provide sufficient accuracy for production allocation without requiring frequent complex modeling operations, effectively using 'cheaper' calculation approaches for continuous monitoring.
Solution Approach 2:
The system uses readily available field measurements (downstream temperature, pressure) to automatically calculate flowrates through empirical correlations without requiring external well modeling expertise or complex computational resources. The method is self-sufficient using data already collected during normal well operations.
3Reliability
If continuous rate estimation is performed, then production allocation accuracy improves, but the need for multiple measurement methods increases complexity
Solution Approach 1:
The patent creates a universal calculation method using downstream temperature and pressure measurements that can be applied across different well conditions and production scenarios. This single empirical correlation approach serves multiple functions: estimating flowrate, monitoring production changes, and supporting allocation decisions, thereby reducing the need for multiple specialized measurement systems.
Data Source
AI summary
Computer-implemented systems and computer-implemented methods include the following. A choke/pressure control valve (PCV) gas rate is determined for each well of a group of producing wells. A downstream temperature (DST) gas rate is determined for each well of the group of producing wells. Parameters for a well rate test are determined for each well of the group of producing wells using the choke/PCV gas rate and the DST gas rate. A total gas rate for the producing wells is determined using the parameters. A gas production allocation factor (G-PAF) for the producing wells is determined. A production allocation for each well of the producing wells is determined using the total gas rate.