U.S. patent application number 11/769540 was filed with the patent office on 2007-10-18 for choke for controlling the flow of drilling mud.
Invention is credited to Egbert Jan VAN RIET.
Application Number | 20070240875 11/769540 |
Document ID | / |
Family ID | 30011236 |
Filed Date | 2007-10-18 |
United States Patent
Application |
20070240875 |
Kind Code |
A1 |
VAN RIET; Egbert Jan |
October 18, 2007 |
CHOKE FOR CONTROLLING THE FLOW OF DRILLING MUD
Abstract
A drilling system and method for drilling a well bore in to an
earth formation is provided with drilling means for drilling a well
bore and pumping means for pumping drilling fluid into the wellbore
during drilling. Also provided is a drilling outlet system for
retrieving drilling fluid from the well bore. The drilling fluid
outlet system has choke means for choking the return flow of
retrieved drilling fluid, and alternating means for alternating the
flow direction through the choking means.
Inventors: |
VAN RIET; Egbert Jan;
(Rijswijk, NL) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
30011236 |
Appl. No.: |
11/769540 |
Filed: |
June 27, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10520606 |
Jan 6, 2005 |
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PCT/EP03/06750 |
Jun 24, 2003 |
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11769540 |
Jun 27, 2007 |
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Current U.S.
Class: |
166/91.1 ;
166/316 |
Current CPC
Class: |
E21B 21/106
20130101 |
Class at
Publication: |
166/091.1 ;
166/316 |
International
Class: |
E21B 21/01 20060101
E21B021/01; E21B 21/10 20060101 E21B021/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 8, 2002 |
EP |
02254746.7 |
Claims
1. A drilling system for drilling a well bore into an earth
formation, comprising: drilling means for drilling a well bore;
pumping means for pumping drilling fluid into the well bore during
drilling; and a drilling fluid outlet system for retrieving
drilling fluid from the well bore, said drilling fluid outlet
system comprising a choke means for choking the return flow of
retrieved drilling fluid, and alternating means for alternating the
flow direction through the choking means.
2. The drilling system according to claim 1, wherein the drilling
fluid outlet system comprises an accumulator.
3. The drilling system according to claim 2, wherein the
alternating means comprise a four way valve, having four
connections and wherein the connections are connected two by
two.
4. The drilling system according to claim 2, wherein the choking
means comprise a bidirectional choke.
5. The drilling system according to claim 1, wherein the choking
means comprise at least two unidirectional chokes.
6. The drilling system according to claim 5, wherein the
alternating means comprise a four way valve, having four
connections and wherein the connections are connected two by
two.
7. The drilling system according to claim 1, wherein the
alternating means comprise a four way valve, having four
connections connected two by two, and wherein the choking means
comprise a bi-directional choke.
8. The drilling system according to claim 1, wherein wherein the
drilling fluid outlet system comprises an inlet and an outlet, the
choke means comprise a first inlet/outlet connection, a second
outlet/inlet connection, and the alternating means connect the
inlet alternatingly to the first or second connection and the
outlet alternatingly to the second or first connection and wherein
the alternating means comprise a four way valve, having four
connections and wherein the connections are connected two by
two.
9. The drilling system according to claim 1, wherein wherein the
drilling fluid outlet system comprises an inlet and an outlet, the
choke means comprise a first inlet/outlet connection, a second
outlet/inlet connection, and the alternating means connect the
inlet alternatingly to the first or second connection and the
outlet alternatingly to the second or first connection and wherein
the alternating means comprise a four way valve, having four
connections connected two by two, and wherein the choking means
comprise a bi-directional choke.
10. A drilling fluid outlet system connectable to a well bore for
receiving a return flow of drilling mud retrieved from the well
bore and discharging the drilling mud into a reservoir, the
drilling fluid outlet system comprising a choke means for choking
the return flow of retrieved drilling fluid, and alternating means
for alternating the flow direction through the choking means.
11. The drilling fluid outlet system according to claim 10, wherein
the drilling fluid outlet system comprises an inlet and an outlet,
the choke means comprise a first inlet/outlet connection, a second
outlet/inlet connection, and the alternating means connect the
inlet alternatingly to the first or second connection and the
outlet alternatingly to the second or first connection.
12. The drilling fluid outlet system according to claim 11, wherein
filter means are arranged in the first and second connection of the
choke means.
