Note: Descriptions are shown in the official language in which they were submitted.
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DOWNHOLE DEVICE
TECHNICAL FIELD
The invention pertains to the oil and gas industry and can be
used in technical operations relating to well completion.
PRIOR ART
Known are the safety valves intended for leak-free shutoff of
to the well bore during the oil and gas wells operation RU No. 2312203
C2, E21B34/06, 10.12.2007; RU No. 2311526 C2, E21B34/06,
27.11.2007; RU No. 2293839 C1, E21B34/06, 20.02.2007; RU No.
2234595 C1, E21B34/10, 20.08.2004; RU No. 2224087 C2,
E211334/06,20.02.2004; RU No. 2172815 Cl, E211334/06,27.08.2001;
RU No. 2169829 Cl, E21B34/06, 27.06.2001; RU No. 2160357 C2,
E2 11334/06, 10.12.2000; RU No. 2145024 Cl, E21B34/08, 27.01.2000;
RU No. 2112863 Cl, E21B34/06, 10.06.1998; RU No. 2107152 C1,
E21B34/06, 20.03.1998; RU No. 2094593 Cl, E21B34/06, 27.10.1997;
RU No. 2021490 Cl, E21B34/06, 15.10.1994; RU No. 2011797 Cl,
E21B34/06, 30.04.1994; RU No. 32183 U1, E21B34/06, 10.09.2003;
RU No. 25527 Ul, E21B34/06, 10.10.2002; RU No. 22174 U1,
E21B34/06, 10.03.2002.
The known downhole shutoff devices are characterized by the
significant reduction of flow channel diameter compared to the
producing well diameter.
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Also known is a preventer containing the housing, sealing
elements equipped with hydraulic drives RU No. 2304693 C2,
E21B33/06, 20.08.2007; RU No. 2125643 C1, E21B33/06, 27.01.1999;
RU No. 37762 U1, E21B34/06, 10.05.2004.
Known is a rotating preventer containing the housing, rotating
shaft with a sealing element, rotating assembly and a chevron seal RU
No. 2027847 Cl, E21B33/06, 27.01.1995; RU No. 76961 U1,
E21B33/06, 10.10.2008.
Known is the rotating universal hydraulic preventer containing a
to housing with a cavity and a central opening, a cover with an opening,
bearings, a shell, a sealing element located in the shell RU No. 2208126
C2, E21B33/06, 10.07.2003; RU No. 2013519 Cl, E21B33/06,
30.05.1994; RU No. 45770 U1, E21B33/06, 27.05.2005.
The known rotating preventers, which are installed on the well
opening, have overall dimensions significantly exceeding the well
diameter; they do not completely overlap the cross-section.
Known is a rotating preventer containing a housing, a bearing
assembly, a shaft rotating in the bearing assembly and a sealing device
connected with the well equipment, RU No. 2341643 C1, E21B33/06,
20.12.2008.
This technical solution is accepted as the "closest analog" of the
present invention.
The sealing device of the "closest analog" preventer is made in
the form of a spacer ring with a groove on the inner surface and is
located on the coupling connecting the drill string and the kelly stem.
The groove in the spacer ring is connected with the inner cavity of the
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coupling. The drill string together with the coupling is lowered into
the well and the drill pump is switched on; at that, the sealing device,
under action of drill fluid pressure, is expanded and retained against
the shaft, thus creating a reliable sealing of the annulus.
However, the sealing device of the "closest analog" preventer
seals the well opening during drilling operations and such sealing is
possible only under action of drill fluid, which limits execution of
other process operations.
The "closest analog" preventer belongs to devices that seal the
to well opening during drilling.
Summary of the invention
The invention solves the problem of expanding execution of
process operations, provide conditions for any operations on well
completion without loss of flow channel diameter by more than the
normative value, prevent inflow of formation fluids and increase the
well productivity.
According to the invention this problem is solved by using a
borehole device containing a housing; a bearing assembly; and a
sealing device connected with the borehole equipment.
The device acts as a sealing device by using a seal.
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The seal separates the well into the upper and lower cavity with
the presence of hydraulic connection between the well opening and
the upper cavity and between the lower cavity and the producing
formation respectively.
The seal has a collet with segments in the lower part and is made
capable of separating at interaction with the well equipment, is
equipped with additional seals on lateral surfaces, a liner on external
surfaces, springs and casing located in the lower part and providing
arrangement of segments during their separation.
The seal is located in the housing provided with the upper thread
and fastened in the beating assembly.
The device further includes an adjustment insert that is capable of
interacting with the well equipment upon the installation thereof and
of moving same so as to open the channel of a hydraulic connection
is between the well opening, the upper cavity, the lower cavity and the
producing formation.
The invention is characterized by a number of optional features,
namely:
- bearing assembly contains an oil-filled sealed bearing;
- liner is made of a strong flexible material;
- lower thread is additionally made on the housing.
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The applicant has not identified any sources of information
which contain data on technical solutions identical to the device
described herein.
Thus, in the applicant's opinion, the invention meets the
5 "novelty" (N) criterion.
The immediate technical result is implementation of technical
operations on well completion without creation of overbalance on the
productive deposits by the washer fluid column, with the help of the
suggested device made as a sealing device by means of the seal
io separating the well into the upper and lower cavities, containing the
collet with segments in the lower part capable of separating at
interaction with the well equipment and located in the housing
fastened in the bearing assembly.
This technical result does not come from the known properties,
is which, in the applicant's opinion, means that the technical solution
applied for meets the the "inventive step" (IS) criterion.
