The method includes installation in a well of a high strength tubing, a mechanical anchoring device, a turning device, a sealing device, a deflector, a circulation unit, a packer and a re-entry guide, a running hydromonitor nozzle, a wellbore trajectory control module, a navigation system, work and supply coil tubing sections, a flow re-distribution device, a check valve. By aerated fluid supply into an annulus between tubing and coil tubing and running coiled tubing, hydromonitor underbalance drilling of planned length of controlled radial channel in the formation is performed. Fluid with cuttings coming out the well through annulus between tubing and casing string, cleaned at surface and circulated back. After work coil tubing section retrieval from the formation and well underbalance circulation, the deflector is re-positioned to a different plane by mechanical turning device; the working cycle is repeated for the next radial channel. Milling of windows for all radial channels is performed before drilling stage, all subsequent works performed without well killing.

A multi-fluid drilling system 10 drilling is disclosed for drilling a hole or well 11. The system 10 is coupled to a dual wall drill string 12. The drill string 12 is configured to enable separate flow of a first fluid 14 and a second fluid 16. The system 10 has a hammer 22 and a downhole motor 24. Both the hammer 22 and the motor 24 are supported by and are coupled to the drill string 12. The motor 24 is uphole of the hammer 22. The hammer 22 is arranged so that when supported by the drill string 12 the first fluid 14 when flowing through the drill string 12 is able to flow to and power the hammer 22. As the motor 24 is disposed between the hammer 22 and the drill string 12 the first fluid 14 is also able to flow through the motor 24. To this end the motor 24 has a channel 25 to enable the first fluid to flow from the drill sting 12 to the hammer 22. The channel 25 acts as a part of a flow path or conduit for the first fluid 14.

A ball drop two stage valve includes a tubular having a body defined by an outer surface and an inner surface that defines a fluid flow path. A stimulation port is formed in the body. The stimulation port extends through the body. At least one flow port is formed in the body longitudinally spaced from the stimulation port. The at least one flow port extends through the body. A first sleeve is slidingly positioned along the fluid flow path in the body. The first sleeve includes a first ball seat and is selectively positionable to selectively block flow through the stimulation port. A second sleeve is slidingly positioned along the fluid flow path in the body. The second sleeve includes a second ball seat and is selectively positionable to selectively block flow through the flow port and the stimulation port.

A ball drop two stage valve includes a tubular having a body defined by an outer surface and an inner surface that defines a fluid flow path. A stimulation port is formed in the body. The stimulation port extends through the body. At least one flow port is formed in the body longitudinally spaced from the stimulation port. The at least one flow port extends through the body. A first sleeve is slidingly positioned along the fluid flow path in the body. The first sleeve includes a first ball seat and is selectively positionable to selectively block flow through the stimulation port. A second sleeve is slidingly positioned along the fluid flow path in the body. The second sleeve includes a second ball seat and is selectively positionable to selectively block flow through the flow port and the stimulation port.

An apparatus for continuously generating and controlling the density of foam has a fluid in-flow manifold in communication with a source of liquid and comprising a pressure sensor. A plurality of branch lines are in fluid communication with the in-flow manifold a foam out-flow manifold. Each branch line has a flow control valve, a Venturi tube and in fluid communication with a throat of each Venturi tube an air induction control valve. The foam out-flow manifold has a pressure sensor. At least one in-flow control valve is disposed between the source and the in-flow manifold and at least one out-flow control valve is in communication with the out-flow manifold. The branch valves, air valves, the in-flow control valve and the out-flow control valve are operable to provide a chosen flow rate of the liquid and a selected foam product flow rate at a selected density of the foam product.

An apparatus for continuously generating and controlling the density of foam has a fluid in-flow manifold in communication with a source of liquid and comprising a pressure sensor. A plurality of branch lines are in fluid communication with the in-flow manifold a foam out-flow manifold. Each branch line has a flow control valve, a Venturi tube and in fluid communication with a throat of each Venturi tube an air induction control valve. The foam out-flow manifold has a pressure sensor. At least one in-flow control valve is disposed between the source and the in-flow manifold and at least one out-flow control valve is in communication with the out-flow manifold. The branch valves, air valves, the in-flow control valve and the out-flow control valve are operable to provide a chosen flow rate of the liquid and a selected foam product flow rate at a selected density of the foam product.

Systems and methods for measuring the viscosity of a fluid may comprise a rotor cup having an inner chamber; a first bob rotatably disposed within a first region of the inner chamber; and a second bob rotatably disposed within a second region of the inner chamber, wherein the second bob rotates relative to the first bob based on a difference in viscosity of fluid in the first region and the second region.

A system for use in the drilling of oil or gas wells in conjunction with a mud injection device, said mud injection device adapted to maintain fluid pressure control within the borehole of a well bore when operating a drillstring therethrough, the system comprising: a gas reservoir containing gas; adapted for injection to control borehole pressure; compression system fluidly connected to the gas reservoir and the borehole; a pressure regulation system operatively connected to the gas reservoir and the borehole and adapted to measure the pressure within the annulus and relay such to a computer; wherein, when a drilling operation is halted to add a new stand to the drillstring and the mud injection device is stopped, the gas is injected to maintain the borehole pressure within the annulus of the borehole at a near constant value.

A method for conducting a wellbore operation includes drilling a wellbore through one or more hydrocarbon bearing subterranean formations with a drill bit arranged at an end of a drill string, wherein an annulus is defined between the drill string and an inner wall of the wellbore. A foam is generated with a foam generator of an annular injection system in communication with the annulus, and the foam is introduced into the annulus with the annular injection system.

A method for conducting a wellbore operation includes drilling a wellbore through one or more hydrocarbon bearing subterranean formations with a drill bit arranged at an end of a drill string, wherein an annulus is defined between the drill string and an inner wall of the wellbore. A foam is generated with a foam generator of an annular injection system in communication with the annulus, and the foam is introduced into the annulus with the annular injection system.