Permeability Calculation via Spherical Flow Regime
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Solution Overview
Problem
Current methods for determining horizontal and vertical permeability in reservoirs face challenges, particularly in thick formations where radial flow is not easily observed due to the short duration of interval pressure transient testing (IPTT), making it difficult to select the correct thickness and obtain accurate permeability data.
Innovation Solution
A method using a packer-probe formation testing tool that generates fluid flows from the reservoir, obtains pressure data, identifies a spherical flow regime, and calculates horizontal and vertical permeability independently of formation thickness, applicable to both vertical and horizontal wellbores, including slanted wells with additional data from nonlinear regression analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If interval pressure transient testing is performed in thick formations, then the testing duration is extended, but radial flow is still not observed due to the short duration nature of IPTT
Solution Approach 1:
The patent introduces an intermediary mathematical model (spherical flow regime model) that mediates between the short testing duration and the need to observe radial flow. This model allows interpretation of pressure transient data without requiring actual observation of radial flow, enabling permeability calculation in thick formations where radial flow is not naturally observed during IPTT.
Solution Approach 2:
The patent changes the flow regime parameter from radial flow to spherical flow regime. By using spherical flow theory instead of traditional radial flow theory, the method can accurately calculate horizontal and vertical permeability in thick formations where radial flow is not observed, thus resolving the contradiction between testing duration and measurement precision.
2Measurement precision
If formation thickness is selected for nonlinear regression analysis, then permeability can be determined, but the process becomes complex and thickness selection is difficult in thick formations
Solution Approach 1:
The patent extracts the thickness parameter from the permeability calculation process. By using spherical flow regime analysis, the method determines horizontal and vertical permeability independently of formation thickness, thus eliminating the complex step of thickness selection and simplifying the overall process while maintaining measurement precision.
Solution Approach 2:
The patent segments the permeability determination into independent horizontal and vertical components using spherical flow theory. This segmentation allows each permeability component to be calculated separately without requiring knowledge of formation thickness, reducing the complexity of the layer cake model building process.
3Ease of operation
If conventional transient test methods are used, then thickness is assumed equal to perforated interval thickness, but this assumption is incorrect when multiple flow units exist across the formation
Solution Approach 1:
The patent introduces spherical flow regime analysis as an intermediary method that mediates between the simplicity of conventional tests and the complexity of multi-flow-unit formations. This method provides accurate permeability measurement without requiring knowledge of formation thickness or flow unit configuration, thus resolving the contradiction between ease of operation and measurement precision.
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 accurate estimation of horizontal and vertical permeability without requiring knowledge of formation thickness, providing unique estimates for vertical and horizontal wellbores and refining parameters through nonlinear regression analysis, thus improving reservoir management and oilfield operations.
Implementation Method 1
generating, using a dual packer tool module, fluid flows from the reservoir into a wellbore
Implementation Method 2
obtaining pressure data associated with the fluid flows using an observation probe tool module
Implementation Method 3
identifying a portion of the pressure data corresponding to a spherical flow regime
Implementation Method 4
determining horizontal permeability based on the portion of the pressure data
Data Source
AI summary
A method for determining permeability of a reservoir using a packer-probe formation testing tool. The elements of the method include generating, using a dual packer tool module, fluid flows from the reservoir into a wellbore, obtaining pressure data associated with the fluid flows using an observation probe tool module, wherein the packer-probe formation testing tool comprises the dual packer module and the observation probe tool module, identifying a portion of the pressure data corresponding to a spherical flow regime, determining horizontal permeability based on the portion of the pressure data, and displaying an output generated using the horizontal permeability.