Centralizer

Patent metadata

Field	Value
Publication number	US-9963942-B2
Application number	US-201615344010-A
Country	US
Kind code	B2
Filing date	Nov 4, 2016
Priority date	Jan 7, 2011
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A centralizer includes a centralizer body to be situated at the outer surface of a pipe string in the form of casing, liner, or the like used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis thereof, wherein the centralizer body has an separate split inner tube secured to the pipe string by means of a press fit, and low friction inner surface of the centralizer body and separate center tube facing each other are made from low friction material.

First claim

The invention claimed is:

1. A centralizer comprising a centralizer body to be situated at the outer surface of a pipe string in the form of casing or liner used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis of the centralizer,
wherein the centralizer comprises a split inner tube secured to the pipe string,
wherein the centralizer body is arranged to be rotatable around the split inner tube,
wherein the centralizer further comprises a centre tube provided between the centralizer body and the split inner tube,
wherein facing surfaces on the centre tube and the centralizer body and the split inner tube comprise a low friction material,
wherein the centralizer further comprises a first stop collar and a second stop collar, the first and second stop collars being arranged at opposite ends of said centralizer body, the centralizer body being arranged to be rotatable relative to said first and second stop collars, wherein at least one end surface on the centralizer body and/or the first and second stop collars comprises a low friction material, and
wherein the centralizer body includes a first recess and a second recess at opposite ends thereof, ends of each of the first and second stop collars facing the centralizer body are accommodated within the first and second recesses, respectively, and the first and second stop collars are separately secured about the pipe string to hold the centralizer in place.

2. The centralizer according to claim 1 , wherein an annular ring coated with or made of the low friction material is situated between the centralizer body and at least one stop collar of the first and second stop collar.

3. The centralizer according to claim 1 , wherein each of the first and second stop collars is provided with a bevel at the end remote from the centralizer body.

4. The centralizer according to claim 1 , wherein each of the first and second stop collars comprises a split main body with a longitudinal gap provided with a fastening device configured to fix the first and second stop collars to the pipe string, and an inner surface made from a high friction material.

5. The centralizer according to claim 1 , wherein the outer centralizer blades are provided with at least one outer protruding portion.

6. The centralizer according to claim 5 , wherein each protruding portion is provided with a coating made of low friction material.

7. The centralizer according to claim 5 , wherein each protruding portion is in the form of a pad made of low friction material.

8. The centralizer according to claim 5 , wherein each protruding portion is in the form of a roller.

9. The centralizer according to claim 8 , wherein each roller is located in a recess in the centralizer body and extends a predetermined distance radially outwards from said centralizer blades.

10. The centralizer according to claim 8 , wherein each roller extends radially outwards through an opening in the outer circumferential surface of the centralizer blades, and that the opening is smaller than the roller outer diameter at each point along its length.

11. The centralizer according to claim 8 , wherein each roller has an oval basic shape.

12. The centralizer according to claim 1 , wherein the outer centralizer blades are formed with a curved or helical configuration.

13. The centralizer according to claim 1 , wherein the separate split inner tube comprises a longitudinal split and an inner surface made from high friction material allowing for the press fit against the pipe string.

14. The centralizer according to claim 1 ,
wherein each of the first and second stop collars comprises a first surface arranged to face the pipe string and a second surface arranged to face the centralizer body, wherein the first surface is made of a first material and the second surface is made of a second material, and wherein the first material has a higher friction coefficient than the second material.

15. The centralizer according to claim 1 , wherein the split inner tube comprises an inner surface made of a first material, wherein the split inner tube comprises an outer surface made of a second material, and wherein the first material has a higher friction coefficient than the second material.

Assignees

• Statoil Petroleum As

Inventors

• Eidem Morten
• Weltzin Tore
• Grindhaug Gaute
• Abdollahi Jafar

Classifications

• E21B17/1078 Primary

  Stabilisers or centralisers for casing, tubing or drill pipes (E21B17/1007 - E21B17/1064 take precedence) · CPC title

• E21B17/1057

  Centralising devices with rollers or with a relatively rotating sleeve (E21B17/1014 takes precedence) · CPC title

• E21B17/105 Primary

  split type · CPC title

• E21B17/1064

  Pipes or rods with a relatively rotating sleeve · CPC title