Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02716039 2010-09-27
SYSTEM, APPARATUS AND PROCESS FOR COLLECTING BALLS
2 FROM WELLBORE FLUIDS CONTAINING SAND
3
4 FIELD OF THE INVENTION
This invention relates generally to apparatus and process for the
6
retrieval of balls from a wellbore, such as drop balls, frac balls, packer
balls and
7 other
balls for interacting with downhole tools in the wellbore. The balls are
8
recovered from a wellbore fluid stream containing sand therein, which flows
from the
9
wellbore, such as after stimulation operations. More particularly, the
apparatus and
process uses apparatus affixed to the wellhead for receiving wellbore fluids
11
containing sand therein and having balls, discharging a portion of the
wellbore fluids
12 and
sand contained therein through a first flow outlet, redirecting or diverting
the
13 balls
to a retaining chamber, and blocking the balls from discharging from the
14
retaining chamber while permitting the wellbore fluids and sand contained
therein to
discharge from the ball catcher and be directed to downstream equipment for
16 treatment.
17
18 BACKGROUND OF THE INVENTION
19 It is
known to conduct fracturing or other treating procedures in a
wellbore by isolating zones in the wellbore using packers and the like and
subjecting
21 the
isolated zone to treatment fluids at treatment pressures. In a typical
fracturing
22
procedure, for example, the casing of the well is perforated to admit oil
and/or gas
23 from
the formation into the well and fracturing fluid is then pumped into the well
and
24
through these perforations into the formation. Such treatment opens and/or
enlarges
1
CA 02716039 2010-09-27
1 draining channels in the formation, enhancing the producing ability of
the well.
2 Alternatively, the completion can be an open hole type that is completed
without
3 casing in the producing formation area.
4 It is desired to stimulate multiple zones, or intervals within the
same
zone, using onsite stimulation fluid pumping equipment (pumpers). A packer
6 arrangement is inserted at intervals isolating one zone from an adjacent
zone. It is
7 known to introduce a drop ball through the wellbore to engage one of the
packers (or
8 packer interval) in order to block fluid flow therethrough. Passage
through a
9 downhole packer is thereby plugged off with this drop ball that is pumped
into the
wellbore during the stimulation flush. The drop ball blocks off this downhole
packer,
11 isolating the wellbore uphole of the downhole packer and consequently a
second
12 zone, above this downhole packer, can be stimulated. Once stimulated, a
13 subsequent drop ball can be dropped to block off a subsequent packer
uphole of the
14 blocked packer for stimulation thereabove. This continues until all the
desired zones
are stimulated.
16 At surface, the wellbore is generally furnished with a frachead
unit
17 including a multi-port block or a V-type frac header, isolation tool or
the like, which
18 provides fluid connections for introducing stimulation fluids including
sand, gels and
19 acid treatments.
After well operations, fluid from the well is flowed to surface through
21 the wellhead or frachead. The fluid is urged from the well such as under
formation
22 pressures and/or the influence of a gaseous charge of CO2 or N2. The
fluid from the
23 well exits the wellhead from a horizontally extending fitting. To
separate the balls
2
CA 02716039 2010-09-27
1 from the fluid, it is known to use a cross fitting apparatus such as a
plate extending
2 across the flow path from the wellhead. The plate is typically a plate
across the flow
3 path having large slots or screen at the face such as an upside down "U"
or fork
4 shape for impeding balls recovered with the fluid while permitting fluid
to flow
therethrough the "U" shape
6 It is known for balls, of which various sizes are employed in one
well
7 operation, to become lodged at the prior art U-shape or screen and block
fluid flow.
8 In other instances, the balls can break apart which encourages further
blockages.
9 During maximum flow back operations involving wellbore fluids
containing sand, stagnation of the wellbore fluids in the ball catcher and
related
11 apparatus can cause the sand entrained therein to settle and rapidly
accumulate,
12 interfering with ball catcher performance. Failure of the ball catcher
can result in
13 wellbore plugging and other complications.
14 Therefore, there is a need for a more effective apparatus for
retrieving
balls from wellbore fluids containing sand after a well operation.
16
3
CA 02716039 2010-09-27
1 SUMMARY OF THE INVENTION
2
Embodiments of the present invention intercept and divert balls
3
returning with wellbore fluid into a ball-recovery reservoir. A ball catcher
body
4
includes a replaceable diverter which separates balls and debris from the
fluid flow.
In embodiments, a sand-tolerant ball-retaining system continually removes
produced
6 sand
for avoiding sand accumulation in the ball catcher and associated apparatus,
7 resulting in improved, reliable ball catcher operations.
8 In one
aspect of the invention, apparatus is provided for retrieving
9
oversize debris and balls carried with a fluid flow from a wellhead port. A
catcher
body is adapted to be fluidly connected to the wellhead port and has a flow
outlet. A
11
diverter is fit to the catcher body and has a wellhead end positioned to
intercept the
12 fluid
flow from the wellhead port so as to divert debris and balls carried therein
into a
13 ball-
recovery chamber. The diverter has a wellhead end has flow passages formed
14
therethrough for receiving the fluid flow free of debris and balls. The
diverter has a
bore in fluid communication with the flow outlet. Fluid flow through the flow
16 passages enters the bore for discharge from the catcher body.
