Pressurized NMR Core Holder for Accurate Downhole Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Core samples from subterranean formations lose accuracy due to gas and fluid escape when brought to the surface, as the native pressure is higher than surface pressure, leading to inaccurate NMR analysis.
Innovation Solution
A pressurized NMR core holder that maintains core samples at high pressure and temperature from downhole collection to NMR measurements, using a housing with NMR coils and a control system, and filled with non-reactive fluids to retain the native state of the samples, allowing for accurate NMR analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If core samples are brought to the surface for analysis, then the core samples can be analyzed using NMR, but the gases and light fluids escape from the core sample due to pressure difference, making the analysis inaccurate
Solution Approach 1:
A pressure maintenance system acts as an intermediary between the core sample and the external environment, maintaining downhole pressure conditions during surface analysis. The system includes a pressure vessel and fluid injection system that mediates the pressure difference, preventing fluid escape while allowing NMR analysis to proceed.
Solution Approach 2:
The pressure parameter is changed and maintained at downhole levels during surface analysis. The system dynamically adjusts and maintains pressure parameters to match reservoir conditions, preventing the pressure-driven fluid loss that would otherwise occur when bringing core samples to the surface.
2Reliability
If the core sample is preserved by hermetically sealing in wax or freezing, then the core sample is protected from environmental changes, but the gases and light fluids still escape due to native pressure being higher than surface pressure
Solution Approach 1:
A hydraulic pressure maintenance system is used to counteract the native pressure of the core sample. The system uses fluid injection and pressure control mechanisms to balance the pressure differential, preventing gas and fluid escape while maintaining sample integrity during preservation and analysis.
3Loss of time
If the core sample is analyzed immediately upon reaching the surface, then the analysis can be performed quickly, but the pressure difference causes fluids to escape and reduces measurement accuracy
Solution Approach 1:
Pressure maintenance capabilities are built into the core sample handling system before analysis begins. The pressure vessel and control system are prepared in advance, allowing immediate analysis to proceed without delay while maintaining accurate pressure conditions throughout the measurement process.
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 pressurized NMR core holder effectively maintains the reservoir fluids in a downhole fluid saturation state, ensuring accurate NMR measurements by maintaining pressure and temperature conditions similar to those at the formation, thereby reducing fluid loss and maintaining sample integrity.
Implementation Method 1
pressurized nuclear magnetic resonance (NMR) core holder
Implementation Method 2
NMR coils
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Core samples may been collected in a subterranean formation, preserved downhole in a pressurized nuclear magnetic resonance (NMR) core holder (1) comprising components for NMR imaging and (2) capable of maintaining the core samples at downhole fluid saturation state. For example, a pressurized NMR core holder may comprise a housing capable of containing downhole fluid pressures; a coil holder lining an inside of the housing and defining a core chamber; and one or more NMR coils maintained in a longitudinal position along the housing by the coil holder. Further, a system for performing the NMR imaging may comprise: a holder that maintains a pressurized NMR core holder in a desired position; and one or more magnets that are longitudinally movable along the pressurized NMR core holder.