Note: Descriptions are shown in the official language in which they were submitted.
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COMPOSITE WATER-CONTROLLING AND FLOW-LIMITING
DEVICE AND SCREEN PIPE THEREOF
TECHNICAL FIELD
[0001] The invention relates to a water-controlling and flow-limiting device,
and
particularly to a composite water-controlling and flow-limiting device and a
screen pipe
thereof.
BACKGROUND ART
[0002] During exploitation of oil and natural gas, horizontal wells are
largely developed
and applied due to advantages of high liquid production capacity, small
differential pressure
of production and low flow resistance. The horizontal wells have the
characteristic of
imbalance of the flowing production liquid profile, and with exploitation time
prolonged,
such imbalance flowing profile will cause earlier water breakthrough to reduce
life of the
well, and affect production capability of the well.
[0003] Water-controlling technology of the current horizontal wells uses two
methods. One
is a passive water-controlling method of finding water firstly, and then
controlling water.
Such method is complicated in construction process, has a high technical
requirement and
more procedures, and is difficult in operation in the production state. Once
water coning
occurs, this water-controlling method is failure. The other controls water
using an inflow
control tool, and prolongs balanced depressurization of the horizontal well
section through
sand prevention filter and throttle regulation, which can suppress phenomenon
of imbalance
of water crest movement of bottom water and edge water, thereby improving
production
capacity of the entire horizontal section, and prolonging life of the
horizontal wells.
However, the above technology must collect oil data in advance for design and
field
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regulation. In addition, inflow control of some automatic water-controlling
technology is
relatively single, and it is difficult to achieve water-controlling of the
whole period.
DISCLOSURE OF THE PRESENT INVENTION
[0004] With respect to the deficiencies of the prior art, the technical
problem to be solved
by the invention is to provide a composite water-controlling and flow-limiting
device and a
screen pipe thereof, which can automatically control the flow of fluid
according to fluid
characteristics, balance the inflow profile, implement simple and easy-to-
operate active
water control and oil-stabilizing production, and allow the water-controlling
and oil-
increasing functions thereof to be effective during the entire production
period of an oil well.
[0005] To achieve the above object, the invention provides a composite water-
controlling
screen pipe, comprising:
a base pipe;
a self-adaptive internal flow control device mounted on the base pipe and used
for a
circulation channel for fluids inside and outside the base pipe and
controlling an opening
degree of the circulation channel according to the change in viscosity of
different fluids so
as to automatically limit flow;
a flow control device mounted on the base pipe and adjacent to the self-
adaptive
internal flow control device for controlling an overflow of the base pipe; and
a screen pipe coaxially and threadedly connected to the base pipe, wherein an
inner
diameter of the screen pipe is the same as that of the base pipe.
[0006] As regards to the composite water-controlling screen pipe, the self-
adaptive internal
flow control device is in a float-type structure, and controls an opening
degree of a buoy
according to the change in viscosity of different fluids so as to
automatically limit flow.
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[0007] As regards to the composite water-controlling screen pipe, the self-
adaptive internal
flow control device is made of tungsten carbide hard alloy.
[0008] As regards to the composite water-controlling screen pipe, the flow
control device
comprises:
a support diversion disc opened with an overflow groove and a diversion pipe;
and
a rotatable balance disc connected to the support diversion disc, and provided
with a
throttle hole to cooperate with the overflow groove and the diversion pipe,
the balance disc
rotated as needed to regulate the number of plugged holes of the throttle hole
to control the
overflow of the base pipe, and locked with a lock nut.
[0009] As regards to the composite water-controlling screen pipe, the throttle
hole is
mounted with a tungsten alloy nozzle.
[0010] As regards to the composite water-controlling screen pipe, the screen
pipe comprises:
a body; and
a filter sleeve comprising an outer protective jacket, a filter jacket and an
inner
protective jacket fitted sequentially, the filter jacket comprising a
plurality of filter screens
stacked successively, wherein hole sizes of the filter screens are set
depending on
requirement for oil reservoir.
[0011] As regards to the composite water-controlling screen pipe, the inner
protective
jacket, the outer protective jacket and the filter screen are all made of acid-
proof and
antisepticise materials.