Implementation of the technical solution applied for is confirmed
by the research, development and testing of experimental batches; in
the downhole device the use is made of parts and assemblies which are
20 widely used in the oil and gas producing industry; therefore, in the
applicant's opinion, it meets the "industrial applicability" (IA)
criterion.
Brief description of the drawings
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Further on the technical solution applied for shall be explained
by description of an example of its implementation with references to
the attached drawings, where
in Fig. 1 - Downhole device, general view;
in Fig. 2 - Downhole device, section;
in Fig. 3 - Collet segments, section;
in Fig. 4 - Downhole device in setting position, section;
in Fig. 5 - Well in operating position, schematically;
in Fig. 6 - Section A-A on fig. 5;
io in Fig. 7 - Well with downhole device, schematically.
Best enbodiment of the invention
The downhole device contains:
Housing - 1,
upper thread (on housing 1) - 2,
lower thread (on housing 1) - 3,
Oil-filled sealed bearing - 4.
Seal (in housing 1) - 5.
Encasing (of housing 1) - 6.
Collet (of seal 5) - 7,
segments (of collet 7) - 8.
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additional seals (on lateral surfaces of segments 8) - 9,
liner (on external surface of collet 7) - 10,
springs (of collet 7) - 11.
Locating insert - 12,
channels of hydraulic connection - 13.
Drill-through cover - 14.
Installation and operation of the device is provided by:
Well - 15,
upper cavity (well 15) - 16,
lower cavity (well 15) - 17.
Casing string - 18.
Drill string - 19,
drillbit - 20.
The borehole device contains a housing (1), bearing assembly
(4) and seal (5).
The device acts as a sealing device by using a seal (5).
The seal (5) separates the well into the upper (16) and the lower
(17) cavity with the presence of hydraulic connection between the
well opening and the upper cavity and between the lower cavity and
the producing formation respectively.
The seal (5) contains a funnel-shaped collet (7). The collet (7) in
the encasing (6) in the lower part contains segments (8) closely fitting
to each other, capable of separating and equipped with the additional
seals (9) on the lateral surfaces. The collet (7) contains a liner (10) on
its external surfaces. The liner (10) is made of a strong flexible material.
The collet (7) contains springs (11). The encasing (6) is located in the
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lower part of the collet (7) providing arrangement of segments (8)
during their separation. The space between the seal (5) and the encasing
(6) is filled with grease.
The seal (5) is located in the housing (1) provided with the upper
thread (2) and fastened in the beating assembly. The bearing assembly
contains the oil-filled sealed bearing (4). The lower thread (3) is made
on the housing (1) for installation of the device between the pipes of
the casing string (18), if necessary.
The device further includes an adjustment insert (12). The
io adjustment insert (12) is capable of interacting with the well
equipment during its installation, for example, with the drill string
(19), and of moving the same so as to open the channel of a hydraulic
connection (13) between the well opening, the upper cavity, the lower
cavity and the producing formation.
The device is additionally equipped with the drill-through cover
(14). The drill-through cover (14) is made of easily drillable material,
for example, A16.
Process operations on well completion are executed using the
device as follows.
The locating insert (12) in installed in the seal (5). The space
between the seal (5) and the encasing (6) is filled with grease to
prevent crushing of the encasing (6) under external pressure during
lowering of the device into the well (15).
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The housing (1) of the device is connected by means of the upper
thread (2) and the lower thread (3) with the pipe of the string (18)
located below. The casing string (18) together with the device is
lowered into the well.
Process operations on the well (15) fastening are then performed.
The drill string (19) is lowered down to the device and the
locating insert (12) is pushed out by subsequent pressing, thus breaking
the drill-through cover (14).
Segments (8) of the collet (7) are separated and the channels of
io the hydraulic connection (13) between the well opening, the upper
cavity, the lower cavity and the producing formation open. The
encasing (6) provides the guaranteed space for location of the separated
segments (8).
The drill string (19) is lowered down to the productive deposits.
After execution of process operations on the well (15) deepening
according to the project the drill string (19) is removed from the well
(15).
After the drillbit (20) comes out of the seal (5) the collet (7) takes
up the "closed" position under action of the own potential energy, as
well as under action of springs (11) and liner (10), thus shutting off the
channels of the hydraulic connection (13) and separating the upper (16)
and the lower (17) cavities of the well (15).
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If it is necessary to continue operations on the well (15)
deepening, the drill string (19) is lowered in the similar way through the
device.
If other process operations are executed, for example, lowering
5 of the tail pipe (not shown) or other equipment, the device supports
their installation and operation in the required modes.
Completion of the device with the housing, the bearing assembly
and the seal makes it possible to lower it together with the casing string,
to locate it inside the well and to perform any process operations on the
1o well completion without any diameter loss.
Installation of the device in the well over the productive deposits,
which operates on the "normally closed" principle and is opened by
external actuation to let the well equipment pass through, is a necessary
step to complete the well, if development of the productive deposits is
carried out without creation of the overbalance.
Availability of the collet in the seal, which provides interaction
with the well equipment and opening of the channel of the hydraulic
connection between the well opening, the upper cavity, the lower
cavity and the producing formation prevents inflow of formation
fluids, when necessary.
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Industrial applicability
The suggested downhole device can be used during execution of
the process operations on the well completion without loss of flow
channel diameter by more than the normative value, during prevention
of the formation fluids inflow and during application of the known
parts and assemblies manufactured industrially and widely used in the
oil and gas producing industry, and the research, development and
testing of the experimental batches confirme, in the applicant's
opinion, its compliance with the "industrial applicability" (IA)
criterion.
