Measuring method for contact angle of gas-liquid phase interface in micrometer capillary passage

Abstract

The invention provides a measuring method for a contact angle of a gas-liquid phase interface in a micrometer capillary passage. The pressures or flow speeds of flowing processes of a gas phase and aliquid phase in a micrometer-scale capillary are controlled by using a dynamic testing device, and the dynamic contact angle measurement in the states of small capillary number and small Bond number is realized for the first time. The measurement for the contact angle and phase interface speed based on an image processing method is firstly adopted, so that the data processing efficiency and the measuring precision are greatly improved. The invention further provides various algorithms for controlling the pressure of a two-phase flowing process and the speed of an electric platform, so that theflexibility during actual operation is improved, and furthermore, demands under various working conditions are met.

Description

technical field [0001] The invention relates to the field of enhanced petroleum exploitation, in particular to a method for obtaining the contact angle of the gas-liquid dynamic displacement phase interface by using a dynamic measuring device equipped with a micron capillary channel. Background technique [0002] The mechanism of two-phase displacement in a single micron-scale capillary is the basis of two-phase displacement in porous media in natural environments. Two-phase displacement in porous media occurs in many industrial or natural processes, such as water in tight oil reservoirs. Gas drive, solution gas drive, water drive and other processes, the above-mentioned industrial processes are characterized by weak viscous force (the range of capillary number is 10 -10 <Ca<10 -5 ), weak gravity (Bond number Bo is less than 10 -4 ). The key factor affecting the displacement process is the capillary force, and the key parameter to calculate the capillary force is th...

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Problems solved by technology

[0007] But adopt above-mentioned two kinds of schemes all can't measure capillary number 10 -10 -5 and Bond number Bo-4 Dynamic contact angle under working conditions

[0008] In addition, in order to observe the contact angle, it is necessary to use a high-magnification microscope to obtain a magnified image, which means that the observation field of view is small

However, the dynamic displacement process means that the phase interface will move a certain distance, so high-magnification microscopes cannot observe the movement process of the phase interface

If a low magnification microscope is used to observe, the change of the position of the phase interface can be observed, but the phase interface cannot be observed, so the contact angle cannot be directly measured

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