Coiled piston assembly

Patent metadata

Field	Value
Publication number	US-11332995-B2
Application number	US-201716606679-A
Country	US
Kind code	B2
Filing date	Jun 9, 2017
Priority date	Jun 9, 2017
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A tubing hanger assembly includes a body having an annular outer surface, a lockdown feature which is located on the body, a load nut which is threadedly connected to the body and has a downward facing load shoulder, and a piston assembly for adjusting a vertical distance between the load shoulder and the lockdown feature. The piston assembly includes an elongated cylinder which is positioned circumferentially around the body axially adjacent the load nut. The cylinder has a first cylinder end which is connected to the body and an open second cylinder end. An elongated piston is slidably received in the cylinder. The piston has a first piston end which is oriented toward the first cylinder end and a second piston end which is configured to extend through the second cylinder end and engage the load nut such that extension of the piston causes the load nut to rotate relative to the body. A seal is positioned between the piston and the cylinder to thereby define a piston chamber between the first cylinder end and the first piston end which is connectable to a source of fluid pressure. In operation of the piston assembly, the piston rotates the load nut to thereby move the load nut axially relative to the body so that the axial distance between the load shoulder and the lockdown feature can be adjusted.

First claim

What is claimed is:

1. A tubing hanger assembly which includes:
a body which comprises an annular outer surface;
a lockdown feature which is located on the body;
a load nut which is threadedly connected to the body, the load nut comprising a downward facing load shoulder; and
a piston assembly which includes:
an elongated cylinder which is positioned circumferentially around the outer surface of the body axially adjacent the load nut, the cylinder comprising a first cylinder end which is connected to the body and an open second cylinder end;
an elongated piston which is slidably received in the cylinder, the piston comprising a first piston end which is oriented toward the first cylinder end and a second piston end which is configured to extend through the second cylinder end and engage the load nut such that extension of the piston causes the load nut to rotate relative to the body; and
a seal which is positioned between the piston and the cylinder to thereby define a piston chamber between the first cylinder end and the first piston end, the piston chamber being connectable to a source of fluid pressure;

wherein in operation of the piston assembly, the piston rotates the load nut to thereby move the load nut axially relative to the body;
whereby an axial distance between the load shoulder and the lockdown feature is adjustable.

2. The tubing hanger assembly of claim 1 , wherein the piston and the cylinder each comprise a helical configuration.

3. The tubing hanger assembly of claim 2 , wherein the piston comprises at least two winds.

4. The tubing hanger assembly of claim 2 , wherein the body includes a first outer surface portion comprising a first diameter and an axially adjacent second outer surface portion comprising a second diameter which is less than the first diameter, and wherein the piston assembly is positioned around the second outer surface portion.

5. The tubing hanger assembly of claim 4 , wherein the piston assembly is positioned between the first outer surface portion and the load nut.

6. The tubing hanger assembly of claim 5 , wherein the load nut comprises an end surface located opposite the load shoulder and a contact surface which extends generally axially from the end surface, and wherein the second piston end is configured to engage the contact surface.

7. The tubing hanger assembly of claim 5 , wherein the first outer surface portion comprises a recess which defines a radially extending mounting surface to which the first cylinder end is connected.

8. The tubing hanger assembly of claim 7 , wherein the body includes a fluid conduit which is connectable to the source of fluid pressure and comprises a first conduit end that terminates at the mounting surface, and wherein the first cylinder end is connected to the first conduit end via a fluid coupling.

9. The tubing hanger assembly of claim 1 , wherein the tubing hanger assembly is configured to be installed in a wellhead which comprises a central bore in which a casing hanger is positioned, the load shoulder being configured to land on a seat which is formed on the casing hanger to thereby support the tubing hanger in the wellhead.

10. The tubing hanger assembly of claim 9 , wherein the central bore comprises a locking profile and the lockdown feature comprises a number of locking dogs which are supported on the body and are expandable into the locking profile to thereby secure the tubing hanger assembly to the wellhead.

11. The tubing hanger assembly of claim 10 , wherein in operation of the piston assembly, the piston rotates the load nut until a distance between the load shoulder and the locking dogs is the same as a distance between the seat and the locking profile.

12. A method for installing a tubing hanger in a wellhead, the wellhead comprising a first tubing hanger lockdown feature and a central bore in which a casing hanger is positioned, and the tubing hanger comprising a second tubing hanger lockdown feature which is configured to engage the first tubing hanger lockdown feature, an annular body, and a load nut which is threadedly connected to the body, the load nut comprising a downward facing load shoulder which is configured to land on a seat that is formed on the casing hanger, the method comprising:
lowering the tubing hanger into the wellhead; and then
adjusting the axial position of the load nut until an axial distance between the load shoulder and the second tubing hanger lockdown feature is the same as a second axial distance between the seat and the first tubing hanger lockdown feature.

13. The method of claim 12 , further comprising engaging the first and second tubing hanger lockdown features to thereby secure the tubing hanger to the wellhead.

14. The method of claim 13 , wherein the step of engaging the first tubing hanger lockdown feature with the second tubing hanger lockdown feature is performed prior to the step of adjusting the axial position of the load nut.

15. The method of claim 12 , wherein the tubing hanger further comprises a piston assembly which is positioned circumferentially around the body, the piston assembly comprising an elongated cylinder which is connected to the body and an elongated piston which is slidably received in the cylinder and is configured to extend from the cylinder and engage the load nut such that extension of the piston causes the load nut to rotate relative to the body, and wherein the step of adjusting the axial position of the load nut is performed by operating the piston assembly.

16. A piston assembly which includes:
a helical cylinder which comprises first and second cylinder ends;
a helical piston which is slidably received in the cylinder, the piston comprising a first piston end which is oriented toward the first cylinder end and a second piston end which is configured to extend through the second cylinder end; and
a seal which is positioned between the piston and the cylinder to thereby define a piston chamber between the first cylinder end and the first piston end;
wherein in operation of the piston assembly, pressurization of the piston chamber forces the piston to extend from the cylinder.

17. A piston assembly for use in securing an inner member to an outer member which surrounds at least a portion of the inner member, the inner member comprising first and second axially spaced inner features and the outer member comprising first and second axially spaced outer features which are configured to engage the first and second inner features, respectively, to secure the inner member to the outer member, one of the first inner feature and the first outer feature being formed on a load nut which is threadedly connected to one of the inner member and the outer member such that rotation of the load nut relative to said one of the inner member and the outer member moves the load nut axially relative to said one of the inner member and the outer member, the piston assembly comprising:
a helical cylinder which is positioned around said one of the inner member and the outer member to which the load nut is connected, the cylinder comprising first and second cylinder ends, the first cylinder end being connected to said one of the inner member and the outer member to which the load nut is connected; and
a helical piston which is slidably received in the cylinder, the piston comprising a first piston end which is oriented toward the first cylinder end and a second piston end which is configured to extend through the second cylinder end and engage the load nut;
wherein with the second inner feature engaged with the second outer feature, th

Assignees

• Fmc Tech Inc

Inventors

• Murphy Richard M

Classifications

• B66F3/25

  Constructional features · CPC title

• E21B33/0355

  Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads · CPC title

• E21B33/0415 Primary

  rotating or floating support for tubing or casing hanger · CPC title

• E21B33/043

  specially adapted for underwater well heads ({E21B33/0407,} E21B33/047 take precedence) · CPC title