Condensate Saturation Measurement with 1D/2D NMR Difference Spectroscopy
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Solution Overview
Problem
Current methods for measuring critical condensate saturation pressure and condensate saturation in condensate gas reservoirs are inaccurate due to reliance on one-dimensional nuclear magnetic resonance spectroscopy for porosity determination and artificial zoning, which leads to errors in fluid identification and saturation measurement.
Innovation Solution
A method combining one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy to directly measure condensate saturation by analyzing signal intensity changes during depletion, using improved difference spectroscopy to correct for artificial zoning errors and accurately determine critical condensate saturation pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If one-dimensional nuclear magnetic resonance spectroscopy is used for porosity determination, then the measurement process is simple, but the measurement precision of condensate saturation is poor due to lack of fluid identification capability
Solution Approach 1:
The patent transitions from one-dimensional nuclear magnetic resonance spectroscopy to two-dimensional nuclear magnetic resonance spectroscopy. This dimensional expansion enables fluid identification capability while maintaining measurement efficiency, resolving the contradiction between operational simplicity and measurement precision for condensate saturation.
2Ease of operation
If artificial zoning method is used for oil and gas signal differentiation, then the operation is straightforward, but the measurement precision of condensate saturation deteriorates due to signal overlap errors
Solution Approach 1:
The patent introduces an improved difference spectroscopy method as an intermediary processing technique between signal acquisition and interpretation. This method effectively separates overlapping oil and gas signals by comparing saturated and unsaturated spectra, eliminating artificial zoning errors while maintaining operational simplicity.
3Ease of manufacture
If traditional depletion experiment with long rock core is used, then the experimental setup is conventional, but the measurement precision of critical condensate saturation pressure is poor due to pipeline dead volume effects
Solution Approach 1:
The patent replaces the conventional mechanical observation and pressure measurement system with nuclear magnetic resonance spectroscopy for direct detection of condensate saturation. This substitution eliminates pipeline dead volume effects by measuring saturation directly within the rock core, achieving high precision critical condensate saturation pressure determination.
4Measurement precision
If two-dimensional nuclear magnetic resonance spectroscopy is used for fluid identification, then the measurement precision of condensate saturation is improved, but the device complexity increases
Solution Approach 1:
The patent performs preliminary calibration by acquiring spectra from both saturated and unsaturated rock cores before the actual depletion experiment. This preliminary action creates reference data that simplifies subsequent analysis, enabling accurate fluid identification and condensate saturation measurement while managing system complexity through pre-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
This approach allows for precise measurement of condensate saturation and critical condensate saturation pressure, reducing errors associated with artificial zoning and pipeline dead volume, thereby improving the accuracy of condensate recovery in reservoir development.
Implementation Method 1
principle of this method is as follows: an occasion at which condensate oil starts to flow is judged by using changes of the total signal intensity of the fluid inside the rock core during the depletion process, the nuclear magnetic resonance may detect the signal intensity of hydrogen-containing fluid inside the rock core
Data Source
AI summary
Disclosed is a method for measuring critical condensate saturation pressure and critical condensate saturation of condensate gas by combining one-dimensional and two-dimensional nuclear magnetic resonance techniques, which solves low measurement precision and complex test method. The present invention detects signal intensity of the hydrogen-containing fluid in a rock core by combining a one-dimensional nuclear magnetic resonance T2 spectrum testing technology and a two-dimensional nuclear magnetic resonance T1-T2 spectrum testing technology, achieves the optimization of an artificial zoning method by an improved difference spectroscopy method to reduce errors, greatly improves condensate signal identification precision, and more quickly and accurately measures the critical condensate saturation pressure and the critical condensate saturation. Therefore, the flow law of condensate oil and gas two-phases in a formation is better studied, a more reasonable development plan is favorably formulated by a gas reservoir, and theoretical guidance is provided for improving condensate recovery ratio.