A vortex-controlled variable flow resistance device ideal for use in a backpressure tool for advancing drill string in extended reach downhole operations. The characteristics of the pressure waves generated by the device are controlled by the growth and decay of vortices in the vortex chamber(s) of a flow path. The flow path includes a switch, such as a bi-stable fluidic switch, for reversing the direction of the flow in the vortex chamber. The flow path may include multiple vortex chambers, and the device may include multiple flow paths. A hardened insert in the outlet of the vortex chamber resists erosion. This device generates backpressures of short duration and slower frequencies approaching the resonant frequency of the drill string, which maximizes axial motion in the drill sting and weight on the bit. Additionally, fluid pulses produced by the tool enhance debris removal ahead of the bit.

Example apparatus for regulator heat transfer are disclosed. An example apparatus includes a housing including an inlet, an outlet, a first valve, and a stem disposed therein. The example apparatus includes a vortex generator disposed in the housing. A fluid is to flow from the inlet through the vortex generator. The example apparatus includes a second valve disposed in the vortex generator. In the example apparatus, the vortex generator is to generate heat prior to the fluid flowing through the second valve to the outlet. The stem is to control the first valve and the second valve to regulate an amount of the heat conveyed to the first valve.

Example apparatus for regulator heat transfer are disclosed. An example apparatus includes a regulator including a body, a stem disposed therein, a first inlet and a first outlet. The regulator regulates a pressure of a fluid flowing from the first inlet to the first outlet. The example apparatus comprises a vortex generator disposed within the body to convey heat to a valve of the regulator. The stem controls the regulator and the vortex generator.

Example apparatus for regulator heat transfer are disclosed. An example apparatus includes a housing including an inlet, an outlet, a first valve, and a stem disposed therein. The example apparatus includes a vortex generator disposed in the housing. A fluid is to flow from the inlet through the vortex generator. The example apparatus includes a second valve disposed in the vortex generator. In the example apparatus, the vortex generator is to generate heat prior to the fluid flowing through the second valve to the outlet. The stem is to control the first valve and the second valve to regulate an amount of the heat conveyed to the first valve.

A vortex-controlled variable flow resistance device ideal for use in a backpressure tool for advancing drill string in extended reach downhole operations. The characteristics of the pressure waves generated by the device are controlled by the growth and decay of vortices in the vortex chamber(s) of a flow path. The flow path includes a switch, such as a bi-stable fluidic switch, for reversing the direction of the flow in the vortex chamber. The flow path may include multiple vortex chambers, and the device may include multiple flow paths. A hardened insert in the outlet of the vortex chamber resists erosion. This device generates backpressures of short duration and slower frequencies approaching the resonant frequency of the drill string, which maximizes axial motion in the drill sting and weight on the bit. Additionally, fluid pulses produced by the tool enhance debris removal ahead of the bit.