Net Pay Zone Classification Using Neutron-Density Separation
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Solution Overview
Problem
Existing methods for identifying and classifying net pay zones in shale gas reservoirs are often specific to particular formations and lack general applicability, making it difficult to quickly and accurately characterize hydrocarbon gas pay zones in new areas of exploration and development.
Innovation Solution
A computer-implemented method and system that determines a sweet zone indicator from well log data, calculates rock properties, and identifies classes of net pay zones, including first-class, second-class, and third-class zones, using normalized neutron-density separation and other well log data analysis techniques, to identify areas of interest within subterranean reservoirs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for identifying net pay zones are applied, then identification accuracy for specific formations is improved, but general applicability to new areas deteriorates
Solution Approach 1:
The patent creates a universal classification system that can be applied across different shale gas formations. By establishing general criteria for net pay zone classification based on well log data patterns that are applicable to multiple formations, the system achieves both accuracy in identification and versatility in application to new exploration areas.
Solution Approach 2:
The patent transforms well log data into standardized parameters and indicators that can be consistently applied across different formations. By changing the raw data into classified parameters with defined thresholds and ranges, the system maintains measurement precision while enabling general applicability through standardized parameter sets.
2Measurement precision
If detailed well log data analysis is performed, then classification accuracy of net pay zones is improved, but processing time increases
Solution Approach 1:
The patent segments the complex well log data analysis into distinct classification categories (first-class, second-class, third-class net pay zones) based on different combinations of log parameters. This segmentation allows for systematic processing where each zone type has specific criteria, improving both accuracy and processing efficiency by avoiding exhaustive analysis of all possible parameter combinations.
Solution Approach 2:
The patent performs preliminary classification by establishing threshold values and criteria for different net pay zone classes before detailed analysis. By pre-defining classification boundaries and parameter ranges, the system can quickly sort well log data into appropriate categories without requiring extensive post-processing analysis, thus reducing overall processing time while maintaining accuracy.
Data Source
AI summary
A system and computer-implemented method for characterizing hydrocarbon gas net pay zones in a subterranean reservoir including determining a sweet zone indicator from well log data, determining rock properties from well log data, and identifying one or more classes of net pay zones from the sweet zone indicator and rock properties. The sweet zone indicator may be determined by computing neutron-density separation and using the neutron-density separation and the well log data. The rock properties determined from the well log data may include total water saturation, adsorbed gas saturation, total gas content, porosity, propensity for hydraulic fracturing, uncertainty level of the total water saturation, uncertainty level of the total gas content, and baselines for the porosity and total gas content. Using the sweet zone indicator and rock properties, one or more classes of net pay zones can be identified.