Real-Time Injectivity Index Calculation via Dynamic Injection Rates
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Solution Overview
Problem
Current methods for determining the injectivity index of an injection well, such as the fall-off test, require shutting in the well, which affects productivity and cannot be performed in real-time, limiting the ability to monitor and improve injection well performance effectively.
Innovation Solution
A system and method that involve installing measurement devices on the injection wellhead, injecting fluid at various rates, measuring bottom hole pressures, and using a computer processor to determine the injectivity index by establishing a relationship between injection rates and pressures, allowing for real-time calculation without shutting in the well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fall-off test method is used to determine injectivity index, then measurement precision is improved, but productivity deteriorates due to well shutdown requirements
Solution Approach 1:
The system enables continuous injection testing by maintaining fluid injection through the well throughout the testing process. Multiple injection rates are applied sequentially without shutting in the well, allowing continuous measurement of bottom hole pressures and continuous calculation of injectivity index, thereby eliminating productivity loss while maintaining measurement capability
Solution Approach 2:
The system dynamically adjusts injection rates during the testing process, transitioning between multiple injection rates (e.g., from a first injection rate to a second injection rate) while maintaining continuous injection. This dynamic approach allows the system to gather data across different operating conditions without well shutdown, preserving productivity while enabling comprehensive injectivity assessment
2Measurement precision
If the fall-off test method is used to determine injectivity index, then measurement precision is improved, but loss of time increases due to shutdown and restart procedures
Solution Approach 1:
The testing process maintains continuous injection throughout, eliminating the time-consuming shutdown and restart cycles inherent in traditional fall-off tests. The system continuously injects fluid at varying rates and continuously measures pressures, reducing total test time while maintaining measurement precision through real-time data collection and processing
3Productivity
If real-time injection testing is performed without shutting in the well, then productivity is maintained, but measurement precision may deteriorate
Solution Approach 1:
The system continuously measures bottom hole pressures during injection and uses this feedback to calculate injectivity index in real-time. The computer processor analyzes the relationship between injection rates and measured pressures, applying appropriate mathematical models to derive accurate injectivity values even during continuous operation, thereby maintaining measurement precision while preserving productivity
Solution Approach 2:
The system dynamically transitions between multiple injection rates during continuous operation, allowing it to capture pressure-response relationships under varying flow conditions. This dynamic testing approach enables accurate injectivity determination without well shutdown, as the system adapts injection rates based on measured pressures and continues data collection throughout the process
Data Source
AI summary
A method includes installing a measurement device on the injection wellhead, injecting a fluid into the injection well at a plurality of injection rates using a computer processor, measuring an injection bottom hole pressure at each injection rate to determine a plurality of injection bottom hole pressures using the computer processor, determining a relationship between the plurality of injection rates and the plurality of injection bottom hole pressures using the computer processor, and determining an injectivity index of the injection well using the relationship and the computer processor.