Pulse Interference Testing for Tight Reservoir Permeability
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Solution Overview
Problem
Conventional well testing methods for determining reservoir and fracture properties in extremely low permeability source rocks or tight reservoirs are impractical due to long testing periods and disturbance of initial reservoir conditions, making it difficult to evaluate production performance of individual fractures.
Innovation Solution
A pulse interference test method between two or more hydraulic fractures, where fractures are isolated by packers and tubings, and pressure data is recorded and analyzed using fiber optic cables to determine permeability and fracture surface area through analytical or numerical simulation models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional well testing methods are used to determine reservoir properties in extremely low permeability source rocks, then accurate permeability and fracture surface area data can be obtained, but the testing period becomes extremely long and initial reservoir conditions are disturbed
Solution Approach 1:
The patent applies periodic action by using pulse interference testing instead of continuous well testing. A pressure pulse is generated at one fracture and the interference pattern is monitored at another fracture. This periodic pulsing approach allows determination of permeability and fracture surface area in a fraction of the time required by conventional continuous testing methods, while preserving initial reservoir conditions between pulses.
2Measurement precision
If conventional continuous injection/production testing is performed, then reservoir properties can be determined, but initial reservoir conditions are disturbed and individual fracture performance cannot be evaluated
Solution Approach 1:
The patent applies segmentation by isolating individual fractures using packers and tubings, allowing separate testing of each fracture. This enables evaluation of individual fracture performance while using brief pressure pulses that do not significantly disturb the overall reservoir conditions. The segmented approach allows targeted testing without the need for continuous injection or production that would alter reservoir state.
3Loss of time
If pressure pulses are used to test fracture performance, then testing time is reduced and reservoir conditions are preserved, but complex isolation systems are required
Solution Approach 1:
The patent uses packers and tubings as intermediary elements to isolate individual fractures within the wellbore. These intermediaries enable the pressure pulse to be applied to one fracture while monitoring at another, without direct hydraulic communication through the wellbore. This intermediary isolation system makes the pulse interference testing feasible by creating the necessary independent test zones.
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 method allows for the evaluation of heterogeneity in permeability and variation of fracture surface area along the wellbore with shorter testing periods, preserving initial reservoir conditions and providing accurate estimates of permeability and fracture surface area.
Implementation Method 1
generating a pressure pulse at the first fracture... waiting until the pressure wave is detected at the second fracture
Data Source
AI summary
Methods and systems for determining reservoir permeability of a subsurface formation and fracture surface area. The method includes creating a first hydraulic fracture and a second hydraulic fracture in a horizontal well, generating a pressure pulse at the first hydraulic fracture, monitoring, using a first pressure gauge the pressure at the first hydraulic fracture, monitoring, using a second pressure gauge, the pressure pulse at the second hydraulic fracture, repeating this test at different locations along the wellbore to evaluate heterogeneity in permeability and variations in fracture surface areas, analyzing pressure and rate data to determine either permeability or fracture surface area by using: analytical/numerical simulation models, or physics-based proxy models inputting pressure front/peak arrival time or peak pressure.