Multi-Capillary Force Curve Averaging for Heterogeneous Reservoir Samples
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Solution Overview
Problem
Current methods for averaging capillary force curves are not suitable for samples with significantly different J functions and lack physical meaning, failing to consider the number of samples, leading to subjective and inconsistent results.
Innovation Solution
A multi-capillary force curve averaging method that performs virtual overall measurement of multiple samples by preprocessing capillary force-saturation curves to ensure monotonicity and extrapolating gentle sections, calculating averaged wet phase saturation using weighted averages, and connecting data points to obtain a consistent averaged capillary force curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If J function interpolation method is used to average capillary force curves, then the calculation process can be simplified, but the results become subjective and lack strict physical meaning due to multiple interpolation methods producing different results
Solution Approach 1:
The patent transforms the capillary force curves into J-function space by changing the parameter representation from (saturation, capillary force) to (J-function, normalized saturation). This parameter transformation enables the use of weighted averaging instead of interpolation, providing both computational simplicity and physical meaningfulness through the establishment of a unique mapping relationship between different curve representations
Solution Approach 2:
The J-function serves as an intermediary transformation that bridges different capillary force curves. By converting curves into J-function space and using normalized saturation as a common coordinate, the method creates a unified framework where curves with different physical characteristics can be meaningfully averaged without subjective interpolation choices
2Productivity
If traditional averaging methods are applied to capillary force curves, then the calculation can be performed, but the methods cannot consider the influence of the number of samples leading to inconsistent results
Solution Approach 1:
The patent performs preliminary normalization of saturation values before averaging, ensuring that all curves are transformed to a common reference frame. This preliminary action of normalizing saturation with respect to the maximum saturation of each curve allows the subsequent weighted averaging to properly account for the number of samples and their respective representations, eliminating inconsistency
Solution Approach 2:
The method creates a virtual copy of the multi-sample system by constructing an averaged J-function that represents the collective behavior of all samples. This copied representation, weighted by the number of reservoirs each sample represents, allows calculation of averaged capillary force curves that consistently reflect the influence of sample quantity without requiring physical remeasurement
3Ease of operation
If direct averaging of capillary force curves is performed, then the process is straightforward, but the method is not suitable for samples with significantly different J functions and pore structures
Solution Approach 1:
The patent segments the capillary force curves into their fundamental J-function components, separating the shape characteristics (captured by J-function) from the scaling characteristics (captured by normalized saturation). This segmentation allows the averaging method to handle samples with significantly different pore structures and J functions by operating in the segmented J-function space rather than attempting to directly average the original curves
Solution Approach 2:
The methodology creates a universal framework that can handle diverse sample types with different physical properties, pore structures, and J functions. By transforming all curves into the unified J-function representation and using weighted averaging based on sample representation, the method achieves multi-functionality across heterogeneous reservoir types while maintaining operational straightforwardness
Data Source
AI summary
The present invention relates to a multi-capillary force curve averaging method based on the overall virtual measurement of a plurality of samples. The method includes the following steps: 1, taking m types of rock samples, obtaining a capillary force-saturation curve, an apparent volume and a porosity of each sample; 2, inspecting the quality of the capillary force-saturation curve of each sample and preprocessing the end points of each curve; 3, calculating an averaged wet phase saturation corresponding to different capillary force values of the plurality of samples under the overall virtual measurement of a plurality of samples; and 4, denoting data points on a graph by using the wet phase saturation as the abscissa and capillary force as the ordinate, and finally connecting all data points smoothly to obtain the averaged capillary force curve. This method of the present invention is reliable in principle and easy to operate, can be directly operated on the capillary force curves, is also suitable for various types of samples with different physical properties in consideration of the influence of the numbers of reservoirs represented by samples, has a wide range of applications, and accurate and convenient calculation results, and is more consistent with actual working conditions.