Well Interval Productivity Assessment via Return Fluid Tracer Analysis
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Solution Overview
Problem
Current methods for evaluating the productivity of individual well intervals are costly and limited, particularly due to the need for multiple tracers and the difficulty in detecting their presence in produced fluids, which complicates the assessment of hydraulic fracturing effectiveness and reservoir properties.
Innovation Solution
A method that analyzes the flow characteristics of return fluid during plug mill-out operations to determine local formation properties such as fracture connectivity, productivity, and rock quality, using a surface-located multiphase flow meter and tracer compounds to characterize the hydraulic fractures and their communication with the wellbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple tracers are injected into the reservoir with fracturing fluid to evaluate interval productivity, then the assessment of hydraulic fracturing effectiveness and reservoir properties is enabled, but the complexity of tracer detection in produced fluids increases and costs increase
Solution Approach 1:
The patent extracts the evaluation function from complex multi-tracer systems and implements it through a single tracer injected with fracturing fluid. The flowback analysis system isolates and measures only the tracer concentration and flow rate, eliminating the need for complex multi-tracer detection while maintaining interval productivity assessment capability
Solution Approach 2:
The patent uses a simplified model where a single tracer concentration measurement combined with flow rate data replicates the information that would otherwise require multiple tracers. The flowback curve analysis creates a mathematical copy of the interval productivity information that is easier to obtain and interpret
2Measurement precision
If production logging tools are run in the well after milling out all plugs to evaluate interval productivity, then direct downhole measurements of fluid properties are obtained, but the cost of the well increases
Solution Approach 1:
The patent performs the productivity evaluation during the flowback operation itself, before the well is put into production. By injecting the tracer with the fracturing fluid and analyzing it during plug mill-out, the evaluation is completed in advance, eliminating the need for additional production logging tool runs and associated costs
Solution Approach 2:
The flowback operation, which is already necessary to clear the well, is used to perform the productivity evaluation. The tracer injected with the fracturing fluid serves dual purposes: tracking fluid movement and enabling interval identification during flowback, making the evaluation process self-sufficient without requiring separate expensive tool interventions
3Measurement precision
If tracer concentration is measured in produced fluids during initial production to evaluate flow contributions, then interval productivity is assessed, but the interpretation of produced fluids becomes more complex and tracer detection becomes more difficult
Solution Approach 1:
The tracer is injected with the fracturing fluid before production begins, and the evaluation is performed during the flowback stage. This preliminary action allows the tracer to be distributed and measured under controlled conditions before the complexity of actual production fluids sets in, making detection and interpretation easier
Solution Approach 2:
The patent measures tracer concentration specifically during the flowback operation rather than attempting to measure it continuously during production. This partial measurement approach focuses resources on the most informative time period when tracer concentrations are highest and most easily detected, avoiding the difficulties of detecting trace amounts in later production phases
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
Enables efficient characterization of well intervals by determining the effectiveness of hydraulic fractures and reservoir properties, optimizing flowback programs and reducing the need for costly tracer usage, thereby improving well productivity assessment.
Implementation Method 1
a surface-located multiphase flow meter measures a flow rate of the return fluid
Implementation Method 2
tracer compounds to characterize the hydraulic fractures and their communication with the wellbore
Implementation Method 3
the data analyzer calculates a concentration of the tracer compound(s) in the return fluid over time
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A method and system is provided that analyzes flow characteristics of return fluid that flows to a surface-located facility during well operations (such as plug mill-out or cleanout/workover operations) in order to characterize local formation properties of the formation. The method and system can be used to characterize a hydraulically-fractured hydrocarbon-bearing formation that is traversed by a well having a number of intervals that are hydraulically isolated from one another by corresponding plugs.