17 In
another aspect of the invention, a catcher body is connected and
18
positioned along a fluid flow path from the wellhead. The catcher body has a
first
19 flow
path contiguous with fluid flow from the wellhead and an intersecting stagnant
ball-recovery reservoir. The catcher body has a catcher flow outlet for fluid
free of
21 debris
and balls. The debris and balls have a first velocity vector along the flow
path
22
towards the catcher flow outlet. A diverter, fit to the catcher body and
having a
23
wellhead end extending into the flow path intercepts the fluid flow. The
diverter has
4
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1 a bore being open at a tail end and in fluid communication with the
catcher flow
2 outlet. The diverter has a diverter face at the wellhead end and being
positioned
3 inline with the first velocity vector for intercepting and substantially
arresting the
4 debris and balls and for diverting the debris and balls along into the
ball-recovery
reservoir. An annular chamber formed in the discharge outlet about the
wellhead
6 end of the diverter receives the fluid flow. A plurality of flow passages
extending
7 through the wellhead end of the diverter conduct fluid flow, free of
debris and balls,
8 from the annular chamber to the bore for discharge through the tail end.
9 In another aspect of the invention, a ball catcher and sand-
tolerant
ball-retaining system is provided for recovering at balls carried in wellbore
fluids
11 having sand. A receiving chamber is fluidly connected to the wellbore
for receiving
12 the wellbore fluids containing sand. The receiving chamber has a first
flow outlet for
13 discharging a portion of the wellbore fluids and sand contained therein
to
14 downstream equipment and a ball outlet for discharging a balance of the
wellbore
fluids also containing sand. A diverter, fit to the receiving chamber,
redirects the
16 balls to the ball outlet. A ball-retaining chamber, fluidly connected
below the ball
17 outlet, receives the redirected balls and the balance of the wellbore
fluids. The ball
18 catcher further has a blocker fit to a second flow outlet from the ball-
retaining
19 chamber for retaining the balls within the ball-retaining chamber while
permitting the
discharge of the balance of the wellbore fluids and sand contained therein,
free of
21 the balls, to the downstream equipment.
22 In another aspect of the invention, a sand-tolerant ball-retaining
system
23 can be positioned between a ball-recovery chamber and an isolation valve
below a
5
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1 ball catcher to enable continual flow of wellbore fluid while safely
recovering
2 collected balls from the ball-recovery chamber.
3 In another aspect, a system for a ball catcher is disclosed which
4 redirects balls carried in wellbore fluids having a sand content to a
ball-recovery
chamber and passes a portion of the wellbore fluids free of the balls to
downstream
6 equipment. The system has a ball-retaining chamber fluidly connected
below the
7 ball catcher for receiving the balls and a balance of the wellbore fluids
and sand
8 contained therein. The ball-retaining chamber has an outlet fit with a
blocker for
9 retaining the within the ball-retaining chamber while discharging and
directing the
balance of the wellbore fluids and sand contained therein, through an
auxiliary flow
11 line to downstream equipment.
12 Yet in another aspect of the invention, a process for recovering
balls
13 carried in wellbore fluids containing sand is disclosed. The process
involves
14 receiving the wellbore fluids containing sand in a receiving chamber;
discharging a
portion of the wellbore fluids and sand contained therein, free of the balls,
through a
16 flow outlet while discharging a balance of the wellbore fluids and sand
contained
17 therein to a ball-retaining chamber, redirecting the at least balls to
the ball-retaining
18 chamber, blocking the at least balls within the ball-retaining chamber
from
19 discharging therefrom, and discharging the portion of the wellbore
fluids and sand
contained therein, free of the balls, from the ball-retaining chamber.
21 As a result, a reliable and easy to clean sand-tolerant ball
catcher is
22 provided for servicing wells after stimulation and cleaning operations.
23
6
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1 BRIEF DESCRIPTION OF THE DRAWINGS
2 Figure
1 is a cross-sectional view of a wellhead of conventional
3
configuration fit with a flow port such as a frachead and a ball catcher
according to
4 one embodiment of the invention;
Figure 2 is a cross section of a ball catcher body according to one
6
embodiment of the invention fit to a flow port of a wellhead illustrating the
sequential
7
movement of a ball carried out of a wellbore with fluid flow to divert for
recovery in
8 the ball-recovery reservoir;
9
Figures ,3A is a side cross-sectional view of an embodiment of a ball
diverter;
11
Figures 3B and 3C are face and partial top views of the diverter of Fig.
12 3A along lines B-B and C-C respectively;
13 Figure
4 is a partial cross-sectional close up view of the diverter of Fig.
