Rock Sample Wettability Determination via 3D Imaging
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Solution Overview
Problem
Current methods for determining wettability in the oil and gas industry are inadequate, particularly for porous and heterogeneous rock surfaces, as they require long times to achieve equilibrium, are prone to hysteresis, and fail to assess spatial heterogeneity, limiting the accuracy of reservoir modeling and oil recovery strategies.
Innovation Solution
A method involving three-dimensional imaging of rock samples using computed X-ray microtomography or neutron microtomography to differentiate void spaces and solid phases, determining mineral distribution, and simulating oil migration to establish equilibrium wettability, allowing for precise modeling of reservoir interactions and optimizing hydrocarbon extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact angle measurement methods are used to determine wettability, then wettability evaluation can be performed, but the measurement requires extremely long time (up to 1000 hours) to achieve equilibrium
Solution Approach 1:
The patent applies preliminary action by pre-processing the rock core sample through controlled saturation with oil and water phases before the actual wettability measurement. This preliminary saturation establishes the equilibrium wettability state in advance, eliminating the need for extremely long measurement times (up to 1000 hours) required by conventional methods. The sample is prepared in a controlled laboratory environment to achieve equilibrium conditions before observation, thus resolving the time-accuracy contradiction.
2Productivity
If conventional displacement methods (USBM or Amott-Harvey) are used to determine wettability, then a single wettability parameter can be obtained, but the method provides no information about spatial distribution of wettability on the core surface
Solution Approach 1:
The patent employs copying by creating a visual replica or image of the wettability distribution on the core surface. Instead of relying solely on bulk displacement measurements that yield a single average parameter, the method produces a visual copy (photograph or image) showing the spatial distribution of wetting and non-wetting phases across the core surface. This allows simultaneous获得 of both overall wettability characteristics and local spatial variations, resolving the contradiction between measurement efficiency and information completeness.
3Measurement precision
If conventional methods are used for wettability determination, then average wettability can be assessed, but the complex internal pore structure of the rock has an additional effect on test results that cannot be separated from wettability effects
Solution Approach 1:
The patent applies segmentation by separating the wettability measurement process from the pore structure effects. The method uses visual observation of phase distribution on the core surface after controlled saturation, which directly reveals wettability characteristics without being confounded by internal pore structure complexities. By segmenting the measurement approach to focus on surface phase distribution rather than bulk flow behavior, the method isolates wettability effects from pore structure influences, resolving the precision-complexity contradiction.
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 enables the determination of equilibrium wettability distribution across rock surfaces, providing a more accurate model for reservoir management and enhancing the selection of optimal oil recovery methods by accounting for the interaction between rock phases and fluids, thus improving the efficiency of hydrocarbon extraction.
Implementation Method 1
obtaining a three-dimensional image of the internal structure of the sample... by computed X-ray microtomography
Implementation Method 2
by neutron microtomography
Implementation Method 3
A process of oil migration to the void space filled with stratum water at the initial stage of formation of an oil and gas field is numerically simulated
Implementation Method 4
Wettability is a surface phenomenon that occurs at a boundary line between phases, one of which is a solid body, and the others are incompatible liquids or liquid and gas
Data Source
AI summary
The method for determining equilibrium wettability of an interface between a void space and a solid phase of a rock sample comprises obtaining a three-dimensional image of the internal structure of the sample. On the obtained image of the internal structure of the sample, a void space and a solid phase are differentiated. An interface between the void space and the solid phase of the sample and distribution of minerals on this surface are determined. Wettability of the solid phase at each point of the interface between the void space and the solid phase of the rock sample is determined. A process of oil migration to the void space filled with stratum water at the initial stage of formation of an oil and gas field is numerically simulated, and finally, the equilibrium wettability of the interface between the void space and the solid phase of the rock sample is determined.