Source Rock Thickness Prediction Using Well Logs and TOC Cutoffs
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Solution Overview
Problem
Existing methods for determining total organic content (TOC) and net thickness of source rocks require expensive retrieval and analysis of rock core samples, which is time-consuming and costly.
Innovation Solution
A method and system utilizing well logs, core samples, and advanced analytical techniques like pyrolysis, inductively coupled plasma-mass spectrometry, and X-ray fluorescence to determine TOC and net source rock thickness with minimal core sampling, using a computer processor for data analysis and prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extensive core sampling and laboratory analysis are used to determine TOC and net source rock thickness, then measurement precision is improved, but loss of time and productivity deteriorate
Solution Approach 1:
The patent replaces mechanical core sampling and laboratory analysis with electronic well log measurements and automated computer-based analysis. Well logs (gamma ray, resistivity, density, neutron porosity) are used to detect and characterize source rock intervals, and a computer processor automatically calculates TOC and net thickness using integrated algorithms, eliminating the need for physical core retrieval and lab processing.
Solution Approach 2:
The patent creates a multi-functional system where well logs serve multiple purposes: identifying source rock intervals, determining TOC values, calculating net thickness, and assessing hydrocarbon potential. The integrated computer-based system performs multiple assessment functions simultaneously using the same well log data, replacing multiple separate operations (core sampling, lab analysis, manual interpretation).
2Measurement precision
If extensive core sampling is performed to determine TOC and net source rock thickness, then measurement precision is improved, but loss of time deteriorates
Solution Approach 1:
The patent performs preliminary measurements by acquiring well logs during or immediately after well drilling operations, before core sampling and laboratory analysis would be conducted. The well logs provide real-time or near-real-time data that can be used to identify source rock intervals and estimate TOC and net thickness without waiting for core analysis results.
Solution Approach 2:
The patent replaces the time-consuming mechanical processes of core retrieval, transportation, and laboratory analysis with electronic well log measurements and automated computer processing. The entire determination process is accelerated by using electronic data acquisition and algorithm-based calculation instead of physical sample handling and manual or semi-automated lab procedures.
3Productivity
If automated prediction methods are used to determine net source rock thickness, then productivity is improved, but measurement precision may worsen
Solution Approach 1:
The patent incorporates feedback mechanisms where the computer-based prediction system uses well log data to automatically adjust and refine TOC and net thickness calculations. The system compares predicted values with established geological models and criteria, and iteratively optimizes the results to improve accuracy while maintaining high productivity through automated processing.
Solution Approach 2:
The patent uses a composite approach by integrating multiple types of well log data (gamma ray, resistivity, density, neutron porosity) and combining them with geological knowledge and empirical relationships to create a comprehensive prediction model. This multi-parameter integration improves measurement precision by compensating for limitations of individual log types while maintaining automated high-speed processing.
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
Enables fast and cost-effective determination of TOC and net source rock thickness, improving the accuracy of hydrocarbon resource assessment without the need for extensive core sampling.
Implementation Method 1
obtaining a second plurality of core samples from the segment; and for each of the second plurality of core samples determining organic material data, using pyrolysis
Implementation Method 2
obtaining at least one well log from at least one a segment of a wellbore penetrating the subterranean region of interest, obtaining a first plurality of core samples from the segment
Implementation Method 3
utilizing well logs, core samples, and advanced analytical techniques like pyrolysis, inductively coupled plasma-mass spectrometry
Data Source
AI summary
A system and method for determining a net source rock thickness is disclosed. The method includes obtaining at least one well log, a first and second plurality of core samples from a wellbore, and for each of the first plurality determining a relative abundance of inorganic materials, and for each of the second plurality a set of organic material data. The method further includes determining a validated total organic content and a measured source rock thickness based on the organic material data and relative abundance of inorganic materials and determining a data and a prediction portion of the wellbore, based on the second plurality sample locations. The method still further includes determining a cut-off value for each well log, predicting a source rock thickness from the cut-off values and the net source rock thickness from a sum of the predicted and the measured source rock thicknesses.