Crosswell Electromagnetic Data Inversion for Well Trajectory Planning
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Solution Overview
Problem
Deep-reading electromagnetic surveys for subsurface hydrocarbon reservoirs are limited by the need for extensive data processing and slow evaluation times, making them less effective for real-time control of field development operations like well drilling and enhanced oil recovery.
Innovation Solution
A simplified model and process for interpreting crosswell and surface-to-borehole electromagnetic data, using a heterogeneous background with a limited number of resistivity anomalies, allowing for fast inversion and well trajectory planning, which reduces the number of unknown parameters and accelerates data interpretation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electromagnetic data acquisition methods are used for deep-reading surveys, then comprehensive subsurface data can be obtained, but the data processing time is extensive and evaluation is slow
Solution Approach 1:
The patent segments the subsurface into discrete geological layers and models electromagnetic wave propagation through each layer separately. This segmentation allows for efficient calculation of apparent resistivity values for different depths, enabling rapid data processing while maintaining measurement precision for deep-reading surveys
Solution Approach 2:
The patent transforms the complex electromagnetic data into apparent resistivity parameters that can be directly interpreted in terms of subsurface geological properties. By changing the parameter representation from raw electromagnetic signals to geologically meaningful resistivity values, the system achieves both accurate subsurface characterization and rapid evaluation
2Length of stationary object
If deep-reading electromagnetic surveys are conducted for hydrocarbon reservoir monitoring, then reservoir parameters can be determined at distances of 10 meters or more from sensors, but the evaluation speed is too slow for real-time control of field development operations
Solution Approach 1:
The patent performs preliminary modeling of electromagnetic wave propagation through predefined geological layers before actual field data collection. By establishing the theoretical framework and expected responses in advance, the system can rapidly compare field measurements against models, achieving fast evaluation of deep-reading data for real-time operational control
Solution Approach 2:
The patent replaces traditional slow iterative inversion methods with a direct calculation approach based on layered earth models. This substitution of the computational mechanism allows rapid determination of apparent resistivity values at distances of 10 meters or more from sensors, enabling real-time productivity without sacrificing measurement distance capability
3Measurement precision
If extensive data processing is performed on electromagnetic survey data, then accurate subsurface characterization is achieved, but the effectiveness for real-time control of field development operations is reduced
Solution Approach 1:
The patent extracts only the essential electromagnetic parameters (apparent resistivity values at different depths and orientations) from the complete dataset, discarding redundant information. This extraction approach maintains accurate subsurface characterization by focusing on the most geologically meaningful parameters while dramatically reducing processing requirements for real-time operational control
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 enables rapid data inversion and well planning within days or hours, improving the effectiveness of deep-reading surveys and reducing the risk of drilling failures by accurately delineating hydrocarbon and water zones, thus enhancing the efficiency of hydrocarbon reservoir management.
Implementation Method 1
Deep-reading electromagnetic field surveys of subsurface areas typically involve large scale measurements from the surface, from surface-to-borehole, and/or between boreholes
Implementation Method 2
the electrical resistivity of geologic formations is a function of both porosity of the formations and resistivity of the fluids
Data Source
AI summary
A method of measuring a parameter characteristic of a rock formation is provided, the method including the steps of obtaining crosswell electromagnetic signals between two wells and using an inversion of said signals to investigate or delineate the presence of a resistivity anomaly, such as brine in a low resistivity background, wherein the resistivity anomaly is assumed to be distributed as one or more bodies characterized by a limited number of geometrical parameters and the inversion is used to determine said geometrical parameters. The method can also be applied to determine the trajectory of an in-fill well to be drilled.