U.S. patent application number 12/316410 was filed with the patent office on 2010-06-17 for columnar downhole gas separator and method of use.
Invention is credited to Ron Swaringin.
Application Number | 20100147514 12/316410 |
Document ID | / |
Family ID | 42239150 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100147514 |
Kind Code |
A1 |
Swaringin; Ron |
June 17, 2010 |
Columnar downhole gas separator and method of use
Abstract
A gas separator is provided including a tapered portion, the
"bell section" and a wide portion, the "shroud." The bell section
resides on the lower end of the gas separator where it attaches to
the production pipe. The shroud is substantially larger in diameter
than the production pipe and allows mixed fluid and gas to enter
through an open top. The gas separator is attached at the string of
production pipe, so that some of the production pipe extends below
the gas separator. A section of production pipe that is covered by
the gas separator is perforated. Gas bubbles are removed from the
mixed fluid by gravity, abrupt changes in direction, and
perforations that restrict the flow area of the fluid.
Inventors: |
Swaringin; Ron; (Colorado
City, TX) |
Correspondence
Address: |
George R. Schultz;Schultz & Associates, P.C.
One Lincoln Centre, 5400 LBJ Freeway, Suite 1200
Dallas
TX
75240
US
|
Family ID: |
42239150 |
Appl. No.: |
12/316410 |
Filed: |
December 12, 2008 |
Current U.S.
Class: |
166/265 ;
166/105.5 |
Current CPC
Class: |
E21B 43/38 20130101 |
Class at
Publication: |
166/265 ;
166/105.5 |
International
Class: |
E21B 43/38 20060101
E21B043/38; E21B 43/34 20060101 E21B043/34 |
Claims
1. An apparatus to separate gas bubbles from a production fluid
comprising: a bell collar having a means to concentrically attach a
gas separator to a production pipe string; the production pipe
string having a set of perforations and extending below the bell
collar; a circular shroud having a first diameter extending above
the bell collar; the shroud having a top opening with a second
diameter; and, wherein the gas separator covers the set of
perforations.
2. The apparatus of claim 1 wherein the top opening is beveled.
3. The apparatus of claim 1 wherein the second diameter is larger
than the first diameter.
4. The apparatus of claim 1 further comprising a gas anchor located
inside the production pipe string below the gas separator.
5. The apparatus of claim 4 wherein the gas anchor extends below
the bell collar.
6. The apparatus of claim 5 wherein the production pipe string is
closed below the gas anchor.
7. The apparatus of claim 6 wherein the gas anchor does not extend
to the bottom of the production pipe string.
8. The apparatus of claim 1 wherein the gas separator is comprised
of a bell section removably connected to a shroud section.
9. A gas separator comprising: a bell collar; the bell collar
having a gas separator concentrically attached to production pipe
string; a gas anchor located inside the production pipe string; the
gas anchor extending below the bell collar; the production pipe
string extending below the gas separator; the production pipe
string being closed on the lower end; a shroud extending above the
bell collar; the shroud having a top opening; the gas separator
covering a set of perforations in the production pipe string.
10. The apparatus of claim 9 wherein the gas anchor does not extend
to the lowest end of the production pipe string.
11. A method for separating gas bubbles from a mixed fluid,
composed of fluid with gas bubbles suspended therein, comprising
the steps of: providing a plurality of sections of production pipe
having a first diameter; providing a gas separator with a top
opening, the gas separator further comprising a bell collar and a
shroud section with a top opening and a second diameter larger than
the first diameter; providing a set of perforations in the
production pipe; connecting the bell collar to the production pipe
with the top opening facing upward; connecting the production pipe
within the gas separator, adjacent to the set of perforations;
lowering the production pipe and the gas separator into the mixed
fluid; separating gas bubbles from the mixed fluid as the mixed
fluid flows through the gas separator and the plurality of sections
of production pipe.
12. The method of claim 1 1 further comprising: providing a section
of production pipe with a closed end below the gas separator.
13. The method of claim 11 further comprising: providing a pump;
attaching the pump to the production pipe string; separating the
gas bubbles from the mixed fluid by lowering pressure in at least
one section of production pipe from the plurality of sections of
production pipe with the pump, thereby causing the mixed fluid to
rise.
14. The method of claim 13 further comprising: concentrically
passing a gas anchor through the production pipe string; attaching
the gas anchor to the pump; raising the fluid through the gas
anchor with the pump.
15. The method of claim 14 further comprising: positioning a
section of production pipe of the plurality of sections of
production pipe below the gas anchor.
