Abstract: Drill string flow control valves and more particularly, drill string flow control valves for prevention of u-tubing of fluid flow in drill strings are provided. Drill string flow control valves may comprise a valve housing, a valve sleeve axially movable within a valve housing from a closed position to an open position, a piston axially movable within said valve housing and bearing against the valve sleeve, a biasing mechanism for biasing the valve sleeve into the closed position, a static pressure port for actuating said piston utilizing internal fluid pressure within said valve and a plurality of dynamic pressure ports for allowing a differential pressure to be exerted on the valve sleeve during dynamic flow conditions. The differential pressure exerted on the valve sleeve may be the result of an upstream pressure and a downstream pressure during fluid flow through said valve.

Abstract: Drill string flow control valves and more particularly, drill string flow control valves for prevention of u-tubing of fluid flow in drill strings are provided. Drill string flow control valves may comprise a valve housing, a valve sleeve axially movable within a valve housing from a closed position to an open position, a piston axially movable within said valve housing and bearing against the valve sleeve, a biasing mechanism for biasing the valve sleeve into the closed position, a static pressure port for actuating said piston utilizing internal fluid pressure within said valve and a plurality of dynamic pressure ports for allowing a differential pressure to be exerted on the valve sleeve during dynamic flow conditions. The differential pressure exerted on the valve sleeve may be the result of an upstream pressure and a downstream pressure during fluid flow through said valve.

Abstract: Drill string flow control valves and more particularly, drill string flow control valves for prevention of u-tubing of fluid flow in drill strings are provided. Drill string flow control valves may comprise a valve housing, a valve sleeve axially movable within a valve housing from a closed position to an open position, a piston axially movable within said valve housing and bearing against the valve sleeve, a biasing mechanism for biasing the valve sleeve into the closed position, a static pressure port for actuating said piston utilizing internal fluid pressure within said valve and a plurality of dynamic pressure ports for allowing a differential pressure to be exerted on the valve sleeve during dynamic flow conditions. The differential pressure exerted on the valve sleeve may be the result of an upstream pressure and a downstream pressure during fluid flow through said valve.

Abstract: Drill string flow control valves and more particularly, drill string flow control valves for prevention of u-tubing of fluid flow in drill strings are provided. Drill string flow control valves may comprise a valve housing, a valve sleeve axially movable within a valve housing from a closed position to an open position, a piston axially movable within said valve housing and bearing against the valve sleeve, a biasing mechanism for biasing the valve sleeve into the closed position, a static pressure port for actuating said piston utilizing internal fluid pressure within said valve and a plurality of dynamic pressure ports for allowing a differential pressure to be exerted on the valve sleeve during dynamic flow conditions. The differential pressure exerted on the valve sleeve may be the result of an upstream pressure and a downstream pressure during fluid flow through said valve.

Abstract: A method and apparatus for controlling drilling mud density at a location either at the seabed (or just above the seabed) or alternatively below the seabed of wells in deep water and ultra deep water applications combines a base fluid of lesser density than the mud required at the wellhead to produce a diluted mud in the riser. By combining the appropriate quantities of drilling mud with base fluid, a riser mud density at or near the density of seawater may be achieved. A wellhead injection device for attachment to the wellhead is used for injecting the base fluid into the rising drilling mud at a location below the seabed. The riser charging lines are used to carry the low density base fluid to the injection device for injection into the drilling mud below the seabed. The cuttings are brought to the surface with the diluted mud and separated in the usual manner. The diluted mud is then passed through a centrifuge system to separate the heavier drilling mud from the lighter base fluid.

Abstract: A method and apparatus for controlling drilling mud density at a location either at the seabed (or just above the seabed) or alternatively below the seabed of wells in deep water and ultra deep water applications are disclosed. The present invention combines a base fluid of lesser density than the mud required at the wellhead to produce a diluted mud in the riser. By combining the appropriate quantities of drilling mud with base fluid, a riser mud density at or near the density of seawater may be achieved. The present invention also includes a wellhead injection device for attachment to the wellhead and for injecting the base fluid into the rising drilling mud at a location below the seabed. The riser charging lines are used to carry the low density base fluid to the injection device for injection into the drilling mud below the seabed. The cuttings are brought to the surface with the diluted mud and separated in the usual manner.

Abstract: A method and apparatus for controlling drilling mud density at or near the seabed of wells in deep water and ultra deep-water applications combines a base fluid of lesser density than the mud required at the wellhead to produce a diluted mud in the riser. By combining the appropriate quantities of drilling mud with base fluid, a riser mud density at or near the density of seawater may be achieved. No additional hardware is required below the surface. The riser charging lines are used to inject the low-density base fluid at or near the BOP stack on the seabed. The cuttings are brought to the surface with the diluted mud and separated in the usual manner. The diluted mud is then passed through a centrifuge system to separate the heavier drilling mud from the lighter base fluid.

Abstract: A method and apparatus for controlling drilling mud density at or near the seabed of wells in deep water and ultra deep-water applications combines a base fluid of lesser density than the mud required at the wellhead to produce a diluted mud in the riser. By combining the appropriate quantities of drilling mud with base fluid, a riser mud density at or near the density of seawater may be achieved. No additional hardware is required below the surface. The riser charging lines are used to inject the low-density base fluid at or near the BOP stack on the seabed. The cuttings are brought to the surface with the diluted mud and separated in the usual manner. The diluted mud is then passed through a centrifuge system to separate the heavier drilling mud from the lighter base fluid.