14 4 installed in the ball catcher body;
Figures 5A, 5B, 5C, 5D and 5E are cross-sectional views of various
16 embodiments of a diverter;
17 Figure
6 is a cross-section of an alternate embodiment of a ball catcher
18 body and illustrating a diverter accordingly to Fig. 5E;
19 Figure
7 is a cross-sectional view of a wellhead of conventional
configuration fit with a first ball catcher and showing a second ball catcher
for
21 connection to the wellhead according to another embodiment of the
invention;
22 Figure
8 is a flow chart of a process of an embodiment of the present
23 invention;
7
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1 Figure
9 is schematic representation of an embodiment of the present
2
invention illustrating the flow of wellbore fluids through a ball catcher
having a ball
3
receiving chamber, a first flow outlet, a ball outlet, a ball-retaining
chamber, and an
4 auxiliary flow line;
Figure 10 is a schematic representation of an embodiment of the
6
present invention illustrating a ball catcher having a ball receiving chamber,
a first
7 flow
outlet, a ball outlet, a diverter, a ball-retaining chamber, a blocker and an
8 auxiliary flow line;
9 Figure
11A is a cross-sectional view of an embodiment of the present
invention illustrating a blocker having a blocker bore therethrough and a
chamber
11 end having a fluid passageway;
12 Figure
1 1B is a cross-sectional view of an embodiment of the present
13
invention illustrating a blocker having a blocker bore therethrough and a
chamber
14 end having two or more fluid passageways;
Figures 11C and 1 1 D are a cross-sectional view of an embodiment of
16 the
present invention illustrating a blocker having a blocker bore therethrough
and a
17 chamber end comprising a fluid passageway and a plurality of radial
passageways;
18 Figure
11E is a cross-sectional view of an embodiment of the present
19
invention illustrating a blocker having a blocker bore therethrough and a
chamber
end comprising a fluid passageway and a plurality of radial passageways
axially
21 angled;
22 Figure
12 is a schematic representation of an embodiment of the
23
present invention illustrating a blocker having a chamber end shaped to
prevent
8
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1 recovered balls from blocking a fluid passageway and the plurality of
radial
2 passageways from fluidly communicating wellbore fluids;
3 Figure 13 is a schematic representation of an embodiment of the
4 present invention illustrating a ball-recovery chamber fluidly connected
to the bottom
of a ball-retaining chamber;
6 Figure 14 is a side cross-sectional view of an embodiment of a ball
7 diverter comprising a diverter face having a substantially vertical top
face and an
8 angled lower face;
9 Figure 15 is a schematic representation of an embodiment of the
ball
catcher of Fig. 9 wherein the flow from the first flow outlet and the
auxiliary flow line
11 are directed separately to the same downstream equipment; and
12 Figure 16 is a schematic representation of an embodiment of the
ball
13 catcher of Fig. 9 wherein the flow from the first flow outlet and the
auxiliary flow line
14 are directed separately to distinct downstream equipment.
16 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
17 With reference to Fig. 1, in the context of fracturing a formation
18 traversed by a wellbore and recovering fluid therefrom, a wellhead 10 is
connected
19 to the wellbore (not shown) for introducing fracturing fluid and drop
balls for various
operations to the wellbore. The wellhead comprises a shutoff valve 11 and a
flow
21 port 12 thereabove, typically integrated with a frachead. Thereafter a
fluid flow F
22 carrying debris and drop balls B are flowed out of the well through the
flow port along
23 a fluid path 13. While a variety of materials such as frac sand are
carried out of the
9
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1 wellbore with the fluid flow, for the purposes of simplicity herein, this
application
2 discusses the apparatus and operations in the context of the recovery of
balls.
3 With reference to Fig. 2, an embodiment of a ball catcher 20 is
adapted
4 to be connected to the wellhead's flow port 12, such as through an
isolation valve 14,
for catching drop balls B before they travel downstream and adversely affect
other
6 equipment.
7 As shown, the ball catcher 20 comprises a catcher body 21 fit to
the
8 wellhead 10 or isolation valve 14 at a wellhead connection using industry
approved
9 threaded or flanged connections. The catcher body 21 further comprises a
stagnant
reservoir or ball-recovery chamber 22 which intersects the fluid path 13.
Fluid flow F
11 flows along a first velocity vector or fluid path 13 and is interrupted
with a diverter 23
12 fit to a catcher flow outlet 24. The fluid flow F carries the balls to
impact the diverter,
13 separating fluid flow F and the balls B for discharge of the fluid flow
from the catcher
14 flow outlet 24 and recovery of the balls at the ball-recovery chamber
22.
With reference also to Figs. 3A-3C, the diverter 23 has a wellhead end
16 30 for intercepting the fluid flow F and a diverter body 31 fluidly
sealed, such as by
17 an 0-ring 29, to the catcher flow outlet 24. The diverter body 31 has
bore 32 and a
18 fluid discharge or tail end 33. The bore 32 is open at the tail end 33
and in fluid
19 communication with the catcher flow outlet 24 for the collection and
discharge of fluid
flow F liberated of oversize solids such as the balls B. The wellhead end 30
of the
21 diverter 23 projects into the fluid path 13 and comprises a diverter
face 34 positioned
22 in the fluid path 13. The diverter face 34 is positioned inline with the
first
CA 02716039 2016-03-09
1 velocity vector for intercepting and substantially arresting the debris
and balls B and
2 for diverting the debris and balls along into the ball-recovery chamber
22.
3 Referring also to Fig. 2, kinetic energy in balls B is dissipated
at the
4 diverter face 34 and the balls fall under gravity into the ball-recovery
chamber 22.
The ball-recovery chamber 22 is intersects and fluidly contiguous with, but
diverges
6 from, the flow path 13. As shown, the flow path can be substantially
horizontal from
7 the wellhead 10 and ball-recovery chamber 22 is positioned below the
diverter face
8 34. The diverter face 34 can be angled downward, from top to bottom and
away from
9 the fluid path 13, for directing, deflecting or urging the balls downward
into the ball-
recovery chamber 22. A cross-sectional dimension of the diverter face 34 can
be
11 substantially the diameter of that of the flow path 13. Best seen in
Fig. 3, the diverter
12 face 34 can have a concave face having an axis oriented generally
downwards
13 towards the ball-recovery chamber 22.
14 With reference to Fig. 4, the diverter face 34 diverts oversize
solids,
such as debris or balls B.