[0012] As regards to the composite water-controlling screen pipe, both ends of
the filter
sleeve are respectively welded to the flow control device and a positioning
step of the body,
and fluid flowing through the filter screen flows into the base pipe via the
self-adaptive
internal flow control device after passing through the flow control device.
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[0013] As regards to the composite water-controlling screen pipe, the filter
sleeve is fixed
onto the body via a support disc.
[0014] To better achieve the above object, the invention further provides a
composite
water-controlling and flow-limiting device, comprising a composite water-
controlling
screen pipe, wherein the composite water-controlling screen pipe is the above-
mentioned
composite water-controlling screen pipe.
[0015] Hereinafter the invention is explicitly described with reference to
accompanying
drawings and detailed embodiments, but the invention is not limited thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a structure diagram of one embodiment according to the
invention.
[0017] FIG. 2 is a partial enlarged diagram of a self-adaptive internal flow
control device
and a flow control device in one embodiment of the invention.
[0018] FIG. 3 is a water-controlling diagram during early production of a
composite water-
controlling screen pipe according to the invention.
[0019] FIG. 4 is a water-controlling diagram during middle and late production
of the
composite water-controlling screen pipe according to the invention.
EMBODIMENTS
[0020] Hereinafter structure principle and operating principle of the
invention are
specifically described with reference to the accompanying drawings:
[0021] Referring to FIG. 1, which is a structure diagram of one embodiment
according to
the invention. The composite water-controlling and flow-limiting device of the
invention
comprises a composite water-controlling screen pipe, comprising: a base pipe
1; a self-
adaptive internal flow control device 3 mounted on the base pipe 1 for a
single circulation
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channel for fluids inside and outside the base pipe 1, and based on the
principle of
constancy of a sum of fluid dynamic pressure and local pressure loss in
Bernoulli equation,
controlling an opening degree of a buoy within a valve body according to the
change in
viscosity of different fluids flowing through the valve body to control an
opening degree of
the circulation channel so as to automatically limit flow; a flow control
device 4 mounted
on the base pipe 1 and adjacent to the self-adaptive internal flow control
device 3 for
controlling an overflow of the base pipe 1; and a screen pipe coaxially and
threadedly
connected to the base pipe 1, wherein an inner diameter of the screen pipe is
the same as
that of the base pipe 1. The screen pipe comprises: a body 8; and a filter
sleeve 5
comprising an outer protective jacket, a filter jacket and an inner protective
jacket fitted
sequentially, the filter jacket comprising a plurality of filter screens
stacked successively,
wherein hole sizes of the filter screens are set depending on requirement for
oil reservoir.
The inner protective jacket, the outer protective jacket and the filter screen
are all made of
acid-proof and antisepticise materials such as SS304, SS316, or higher level.
Both ends of
the filter sleeve 5 are respectively welded to the flow control device 4 and a
positioning step
of the body 8, and fluid flowing through the filter screen flows into the base
pipe 1 via the
self-adaptive internal flow control device 3 after passing through the flow
control device 4.
The filter sleeve 5 is fixed onto the body 8 via a support disc 6. One end of
the body 8 is
further mounted with a collar 7.
[0022] Referring to FIG. 2, which is a partial enlarged diagram of the self-
adaptive internal
flow control device 3 and the flow control device 4 in one embodiment of the
invention.
The self-adaptive internal flow control device 3 is preferably in a float-type
structure, and
controls the opening degree of the buoy according to the change in viscosity
of various
fluids so as to limit flow automatically. The self-adaptive internal flow
control device 3 is
preferably made of tungsten carbide hard alloy, and has the advantages of heat
resistance,
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pressure resistance and corrosion prevention. The flow control device 4
comprises: a
support diversion disc 41 opened with an overflow groove 43 and a diversion
pipe 44; a
rotatable balance disc 42 connected to the support diversion disc 41, and
provided with a
throttle hole 45 to cooperate with the overflow groove 43 and the diversion
pipe 44, the
balance disc 42 rotated as needed before operation to regulate the number of
plugged holes
of the throttle hole 45 to control the overflow of the base pipe 1, and locked
with a lock nut.
The throttle hole 45 is preferably mounted with a tungsten alloy nozzle.
