Rotary flow control apparatus
A rotary flow control apparatus may comprise a rotary drive mechanism coupled to a ball controller comprising a ball disposed within a cavity. The apparatus may be disposed within a tubing string in a wellbore. Fluid flow is provided though the tubing, causing the rotation of the rotary drive mechanism. The flow passes through a ball cage above a seat disc that incorporates a flow port. The ball orbits around the cavity in response to the motion of an axially extending surface or “kicker.” When the ball obstructs the flow port, it substantially blocks the flow of fluid through the assembly, generating a water hammer impulse in the tubing above the rotary drive mechanism. The rotating kicker moves the ball off the flow port at one angular position and then allows the ball to reseat at a second angular position.
1 . A flow control apparatus comprising:
a central longitudinal axis;
a flow inlet;
a flow outlet;
a flow port disposed between the flow inlet and the flow outlet;
a ball configured to intermittently obstruct at least a portion of a flow of fluid through the flow port;
a ball controller configured to rotate about the central longitudinal axis and comprising:
a volume within which the ball is disposed;
a lower radial surface; and
a surface axially extending from the lower radial surface;
a rotary drive mechanism coupled to the ball controller and configured such that, during each rotation, the ball controller will have:
a first angular position in which the ball at least partially obstructs the flow port; and
a second angular position in which the ball does not obstruct the flow port.
2 . The flow control apparatus of claim 1 , wherein the rotary drive mechanism is further configured such that, during each rotation, the ball controller will have a third angular position in which the ball is able to move freely toward the flow port.
3 . The flow control apparatus of claim 2 , wherein the ball at least partially obstructs the flow port when the ball controller is in the third angular position.
4 . The flow control apparatus of claim 1 , further comprising a bypass port that allows fluid to flow from the inlet to the outlet when the ball controller is in the first angular position.
5 . The flow control apparatus of claim 1 , wherein the rotary drive mechanism comprises a positive displacement power section.
6 . The flow control apparatus of claim 5 , wherein the positive displacement power section comprises:
a rotor comprising four lobes; and
a stator comprising five lobes.
7 . The flow control apparatus of claim 1 , wherein the rotary drive mechanism is rigidly coupled to the ball controller.
8 . The flow control apparatus of claim 1 , wherein the rotary drive mechanism is flexibly coupled to the ball controller.
9 . The flow control apparatus of claim 1 , further comprising an expanding, conical passage disposed between the flow port and the outlet.
10 . The flow control apparatus of claim 1 , wherein the ball controller further comprises a removeable wear insert.
11 . The flow control apparatus of claim 1 , further comprising a wear ring disposed within the flow port.
12 . The flow control apparatus of claim 1 , wherein the ball is formed from one of carbide cermet, silicon nitride, or zirconia.
13 . The flow control apparatus of claim 1 , further comprising a seat disc in which the flow port is disposed.
14 . A method of generating pressure pulses in a wellbore, the method comprising:
introducing into the wellbore a flow control apparatus comprising:
a central longitudinal axis;
a flow inlet;
a flow outlet;
a flow port disposed between the flow inlet and the flow outlet;
a ball configured to intermittently obstruct at least a portion of a flow of fluid through the flow port;
a ball controller configured to rotate about the central longitudinal axis and comprising:
a volume within which the ball is disposed;
a lower radial surface; and
a surface axially extending from the lower radial surface;
a rotary drive mechanism coupled to the ball controller and configured such that, during each rotation, the ball controller will have:
a first angular position in which the ball at least partially obstructs the flow port; and
a second angular position in which the ball does not obstruct the flow port; and
pumping fluid into the wellbore and through the inlet, causing rotation of the rotary drive mechanism and the ball controller, such that obstruction of fluid flow through the flow port when the ball controller rotates through the first angular position generates a pressure pulse.
15 . The method of claim 14 , wherein the flow control apparatus further comprises a bypass port that allows fluid to flow from the inlet to the outlet when the ball controller is in the first angular position.
16 . The method of claim 14 , wherein the rotary drive mechanism comprises a positive displacement power section.
17 . The method of claim 14 , wherein the rotary drive mechanism is rigidly coupled to the ball controller.
18 . The method of claim 14 , wherein the flow control apparatus further comprises an expanding, conical passage disposed between the flow port and the outlet.
19 . A method of extending the reach of tubing within a wellbore, the method comprising:
introducing into the wellbore a section of tubing which includes a flow control apparatus comprising:
a central longitudinal axis;
a flow inlet;
a flow outlet;
a flow port disposed between the flow inlet and the flow outlet;
a ball configured to intermittently obstruct at least a portion of a flow of fluid through the flow port;
a ball controller configured to rotate about the central longitudinal axis and comprising:
a volume within which the ball is disposed;
a lower radial surface; and
a surface axially extending from the lower radial surface;
a rotary drive mechanism coupled to the ball controller and configured such that, during each rotation, the ball controller will have:
a first angular position in which the ball at least partially obstructs the flow port; and
a second angular position in which the ball does not obstruct the flow port; and
pumping fluid into the tubing and through the inlet, causing rotation of the rotary drive mechanism and the ball controller, such that obstruction of fluid flow through the flow port when the ball controller rotates through the first angular position generates a pressure pulse;
wherein the pressure pulse generated by the flow control apparatus creates a net downhole force thereby moving the tubing farther into the wellbore.
20 . The method of claim 19 , wherein the rotary drive mechanism comprises a positive displacement power section.