16 In one embodiment, the diverter face 34 diverts a portion or all of
the
17 fluid flow F therearound. An annular chamber 40 is formed in the catcher
body 21 or
18 catcher flow outlet 24 about the wellhead end 30 of the diverter 23. The
annular
19 chamber 40 receives fluid flow F continuing to flow substantially along
the flow path
13 and about the diverter face 34. The fluid flow F flows through the annular
21 chamber 40 and inward through flow passages 41 formed or extending
through the
22 wellhead end 30. The bore 32 receives fluid flow F free of debris and
balls for
23 discharging the fluid flow from the catcher body.
11
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1 With
reference to Figs. 5A ¨ 5C, the diverter 23 can be removably fit to
2 the
catcher body, similar to a cartridge, for ease of replacing the wear
components.
3 The
diverter body 31 can be one piece 31s, as shown in Fig. 5C, or two or more
4 pieces
31m, as shown in Figs. 5A and 5B. A two-piece body 31m permits the most
wear prone portion, the wellhead end 30, being separable from the tail end 33.
The
6
wellhead end 30 could be manufactured of wear resistant material.
Alternatively, the
7 flow
passageways 41 are wear resistant, being coated with wear resistant material
or
8 be
manufactured using replaceable, hardened orifices (not shown). The wellhead
9 end 30
comprises the diverter face 34 and the flow passages 41 for conducting fluid
flow F to the bore 32. The wellhead end 30 of a two-piece diverter body 31m
has a
11
threaded pin portion 42 and fluid seal 43 for sealing to a box end 44 of the
tail end
12 33. The
tail end 33 has a second fluid seal, such as the 0-ring 29, for sealing to the
13 catcher body 21.
14 As
shown in Fig. 4, the diverter body 31 can be cylindrical for insertion
into the catcher flow outlet 24 and secured or retained therein by quick
connection
16 such as
a coupling 50 and hammer nut 51. The diverter can also be retained using a
17 flanged
or similar connection (not shown). The coupling 50 can be threadably
18 engaged
with the diverter's tail end 33. Replacement of the diverter can be effected
19 by
equalizing fluid pressure in the catcher body 21, releasing the hammer nut 51
and
replacing the entire diverter body 31 or replacing a worn wellhead end 30 of a
two
21 piece diverter body 31m.
22 The
flow passages 41 can be radial flow passages 41 or extend
23
substantially in-line with the flow path 13. As shown in Figs 5A-5C and 5E,
some flow
12
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1 passages 41 though the wellhead end 30 can be radial, extending to the
bore 32.
2 Further, the flow passages 41 can be oriented radially and opposingly
positioned to
3 neutralize fluid energy as the fluid flow F enters the diverter bore 32.
The plurality of
4 flow passages can be arranged in pairs of opposing flow passages 41p for
directing
fluid flow F to impinge each other within the bore 32 and dissipate energy to
6 minimize erosion.
7 The flow passages 41 in the diverter are sized to pass the fluid
flow F
8 and can be oversized to accommodate accumulative loss due to plugging.
Further,
9 the fluid passages can be sized to be large for passing a range of
particulates to the
downstream equipment. In another embodiment, the fluid passages can be small
11 (Figs. 5A and 5D) for blocking the passage of large particulates for the
protection of
12 the downstream equipment, the large particulates being collected instead
in the ball-
13 recovery chamber 22. A plurality of small flow passages 41, such as
those shown in
14 Fig. 5A, can act as screen to reject undesirable particulates.
Similarly, a cylindrical
screen could be fit over larger flow ports.
16 For example, with reference to the embodiment of Fig. 4, eight flow
17 passages 41 arranged in four pairs 41p, positioned at quadrants, at 1/8"
diameter
18 each can pass 5-7 m3 (per hour) of fluid (such as water or lighter
hydrocarbons).
19 Eight flow ports at 5/32" diameter can (each) pass 9-11 m3 / hour and
1/4" ports can
(each) pass 20-25 m3 (per hour). The greater the number of flow passages
passing
21 the return fluid, the less the erosion, thus increasing the life and
efficiency of the
22 diverter or diverter cartridge.
13
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1 With
reference to Fig. 6, in another embodiment, the diverter 23 can
2 further
comprise in-line flow ports through the diverter face 34 and oriented into the
3 fluid
path 13. The in-line flow passages are smaller in diameter than are the solids
or
4 balls B being rejected and collected in the ball-recovery chamber 22.
6 Operation
7 As
shown in the embodiments shown in Fig. 2, upon establishing fluid
8 flow F
from the wellbore, balls B (and other debris) engage the diverter face 34 and
9 are
collected in the ball-recovery chamber 22. Fluid flow F continues downstream,
passes through the diverter's flow passages and is discharged through the
diverter's
11 tail end 33 to other equipment as is the usual practice in the industry.
12
Periodically, the wellhead 10 is shut in and a bleed valve 60 such as
13
positioned atop the catcher body 21, is vented to equalize pressure therein
and the
14 ball-
recovery chamber 22 can be emptied of debris and balls B. The diverter 23 can
be quickly inspected and replaced as necessary, therefore decreasing the down
time
16 in flow
back procedures. The ball-recovery reservoir can further comprise a pup joint
17 55
coupled releaseably to the ball-recovery chamber 22 using quick connect
18
couplings 56. In another embodiment the wellhead 10 can be isolated from a
catcher
19 body 21
and fluid from the downstream equipment can be backflowed through the
diverter 23 and ball-recovery chamber 22 for cleaning.
