The present invention relates to an enclosed circulation tool which is used to remove solids or fluids from the bottom of oil wells.
Sand accumulations tend to choke off production in an oil well. U.S. Pat. No. 5,033,545 (Sudol) is an example of a enclosed circulation tool that is presently used to remove sand from oil wells.
There is provided an enclosed circulation tool for a well including a tubular body having a top end, a bottom end and an interior cavity. A progressive cavity pump positioned at the bottom end of the body, the pump having a rotor mounted within a stator. The rotor has an upper end and a lower end, with the upper end extending into the interior cavity. A drive is coupled to and adapted to rotate the rotor in order to draw sand into the interior cavity. A first fluid conduit is provided along which fluids from pumped from surface pass to fluidize solids within the interior cavity. A second fluid conduit is provided along which fluidized solids from within the interior cavity pass to surface.
These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:
An enclosed circulation tool generally identified by reference numeral 10, will now be described with reference to
Structure and Relationship of Parts:
Pump 16 is preferably a moineau progressive cavity pump as shown, having a rotor 15 and a stator 17. An agitator, such as mixing blade 30, is mounted at a lower end 31 of and rotates with rotor 15. Lower end 31 of rotor 15 protrudes from bottom end 26 of body 14. A universal joint 32 connects an upper end 33 of rotor 15 to drive 18 within interior cavity 28. Drive 18 is coupled to rotor 15 and adapted to drive pump 16 in order to draw sand 34 into interior cavity 28. For the purpose of illustration, sand 34 is shown as a layer in well 12, although sand 34 may be any type of solids or debris that need to be cleaned out of well 12. It will be appreciated that instead of sand 34, well bore fluids may be drawn into interior cavity 28 and carried to surface. Drive 18 is a fluid activated drive 35 activated by fluids pumped from surface 36. First fluid passage 20 is provided along which fluids pumped from surface 36 pass in order to fluidize solids within interior cavity 28. Interior cavity 28 has holes 29 used to transfer fluidized solids into second fluid passage 22. Holes 29 may have various sizes, depending on the type of debris being cleaned out of well 12. In one example, large holes may be employed to clean out well 12 if large particulate matter is present, as opposed to fine sand. Second fluid passage 22 is provided along which fluidized solids from within interior cavity 28 pass to surface 36. First and second fluid passages 20 and 22, respectively, make up part of a concentric tubing string 53. Referring to
A pump 44 is positioned on surface 36 to pump fluid down first fluid passage 20. Arrows 46 indicate the flow of fluid through first fluid passage 20, while arrows 47 indicate the flow of sand and other solid debris being drawn up by pump 16. Arrows 48 indicate the flow of fluid and fluidized solids from interior cavity 28 into second fluid passage 22. A pump 50 may be positioned on surface 36 to pump fluid and fluidized solids from second fluid passage 22 out of well 12. Arrows 52 indicate the flow of fluid through second fluid passage 22 and out of well 12.
Referring to
Operation:
Referring to
Fluid is passed through enclosed circulation tool 10 until no more sand 34 can be removed from well 12 at the current depth. Over the normal course of a well clean out, when no more sand 34 can be removed at a certain depth, enclosed circulation tool 10 is then lowered further, in order to clean out sand 34 lower down in well 12. This process is repeated until well 12 is sufficiently clear of solid debris from drilling so that normal drilling operations may be carried out. Clean out tool 10 is designed to draw up fluid consisting of up to 80% sand, or other debris. Enclosed circulation tool 10 may also be used for the production of oil, water, or any type of well fluid. This may be accomplished using the above description with well fluids being removed instead of sand. Tool 10 may be permanently or temporarily installed, depending on the application.
Tool 10 is advantageously used with wells that have low fluid levels with unattainable circulation. This type of well typically absorbs any fluids sent downhole for pumping purposes or otherwise.
Tool 10 can be installed in or retrieved from a well or a main production string using wireline, rods, coiled tubing or regular tubing. It can be installed/retrieved in separate components or as a whole. In addition, it may be assembled downhole.
Additionally, tool 10 may be used for well-testing.
Advantages:
With enclosed circulation tool 10, sand 34 is first drawn into interior cavity 28 by pump 16 and then fluidized so it can be removed to surface 36. With the prior art, sand 34 was fluidized in the well bore 12 and there was a danger of forcing sand 34 into cracks in the formation. When sand 34 is forced into cracks in the formation, it either plugs off the well reducing well efficiency or quickly falls out again forcing you to go back in and clean it out again. As you need not be concerned with forcing sand 34 into the formation with enclosed circulation tool 10, you can use fluids at higher pressures.
Variations:
Drive 18 used to rotated pump 16 is illustrated as being a moineau mud motor 38 having a rotor 40 and a stator 42. It would be possible to use other types of drive 18. For example, if electric power cables were available, for example extending to a measurement while drilling (MWD) tool positioned in the drill string, an electric drive could be used. Alternatively, a screw auger (not shown) could be used in place of pump 16.
Cautionary Warnings:
The enclosed circulation tool may not be suitable for all types of formations. If chunks of rock become jammed in the pump 16 intake, it could prevent the pump from rotating.
In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiments without departing from scope of the Claims.
Number | Date | Country | Kind |
---|---|---|---|
2621041 | Sep 2007 | CA | national |
Number | Name | Date | Kind |
---|---|---|---|
2704579 | Brown | Mar 1955 | A |
4190113 | Harrison | Feb 1980 | A |
4534426 | Hooper | Aug 1985 | A |
4671359 | Renfro | Jun 1987 | A |
4681164 | Stacks | Jul 1987 | A |
4705107 | Council | Nov 1987 | A |
4744420 | Patterson | May 1988 | A |
5033545 | Sudol | Jul 1991 | A |
5178223 | Smet | Jan 1993 | A |
5285204 | Sas-Jaworsky | Feb 1994 | A |
5447200 | Dedora et al. | Sep 1995 | A |
5611397 | Wood | Mar 1997 | A |
5853056 | Landers | Dec 1998 | A |
6050352 | Thompson | Apr 2000 | A |
6173771 | Eslinger | Jan 2001 | B1 |
6367566 | Hill | Apr 2002 | B1 |
6789626 | Wagg | Sep 2004 | B2 |
6966375 | Pluchek | Nov 2005 | B2 |
7090018 | Livingstone | Aug 2006 | B2 |
20030141111 | Pia | Jul 2003 | A1 |
20030173088 | Livingstone | Sep 2003 | A1 |
20040079553 | Livingstone | Apr 2004 | A1 |
20050045337 | Bansal et al. | Mar 2005 | A1 |
Number | Date | Country | |
---|---|---|---|
20090078422 A1 | Mar 2009 | US |