Note: Descriptions are shown in the official language in which they were submitted.
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DOWN-HOLE JET EQUIPMENT FOR LOGGING AND DEVELOPMENT OF
HORIZONTAL WELLS
Field of the Invention
The invention relates to pump engineering, in particular to well pump units
for logging and
developing horizontal wells.
Description of Prior Art
A well jet unit is known, which comprises, all being installed on a pipe
string upwards: a
packer provided with a central channel, and a jet pump which body is provided
with an active
nozzle and a mixing chamber with a diffuser as well as a channel for supplying
a working
medium and a channel for supplying a medium pumped out of a well, a pass being
made in the
jet pump body with the possibility of installing replaceable functional
inserts and a sealing
assembly (see: RU Patent No. 2176336, P04P 5/02, 27.11.2001).
This well jet unit enables to treat a formation below the jet pump level in a
well, including
treatment with creation a pressure differential between pressures above and
below the sealing
unit. However, the capacity of the known well jet device is not used in full,
since a big time is
required for replacing inserts, and such time is often greater than a time of
reaction between an
acid solution and minerals of a producing formation.
The closest to this invention as to its technical essence and achieved result
is a well jet unit for
logging horizontal wells, which comprises, all being arranged on a flexible
smooth pipe
upwards, a packer provided with a central channel, and a jet pump which body
is provided
with a nozzle and a mixing chamber with a diffuser, the diffuser outlet being
connected to the
inner cavity of the flexible smooth pipe via a channel for removing a medium
mixture, as
made in the jet pump body, the inlet of the jet pump nozzle being connected to
the annular
space around the flexible smooth pipe, and the channel for supplying a medium
pumped out of
a well being connected to the inner cavity of the flexible smooth pipe via an
upper and a lower
windows made in the jet pump body, and a check valve being arranged in the
channel for
supplying a pumped-out medium on its inlet at the lower window, a multiple-
measurement
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instrument being arranged on the lower end of the flexible smooth pipe, a
sealing element
shaped as a profiled ring being movably arranged on the flexible smooth pipe
below the
packer, and openings, which communicate the inner cavity of the flexible
smooth pipe with
the annular space below the packer, being made in the wall of the flexible
smooth pipe above
the multiple-measurement instrument (see: RU Patent No. 2324079, P04P 5/54,
10.05.2008).
This well jet unit enables to study horizontal wells and treat producing
formations in them.
However, an installed switch for working medium flows narrows the capacity of
the unit in
studying productivity of a formation during treating it. Furthermore, lack of
the possibility of
blocking the flexible smooth pipe during extracting the unit to the surface
complicates the
process of removing the unit from a well.
Summary of the Invention
The objective of this invention is to improve quality of works aimed at
increasing well
production rates by expanding the unit functionality, in particular, to
perform operations on
treatment of a producing formation without rearranging a flow string and to
simplify the
operation process of the well jet unit.
The technical effect achieved after implementing of the invention is
improvements in
reliability of operation and productivity of a well jet unit in logging and
developing a well.
The said objective is solved and the technical effect is achieved due to the
fact that the
inventive well jet unit comprises, all being arranged on a flexible smooth
pipe upwards, a
multiple-measurement instrument embracing the flexible pipe, a sealing element
arranged
movably, and a jet pump, which body is provided with a nozzle and a mixing
chamber with a
diffuser, the diffuser outlet being connected to the inner cavity of the
flexible smooth pipe, the
inlet of the jet pump nozzle being connected to the annular space around the
flexible smooth
pipe, and check valves being arranged in the channel for supplying a pumped-
out medium, as
made in the jet pump body, on the side of its inlet and on the nozzle input;
further, the flexible
smooth pipe is arranged with the possibility of moving axially in a flow
string provided with a
packer for the purpose of sealing space between the flow string and a casing
string, the said
packer being provided with a through channel which diameter Di is at least 12
millimeters
lesser than the inner diameter D2 of the flow string; openings are made in the
wall of the
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flexible smooth pipe above the multiple-measurement instrument, and the inner
cavity of the
flexible smooth pipe is connected via the said openings to the under-packer
well space; a ball
cock, which is intended for closing the inner cavity of the flexible smooth
pipe when the well
jet unit is removed to the surface, is arranged on the flexible smooth pipe in
its section
between the jet pump and the sealing element; the sealing element is made in
the form of a
cylindrical body filled in its upper part with a set of elastic gaskets
embracing the flexible
smooth pipe, the said gaskets being provided with thrust washers arranged
therebetween, and
with a thrust pressure element; and a bearing sleeve is fixed in the body
lower part and has a
thrust flange in its lower end and a movable thrust ring arranged above the
flange on the
sleeve, an elastic sealing collar is arranged between the said ring and the
lower part of the
cylindrical body; the thrust flange diameter is lesser than the diameter D1 of
the packer
through channel, the thrust ring has the diameter D3 that is greater than the
diameter D1 of the
packer through channel, and the lower face of the thrust ring is coated with
an elastic material.