21 With
reference to Fig. 7, a second ball catcher 20B, or more depending
22 upon
the wellhead, can be fit to the wellhead 10 of Fig. 1, also with isolation
valving
23 14,14
between the wellhead 10 and each of the ball catchers 20,20B. Accordingly,
14
CA 02716039 2016-03-09
1 the
first ball catcher 20 can be serviced, for replacement of the diverter 23 or
2
inspection and cleaning of the chamber 22, while the second ball catcher 20B
is in
3
operation. In this way, wellhead flow is not interrupted. In some wellbores,
even a
4 temporary interruption can result in an unfavorable loss of suspended
materials
which are being elutriated from the wellbore with the fluid flow. Accordingly,
6 redundant ball catchers 20,20B are affixed to two or more flow paths 13 from
the
7
wellhead so that fluid flow F from the wellbore can be substantially
continuous to the
8 second ball catcher 20B while the first ball catcher 20 is taken out of
service.
9
Undesirable sand plugs or debris plugs can occur from the fallout and
or the formation may lose its upward energy and die which requires expensive
coil
11 tubing
to clean the well pipe. Also flowback disruption during coil clean out, or for
12 example
bridge plug mill out, needs to be avoided because the fallout can create a
13 sand
plug and jam around the coil tubing causing further and significant expense.
14 The second ball catcher 20B can be opened for operation, both being used
temporarily, before closing in the first catcher for servicing.
16 In
another embodiment shown in Fig. 6, an isolation valve 62 can be
17
provided to optionally temporarily block the ball-recovery chamber 22 from the
18 catcher
body 21 for servicing. Further, a purge port 63 can be provided to introduce
19
nitrogen to purge the ball-recovery reservoir of noxious gases such as
hydrogen
sulphide.
21 In
summary, when conducting flow back operations involving wellbore
22 fluids
not having a high sand-content, an apparatus for retrieving at least balls
23 carried
within a fluid flow from a wellhead port can comprise a catcher body adapted
CA 02716039 2016-03-09
1 to be
fluidly connected to the wellhead port and having a flow outlet; and a
diverter fit
2 to the
catcher body and having a wellhead end positioned to intercept the fluid flow
3 from
the wellhead port and to divert at least the balls carried therein into a ball
4
recovery chamber, the diverter having a bore in fluid communication with the
flow
outlet and the wellhead end having flow passages formed therethrough to the
bore
6 for
receiving the fluid flow free of at least the balls and discharging the fluid
flow from
7 the
catcher body, wherein an annular chamber is formed between the catcher body
8 and the wellhead end of the diverter and some of the flow passages being
radial
9 passages extending between the annular chamber and the bore, for directing
at
least some of the fluid flow.
11 The
wellhead end of the diverter can have a diverter face that is angled
12 away,
such as having a concave face having an axis generally towards the ball
13
recovery chamber, from the fluid flow for directing at least the balls into
the recovery
14 chamber.
In another embodiment, as shown by the left-hand flow F in Fig. 1 and
16 the
structures 20B,20 set forth in Fig. 7, the ball catcher can further comprise
17
redundant catcher bodies 20,20B affixed to each of two or more flow paths from
the
18
wellhead 10 so that fluid flow from the wellbore can be substantially
continuous to a
19 first catcher body 20 while a second catcher body 20B is taken out of
service.
Yet, in another embodiment, an apparatus for retrieving at least balls
21 carried
within a fluid flow from a wellhead port can comprise a catcher body adapted
22 to
be fluidly connected to the wellhead port and having a flow outlet; and a
diverter fit
23 to
the catcher body and secured in the flow outlet with a quick connection, the
16
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1 diverter having a wellhead end positioned to intercept the fluid flow
from the
2 wellhead port and to divert at least the balls carried therein into a
ball-recovery
3 chamber, the diverter having a bore in fluid communication with the flow
outlet and
4 the wellhead end having flow passages formed therethrough to the bore for
receiving
the fluid flow free of at least the balls and discharging the fluid flow from
the catcher
6 body.
7
8 WELLBORE FLUIDS CONTAINING SAND
9 It has been found that there can be instances during flow back
operations which involve wellbore fluids having sand entrained therein in
sufficient
11 quantities that can cause the sand to accumulate and compact in the ball-
recovery
12 chamber of a ball catcher. The accumulation of the sand in the ball-
recovery
13 chamber can displace or otherwise prevent returning balls from being
recovered and
14 stored therein, causing the balls to collect and jam in the ball catcher
body above the
sand and potentially in the wellhead itself. The jamming of the recovered
balls can
16 cause disruption of the flow of the wellbore fluids through the
wellhead, ball catcher
17 and the isolation valves associated with the ball catcher. Effects of
flow disruption
18 can result in temporary shutdown causing the well to load up, sand to
fall out of the
19 column of uprising wellbore fluid and cause sand plugs which can require
expensive
coil tubing cleanout. Thereafter, even after one flow resumes, the velocity of
the
21 wellbore fluid might be reduced and be insufficient to return balls.
Further, continued
22 flowback around jammed balls can lead to rapid erosion of those parts
exposed to
23 the disrupted flow of the wellbore fluids.
