Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
OIL-WELL SCREW PUMP DRIVEN FROM THE WELLHEAD
Document Type and Number:
WIPO Patent Application WO/2010/098690
Kind Code:
A1
Abstract:
This technical proposal pertains to oil and gas industry, namely, to screw pumps driving the tubing string from the wellhead, hence it can be used for lifting fluid from the wells. Oil-well screw pump driven from the wellhead 1 (designed conventionally) consists of a stator (2) rigidly connected to the tubing string (3) with a rotor (4) installed inside the tubing string (3) and connected to the bottom part of the liner (5), an anchor (6) and a sub (7). The liner (5) end is fitted with a tip (8) allowing for longitudinal motion upward along the inner side of the sub (7). Over the tip (8) the liner (5) is fitted with the end stop (10) made as a landing seat and interacting with the sub (7) from above. The tubing string (3) is driven from the wellhead (1), and the sub (7) is rigidly connected in alignment to the anchor (6) set against the walls of the well (11). Retainers (12) and (13) hold rotor (4) in axial and radial direction against the stator (2). The tubing string (3) is fitted with a screw conveyor (14) on its inner side having a central passage 15 (not less than 1/2 of the inside diameter of the tubing string (3), which provides free fluid flowing in the central part of the tubing string (3).

More Like This:
JP2007071208STATOR SYSTEM
Inventors:
BADRETDINOV, Atlas Misbakhovich (Tatarstan str, 3Almetievsk, 42345, RU)
Application Number:
RU2009/000318
Publication Date:
September 02, 2010
Filing Date:
June 26, 2009
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
BADRETDINOV, Atlas Misbakhovich (Tatarstan str, 3Almetievsk, 42345, RU)
International Classes:
F04C2/107; F04B47/02; F04C11/00
Foreign References:
RU2338927C12008-11-20
JPS5977096A1984-05-02
JPS5990795A1984-05-25
EP0903835A11999-03-24
RU27650U12003-02-10
US20070029245A12007-02-08
Attorney, Agent or Firm:
PROZOROVSKIY, Alexander Yurjevich et al. (1 Basmanny lane, 12 build 1,Box 26, Moscow 8, 10707, RU)
Download PDF:
Claims:
Claim

1. Oil-well screw pump driven from the wellhead consists of a stator rigidly connected to the tubing string able to transmit reciprocating motion, a rotor secured in the axial and radial direction inside the stator and connected at the bottom to the liner making it possible to be set against the walls of the well using the anchor. The distinguishing feature of this assembly is a screw conveyor having a central passage and installed on the inner side of the tubing string. 2. The oil-well screw pump to Claim I5 characterized in that its screw conveyor can be made by sections installed in the tubing string at equal intervals.

Description:
Oil-well screw pump driven from the wellhead

Field of the Invention

This technical proposal pertains to oil and gas industry, namely, to screw pumps driving the tubing string from the wellhead, hence it can be used for lifting fluid from the wells.

Prior Art

The most similar in technical essence and the results achieved is «0il-well screw pump driven from the wellhead)) (Patent RU 2338927, F04C 2 1 OO. F04B 47/12, published in the Bulletin JVa 32 or 20.1 1.2008). This pump consists of a stator tied on the tubing string bearing a rotor tied on the liner, a sub, interacting with the end stop, and an anchor. The liner end is fitted with a tip allowing for longitudinal motion upward against the sub inner side. The stator is rigidly connected to the tubing string to be driven from the wellhead, and the sub is rigidly connected in alignment with anchor set against the walls of the well. The liner is located below the rotor, and is fitted over the tip with the end stop made as a landing seat, rotor being secured in the axial and radial direction against the stator.

The disadvantageous feature of the pump is the fact that during the tubing string movement fluid friction against the walls of the tubing string increases forcing the screw pump to operate at high load especially while lifting high-viscosity or heavy oil reducing its life or making necessary to use more expensive pumps building higher pressure while lifting fluid. Summary of the Invention

Technical goal of the proposed model is to cheapen the design by using less-powered screw pumps for production of oil especially high- viscosity and heavy oil due to reduction of oil friction against the walls of tubing.

This purpose can be achieved by using oil-well screw pumps driving tubing string from the wellhead. This pump consists of a stator rigidly connected to the tubing string to be driven from the wellhead, a rotor secured in the axial and radial direction against the stator and connected at the bottom to the liner making it possible to be set against the walls of the well using the anchor.

The distinguishing feature of this unit is location of a screw conveyor on the inner side of the tubing string having central passage.