13. The drilling fluid outlet system according to claim 10, wherein
the alternating means comprise a four way valve, having four
connections and wherein the connections are connected two by
two.
14. The drilling fluid outlet system according to claim 10, wherein
the drilling fluid outlet system comprises an accumulator.
15. The drilling fluid outlet system according to claim 10, wherein
the choking means comprise a bi-directional choke.
16. The drilling fluid outlet system according to claim 10, wherein
the choking means comprise at least two unidirectional chokes.
Description
CROSS REFERENCE TO EARLIER APPICATION
[0001] The present application is a continuation application of
U.S. application Ser. No. 10/520,606 filed 6 Jan. 2005, which is a
national stage application of International application No.
PCT/EP2003/006750, which claims priority on European Patent
Application 02254746.7 filed 8 Jul. 2002.
BACKGROUND OF THE INVENTION
[0002] The present invention is related to a drilling system, more
particularly, a system for controlling formation pressure while
drilling.
[0003] According to prior art systems, the pressure is controlled
by pumping fluid into the bore hole, via the annulus. Such a
drilling fluid outlet system could further comprise a safety choke,
in case the pump fails.
[0004] However due to large rock debris or contaminated mud, the
safety choke could get clogged or could be damaged, which
jeopardises correct control over the pressure in the well bore.
SUMMARY OF THE INVENTION
[0005] The invention relates to a drilling system for drilling a
well bore into an earth formation, comprising: [0006] drilling
means for drilling a well bore; [0007] pumping means for pumping
drilling fluid into the well bore during drilling; and [0008] a
drilling fluid outlet system for retrieving drilling fluid from the
well bore.
[0009] It is an object of the invention to alleviate the
disadvantages of the prior art and to provide a system that is
capable of regulating the pressure while the flow may contain large
rock debris or contaminated mud.
[0010] This object is achieved by a drilling fluid outlet system
comprising choke means for choking the returned flow of retrieved
drilling fluid and alternating means for alternating the flow
direction through the choke means.
[0011] The invention relates also to a drilling fluid outlet
system.
[0012] In another aspect the invention relates to a method of
drilling a well bore into an earth formation.
[0013] In accordance with this aspect of the invention, the method
comprises: [0014] drilling the well bore by operating drilling
means; [0015] pumping drilling fluid into the well bore during said
drilling; and [0016] retrieving drilling fluid from the well bore
in a drilling fluid outlet system, said drilling fluid outlet
system comprising choke means for choking the return flow of
retrieved drilling fluid, whereby the flow direction of retrieved
drilling fluid through the choking means is alternated for flushing
away any debris from the choke means.
[0017] The invention will be now illustrated by way of example and
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
[0018] In the accompanying drawing:
[0019] FIG. 1 shows a schematic view of a drilling system according
to the invention;
[0020] FIG. 2 shows a schematic view of a first embodiment of a
drilling fluid outlet system according to the invention; and
[0021] FIG. 3 shows a second embodiment of a drilling fluid outlet
system according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Described is a drilling system comprising an drilling fluid
outlet system that comprises choke means for choking the returned
flow of retrieved drilling fluid and alternating means for
alternating the flow direction through the choke means.
[0023] So if the choke means would get clogged, the returned flow
is alternated, such that the choke means are cleaned and the debris
is discharged.
[0024] According to a preferred embodiment, the drilling fluid
outlet system comprises an inlet and an outlet, the choke means
comprise a first inlet/outlet connection, a second outlet/inlet
connection and the alternating means connect the inlet
alternatingly to the first or second connection and the outlet
alternatingly to the second or first connection. So with these
alternating means it is possible to connect the choke means such
that the inlet is used as an inlet or outlet and that at the same
time the outlet is used as outlet or inlet.
[0025] In another embodiment of the drilling system according to
the invention, filter means are arranged in the first and second
connection of the choke means.
[0026] These filter means block large pieces, which could damage
the choke means. Upon alternating the flow direction blocked pieces
at the filter means are discharged.
[0027] In again another embodiment of the drilling system according
to the invention, the alternating means comprise a four way valve,
having four connections and wherein the connections are connected
two by two. With such a valve, which could be actuated
automatically, alternating of the flow is performed quickly. This
will provide a minimum interruption of the flow.
