A gas lift system and a gas lift method

Patent metadata

Field	Value
Publication number	US-2016153268-A1
Application number	US-201414899282-A
Country	US
Kind code	A1
Filing date	Jun 25, 2014
Priority date	Jun 26, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

The present invention relates to a gas lift system ( 1 ) arranged in a well ( 65 ) having a top ( 10 ) and comprising a well fluid ( 11 ), the gas lift system comprising a casing ( 61 ) arranged in the borehole defining a surrounding annulus ( 62 ), an opening ( 86 ) in the casing, and a pumping unit ( 12 ) for pumping gas ( 8 ) into the annulus, wherein the gas lift system further comprises a downhole tool ( 14 ) having a first end ( 15 ) nearest the top of the well and a second end ( 16 ), the down-hole tool comprising a pump section ( 2 ) comprising a housing ( 20 ) comprising a chamber ( 201 ) having an axial extension ( 17 ), a plunger ( 23 ) sliding in the chamber and dividing the chamber into a first compartment ( 203 ) and a second compartment ( 202 ), a plunger rod ( 26 ) connected with the plunger, a chamber inlet channel ( 27 ) and a chamber outlet channel ( 21 ), the inlet channel and the outlet channel being in fluid communication with the second compartment, a sealing element ( 29 ) for isolating a first part ( 66 ) of the casing from a second part ( 67 ) of the casing, the first part and the inlet channel being in fluid communication with the opening, a one-way valve ( 24 ) arranged in the inlet channel to allow fluid to flow into the chamber, and a one-way valve ( 22 ) arranged in the outlet channel to allow fluid to flow out of the chamber. The invention also relates to a gas lift method.

First claim

1 . A gas lift system arranged in a well having a top and comprising a well fluid, the gas lift system comprising:
a casing arranged in the borehole defining a surrounding annulus, an opening in the casing, and a pumping unit for pumping gas into the annulus,
wherein the gas lift system further comprises a downhole tool having a first end nearest the top of the well and a second end, the downhole tool comprising a pump section comprising:
a housing comprising a chamber having an axial extension,
a plunger sliding in the chamber and dividing the chamber into a first compartment and a second compartment,
a plunger rod connected with the plunger,
a chamber inlet channel and a chamber outlet channel, the inlet channel and the outlet channel being in fluid communication with the second compartment,
a sealing element for isolating a first part of the casing from a second part of the casing, the first part and the inlet channel being in fluid communication with the opening,
a one-way valve arranged in the inlet channel to allow fluid to flow into the chamber, and
a one-way valve arranged in the outlet channel to allow fluid to flow out of the chamber.

2 . A gas lift system according to claim 1 , wherein at least part of the inlet channel extends radially from an outer surface of the housing towards the chamber.

3 . A gas lift system according to claim 1 , wherein the plunger comprises a protrusion protruding from a first plunger face of the plunger facing the inlet channel and/or the outlet channel.

4 . A gas lift system according to claim 1 , wherein the sealing element is an annular seal for sealing around the opening.

5 . A gas lift system according to claim 1 , wherein a one-way valve is arranged in the opening to allow fluid to flow into the casing.

6 . A gas lift system according to claim 1 , wherein the sealing element circumferents the housing and is adapted for sealing against the casing.

7 . A gas lift system according to claim 1 , further comprising a second sealing element circumferenting the housing and adapted for sealing against the casing, thereby isolating a part of the first part of the casing opposite the opening.

8 . A gas lift system according to any claim 1 , wherein an inlet of the inlet channel is arranged substantially opposite the opening along the axial extension.

9 . A gas lift system according to claim 1 , wherein an outlet of the outlet channel is arranged closer to the first end of the tool than the inlet channel.

10 . A gas lift system according to claim 1 , further comprising a linear actuator for providing a reciprocating movement of the plunger.

11 . A gas lift system according to claim 1 , wherein the tool comprises a driving unit for propelling the tool forward in the well.

12 . A gas lift system according to claim 1 , wherein the tool comprises a tool section comprising a drilling bit for drilling or milling an opening in the casing.

13 . A gas lift system according to claim 1 , wherein the casing comprises at least one side pocket, and the side pocket is arranged closer to the top than the opening.

14 . A gas lift method comprising the following steps:
inserting the gas lift system according to claim 1 into the borehole, arranging the inlet channel opposite the opening, isolating the first part of the casing from the second part of the casing by means of the sealing element, so that the first part is in fluid communication with the opening and the inlet channel is in fluid communication with the opening, activating the pump unit to pump gas into the annulus, moving the plunger rod in a reciprocating movement, and sucking fluid from the first part of the casing, so that the gas in the fluid in the annulus is sucked towards the opening and into the first part and further into the first compartment and out through the outlet channel.

15 . A gas lift method according to claim 14 , further comprising the step of isolating a part of the first part of the casing opposite the opening to create a suction area between the casing and the tool opposite the opening.

16 . A gas lift method according to claim 14 , further comprising the step of drilling an opening in the casing.

Assignees

• Welltec As

Inventors

• Vasques Ricardo Reves

Classifications

• E21B29/002

  Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe · CPC title

• E21B43/122 Primary

  Gas lift · CPC title

• E21B43/123 Primary

  Gas lift valves · CPC title