17
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1 It has
been found that the wellbore fluids in the ball-recovery chamber
2 remain
stagnant, thus permitting sand in the fluid to settle out and accumulate in
the
3 ball-
recovery chamber. The accumulated sand within the ball-recovery chamber can
4 compact
upon itself, leading to the accumulated sand compacting under its own
mass.
6
Compacted sand has been found to interfere with the normal
7
operations of equipment such as the isolation valve. The compacted sand can be
8 forced
to enter areas for sealing and other cavities leading to premature erosion of
9 these parts as well as possible malfunctions.
Furthermore, the process of the removing any collected balls and sand
11 from
the ball catcher involves isolating the ball catcher from the returning
wellbore
12 fluids.
Such isolation procedures causes a disruption in the wellbore fluid flow which
13 may also cause jamming and malfunctions of the ball catcher.
14 As
shown in Fig. 8, to prevent sand from accumulating and compacting
within the ball-recovery chamber, wellbore fluid is directed therethrough for
clearing
16 sand
which would otherwise settle therein. This is a sand-tolerant ball-retaining
17 system
which is applicable to embodiments of ball catchers disclosed herein and to
18 other
forms of ball catchers which have a wellbore fluid receiving chamber, a
diverter,
19 a ball outlet and a ball-free fluid outlet.
In an embodiment, a process for recovering balls carried in wellbore
21 fluids
containing sand can comprise the steps of receiving the wellbore fluids
22
containing sand 100, discharging a portion of the wellbore fluids and sand
contained
23 therein
through a first flow outlet and discharging a balance of the wellbore fluids
and
18
CA 02716039 2016-03-09
1 sand contained therein to a ball-retaining chamber 110, redirecting balls
to the ball-
2 retaining chamber 120, blocking the redirected balls from discharging
from the ball-
3 retaining chamber 130 and discharging the balance of the wellbore fluids
and sand
4 contained therein from a second flow outlet to downstream equipment 140.
Fig. 9 illustrates the flow F of the wellbore fluids containing sand in an
6 embodiment of the sand-tolerant ball catcher 200. The wellbore fluids
containing
7 sand and having balls carried therein are received in a catcher body 210
which
8 defines a receiving chamber 220 having a first flow outlet 230 for
discharging a
9 portion of the wellbore fluids and sand entrained or contained therein
and a ball
outlet 240 for discharging a balance of the wellbore fluids and sand contained
11 therein. A diverter 250 is fit within the receiving chamber 220 for
redirecting the balls
12 to the ball outlet 240.
13 A ball-retaining chamber 260 is fluidly connected below the ball
outlet
14 240 and receives the redirected balls and the balance of wellbore fluid
and sand
contained therein. A blocker 270, fit within the ball-retaining chamber 260,
blocks
16 balls from leaving therefrom while permitting the balance of the
wellbore fluids and
17 sand contained therein to flow out of the ball-retaining chamber 260. A
blocker 270,
18 can include a device similar in form to the ball diverter as disclosed
in previous
19 embodiments above, or a form of screen, any of which act to block balls
from
discharging with the balance of the wellbore fluid. Similarly, the diverter
could be can
21 include a device similar in form to the blocker as disclosed in
embodiments below,
22 any of which act to block and therefore divert balls from the receiving
chamber.
19
CA 02716039 2016-03-09
1 Thus,
the retaining chamber 260 retains the redirected balls within the
2 ball-
retaining chamber 260, while discharging the balance of wellbore fluids
through
3 to downstream equipment.
4 The
constant flow of the sand-containing wellbore fluids through the
receiving chamber 220, through the ball-retaining chamber 260 and to
downstream
6
equipment keeps sand suspended, preventing sand from settling out,
accumulating
7 and compacting within the ball catcher 200.
8 With
reference to Figs. 9 and 10, an embodiment for the sand-tolerant
9 ball
catcher 200 for recovering at balls from wellbore fluids containing sand is
illustrated. The ball catcher 200 comprises a catcher body 210 defining a
receiving
11 chamber
220 for receiving the wellbore fluids, a first flow outlet 230 for discharging
a
12 portion
of the wellbore fluids and sand entrained therein and a ball outlet 240 for
13
discharging a balance of the wellbore fluids also containing sand. Fit to the
catcher
14 body
210 and within the receiving chamber 220 is a diverter 250 for diverting at
least
balls to the ball outlet 240. The portion of the wellbore fluids discharged
through the
16 first flow outlet 230 is directed to downstream equipment (not shown)
for treatment.
17 The
diverter 250 can be the diverter as disclosed above or can be any
18
diverter known and used in the industry. As shown in Fig. 14, and in an
embodiment,
19 the
diverter 250 can further comprise a diverter face 251 having a substantially
vertical top face 252 and an angled lower face 253.
21 A ball-
retaining chamber 260 is fluidly connected below the ball outlet
22 240 for
receiving the redirected balls and the balance of the wellbore fluids from the
23
receiving chamber 220. The ball-retaining chamber 260 comprises a second flow
CA 02716039 2016-03-09
1 outlet 280 for discharging the balance of the wellbore fluids. An
auxiliary flow line
2 290 is fit between the ball-retaining chamber and the downstream
equipment. Fit
3 along the auxiliary flow line 290 or, as shown in this embodiment, being
fit within the
4 second flow outlet 280, is a blocker 270 for blocking and retaining the
redirected
balls within the ball-retaining chamber 260 while permitting the balance of
the
6 wellbore fluids to flow therethrough and be directed to downstream equipment
via
7 the auxiliary flow line 290. In one embodiment, the auxiliary flow line
290 can be
8 directed separately to the same 292 (see Fig. 15) or distinct downstream
equipment
9 292,294 (see Fig. 16), or in another embodiment as shown, the balance of the
wellbore fluids and sand contained therein from the ball-retaining chamber are
11 directed to, or to combine with the portion of the wellbore fluid from
the first flow
12 outlet.