16. The method of claim 14 wherein: providing a section of
production pipe of the plurality of sections of production pipe
with a closed end below the gas separator.
17. The method of claim 16 further comprising: bottoming a section
of the production pipe of the plurality of section of production
pipe in a well.
18. The method of claim 16 further comprising: positioning the gas
anchor above the closed end whereby a set of sediment particles
that have accumulated in the production pipe are prevented from
obstructing a flow of mixed fluid into the gas anchor.
19. The method of claim 11 further comprising extending a section
of production pipe of the plurality of sections of production pipe
below the gas separator.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to gas separators. More
particularly, the invention relates to gas separators suspended
above the bottom of a production well and used to separate mixed
fluid that consists of gas bubbles suspended in liquid.
BACKGROUND OF THE INVENTION
[0002] Generally, fluid produced from a well must be pumped to the
surface. Most of these fluids are mixed, consisting of gas bubbles
suspended within the fluid. Gas passing through a pump reduces the
efficiency of the pump and increases the cost to produce the fluid
from the well. In extreme circumstances, large quantities of gas
can create "gas lock" within the pump. "Gas lock" prevents fluid
from being displaced, effectively stopping production and
potentially damaging the pump. Therefore, it is considered
desirable to separate the gas from the fluid. Pumping fluid
substantially free from gas prevents the aforementioned problems
and results in lower production costs.
[0003] Separation of gas bubbles from a mixed fluid may be based on
the geometry of the inlet holes as the mixed fluid enters the gas
separator. Additionally, a second stage of separation may be
utilized whereby the fluid is pumped to the surface from a distance
below the gas separator. In a second stage of separation, the fluid
is pumped to the surface through a gas anchor which passes
concentrically through the production pipe and is attached to the
pump. This allows gravity to operate on the gas bubbles remaining
in the fluid. Thus, the fluid pumped to the surface has a reduced
concentration of gas bubbles and is more efficient to pump.
[0004] A difficulty with gas separators that operate at or produce
fluid from the lower end of the production pipe is "silting in."
Often the fluid produced in wells includes silt and heavy particles
that fall out of the fluid as the fluid is pumped to the surface.
As the silt and heavy particles accumulate, the inlet to the pump
or the perforations in a gas separator may become blocked. Blockage
of the pump inlet or gas separator leads to a reduction or complete
stoppage of fluid production. The gas separator, along with the
entire string of production pipe, must be removed from the well and
cleared of silt and heavy particles. "Silting in" results in
additional costs both as a result of removing the gas separator
from the well and from time spent without production from the
well.
[0005] Most prior art gas separators are placed within the
production pipe, effectively reducing the area of the production
pipe. This reduction in area corresponds to a reduction in the
amount of fluid that may be pumped through the production pipe.
Many gas separators that are larger in area than the production
pipe require additional centrifugal or submersible pumps to
operate.
[0006] Those gas separators that are larger in area than the
production pipe and do operate without any additional pumps or
equipment are prone to "silting in." One such gas separator is
disclosed in U.S. Pat. No. 1,554,842 to Coulter. This gas separator
is larger in diameter than the production pipe and attaches to the
lowest end of the production pipe string. The gas separator
encloses a perforated section of the production pipe located at the
lowest end of the production pipe string. Fluid flows into the open
top of the gas separator. The fluid enters the perforated section
of the production pipe and is pulled to the surface through a pump.
The perforated section is located at the lowest point of the string
of production pipe. The pump inlet is located just above the
perforated section. Thus, any silt or heavy particles that do not
pass through the pump build up in the closed end of the gas
separator. As silt builds up in the gas separator, the perforations
in the production pipe are blocked and the volume of fluid produced
is reduced. Eventually, all of the perforations are blocked or the
production of fluid is reduced to the point where the gas separator
must be removed from the well and the silt removed.
[0007] Another such gas separator is disclosed in U.S. Pat. No.
4,241,788 to Brennan. This gas separator operates in a similar
manner, with multiple cups each having perforations on the bottom
to allow fluid to enter the production pipe. A gas anchor is
attached to the pump and passes concentrically through the
production pipe. Fluid is pumped through the gas anchor at the
lowest end of the production string. The end of the production pipe
is enclosed by a gas separator with vents that allow gas to pass
outside to the well. Similar to the Coulter gas separator, this gas
separator is subject to "silting in." The gas anchor is enclosed by
the gas separator. This allows any silt or heavy particles, which
do not flow through the pump, to build up eventually blocking the
inlet to the gas anchor and stopping production.
