Induction Logging Tool Radial Zone Segmentation
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Solution Overview
Problem
Current methods for determining formation resistivity in borehole surveys face challenges in accurately estimating uninvaded formation resistivity and permeability due to invasion effects, which are crucial for hydrocarbon reserve estimation and reservoir productivity analysis.
Innovation Solution
A method involving a resistivity measuring instrument with transmitters and receivers that induce signals indicative of resistivity in multiple subzones within the invaded zone, using filtered signals to estimate resistivity and update estimates with varying frequencies, allowing for the identification of up to five radial zones and iterative gradient methods for permeability estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resistivity measurement methods are used, then the measurement process is simple, but the accuracy of uninvaded formation resistivity estimation is poor due to invasion effects
Solution Approach 1:
The invaded zone is divided into multiple radial subzones (first, second, and third subzones) with different resistivity characteristics. The measurement system uses multiple receiver coils positioned at different radial distances from the borehole to separately measure resistivity in each subzone, enabling detailed characterization of invasion profiles and improved estimation of uninvaded formation resistivity.
Solution Approach 2:
The patent transitions from conventional single-point or bulk resistivity measurements to multi-dimensional radial profiling within the invaded zone. By positioning receiver coils at different radial distances and using multiple frequencies, the system creates a three-dimensional resistivity model that captures spatial variation in the invaded zone, significantly improving measurement precision.
2Measurement precision
If time-lapse resistivity measurements are made to estimate permeability, then permeability information can be obtained, but the process is time-consuming and requires multiple measurements
Solution Approach 1:
The system performs preliminary high-resolution resistivity profiling of the invaded zone using multiple frequencies and receiver coils to accurately characterize the invasion profile and determine formation permeability. This preliminary characterization enables subsequent faster and more accurate hydrocarbon saturation and reserve estimation without requiring repeated time-lapse measurements.
Solution Approach 2:
The patent uses iterative gradient methods that incorporate feedback between simulated resistivity models and actual measurements to refine permeability estimates. By continuously adjusting model parameters based on measurement feedback, the system achieves accurate permeability characterization more efficiently than conventional time-lapse methods.
3Measurement precision
If core analysis is used to determine formation properties, then detailed resistivity and permeability data can be obtained, but the process is expensive and time-consuming with limited sample size
Solution Approach 1:
The patent replaces mechanical core analysis with electromagnetic induction measurements using induction logging tools. The system uses electromagnetic fields to non-invasively measure resistivity and permeability properties of the formation and invaded zone, eliminating the need for physical core sampling. This substitution provides detailed formation property characterization at much lower cost and higher efficiency while maintaining or improving measurement precision through multi-frequency and multi-receiver capabilities.
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 approach enhances the accuracy of resistivity modeling, enabling high-resolution definition of multiple zones within the first 2 feet of the invaded zone, improving the estimation of hydrocarbon saturation and permeability, thus aiding in more precise hydrocarbon reserve estimation and reservoir productivity assessment.
Implementation Method 1
The transmitter is activated and at least one frequency and signals are induced in the plurality of pairs of receivers that are indicative of the resistivity of at least three subzones inside an invaded zone
Data Source
AI summary
Measurements made with an induction logging tool are processed to provide a resistivity model of fluid invasion of the formation. Up to five zones can be determined over a radial distance of about 0.6 m. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.