An analysis of operation of the well jet unit shows that reliability and
efficiency of the device
operation may be improved through optimizing the unit structure and, due to
this, it is possible
to achieve more clean near-well area, shorten time required for carrying out
such works and
expand the functionality of the device when testing and developing wells
without rearranging
the equipment used.
It is found that hydrodynamic action on the near-well area enables to use the
well jet unit most
efficiently when developing and repairing oil and gas wells during works on
intensifying oil
inflow from a producing formation. Further, the unit enables to clean a
producing formation
from mud particles and reaction products after treating a formation with
chemical reagents,
make control measurements both before and during treatment, which, in its
turn, enables to
assess technical condition and productivity of a well as well as properties of
a medium
pumped out of a well. While proceeding from an inflow studies, it becomes
possible to assess
treatment quality of the producing formation near-well area. Providing the
unit with a
multiple-measurement instrument arranged on, and embracing, the flexible
smooth pipe, a
sealing element arranged movably, and a jet pump which body is provided with a
nozzle and a
mixing chamber with a diffuser, as well as arranging the flexible smooth pipe
with the
possibility of moving axially in a flow string provided with a packer for the
purpose of sealing
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a space between the flow string and the casing string enable to carry out
logging of the
horizontal portion of a well in the differential pressure drawdown mode and
remove reaction
products from the formation.
Arranging a supporting ring with a pass opening intended for installing a
sealing element in
the flow string and making the sealing element as a set of elastic gaskets
with thrust washers
therebetween, which embrace the flexible smooth pipe, and a thrust pressure
element on their
top as well as fixing a supporting sleeve provided with a thrust flange in its
lower end and a
movable thrust ring arranged on the sleeve above the flange, provided that an
elastic sealing
collar is arranged between the said ring and the upper part of the cylindrical
body, enables to
install a jet pump in the flow string quickly and automatically and
hermetically separate the
well space below and above the jet pump, when the thrust ring interacts with
the end wall of
the packer through channel. In order to provide for the said interaction, the
unit is made
according to the above ratios of dimensions, and it important not only to
ensure the said
interaction, but also ensure reliable operation while prevent the unit from
jamming, which is
ensured via corresponding optimization of the dimension ratios for the above-
mentioned
elements of the unit design.
A jet pump arranged in a flow string enables to create by using it a series of
drawdown values
at a given differential pressure in a well under-packer area, use a multiple-
measurement
instrument for registering pressures, temperatures and other parameters of the
well and a
medium pumped out of that well, study and test a well, and register a
formation pressure
restoration curve for the well under-packer area without using a special
functional insert. At
the same time, it provides for the possibility of monitoring a differential
pressure drawdown
value by controlling a pumping rate of an active working medium. When testing
a formation,
the pumping mode may be adjusted by changing pressure of an active working
medium
supplied to the jet pump nozzle. At the same time, the provision of the
channel for supplying a
medium pumped out of a well and the nozzle with check valves enables to avoid
a
spontaneous flow of a working medium into the under-packer area when the jet
pump is or is
not operated.
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The arrangement of the logging instrument on the flexible smooth pipe with the
possibility for
the latter of moving axially in a well without using a packer (a sealing
element, which is put
on the flexible smooth pipe, is used instead of a packer) enables to speed up
and,
consequently, simplify the process of moving a multiple-measurement instrument
in a well,
and, hence, simplify the procedure of testing and preparing a well for
operation. Moreover, the
arrangement of a multiple-measurement instrument on the flexible smooth pipe
enables, due
to the latter's elastic properties, to position the multiple-measurement
instrument in an area of
producing formations in horizontal sections of wells, which enables to get
more reliable
reactive information on condition of producing formations, inflow of a
formation fluid and
properties of the latter, and the arrangement of a ball cock on the flexible
smooth pipe in its
section between the jet pump and the sealing element enables to close the
inner cavity of the
flexible smooth pipe when the well jet unit is removed to the surface, which
makes the
procedure of removing the well jet unit to the surface easier.
In the result, works on studying and developing wells are intensified, which
enables to study
and test wells with good quality after drilling and during well-workover
operations as well as
prepare a well for operation after conducting extensive studies and tests in
various modes and,
due to this, improve the device operation reliability.
Brief Description of the Drawings
Figure shows a longitudinal section of the proposed well jet unit for logging
horizontal wells.