[0008] Therefore, a need exists for a gas separator that operates
based on the flow produced by the production pump, minimizes the
reduction in area of the production pipe, and maximizes time in
production by preventing silt and heavy particles from obstructing
the perforations of the gas separator or the inlet to the pump.
SUMMARY OF INVENTION
[0009] The present invention addresses the need to separate mixed
fluid in a production well into gas and a gas bubble free fluid.
The present invention reduces the amount of gas that remains in a
fluid when it reaches the pump. Reduction of gas enables the pump
to operate more efficiently without locking-up. In addition, the
present invention enables the gas separator to remain in the
production well for a longer period of time. Often, the fluid in a
production well contains silt and heavy particles that separate
from the fluid as it is pumped to the surface. The portion of the
production pipe that extends below the gas separator allows the
sediment to gather in the lower portion of the production pipe
without blocking or "silting-in" the perforations that allow fluid
flow.
[0010] The present invention consists of a tapered portion, the
"bell section" and a wide portion, the "shroud." The bell section
resides on the lower end of the gas separator where it attaches to
the production pipe. The shroud is substantially larger in diameter
than the production pipe and allows mixed fluid and gas to enter
through an open top.
[0011] The present invention attaches to a string of production
pipe that is lowered down a well. The gas separator is attached at
some point in the middle of the string of production pipe, so that
some of the production pipe extends below the gas separator. A
section of production pipe that is covered by the gas separator is
perforated. The fluid in the well is a mixed fluid that consists of
fluid and gas bubbles. Initially, the mixed fluid rises in the
well. Some gas bubbles continue to rise and are separated as the
fluid changes direction and enters the open top of the gas
separator. Gravity continues to act on the fluid causing further
gas bubble separation as the mixed fluid is drawn down the length
of the gas separator. The perforations in the production pipe cause
the velocity of the fluid to increase, resulting in additional
separation of gas bubbles from the fluid. The fluid, which has been
separated from some gas bubbles, gathers in the production pipe. As
this fluid continues downward to the opening of the gas anchor,
gravity continues to operate, separating additional gas bubbles. As
the additional bubbles separate, they rise and exit through the
perforations in the production tubing and ultimately the open top
of the gas separator. Thus, the fluid that enters the gas anchor
and is ultimately pumped to the surface has a greatly reduced
amount of gas bubbles. This allows the pump to operate more
efficiently, with less chance of locking-up due to a gas pocket in
the pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the detailed description of the preferred embodiments
presented below, reference is made to the accompanying
drawings.
[0013] FIG. 1 is a side view of a preferred embodiment of the
present invention.
[0014] FIG. 2 is a side view of a second preferred embodiment of
the present invention, where the invention consists of two separate
pieces joined together.
[0015] FIG. 3 is a cross section view of a preferred embodiment of
the present invention. The invention has been cut-away to show a
preferred method of attachment to the production pipe.
[0016] FIG. 4 is a cross section view of the gas separator during
the upstroke of the pump. The flow of mixed fluid is shown. The
mixed fluid travels through the gas separator and is produced as
fluid without gas bubbles after passing through the gas
separator.
[0017] FIG. 5 is a cross section view of the gas separator during
the downstroke of the pump. The escape of the gas bubbles is shown.
The mixed fluid travels through the gas separator and gas bubbles
are separated from the mixed fluid and escape through the
perforated production pipe and the open top of the gas
separator
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] In the descriptions that follow, like parts are marked
throughout the specification and drawings with the same numerals,
respectively. The drawing figures are not necessarily drawn to
scale and certain figures may be shown in exaggerated or
generalized form in the interest of clarity and conciseness.
[0019] With Respect to FIG. 1, gas separator 110 is supported by a
bell collar 130. Bell collar 130 is a cylindrical shape designed to
support the gas separator by attaching to production pipe (not
shown). Taper 170 is an angle between the bell collar 130 and the
shroud 190. Shroud 190 causes mixed fluid to enter the gas
separator 110 through the top opening 150 of the gas separator
110.
[0020] FIG. 2 shows the preferred embodiment of gas separator 110.
Gas separator 110 consists of three pieces; a bell section 210, a
collar 290, and a shroud 230. Shroud 230 has external threads 270.
Additionally, the bell section 210 has bell collar 130. Bell collar
130 attaches to production pipe (not shown). Shroud 230 is
substantially larger in diameter than production pipe and has
external threads 270. Shroud 230 and bell section 210 are connected
by collar 290. Collar 290 has internal threads (not shown).