[0028] Preferably, the drilling fluid outlet system comprises an
accumulator. This accumulator secures a constant flow at the moment
that the flow direction is alternated.
[0029] In yet another embodiment of the drilling system according
to the invention, the choking means comprises a bi-directional
choke. Such a bi-directional choke provides a choking action in
both flow directions. This provides for a compact design.
[0030] In another embodiment the choking means comprise at least
two uni-directional chokes. Such uni-directional chokes provide a
choking action in only one flow direction. Therefore two chokes are
necessary to provide a choking action in both flow directions.
[0031] FIG. 1 shows a schematic view of a drilling system 1
according to the invention. With this drilling system 1 a well bore
2 is drilled into the earth formation 3.
[0032] The drilling system 1 comprises a frame 4 onto which a fluid
chamber 5 is slidably arranged along a guide 6. A drill string 7
with on its bottom end a drill bit 8 is rotated by a top drive 9 in
order to drill the well bore 2. The well bore 2 is partially lined
with a casing 10. The drill string 7 is composes out of a plurality
of drill string joints 11, which are interconnected by connectors
12a and 12b. Drill mud contained in a reservoir 13 is pumped by
pump 14 into the drill string 7 to the drill bit 8. The drilling
mud 25 flows into the annulus between the well bore wall and the
drill string 7 upwards. The annulus is closed off by a rotating
blow out preventer 15. The drilling mud is returned via pipe 16 and
drilling fluid outlet system 17 back to the reservoir 13. When
connecting another drill string joint 11 the feed of drilling mud
is taken over by pump 18, which pumps the drilling fluid into the
chamber 5, such that it can flow into the drill string 7.
[0033] The drilling fluid outlet system 17 ensures that a certain
pressure is maintained in the well bore 2 by choking the flow in
the pipe 16.
[0034] In FIG. 2 the drilling fluid outlet system 17 is shown in
more detail. The system 17 comprises a valve 20 and a bidirectional
choke 21. In the position of the valve 20 as shown in FIG. 2 the
inlet pipe 16 is connected to the first connection pipe 22 of the
choke 21. The outlet pipe 19 is connected to the second connection
23 of the choke 21. When the choke 21 gets clogged, the valve 20 is
rotated, such that the inlet pipe 16 is connected to the second
connection 23 of the choke 21 and the outlet pipe 19 is connected
to the first connection 22 of the choke 21. In this way the flow
direction is alternated and any debris, which is clogging the choke
21 is flushed away through outlet pipe 19.
[0035] In FIG. 3 a second embodiment 30 of a drilling fluid outlet
system according to the invention is shown. The system 30 again
comprises a valve 31 and two uni-directional chokes 32 and 33. Such
chokes 32,33 have a choking action in just one flow direction.
Furthermore, the system 30 comprises filter means 34,35 that
filters large debris in the mud, which could damage the chokes
32,33. An accumulator 36 is connected to the inlet pipe 16, which
ensures that a constant flow is maintained while the flow direction
of the system 30 is alternated by turning the valve 31. Any debris
present on the filter means 34,35 or in the chokes 32,33 is cleaned
by alternating the flow direction of the system 30 and is flushed
away through outlet pipe 19.
[0036] It is remarked that WO-00 79092, for example, discloses a
drilling system for drilling a well bore into an earth formation,
comprising: [0037] drilling means for drilling a well bore; [0038]
pumping means for pumping drilling fluid into the well bore during
drilling; and [0039] a drilling fluid outlet system for retrieving
drilling fluid from the well bore. The drilling fluid outlet system
is used to maintain control over the fluid pressure at the well
bore wall, especially when drilling is stopped or during tripping
of the drill string out of the bore hole. Without maintaining
control over the pressure, there is a potential danger that
undesired fluid flows from the earth formation into the bore hole,
or that the borehole wall collapses.
[0040] While the illustrative embodiments of the invention have
been described with particularity, it will be understood that
various other modifications will be readily apparent to, and can
easily be made by one skilled in the art without departing from the
spirit of the invention. Accordingly, it is not intended that the
scope of the following claims be limited to the examples and
descriptions set forth herein but rather that the claims be
constructed as encompassing all features which would be treated as
equivalents thereof by those skilled in the art to which this
invention pertains.
* * * * *