13 As shown in Fig. 11A, the blocker 270 has a blocker body 271 and a
14 blocker bore 272 extending axially therethrough. A chamber end 273 of
the body 271,
for communication with or extension into the retaining chamber 260 for
intercepting
16 the flow F of the balance of wellbore fluids, has at least one fluid
passageway 274
17 for fluidly communicating the balance of the wellbore fluids from the
retaining
18 chamber 260 into the blocker bore 272. The blocker body 271 has an open
tail end
19 275 in fluid communication with the auxiliary flow line 290 for
discharging the
balance of the wellbore fluids from the ball catcher 200.
21 With reference to Fig. 11B, and in an embodiment, the at least one
fluid
22 passageway can comprise two or more fluid passageways for fluidly
communicating
23 the balance of the wellbore fluids from the retaining chamber 260 into
the blocker
21
CA 02716039 2016-03-09
1 bore 272. The two or more fluid passageways can be arranged to be axially
angled
2 from a longitudinal axis LA of the blocker bore 272 and arranged to
direct wellbore
3 fluids from the ball-retaining to impinge each other within the blocker
bore 272 to
4 dissipate fluid energy and minimize erosion of the blocker bore 272.
As shown in Figs. 11C and 11D, at the chamber end 273 the fluid
6 passageways can further comprise a plurality of radial passageways 276
7 circumferentially spaced about the chamber end 273 extending radially
from the
8 retaining chamber 260 to the blocker bore 272. The plurality of radial
passageways
9 276 can be arranged to direct the wellbore fluids therefrom to impinge
each other
within the blocker bore 272 to dissipate fluid energy and minimize erosion. In
one
11 arrangement, the plurality of radial passageways 276 can be opposing
passageways
12 arranged in pairs to neutralize fluid energy as the wellbore fluid
enters the blocker
13 bore 272.
14 As shown in Fig. 11E, and in another embodiment, the plurality of
radial passageways 276 can be axially angled from the longitudinal axis LA of
the
16 blocker bore 272 to further dissipate the fluid energy imparted by the
wellbore fluids
17 flowing therethrough.
18 With reference to Fig. 12, the chamber end 273 of the blocker 270
19 extends into the retaining chamber 260 and is positioned to intercept
the wellbore
fluids. The chamber end 273 comprises the at least one fluid passageway 274,
21 centrally located on the chamber end 273 and the plurality of radial
passageways
22 276 for permitting wellbore fluids to pass therethrough. The chamber end
273 can be
23 shaped to ensure that any redirected balls adjacent thereto will not
block the at least
22
CA 02716039 2016-03-09
1 one fluid passageway 274 nor the plurality of radial passageways 276 to
disrupt the
2 flow of the wellbore fluids through the blocker 270. In an embodiment,
the chamber
3 end 273 can be conical in shape to urge blocked balls adjacent the chamber
end
4 273 away from the at least one fluid passageway 274 and the plurality of
radial
passageways 276.
6 Similar to the diverter body 31, the blocker body 271 can be
cylindrical
7 for removable fitment to the retaining chamber 260. It can be secured by
quick
8 connection such as a coupling and a hammer nut. The blocker body 271 can
also be
9 retained using a flange or similar connection.
In an embodiment having plurality of radial flow passages 276, the
11 blocker 270 or the ball-retaining chamber 260 need to accommodate
communication
12 of fluid to the radial flow passages 276. Referring back to Figs. 10 and
12, in an
13 embodiment, and similar to the annular chamber 40 formed about the
wellhead end
14 30 of the diverter 23, a blocker annular chamber 310 can be formed in
the second
flow outlet 280 about the chamber end 273 of the blocker 270. Wellbore fluids
16 containing sand from the retaining chamber 260 flow through the blocker
annular
17 chamber 310 and inwards through the plurality of radial flow passages
276. The fluid
18 energy of the wellbore fluids can dissipate somewhat by decreasing the
wellbore
19 fluid velocity when flowing into the blocker annular chamber 310 from
the retaining
chamber 260.
21 In an alternate embodiment, the second flow outlet 280 and the
blocker
22 270 can be positioned below the ball-retaining chamber 260 to
continuously remove
23 and prevent sand from accumulating in the ball catcher 200. In such an
embodiment,
23
CA 02716039 2016-03-09
1 the ball-retaining chamber 260 could be reinforced with wear resistant
materials as
2 the fluid flowing around the collected balls could cause the balls to
bounce around
3 within the ball-retaining chamber 260, increasing the rate of wear on the
retaining
4 chamber 260 and the blocker 270.
In another embodiment, the blocker 270 can be manufactured from
6 wear resistant materials or have a wear resistant coating for prolong the
operational
7 life of the blocker. The at least one fluid passageway 274 and the
plurality of radial
8 passageways 276 can be coated with a wear resistant material for
prolonging the
9 operational life of the blocker 270.
In other embodiments, the retaining chamber 260 can have two or
11 more flow outlet ports for accessing the ball-retaining chamber 260.
