X-Ray Litho-Density Tool for Non-Invaded Formation Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current well logging technologies rely on radioactive isotopes like Cesium 137 for density measurements, which pose safety risks, regulatory challenges, and logistical complexities due to their radioactive nature and short half-life.
Innovation Solution
An x-ray based litho-density tool that uses an x-ray source to measure both invaded and non-invaded formation bulk densities, allowing for increased axial offset of detectors to avoid mud-invaded zones and improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If radioactive isotopes like Cesium 137 are used for density measurements, then gamma rays are readily available for formation evaluation, but safety risks and regulatory challenges increase due to radioactive nature
Solution Approach 1:
The patent replaces the radioactive mechanical/physical system (Cesium 137 isotope emitting gamma rays) with an electronic system (x-ray tube generating x-rays). This substitution eliminates the inherent safety risks and regulatory burdens of radioactive materials while maintaining the core function of generating penetrating radiation for formation density measurement.
Solution Approach 2:
The x-ray tube is a non-radioactive, replaceable component that can be deactivated and replaced if needed, unlike long-lived radioactive isotopes that require secure disposal. This approach treats the radiation source as a consumable electronic component rather than a permanent radioactive hazard.
2Use of energy by moving object
If radioactive isotopes with short half-life are used, then gamma ray supply is maintained, but replacement frequency and operational downtime increase
Solution Approach 1:
The patent substitutes the decaying radioactive isotope system with an electrically powered x-ray tube system. The x-ray tube can be continuously powered without degradation, eliminating the periodic replacement requirements imposed by radioactive half-life and associated operational downtime.
3Measurement precision
If detectors are placed close to the borehole wall for accurate measurements, then measurement precision improves, but mud-invaded zone contamination increases
Solution Approach 1:
The patent extends the detector array axially along the borehole, utilizing the longitudinal dimension to place detectors at various offsets from the borehole wall. This allows selection of detectors positioned in the non-invaded zone while maintaining measurement precision through appropriate geometric configuration and calibration.
4Productivity
If higher logging speeds are used to increase productivity, then output per unit time improves, but measurement precision decreases
Solution Approach 1:
The replacement of radioactive isotopes with an x-ray tube enables higher logging speeds because the electronic system can be rapidly activated and deactivated without safety concerns about radioactive material exposure during tool retrieval or replacement operations.
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
The x-ray based tool enhances the accuracy of litho-density measurements by allowing analysis of the non-invaded zone, reduces the impact of mud-weight and porosity, and enables faster logging speeds while eliminating the risks associated with radioactive isotopes.
Implementation Method 1
A radioactive isotope-based source, usually Cesium 137 (137Cs), applied to the wall of the borehole emits gamma rays into the formation so these gamma rays may be thought of as high velocity particles which collide with the electrons of the atoms that compose the formation. At each collision the gamma rays lose energy to the electrons, and then continue with diminished energy. This type of interaction is known as Compton scattering.
Implementation Method 2
An x-ray based litho-density tool that uses an x-ray source to measure both invaded and non-invaded formation bulk densities
Data Source
AI summary
An x-ray based litho-density tool for measurement of simultaneous invaded and non-invaded formation surrounding a borehole is provided, the tool including at least an internal length comprising a sonde section, wherein sonde section further includes an x-ray source; at least one radiation measuring detector; at least one source monitoring detector; and a plurality of sonde-dependent electronics. In various embodiments, the tool uses x-rays to illuminate the formation surrounding a borehole, and a plurality of detectors are used to directly measure both invaded and non-invaded formation bulk densities. Detectors used to measure borehole standoff such that other detector responses may be compensated for tool standoff; long and ultra-long space detectors disposed in electromagnetic communication with a source located within a collimated tungsten radiation shield; and wear-pads disposed such that the source and detector assembly may be pressed against the side of the borehole to reduce borehole effects are also provided.