NMR Logging Tool for Formation Parameter Measurement
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Solution Overview
Problem
Current methods for determining formation and fluid properties in subterranean reservoirs, particularly hydrocarbon reservoirs, are limited in accuracy and effectiveness when measuring changes in fluid content and permeability after fluid injection, especially in complex environments like carbonate rocks.
Innovation Solution
A method involving injecting a known volume of fluid into the formation, performing NMR-based logging operations at multiple points to create a detailed saturation profile, and using modeling to derive parameters like directional and relative permeabilities from the profile data, with the goal of improving the characterization of reservoir treatments and hydrocarbon production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional logging methods are used to measure formation parameters, then the measurement process is simple, but the measurement precision and accuracy of formation parameters are insufficient
Solution Approach 1:
The patent combines NMR logging measurements with fluid injection operations into an integrated system. The NMR tool is positioned within the injection tool assembly, allowing simultaneous injection of fluid and measurement of saturation profiles, thereby improving measurement precision while managing device complexity through functional integration
Solution Approach 2:
The patent introduces NMR measurements as an intermediary technique to indirectly determine formation parameters such as permeability and fluid saturation. Instead of directly measuring these parameters, the NMR tool measures hydrogen nucleus relaxation properties, which serve as intermediaries to infer the desired formation characteristics with higher precision
2Loss of information
If fluid injection is performed to evaluate reservoir treatment, then information about fluid distribution is obtained, but the ability to accurately determine permeability and saturation profiles is limited
Solution Approach 1:
The patent implements a feedback mechanism where NMR measurements are taken before and after fluid injection to observe changes in saturation profiles. The difference between pre-injection and post-injection NMR signals provides feedback information about fluid distribution, enabling accurate determination of permeability and saturation profiles while maintaining productivity through efficient data acquisition
Solution Approach 2:
The patent performs preliminary NMR logging measurements before fluid injection to establish baseline saturation profiles. This preliminary action allows subsequent comparison with post-injection measurements, enabling accurate determination of fluid distribution and formation parameters without losing critical information about the formation's initial state
3Loss of information
If multiple logging measurements are performed at different depths, then detailed saturation profiles are obtained, but the time and operational complexity increase
Solution Approach 1:
The patent merges multiple logging measurements into a single integrated NMR logging operation. Instead of performing separate measurements for different parameters, the NMR tool simultaneously measures saturation, permeability, and fluid distribution at multiple depths in one continuous operation, reducing measurement time while capturing comprehensive spatial distribution data
Solution Approach 2:
The patent maintains continuous NMR measurement throughout the fluid injection process and subsequent evaluation. The NMR tool remains positioned in the wellbore, continuously acquiring data at different depths and times, ensuring no loss of spatial distribution information while minimizing idle time between measurements
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 precise determination of formation parameters such as permeabilities and fluid saturation profiles, enhancing the accuracy and effectiveness of reservoir treatments and hydrocarbon production by providing detailed spatial distribution data.
Implementation Method 1
NMR measurements are commonly used in the wellbore to probe the NMR decay behavior of the stationary fluid in the reservoir rock. During these measurements, magnetic fields are established in the formation using suitably arranged magnets. The magnetic fields induce nuclear magnetization, which is flipped or otherwise manipulated with on-resonance radio frequency (RF) pulses.
Implementation Method 2
injecting from a tool body suspended into a well at an injection location a known volume of fluid into the formation
Data Source
AI summary
A method of measuring a parameter characteristic of a rock formation in an oil well is provided for evaluating a reservoir treatment applied to a subterranean formation including the steps of injecting from a tool body suspended into a well at an injection location a known volume of fluid into the formation, performing a logging operation sensitive to a change of fluid content at several measuring points below and above the injection location; and using results of the logging operation to determine a depth profile along said well of a parameter related to fluid content.