A solid surface wettability determination method is disclosed. A liquid is sprayed on a surface of an object. A light beam is projected toward the surface, wherein the light beam is reflected by the liquid on the surface to generate a reflected light. The reflected light is received by an optical detector, and the optical detector outputs a determining signal related to a wettability of the surface according to the reflected light. A corresponding signal-angle relation is selected from a database according to type of the liquid and material of the object. The contact angle of the liquid on the surface is obtained by applying the determining signal to the corresponding signal-angle relation.

A method for predicting and calculating aggregate surface energy is provided and includes steps: (1) raw aggregate screening and treatment; (2) surface texture index acquirement of a polished aggregate and an untreated raw aggregate; (3) powdered aggregate testing by a capillary rise method; (4) polished aggregate testing by a sessile drop method; (5) function relationship formula fitting; and (6) surface energy calculation of raw aggregate. The method not only considers the influence of aggregate's own composition on the surface energy, but also considers the influence of the polishing treatment on the aggregate surface texture, analyzes actual surface texture conditions of the aggregate, and significantly improves the test accuracy by combining the sessile drop method and the capillary rise method. Moreover, it can replace vapor adsorption method to test the surface energy of aggregate, which greatly reduces the test cost and operation difficulty.

Disclosed is a method for measuring surface energy of aggregates based on static drop method, comprising (1) aggregates grinding and pretreatment; (2) obtaining the surface texture index; (3) calculating the surface energy based on static drop method experiment; (4) fitting to obtain a functional relationship between the surface texture index and surface energy; (5) calculating the surface energy of the original aggregate. The method considers the influence of the grinding process on the surface texture of the aggregates when measuring the surface energy of the aggregates, which significantly improves the accuracy of the static drop method test. The static drop method can be used to replace the vapor adsorption method to test the surface energy of aggregate, and the low-cost optical contact angle instrument can replace the expensive magnetic suspension weight balance system to test the surface energy of aggregate, which greatly reduces the test cost.

A method for measuring a receding contact angle between a sample surface and a drop of a liquid is provided. The method includes ejecting a dosing volume of the liquid from an opening onto the sample surface such that the liquid is ejected as a continuous jet at a defined flow rate for a defined dosing time period, and the opening comprises an opening diameter. The dosing volume of the liquid is allowed to form a drop on the sample surface. At least one geometrical parameter of the drop formed on the sample surface is measured and a contact angle between the sample surface and the drop is determined based on the at least one geometrical parameter. The flow rate and the dosing time period are selected such that the dosing volume does not exceed the flow rate multiplied by 0.11 s.

A system includes a processor and a memory storing instructions executable by the processor to actuate a component upon determining that a hydrophobic coating of a surface is degraded based on a comparison of a characteristic of a liquid droplet with a threshold value.

The present disclosure discloses a contact angle measuring device, including a light source, a container, a photodetector, a bubble generating unit, and a processing unit. The container includes a first and a second side walls that are opposite. The first side wall is made of a light-transmitting material, the container is filled with a liquid with light transmission inside. The monochromatic light emitted by the light source passes through the first side wall and enters an interface between the first side wall and the liquid. The bubble generating unit is configured for generating a bubble that is in contact with an inner surface of the first side wall. The photodetector is configured for detecting light intensity distribution of the monochromatic light through the liquid.

Systems, methods, and apparatus for a three-dimensional (3D)-printed vessel for wettability assessment of fracturing proppants are disclosed. The vessel includes a base component including a threaded cylindrical portion extending outward from a first side of the base component. The cylindrical portion has a particular thread profile. The base component defines a cavity sized to contain a proppant sample. A cap is configured to be screwed onto the threaded cylindrical portion after the proppant sample is injected into the cavity. A surface of the cap is shaped to flatten a proppant surface of the proppant sample. The cap is threaded with the particular thread profile. A pin is configured to be partially screwed onto a second side of the base component before the proppant sample is injected into the cavity. The second side is opposite to the first side. Other embodiments may be described or claimed.

A method and system for selecting chemical reagents in measurement of asphalt surface energy are provided. The method includes: selecting different chemical reagents and obtaining contact angle values formed between the respective chemical reagents and asphalt slides; obtaining asphalt surface energy parameters corresponding to each of combinations of the chemical reagents according to the contact angle values; obtaining variation coefficients of the asphalt surface energy parameters corresponding to each of the combinations of the chemical reagents and selecting a group of combinations of the chemical reagents according to the variation coefficients; and obtaining numbers of abnormal values of asphalt surface energy components in the group of combinations of the chemical reagents and obtaining a target combination of the chemical reagents according to the numbers of the abnormal values. The combination of the chemical reagents with high stability of testing data can be selected by using the method.

Systems, methods, and apparatus for a three-dimensional (3D)-printed vessel for wettability assessment of fracturing proppants are disclosed. The vessel includes a base component including a threaded cylindrical portion extending outward from a first side of the base component. The cylindrical portion has a particular thread profile. The base component defines a cavity sized to contain a proppant sample. A cap is configured to be screwed onto the threaded cylindrical portion after the proppant sample is injected into the cavity. A surface of the cap is shaped to flatten a proppant surface of the proppant sample. The cap is threaded with the particular thread profile. A pin is configured to be partially screwed onto a second side of the base component before the proppant sample is injected into the cavity. The second side is opposite to the first side. Other embodiments may be described or claimed.

Methods, systems, and apparatus for analytical wettability assessment of fracturing proppants for improving fluid recovery are disclosed. Embodiments include determining, for a proppant sample, a first value related to an oil-wet index of the proppant sample. Embodiments further include determining, for the proppant sample, a second value related to a water-wet index of the proppant sample. Embodiments further include determining, for the proppant sample based on the first value and the second value, a third value related to a wettability index of the proppant sample. Embodiments further include determining, based on the third value, a wetting characteristic of the proppant sample. Other embodiments may be described.