Apparatus and method for controlling the flow of fluids from a well bore

A valve for controlling and varying the quantity of a liquid flowing therethrough which comprises (a) a valve housing having an inlet and an outlet, said outlet defining an axial bore and (b) a bolt-like plug means axially aligned with and movable within said bore, said bore and said plug means cooperating to form a helical flow path through said outlet, which flow path has a decreasing flow area as said plug means is further inserted within said bore.

Choke valve means for controlling the flow of a fluid which comprises a valve housing having an inlet and an outlet defined therein, and a movable solid bolt-like plug means cooperating with said outlet to selectively engage and disengage with said outlet and having threads thereon to define with said outlet a helical dust when said plug is engaged in said outlet through which said fluid passes, and an abutment head on said plug means to engage with said outlet to completely close the valve when said plug means is fully inserted within said outlet.

Choke means for controlling the flow in a well choking system comprising:

• a choke line of the type used in well drilling operations;
• a choke valve means in said choke line adapted to pass fluid from a well bore therethrough, comprising a valve housing having an inlet and an outlet defined therein, each cooperating with said choke line, a movable bolt-like plug means cooperating with said outlet to selectively engage and disengage with said outlet, a spiral groove defined in the surface of said outlet in said housing and cooperating with said movable plug means to define a spiral duct in said outlet when said plug means is engaged in said outlet through which said fluid passes, a piston means controlling the movement of said movable plug, and a surface means associated with said plug means and said piston means which is instantaneously responsive to a change in pressure at said valve inlet to move said plug means within said outlet in a direction to dissipate said pressure change.

Choke means for controlling the flow in a well choking system including:

• a choke line of the type used in well drilling operations;
• and
• a choke valve means in said choke line adapted to pass fluid from a well bore therethrough, comprising a valve housing, having an inlet and an outlet defined therein, each cooperating with said choke line, a movable solid bolt-like plug means cooperating with said outlet to selectively engage and disengage with said outlet, said plug means having thread means thereon to define with said outlet a spiral duct when said plug means is received in said outlet through which said fluid passes, and a piston means controlling the movement of said movable plug means, said piston means comprising an essentially cylindrical piston shaft and said plug means having a generally cylindrical bolt-like plug head section whose diameter is smaller than the diameter of said piston shaft.

In combination with a choke means for a well choking system having a choke valve comprising a movable plug means for controlling well bore pressure and a piston for controlling the movement of said movable plug means, an indicating system containing hydraulic fluid, said system indicating the position of said movable plug means and comprising an accumulator means, a pressure gauge means, a fluid pressure generating means responsive to the relative position of said movable plug means, and fluid connecting means establishing fluid communication between said gauge means, said accumulator means and said fluid pressure generating means whereby movement of said plug means automatically alters the pressure within said gauge means.

A method of controlling well bore pressure comprising the steps of:

• providing a chamber having an inlet and an outlet in the flow path of fluid exiting a well bore;
• causing said fluid to flow through an elongated duct in said outlet to control the flow conditions therethrough and the fluid pressure in the chamber and
• instantaneously changing the length of said elongated duct in response to changes in the pressure in said chamber in a manner to dissipate said pressure changes and thereby control the pressure in said well bore.

Choke means for controlling the flow in a well choking system including a choke line of the type used in well drilling operations and a choke valve means in said choke line adapted to pass fluid from a well bore therethrough, comprising means defining a valve chamber having an inlet and an outlet, said outlet defined by an axial bore, and a movable rod means having at least two generally cylindrical, axially aligned sections, one section having a smaller diameter and the other section having a larger diameter to define an annular surface therebetween, the smaller diameter section received within said outlet bore to define a flow path through said outlet determined by the relative position of said smaller diameter section in said outlet bore and said annular surface being responsive to a change in pressure in said valve chamber to automatically move said rod means within said outlet bore in a direction to dissipate said pressure change.