[0021] FIG. 3 shows the preferred method of attaching gas separator
110 to production pipes 350 and 370. Production pipes 350 and 370
are externally threaded at the ends 390. Gas separator 110 is
supported by bell collar 130. Bell collar 130 is internally
threaded 330 to accept the threaded ends 390 of production pipes
350 and 370. Additionally, production pipe 370 contains
perforations 360. While the perforations may extend for any length
along production pipe 370, the perforations in the preferred
embodiment stop approximately 12 inches before the upper end gas
separator 110, but the distance may be varied depending on well
conditions.
[0022] FIG. 4 shows the preferred method of production using gas
separator 110. Gas separator 110 is attached to production pipe
string 480, such that some of production pipe string 480 extends
below gas separator 110. Gas separator 110 and pipe string 480
reside in a production well. The production well consists of well
casing 410 having vents 420. Vents 420 allow mixed fluid 430 (fluid
combined with gas bubbles) to enter well casing 410.
[0023] Gas anchor 450 is attached to pump 440 and suspended
concentrically in production pipe string 480. In the preferred
embodiment, gas anchor 450 extends 10 to 15 feet below gas
separator 110.
[0024] In use, gas separator 110 is attached to production pipes
350 and 370 as shown in FIG. 3. The 23/8-inch diameter production
pipes 350 and 370 pass through gas separator 110 and thread into
bell collar 130. Additional sections of production pipe are added
above production pipe 370 as gas separator 110 is lowered into
position in a production well as shown in FIG. 4. Preferred
embodiments of gas separator 110 include pipes having a 41/2 inch
to a 125/8 inch outside diameter and lengths of approximately 7
feet. However, length and diameter of the gas separator may be
adjusted to individual well size and fluid consistency.
[0025] Referring to FIG. 4, the mixed fluid 430 rises due to
pressure, either natural or artificial. The pressure causes mixed
fluid 430 to rise until it meets gas separator 110. The mixed fluid
430 decreases velocity as it encounters taper 130 and shroud 190.
As mixed fluid 430 loses velocity, gravity continues to act on gas
bubbles causing them to be released from mixed fluid 430.
[0026] Pump 440 reduces the pressure below gas separator 110, at
the end of gas anchor 450. The reduction in pressure causes mixed
fluid 490 to enter gas separator 110. Gravity continues to act on
the mixed fluid 490, allowing the gas bubbles 491 to rise. The
change in direction of mixed fluid 490 combined with gas bubbles
491 rising due to gravity acting on the mixed fluid 490 causes
further separation between the fluid 490 and gas bubbles 491
located therein. As the mixed fluid 490 continues downward in gas
separator 110, gravity continues to separate the mixed fluid 490
and gas bubbles 491. The mixed fluid 490 continues downward passing
through perforations 360 into production pipe string 480. Again,
the abrupt change of direction causes a separation of gas bubbles
492 from the mixed fluid 490. As the mixed fluid 490 continues
downward in production pipe string 480, gravity continues acting on
the gas bubbles 493 causing them to separate from the mixed fluid
490. The fluid that has a greatly reduced concentration of gas
bubbles 494 again has an abrupt change of direction as it enters
gas anchor 450 and begins travelling upward to pump 440. The fluid
that enters gas anchor 450 has a much reduced concentration of gas
bubbles from the original mixed fluid 430.
[0027] Silt or heavy particles that entered gas separator 110 in
mixed fluid 490 may fall rather than pass upward through the gas
anchor 450. Gas anchor 450 is suspended above the lowest end of
production pipe string 480, which may be closed. This allows silt
and heavy particles 470 to accumulate without blocking or
"silting-in" gas anchor 450 or perforations 360.
[0028] The majority of gas bubbles escape the gas separator 110
during the downstroke of pump 440, as shown in FIG. 5. The flow of
fluid separated from gas bubbles 494 is suspended during the
downstroke of pump 440. Gas bubbles 491 escape through the open top
150 of gas separator 110. Gas bubbles 492 that are separated from
the fluid 490 at perforations 360 rise and escape through top
opening 150 of gas separator 110. Gas bubbles 493 that are
separated after perforations 360 rise through perforations 360 and
ultimately top opening 150 during the downstroke of pump 440.
[0029] It will be appreciated by those skilled in the art that
changes could be made to the embodiments described above without
departing from the broad inventive concept thereof. It is
understood, therefore, that this invention is not limited to the
particular embodiments disclosed, but it is intended to cover
modifications within the spirit and scope of the present invention
as defined by the following claims.
* * * * *