One more distinguishing feature is the fact that the screw conveyor is made by sections installed in the tubing string at equal intervals.

Detailed Description of the Invention

See cut-away drawing fig. l of the showing an oil-well screw pump tripped in hole, tubing string being driven from the wellhead. Oil-well screw pump driven from the wellhead 1 (designed conventionally) consists of a stator (2) rigidly connected to the tubing string (3) with a rotor (4) installed inside the tubing string (3) and connected to the bottom part of the liner (5), an anchor (6) and a sub (7).

The liner (5) end is fitted with a tip (8) allowing for longitudinal motion upward along the inner side of the sub (7). Over the tip (8) the liner (5) is fitted with the end stop (10) made as a landing seat and interacting with the sub (7) from above. The tubing string (3) is driven from the wellhead (1), and the sub (7) is rigidly connected in alignment to the anchor (6) set against the walls of the well (11). Retainers (12) and (13) hold rotor (4) in axial and radial direction against the stator (2). The tubing string (3) is fitted with a screw conveyor (14) on its inner side having a central passage 15 (not less than 1/2 of the inside diameter of the tubing string (3), which provides free fluid flowing in the central part of the tubing string (3).

Screw conveyor 14 can be made by sections 14* set in the tubing string (3) at equal intervals (L). The more the viscosity and density of well fluid are, the smaller the interval L is. For example, oil density is less than 0,920 g/cm3, then L = 30 - 50 m; for heavy oil having density higher than 0.920 g/cm3, L = 20 - 30 m; for heavy oil having density higher than 1000 g/cm3 and viscosity less than 10000 MPA*, L = 10 - 20 m, for natural bitumen with density of more than 1000 g/cm3 and viscosity greater than 10000 MPA*, L = O m, i.e., the screw conveyor (14) shall be set along the entire length of the tubing string (3). Oil-well screw pump operates as follows.

Anchor (6) and sub (7) are run in hole (11) to be set at the desired interval (for example, below the pay zone of the well 11), where the anchor (6) is set by hydraulic or mechanical action on the walls of the well 11. In actual practice, a hydraulic anchor (6) is normally run in hole on tubing joints (not shown in the drawing), anchor slips being set on end points after fixing pump anchor (6) on the walls of the well (1 1). Then tubing string (3) is tripped in the hole with the screw conveyor (14) inside the tubing, and the stator (2) at the bottom with a rotor (4) inside. Retainers (12) and (13) prevent rotor (4) from dropping or displacement against the stator (2). The tubing string (3) and stator 2 can be centered against the walls of the well 11 by any method known like bow springs centralizers (not shown in the drawing). They keep on tripping in until the tip (8) of the liner (5) of the rotor (4) goes into the inner side (9) of the sub (7) and as long as the landing seat (10) interlocks the sub (7), which is identified in the wellhead (3) by dynamometer (not shown in the drawing) as the total weight of the tubing string (3) reduces. The outer surface of the tip (8) and the inner side (9) of the sub 7 are made as mating surfaces (such as slotted or hexagonal joint), which allows these surfaces to move only axially after their interaction and without any slip. Then the wellhead (11) is sealed-off, and the upper end of the tubing string (3) is tied on the wellhead drive 1. After that the wellhead drive 1 starts moving tubing strings (3). The tip 8 of the liner 5 prevents the rotor 4 from moving causing movement of the stator 2 against the rotor (4). The result is that the screw pump pumps well fluid through the tubing string 3 to the wellhead, where it is pumped off through the pipeline 17 (designed conventionally), and the screw conveyor 14 (with its sections 14") moving with the tubing string 3 produces additional lifting force reducing fluid flow resistance in the tubing string 3.

Where required to simplify installation of screw conveyor (14) sections 14*), the screw conveyor can be placed inside the purpose-made joints (not shown in the drawing) to join the pipes of the tubing string 3 at equal tubing spacing L.

Due to location of the screw conveyor 14 inside the tubing string

3, fluid flow resistance in the tubing string is reduced by 10 - 40% (the higher the density and viscosity of the well fluid are, the higher the percentage is) making it possible to use cheaper screw pumps with a less-powered wellhead drive 1. The proposed less powered oil-well screw pump is cheaper and more reliable due to reduction of oil friction against the walls of tubing (especially high-viscosity and heavy oil).

Industrial Applications

This invention is embodied with the use of multifunctional and easily available up-to-date equipment and substances that are widely used in the industry and health care.