NMR Logging Correction for Solid Particle Invasion Effects
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Solution Overview
Problem
Nuclear magnetic resonance (NMR) measurements in geologic formations are affected by solid invasion, leading to underestimation of porosity and alteration of relaxation time constants, which complicates the characterization of formations and fluid properties.
Innovation Solution
A method and apparatus that quantify the effect of solid particle invasion on NMR measurements by conveying a carrier with an NMR tool through a borehole, performing measurements, and using a processor to receive and analyze information about the solid particles, allowing for correction of measured relaxation time constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NMR measurements are performed in formations with solid particle invasion, then formation properties can be characterized, but the measurements are affected by solid invasion leading to underestimation of porosity and alteration of relaxation time constants
Solution Approach 1:
The patent measures the NMR properties of the invading solid particles themselves and uses this information to characterize the invasion. By treating the harmful invasion as a measurable phenomenon with its own T1 and T2 relaxation characteristics, the system converts the problem into a diagnostic tool that quantifies invasion severity and enables correction of formation property measurements.
Solution Approach 2:
The patent separates the NMR signal into distinct components: formation fluid signal and solid particle signal. By analyzing different relaxation time constants and assigning them to different sources, the system can isolate and correct for solid invasion effects. The segmentation allows independent characterization of invasion parameters and formation properties.
2Productivity
If solid particles invade into formation pores, then drilling operations can proceed, but the NMR relaxation time constants are altered and porosity is underestimated
Solution Approach 1:
The system uses NMR measurements to detect solid particle invasion in real-time and feeds this information back to correct the formation property calculations. By continuously monitoring relaxation time constants and comparing them against expected formation characteristics, the system identifies invasion and applies corrections to maintain accurate porosity and fluid property measurements throughout drilling 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
Enables accurate characterization of formation properties by compensating for the effects of solid invasion, improving the interpretation of NMR data and determining true porosity and other formation properties.
Implementation Method 1
One type of downhole tool is a nuclear magnetic resonance (NMR) tool that measures the nuclear magnetic properties of formation materials.
Data Source
AI summary
A method for estimating an effect on nuclear magnetic resonance (NMR) measurements of an invasion of solid particles into pores of an earth formation penetrated by a borehole includes conveying a carrier through the borehole and performing an NMR measurement on a volume of interest in the formation to provide a relaxation time constant using an NMR tool disposed at the carrier. The method further includes receiving information describing the solid particles in the pores and quantifying, using a processor, an effect on the measured relaxation time constant due to the invasion of solid particles using the received information.