Abstract: The tool assembly vibrates a casing string or drill string in a wellbore. The tool assembly includes a housing, an insert mounted in the housing as a fluidic agitator, and a cover fitted over the insert. The insert includes an inlet chamber, a vortex chamber, and a feedback chamber, and the fluid flow through the insert has a pressure profile with a plurality of levels determined by the feedback chamber. The strength and frequency of the pressure profile can be regulated by the feedback chamber according to position, size and asymmetry of the transition channels connected to the feedback chamber. The high strength and low frequency pressure pulses can be achieved in the limited space of the housing for placement of the inlet and outlet.

Abstract: A surfactant that changes the wettability of tight sandstone and its preparation method and application. By adding the aqueous phase solution into the oil phase solution, and under the action of the emulsifier, a uniformly dispersed phase is achieved. Then adding initiator, stirring and raising the temperature, reacting the reaction at the temperature to obtain a colorless and transparent liquid, i.e., high polymer. At room temperature, adding fluorocarbon surfactant and biosurfactant and stirring was continued for 4 hours to obtain a surfactant that changes the surface wettability of tight sandstone. The surfactant of the present invention can reduce the oil-water interfacial tension, transform the oil-wet surface into water-wet surface, which reduces the adhesion of oil droplets to rock surface and improves the flowability of crude oil in the original stratum, and improves the recovery of low-permeability reservoir.

Abstract: The tool assembly vibrates a casing string or drill string in a wellbore. The tool assembly includes a housing, an insert mounted in the housing as a fluidic agitator, and a cover fitted over the insert. The insert includes an inlet chamber, a vortex chamber, and a feedback chamber, and the fluid flow through the insert has a pressure profile with a plurality of levels determined by the feedback chamber. The strength and frequency of the pressure profile can be regulated by the feedback chamber according to position, size and asymmetry of the transition channels connected to the feedback chamber. The high strength and low frequency pressure pulses can be achieved in the limited space of the housing for placement of the inlet and outlet.

Abstract: The tool assembly vibrates a casing string or drill string in a wellbore. The tool assembly includes a housing, an insert mounted in the housing as a fluidic agitator, and a cover fitted over the insert. The insert includes an inlet chamber, a vortex chamber, and a feedback chamber, and the fluid flow through the insert has a pressure profile with a plurality of levels determined by the feedback chamber. The strength and frequency of the pressure profile can be regulated by the feedback chamber according to position, size and asymmetry of the transition channels connected to the feedback chamber. The high strength and low frequency pressure pulses can be achieved in the limited space of the housing for placement of the inlet and outlet.

Abstract: The tool assembly vibrates a casing string or drill string in a wellbore. The tool assembly includes a housing, an insert mounted in the housing as a fluidic agitator, and a cover fitted over the insert. The insert includes an inlet chamber, a vortex chamber, and a feedback chamber, and the fluid flow through the insert has a pressure profile with a plurality of levels determined by the feedback chamber. The strength and frequency of the pressure profile can be regulated by the feedback chamber according to position, size and asymmetry of the transition channels connected to the feedback chamber. The high strength and low frequency pressure pulses can be achieved in the limited space of the housing for placement of the inlet and outlet.

Abstract: A surfactant that changes the wettability of tight sandstone and its preparation method and application. By adding the aqueous phase solution into the oil phase solution, and under the action of the emulsifier, a uniformly dispersed phase is achieved. Then adding initiator, stirring and raising the temperature, reacting the reaction at the temperature to obtain a colorless and transparent liquid, i.e., high polymer. At room temperature, adding fluorocarbon surfactant and biosurfactant and stirring was continued for 4 hours to obtain a surfactant that changes the surface wettability of tight sandstone. The surfactant of the present invention can reduce the oil-water interfacial tension, transform the oil-wet surface into water-wet surface, which reduces the adhesion of oil droplets to rock surface and improves the flowability of crude oil in the original stratum, and improves the recovery of low-permeability reservoir.