Acoustic Testing of Laminated Rock for TOC Content
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Solution Overview
Problem
Current methods for assessing total organic carbon (TOC) content and other reservoir properties in laminated rock are time-consuming and costly, relying heavily on core sampling, which delays and increases costs in petroleum exploration and production.
Innovation Solution
Acoustic testing systems and methods that generate a rock model based on relationships between acoustic velocity, net stress, lamination orientation, TOC content, and composition, allowing for real-time determination of rock properties using tri-axial test fixtures and computer processing to analyze acoustic velocities and determine TOC content and other properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If combustion-based techniques are used to measure TOC content, then direct estimation of TOC is achieved, but the process is time-consuming and costly requiring core sampling
Solution Approach 1:
The patent replaces the mechanical/chemical combustion-based TOC measurement system with an acoustic testing system. Acoustic waves are transmitted through rock cores under controlled stress conditions, and the acoustic velocity measurements are used to determine TOC content through a developed rock model, eliminating the need for time-consuming combustion analysis of pulverized samples
Solution Approach 2:
The patent performs preliminary acoustic testing on core samples to develop a rock model that correlates acoustic velocity with TOC content. This preliminary work enables subsequent rapid TOC determination without requiring actual core sampling and combustion analysis for each measurement, as the model can be applied to acoustic velocity data obtained during drilling operations
2Measurement precision
If core sampling is performed to determine reservoir properties, then accurate TOC content is obtained, but drilling operations must be suspended and costs increase
Solution Approach 1:
The patent replaces the core sampling and combustion analysis workflow with an acoustic testing approach. Acoustic transducers mounted on the drilling tool transmit acoustic waves through the rock formation during drilling operations, allowing continuous real-time TOC determination without suspending drilling to extract and analyze core samples
Solution Approach 2:
The patent enables continuous acoustic testing and TOC determination during drilling operations. The acoustic testing system operates continuously as the drill bit advances, providing uninterrupted real-time reservoir property assessment rather than requiring intermittent suspension of drilling for discrete core sample extraction and analysis
3Productivity
If traditional well logging is used for in-situ assessment, then real-time TOC content can be determined, but the techniques are not sufficiently accurate for laminated rock
Solution Approach 1:
The patent applies local quality by developing specific acoustic testing protocols and a specialized rock model for laminated rock formations. The system accounts for the unique properties of laminated rock, including lamination orientation and net stress effects, to provide accurate TOC determination in this specific formation type rather than using generic well logging techniques
4Measurement precision
If acoustic testing with tri-axial compression is performed, then accurate rock model is generated, but the testing process becomes complex
Solution Approach 1:
The patent develops a universal rock model that can be applied to various laminated rock formations and well logging scenarios. The acoustic testing system and rock model are designed to be broadly applicable to different reservoir conditions and formation types, reducing the need for formation-specific complex testing procedures while maintaining accuracy
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 accurate, timely, and cost-effective assessment of TOC content and other properties in-situ, reducing the need for core sampling and enhancing the efficiency of petroleum exploration and production operations.
Implementation Method 1
transmit an acoustic pulse through each of the oriented samples while tri-axially compressing the oriented sample at the stress-level to generate test data indicative of acoustic velocities through the laminated rock
Data Source
AI summary
Provided in some embodiments are systems and methods for preparing oriented samples of a laminated rock having different lamination orientations, for each of different stress-levels, transmitting an acoustic pulse through each oriented sample while tri-axially compressing the oriented sample at the stress-level to generate test data indicative of acoustic velocities through the laminated rock at different combinations of lamination orientations and stress levels, determining acoustic velocities through the laminated rock at the different combinations of lamination orientations and stress levels based on the test data, generating a rock model for the laminated rock based on the acoustic velocities, and determining a property of a second laminated rock (e.g., total organic carbon (TOC) content) based on the rock model for the laminated rock.