Acoustic Logging Tool Density Measurement Without Radioactive Sources
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of radioactive sources for density logging in hydrocarbon reservoir exploration poses health risks to workers, regulatory challenges, and significant operational costs due to radiation exposure and compliance issues, with traditional gamma-ray based methods being inefficient and in short supply.
Innovation Solution
Acoustic logging techniques that measure formation density using compressional and shear wave velocities and borehole fluid acoustic impedance, eliminating the need for radioactive sources and providing real-time density logs in both wireline and logging-while-drilling environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gamma-ray density logging with radioactive sources is used, then formation density can be measured, but radiation exposure risks to workers and health hazards increase
Solution Approach 1:
The patent removes the radioactive source from the logging tool, extracting the harmful radiation-generating component while retaining the density measurement capability through alternative acoustic methods
Solution Approach 2:
The patent replaces the gamma-ray based density measurement system with an acoustic wave-based system, substituting a mechanical/acoustic field for a nuclear field to achieve the same measurement objective without radiation
2Measurement precision
If radioactive sources are used for density logging, then accurate formation density data can be obtained, but regulatory compliance costs and operational delays increase
Solution Approach 1:
The patent eliminates the radioactive source from the system, thereby removing all associated regulatory compliance requirements, safety procedures, and administrative overhead that cause operational delays
Solution Approach 2:
The acoustic logging tool uses short-lived acoustic waves instead of long-lived radioactive sources, eliminating the need for long-term regulatory compliance, storage, and disposal procedures
3Measurement precision
If radioactive sources are used for density logging, then formation density can be measured, but the complexity of safety procedures and monitoring equipment increases
Solution Approach 1:
The patent removes the radioactive source and all associated safety infrastructure including radiation sensors, wipe test equipment, monitoring badges, and specialized storage facilities, dramatically simplifying the overall system
Solution Approach 2:
The acoustic logging tool is self-contained and requires no external radiation safety infrastructure, monitoring systems, or specialized handling procedures, making the system inherently simpler and more autonomous
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
This approach offers improved precision and safety by eliminating radiation exposure risks, reducing regulatory burdens, and providing accurate formation density logs without the need for radioactive materials, particularly in rugose boreholes.
Implementation Method 1
measuring propagation velocities of compressional and shear waves through the formation
Implementation Method 2
measuring propagation velocities of compressional and shear waves through the formation
Implementation Method 3
a fluid cell measures an acoustic impedance of the borehole fluid
Data Source
AI summary
Formation density is calculated from acoustic logging measurements. This technique does not require a radioactive source and in fact it may offer better precision particularly in rugose boreholes. In at least some embodiments, the technique exploits an observed relationship between a transmission coefficient T(pb, Vc, pmVm) and a breakdown resistance μB(pb, Vc, Vs) to enable determination of the formation density pb from measurements of the formation's compressional wave velocity Vc, the formation's shear wave velocity Vs, and the borehole fluid's acoustic impedance pmVm. The desired measurements can be acquired by attaching or integrating a fluid cell with an acoustic logging tool that measures acoustic wave propagation velocities. Real-time density logs can be obtained from both wireline and logging-while-drilling implementations.