Description of the Best Embodiment
The proposed well jet device comprises, all being arranged on a flexible
smooth pipe I
upwards: a multiple-measurement instrument 2 embracing the flexible pipe 1, a
sealing
element 3 arranged movably and a jet pump 4 which body 5 is provided with a
nozzle 6 and a
mixing chamber 7 with a diffuser 8. The outlet of the diffuser 8 is connected
to the inner
cavity of the flexible smooth pipe 1, and the nozzle 6 of the jet pump 4 is
connected, on the
side of its inlet, to the annular space around the flexible smooth pipe 1. A
check valve 10 is
arranged in the channel 9 for supplying a medium pumped out of a well, the
channel being
made in the body 5 of the jet pump 4, and is arranged in the inlet portion of
the channel. The
flexible pipe 1 is arranged with the possibility of moving axially in a flow
string 11 provided
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with a packer 12 for the purpose of sealing the space between the flow string
11 and a casing
string 13. The diameter D1 of the through channel of the packer 12 is at least
12 millimeters
lesser than the inner diameter D2 of the inner cavity of the flow string 11.
Openings 14 are
made in the wall of the flexible smooth pipe I above the multiple-measurement
instrument 2
and are used for connecting the inner cavity of the flexible smooth pipe 1 to
the under-packer
area of the well.
The sealing element 3 is made in the form of a cylindrical body 15 arranged in
its upper
portion and filled with a set of elastic gaskets 16 with thrust washers 17
arranged
therebetween, the gaskets embracing the flexible smooth pipe 1, and a thrust
pressure element
18 is arranged on the top of the set; a supporting sleeve 19 is fixed in the
lower portion of the
cylindrical body 15 and is provided in its lower end with a thrust flange 20
above which and
on the sleeve 19 a movable thrust ring 21 is arranged; a sealing collar 22 is
arranged between
the movable thrust ring 21 and the lower portion of the cylindrical body 15.
The diameter of
the thrust flange 20 is lesser than the diameter D1 of the through channel of
the packer 12, the
thrust ring 21 has the diameter D3 that is greater than the diameter D1 of the
through channel
of the packer 12, the lower face of the thrust ring 21 is coated with an
elastic material, and a
ball cock 23, which is intended for closing the inner cavity of the flexible
smooth pipe 1 when
the well jet unit is removed to the surface, is arranged on the flexible
smooth pipe 1 in its
section between the jet pump 4 and the sealing element 3. A check valve 24 is
arranged at the
inlet of the nozzle 6 of the jet pump 4.
The packer 12 is lowered on the flow string 11 to a vertical section of a
well. Then, the packer
12 is released, and an acid solution and/or a hydrofracturing fluid are pumped
via the flow
string 11 to a producing formation of the well. After this, the multiple-
measurement
instrument 2, the sealing element 3 and the jet pump 4 are lowered on the
flexible smooth pipe
1 to a horizontal section of the well. The sealing element 3 is arranged on
the end wall of the
through channel of the packer 12, and the multiple-measurement instrument 2 is
arranged in
the area of the producing formation of the well horizontal section, while
registering the well
geophysical parameters along the well bore, such as pressure and temperature
in the under-
packer area, including the area of the producing formation. Then, a
pressurized working
medium is supplied via the annular space around the flexible smooth pipe 1 to
the nozzle 6 of
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the jet pump 4, the well is drained, and reaction products and/or the
hydrofracturing fluid are
removed from the producing formation, while regularly measuring well rates at
different
values of differential pressure drawdown to the producing formation and
continuously
recording bottomhole pressure and composition of a pumped out liquid medium
with the use
of the multiple-measurement instrument 2. Due to a pressure of the working
medium in the
flow string 11, the thrust pressure element 18 exerts pressure on the elastic
gaskets 16, thus
expanding them and sealing an annular gap around the flexible smooth pipe 1.
Simultaneously, under the medium pressure in the flow string 11, the
cylindrical body 15
moves downward and expands the sealing collar 22, thus sealing the annular gap
relative to
the flow string 11. Then, without stopping drainage from the well, the
multiple-measurement
2 is raised to the vertical section of the horizontal well, thus registering
the geophysical
parameters in the under-packer area, including the area of the producing
formation.
After this the jet pump 4 is stopped, and the inner cavity of the flexible
smooth pipe 1 above
the jet pump 4 together with the annular space above the sealing element 3 is
separated from
the inner cavity of the flexible smooth pipe I under the jet pump 4 together
with the under-
packer area, while keeping a low bottomhole pressure under the packer 12, at
which pressure a
curve of formation pressure recovery is recorded with the use of the multiple-
measurement
instrument 2. Then a pressurized gas is supplied via the flexible smooth pipe
1, thus expelling
the liquid medium from it and from the annular space around it, after this the
ball cock 23 is
closed, and the flexible smooth pipe 1 with the jet pump 4, the sealing
element 3 and the
multiple-measurement instrument 2 are removed from the well to the surface.
Then a decision
on either to continue studying the well or to put it into the operation mode.
Industrial Applicability
This invention may be used in the coal industry during operation of coal
fields.
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