A method of determining foam stability includes placing a core plug and two porous plates into a core holder of a vesselcore plug. The first porous plate and the second porous plate are disposed on opposite sides of the core plug, and the core plug, the first porous plate, and the second porous plate are saturated with surfactant. The method further includes alternating surfactant solution injections between a first injection area located on the first porous plate and a second injection area located on the second porous plate, while ensuring that the surfactant solution is being continuously fed, thereby forming continuously flowing foam in-situ within the core plug, in which the surfactant solution comprises gas and the surfactant; and monitoring the pressure drop to determine the stability of the foam in the core plug.

Tools, methods, and systems for evaluating a demulsifier performance from an emulsion mixture are described. The systems include a measuring instrument including a body with an open end, a cover attachable to the body, a sample holder sized to hold the emulsion mixture and to be received inside the body, the body and the cover define a sealable chamber; a sensor system positioned inside the sealable chamber an environmental control system positioned to enclose the sealable chamber; a data acquisition and processing system is in electronic communication with the sealable chamber, the sensor system, and the environmental control system. The sensor system includes a handle attached to and extruding from the cover of the measuring instrument; and a sensor loaded onto the handle, sized to be submerged inside the emulsion mixture of the sample holder, and operable to measure performance of the demulsifier.

Tools, methods, and systems for evaluating a demulsifier performance from an emulsion mixture are described. The systems include a measuring instrument including a body with an open end, a cover attachable to the body, a sample holder sized to hold the emulsion mixture and to be received inside the body, the body and the cover define a sealable chamber; a sensor system positioned inside the sealable chamber an environmental control system positioned to enclose the sealable chamber; a data acquisition and processing system is in electronic communication with the sealable chamber, the sensor system, and the environmental control system. The sensor system includes a handle attached to and extruding from the cover of the measuring instrument; and a sensor loaded onto the handle, sized to be submerged inside the emulsion mixture of the sample holder, and operable to measure performance of the demulsifier.

Methods and apparatuses for determining surface wetting of metallic materials at downhole wellbore condition with fixed or changing well fluids are disclosed. In general, the methods according to the disclosure include carrying out an electrical impedance spectroscopy (“EIS”) for a system simulating downhole conditions for the wetting of a surface by simultaneously dynamically moving electrodes exposed to the well fluid while measuring the changes in electrical characteristics between the electrodes.

Methods and apparatuses for determining surface wetting of metallic materials at downhole wellbore condition with fixed or changing well fluids are disclosed. In general, the methods according to the disclosure include carrying out an electrical impedance spectroscopy (“EIS”) for a system simulating downhole conditions for the wetting of a surface by simultaneously dynamically moving electrodes exposed to the well fluid while measuring the changes in electrical characteristics between the electrodes.

A method and testing apparatus determine receding contact angles of liquids on surfaces by depositing a liquid in a manner whereby the volume of the drop is increased through stepwise addition of smaller drops. Each increment of volume growth causes the perimeter of the drop to advance across the surface. The incremental volume elements impart sufficient energy to the growing drop such that the drop perimeter expands beyond its equilibrium diameter for that volume. The drop perimeter tends to contract between volume additions as the excess energy is dissipated. The method and testing apparatus determine the receding contact angle between the incremental volume additions.

A method and testing apparatus determine receding contact angles of liquids on surfaces by depositing a liquid in a manner whereby the volume of the drop is increased through stepwise addition of smaller drops. Each increment of volume growth causes the perimeter of the drop to advance across the surface. The incremental volume elements impart sufficient energy to the growing drop such that the drop perimeter expands beyond its equilibrium diameter for that volume. The drop perimeter tends to contract between volume additions as the excess energy is dissipated. The method and testing apparatus determine the receding contact angle between the incremental volume additions.

Tensiometer device for measuring soil water tension. A pair of screws secures a load cell or strain gauge to an inner frame, a dowel pin transmits force to the load cell, a polymer chamber is enclosed on one side by a rubber dam that retains the polymer within the polymer chamber, and a hydrophilic porous window covers the rubber dam. A second pair of screws secure an outer frame to the inner frame holding the components of one or more tensiometers spaced across the frame, and an end cap. The load cell acts as a strain gauge transferring the force exerted on it as a change in electrical voltage that can be converted to a soil water tension (SWT) measurement.

Various examples are provided related to determination of contact angle of sessile drops. In one example, a method includes determining a volume of a sessile drop of fluid disposed on a test surface; determining a height of the sessile drop of fluid; and determining a contact angle of the sessile drop of fluid based upon the volume and the height of the sessile drop. In another example, a system includes a volume sensing, a height sensing, and computing that can determine a volume and height of a sessile drop using volume and height data from the sensing, and determine a contact angle of the sessile drop with the volume and the height. The contact angle and surface tension can be determined with at least three of volume, a height, a footprint radius, a radius of maximum horizontal extent, and/or an apex radius of curvature of the drop.

Various examples are provided related to determination of contact angle of sessile drops. In one example, a method includes determining a volume of a sessile drop of fluid disposed on a test surface; determining a height of the sessile drop of fluid; and determining a contact angle of the sessile drop of fluid based upon the volume and the height of the sessile drop. In another example, a system includes a volume sensing, a height sensing, and computing that can determine a volume and height of a sessile drop using volume and height data from the sensing, and determine a contact angle of the sessile drop with the volume and the height. The contact angle and surface tension can be determined with at least three of volume, a height, a footprint radius, a radius of maximum horizontal extent, and/or an apex radius of curvature of the drop.