Hydraulic cushion

Patent metadata

Field	Value
Publication number	US-9534458-B2
Application number	US-201314020568-A
Country	US
Kind code	B2
Filing date	Sep 6, 2013
Priority date	Mar 15, 2013
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

Drilling mud is lifted subsea to a drilling vessel with a mud pump having an internal bladder. Applying pressurized water to one side of the bladder urges it against a quantity of the mud to impart a lifting force onto the mud. Mud flow to and from the pump is controlled by valves driven by actuators. The actuators include a piston in a cylinder, a stem that connects the piston to a valve member, and ports for supplying fluid to opposing ends of the piston for selectively reciprocating the piston. Cavities are strategically location in the cylinder for absorbing vibrational forces generated when the piston reaches an end of its stroke.

First claim

What is claimed is:

1. A system for lifting drilling mud from a subsea wellbore comprising:
a mud pump selectively disposed subsea;
a valve in a flow line that contains drilling mud from the wellbore; and
an actuator coupled with the valve comprising,
an actuator body,
a valve body coupled to the actuator body,
a cylinder in the actuator body having a first end and a second end,
a piston in the cylinder, the piston having a first end, a second end, and a stem extending from the second end of the piston into the valve body,
first and second inlet ports in the actuator body to allow ingress of hydraulic fluid into the cylinder to stroke the piston axially within the cylinder between a maximum second end position and a maximum first end position, respectively,
the first end of the piston being closer to the first end of the cylinder than the first inlet port while the piston is in the maximum first end position, and
a first end cavity projecting beyond the first end of the cylinder and in unrestricted communication with the cylinder, the first end cavity being located beyond the first end of the piston while the piston is in the maximum first position.

2. The system of claim 1 , further comprising:
an annular recess formed in an inner diameter of the actuator body that surrounds an outer diameter of the cylinder, the first inlet port extending through a side wall of the actuator body into the recess and from the recess through a side wall of the cylinder into an interior of the cylinder.

3. The system of claim 1 , wherein the cylinder comprises a sleeve disposed within the actuator body.

4. The system of claim 1 , wherein the first end cavity has a frustoconical side wall that projects axially away from the first end of the cylinder in a first direction and a closed end at a first end of the frustoconical side wall.

5. The system of claim 1 , further comprising a second end annular recess between an outer diameter of the cylinder and an inner diameter of the actuator body, the second inlet port extending through actuator body into the recess and from the recess through a side wall of the cylinder into an interior of the cylinder.

6. The system of claim 1 , wherein the mud pump comprises a housing with a bladder disposed inside to define a water space on one side that is in communication with a water supply line and a water discharge line, and a mud space on an opposite side that is in communication with a mud supply line and a mud discharge line, and wherein selectively providing pressurized water in the water supply line pressurizes mud in the mud space.

7. A system for lifting drilling mud from a subsea wellbore comprising:
a mud pump comprising,
a housing;
a water space in the housing;
a mud space in the housing that is in pressure communication with the water space;
a bladder mounted in the housing having a side in contact with the water space and an opposing side in contact with the mud space, and that defines a flow barrier between the water and mud space;

a mud valve disposed in a line having drilling mud and that is in communication with the mud space; and
a hydraulic actuator coupled with the mud valve, having an actuator body, a cylinder mounted within the actuator body, a piston that reciprocates in the cylinder, up stroke and down stroke inlet ports that extend through a side wall of the actuator body and through a side wall of the cylinder to allow ingress of hydraulic fluid into the cylinder to urge the piston axially within the cylinder between a maximum up stroke position and a maximum down stroke position, and up stroke and down stroke cavities in the actuator body proximate up stroke and down stroke ends of the cylinder, respectively so that when the piston is at the maximum up stroke and maximum down stroke positions, hydraulic fluid pools in the up stroke and down stroke cavities, respectively to define a cushion that absorbs energy from a deceleration of the piston; wherein

each of the up stroke and the down stroke cavities comprises an annular recess located between an inner diameter of the actuator body and an outer diameter of the cylinder, and
each of the up stroke and down stroke inlet ports extends into one of the recesses.

8. The system of claim 7 , wherein the up stroke cavity further comprises an upper chamber that projects upward from the up stroke end of the cylinder, the upper chamber having a closed upper end spaced above the piston while the piston is in the maximum up stroke position.

9. The system of claim 8 , wherein the down stroke inlet port extends through the cylinder at a point below an upper end of the piston while the piston is in the maximum up stroke position.

10. The system of claim 8 , wherein the upper chamber has a frustoconical side wall.

11. The system of claim 7 , wherein the mud valve comprises a mud inlet valve that is disposed in the line between mud flowing from the wellbore and to the mud pump.

12. The system of claim 7 , wherein the mud valve comprises a mud outlet valve that is disposed in the line between the mud pump and sea surface.

13. The system of claim 7 , wherein the mud pump further comprises,
a water inlet line having an entrance in selective communication with a source of pressurized water, and an exit in communication with the water space; and
a water discharge line having an entrance in communication with the water space, and an exit in selective communication with a water effluent line.

14. The system of claim 7 , further comprising an annular seal ring located between the outer diameter of the cylinder and the inner diameter of the actuator body at a point between the up stroke and the down stroke cavities.

15. A system for lifting drilling mud from a subsea wellbore comprising:
a mud pump selectively disposed subsea that connects with a mud supply line that contains mud from the wellbore, and that connects to a discharge line having drilling mud discharged from the pump and that terminates above sea surface;
a selectively openable and closeable mud inlet valve in the mud supply line; and
an actuator comprising,
a body,
a cylinder mounted in the body, the cylinder having an axis, a first end and a second end,
a piston reciprocatingly disposed in the cylinder, the piston having a first end and a second end,
a first end inlet port and a second end inlet port extending through a side wall of the body and through a side wall of the cylinder to allow ingress of hydraulic fluid into the cylinder to stroke the piston axially within the cylinder between a maximum first end position and a maximum second end position,
a stem connected between the piston and a valve member in the mud inlet valve, and
a first end chamber at the first end of the cylinder and extending axially from the first end of the piston while the piston is in the maximum first end position,
an annular first end recess between an outer diameter of the cylinder and an inner diameter of the body that is intersected by the first end inlet port;
an annular second end recess between the outer diameter of the cylinder and the inner diameter of the body that is intersected by the second end inlet port; and
an annular seal ring between the outer diameter of the cylinder and the inner diameter of the body at a point axially between the first end recess and the second end recess.

16. The system of claim 15 , wherein the end of the piston moves axially past the first end inlet port while being stroked from the maximum second end position to the maximum first end position.

17. The system of claim 15 , wherein the

Assignees

• Hydril Usa Distrib Llc

Inventors

• Duman Ahmet
• Denk Michael
• Daniel Devon

Classifications

• F04B15/02

  the fluids being viscous or non-homogeneous · CPC title

• F04B53/1022

  having means for guiding the closure member axially · CPC title

• E21B21/106

  Valve arrangements outside the borehole, e.g. kelly valves (valves specifically for maintaining circulation of drilling fluid while connecting or disconnecting tubular joints E21B21/019) · CPC title

• F04B7/02

  the valving being fluid-actuated · CPC title

• E21B21/001 Primary

  specially adapted for underwater drilling (dual gradient drilling E21B21/082) · CPC title