Each of the two
12 or more flow outlets can be positioned either at a side of the ball-
retaining chamber
13 260 or can be positioned at a bottom of the retaining chamber 260. The
additional
14 flow outlet ports can allow an operator to customize the ball catcher
200 to suit their
particular needs. In one embodiment, an extra flow outlet can be used to
access the
16 retaining chamber 260 to remove collected balls. In another embodiment,
an extra
17 flow outlet can be used to access the retaining chamber with another
redundant
18 blocker to serve as a backup blocker and flow outlet in case the first
blocker fails.
19 Yet in another embodiment, an extra flow outlet can be used to install a
valve to
bleed off pressure within the retaining chamber.
21 In an embodiment, and as shown in Figs. 9, 10, 12 and 13, isolation
22 valves 330, 331, 332 can be installed between the ball catcher 200 and
the wellhead
23 (not shown), between the receiving chamber 220 and the retaining chamber
260,and
24
CA 02716039 2016-03-09
1 between the retaining chamber 260 and the auxiliary flow line 290. The
isolation
2 valves 330, 331, 332 can be used to isolate fluid flow through either the
first flow
3 outlet in the catcher body 210 or through the auxiliary flow line 290
from the retaining
4 chamber 260 to maintain a continual flow of wellbore fluids through of
the ball
catcher 200.
6 For example, during flow back operations, all three isolation
valves 330,
7 331, 332 are open to allow wellbore fluids to flow into the ball catcher
200. As flow
= 8 back operations continue, the retaining chamber 260 will collect
balls from the
9 balance of wellbore fluids containing sand passing therethrough,
necessitating the
eventual removal of the balls from the retaining chamber 260.
11 To remove collected balls, isolation valves 331, 332 between the
12 receiving chamber 220 and the retaining chamber 260, and between the
retaining
13 chamber 260 and the auxiliary flow line 290 can be closed to isolate the
retaining
14 chamber 260. The closing of isolation valves 331, 332 still maintains a
continual fluid
flow from the wellhead (not shown), through the receiving chamber 220, through
the
16 first flow outlet 230 and to downstream equipment.
17 With particular reference to Fig. 12, a bleed off valve 340 can
be
18 opened to bleed off pressure within the retaining chamber 260. The
collected balls
19 can be removed safely by accessing the retaining chamber 260 through a
bottom
outlet port 350 on the bottom of the retaining chamber 260. During removal of
the
21 balls, the wellbore fluids containing sand continue to flow from the
wellhead (not
22 shown), through the receiving chamber 220 and out the first flow outlet
230,
23 preventing sand from settling and accumulating in the ball catcher 200.
The
CA 02716039 2016-03-09
1 continual flow of wellbore fluids containing sand also prevents balls
still to be
2 recovered from jamming in the ball catcher 200 and the wellhead.
3 The embodiments discussed herein so far relate to a preferred
4 embodiment of the present invention, having the blocker 270 positioned at
a side of
the retaining chamber 260 while reserving an outlet port at the bottom of the
6 retaining chamber 260 for the removal of any recovered balls from the
retaining
7 chamber 260. Removal of recovered balls through the bottom outlet port
350 eases
8 the removal operation as the recovered balls can simply drop from the
retaining
9 chamber 260 by force of gravity.
However, a person of ordinary skill in the art would understand that in
11 an alternate embodiment, the blocker 270 can be positioned below the
retaining
12 chamber 260 and a side outlet port can be used to remove any recovered
balls from
13 the retaining chamber 260. In using such as embodiment, an operator
cannot simply
14 rely on the force of gravity to cause recovered balls to fall from the
retaining chamber
260. Instead, the operator must physically remove the recovered balls from the
16 retaining chamber 260, making the removal operation much more arduous.
17 In another embodiment, and as shown in Figs. 9 and 13, a ball
18 recovery chamber 320 is fluidly connected below the ball-retaining
chamber 260 for
19 allowing the redirected balls to be removed from the flow passage area
of the ball
retaining chamber 260 and collect in the ball-recovery chamber 320. In the
event
21 that the flow back is extremely high in sand content, sand can
accumulate and
22 compact in the ball-recovery chamber 320. However, as the level of the
accumulated
23 and compacted sand reaches the blocker 270, the at least one fluid
passageway 274
26
CA 02716039 2016-03-09
1 and the plurality of radial passageways 276 permit a slurry of sand to
continuously
2 flow through the blocker 270 and be expelled from the ball catcher 200
through the
3 auxiliary flow line 290. This prevents accumulated sand to compact higher
than the
4 blocker 270, preventing a jamming of the ball catcher 200 with recovered
balls.
In another embodiment for accessing the ball-retaining chamber 260
6 for removing collected balls, and as shown in Fig. 12, the ball-retaining
chamber 260
7 has a bleed valve 340 for bleeding off any pressure in the ball-retaining
chamber 260
8 after isolation valves 331,332 are closed. Once the pressure is safely
bled off, one
9 can remove collected balls and other collected debris from the ball-
retaining
chamber 260 and ball-recovery chamber 320. Thus, in one process for removing
11 collected balls, one isolates the ball-retaining chamber from the
receiving chamber
12 and directing the wellbore fluids and sand contained therein to the
downstream
13 equipment, isolates the ball-retaining chamber from the downstream
equipment,
14 bleeds off any pressure from the ball-retaining chamber, and accesses
the ball
retaining chamber for removing balls collected therein.
27
