Cutoff Value Selection for Hydrocarbon Volume Estimation

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Solution Overview

Problem

Selecting appropriate porosity and water saturation cutoff values for estimating hydrocarbon volume in reservoirs is complex and often relies on intuition, lacking objective criteria to assess sensitivity and confidence in the estimates.

Innovation Solution

A computer-implemented method to assess the joint sensitivity of estimated hydrocarbon volume to variations in porosity and water saturation cutoff values, using plots and equations to select cutoff values that minimize sensitivity, thereby providing a more confident estimation of economically viable hydrocarbon volumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If porosity and water saturation cutoff values are selected based on intuition, then the estimation process is simple, but the reliability and precision of the hydrocarbon volume estimate deteriorates

Engineering Contradiction:
Improvesimplicity of cutoff value selectionVSAvoidconfidence in hydrocarbon volume estimate
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a sensitivity analysis that provides feedback on how variations in cutoff values affect hydrocarbon volume estimates. The system calculates sensitivity metrics and presents them to users, enabling them to adjust cutoff values based on quantitative feedback rather than intuition alone. This feedback mechanism transforms the subjective selection process into an objective, data-driven approach that improves estimate reliability while maintaining ease of operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent systematically varies porosity and water saturation cutoff values to assess their impact on hydrocarbon volume estimates. By changing these parameters and observing the resulting sensitivity metrics, the system identifies optimal cutoff value combinations that minimize estimation uncertainty. This parameter exploration approach replaces intuitive selection with a structured method for finding reliable cutoff values.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple cutoff value combinations are evaluated to assess sensitivity, then the confidence in estimation improves, but the complexity of the process increases

Engineering Contradiction:
Improveprecision of hydrocarbon volume estimateVSAvoidcomplexity of cutoff value selection process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces sensitivity metrics as an intermediary that simplifies the evaluation of multiple cutoff value combinations. Instead of requiring users to directly analyze complex variations in hydrocarbon volume estimates, the system computes sensitivity metrics that serve as intermediate indicators. These metrics condense complex sensitivity information into manageable form, allowing users to assess precision without being overwhelmed by the underlying computational complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system automatically performs the sensitive evaluation of multiple cutoff value combinations without requiring manual intervention. The computer-implemented method autonomously varies cutoff values, calculates sensitivity metrics, and identifies optimal combinations, thereby managing the process complexity internally while presenting simplified results to users. This self-service approach maintains measurement precision while shielding users from computational complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3175264B1Tool for cutoff value determination in net-pay computation workflow
Publication Date: 2023.04.12 SERVICES PETROLIERS SCHLUMBERGER SA
  • EP3175264B1 patent drawingFigure 1
  • EP3175264B1 patent drawingFigure 2
  • EP3175264B1 patent drawingFigure 3

AI summary

Methods, systems, and computer-readable media for assessing porosity and water saturation cutoff values for hydrocarbon volume estimation are described. The techniques can include determining a plurality of water saturation and porosity value pairs for locations regularly-spaced along at least one borehole. The techniques can further include plotting the plurality of water saturation and porosity value pairs on a graph and representing a plurality of percentiles of the estimated maximal hydrocarbon volume on the graph. The techniques can also include causing the graph to be displayed to a user, such that the user can visually observe a combined sensitivity to porosity and water saturation cutoffs values. The user can take various actions based on the display.