[0023] The base pipe 1 and the body 8 of the screen pipe are threadedly
connected. During
assembly, the self-adaptive internal flow control device 3 is firstly
assembled, and the flow
control device 4, the self-adaptive internal flow control device and the lock
nut 2 are
assembled sequentially from one end, then the support disc 6 and the filter
sleeve 5 are
assembled on the body 8 of the screen pipe, and next, the self-adaptive
internal flow control
device 3 is threadedly connected to the screen pipe. The base pipe 1 of the
self-adaptive
internal flow control device 3 is provided with a male thread, which functions
to connect
upper and lower pipe columns together with the collar 7, and the support disc
6 functions to
fix the filter sleeve 5. The fluid carrying sand filters the sand outside the
screen pipe after
filtering of the filter sleeve 5, the fluid without sand flows through the
flow control device 4
for overflow limitation, and then the fluid passes through the self-adaptive
internal flow
control device 3 for overflow limitation, enters into the body 8 of the device
and rises to a
mouth of the well along with the pipe columns.
[0024] Referring to FIGS. 3 and 4, the single composite water-controlling
screen pipe can
only limit inflow of the fluid, and only if the entire pipe string is designed
after stratigraphic
analysis, the inflow profile can be balanced. Oil and water profile of the
stratum and
information of permeability, pressure and water holding of each section are
obtained by
performing physical property analysis on the stratum of pitshaft, and then the
number of
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flow channels of the flow control device 4 are set according to data to
control inflow of the
fluid, regulate the oil and water profile, and prevent partial coning of
bottom water or edge
water, which are to balance the inflow profile by the way of controlling fluid
flow during
early period (see FIG. 3). During middle and late period, since partial well
section may have
water breakthrough, it is also difficult for the flow control device 4 to take
effect, and at this
time, the self-adaptive internal flow control device 3 is turned on or off
according to fluid
properties. After water breakthrough, the self-adaptive internal flow control
device 3 is
turned off, such that oil recovery of other layer can be enhanced.
[0025] The water-controlling principle of the invention fully reflects the
life cycle design
conception, and the water-controlling and oil-increasing functions thereof are
effective
during the entire production period of an oil well. According to
characteristics of the
invention, the water-controlling mechanism of the device combining with the
production
period of the oil well can be divided into two water-controlling stages. The
first water-
controlling stage is early production of the oil well. The number of hole
plates on the flow
control device 4 is designed with numerical simulation software according to
actual data of
oil and gas reservoir, and differential pressure of production of each section
is reasonably
controlled to maintain balance of oil and water interface, prevent earlier
water breakthrough,
delay coning of edge water and bottom water, and achieve the object of earlier
liquid
control while remedying the deficiency of incapability of controlling liquid
of the self-
adaptive internal flow control device 3 during the early period. The second
water-
controlling stage is middle and late production of the oil well. Different
production sections
of the oil well have different water holding degrees, and the float-type self-
adaptive internal
flow control device 3 can change the opening degree of the buoy according to
different
water holding degrees (i.e., comprehensive viscosities of fluids) of the
production segments,
thereby achieving automatic water-controlling throttle effect.
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[0026] Of course, the invention may further have several other embodiments,
and those
skilled in the art shall make various corresponding modifications and
variations according
to the invention without departing from spirit and essence of the invention,
but these
corresponding modifications and variations shall belong to the extent of
protection of the
appended claims of the invention.
Industrial Applicability
[0027] As compared to the water-controlling screen pipe of the conventional
water-
controlling and flow-limiting device, the composite water-controlling and flow-
limiting
device of the invention has a strong effect of limiting flow during the early
period, and can
suppress water automatically according to the change in viscosity of the fluid
during the
middle and late period, and the water-controlling and oil-increasing functions
thereof are
effective during the entire production period of the oil well.
[0028] A filtering portion of the composite water-controlling and flow-
limiting device uses
the form of an integral sleeve, and has the characteristics of good
permeability, high
strength, strong non-deformability, and good corrosion prevention.
[0029] A step of the filtering portion of the composite water-controlling and
flow-limiting
device is tightly connected to the base pipe using a hexagon bolt, and then
using surface
welding. Such specific process can effectively prevent slippage between the
base pipe and
the filter medium that may be caused when going down to the well while
ensuring
concentricity of the whole screen pipe, and improving strength of the screen
pipe and safety
of entry. The inner protective sleeve uses a bridge structure to have an
annular discharge
area, changes oil flowing channel, prevents sand deposition of the filter
medium, and solves
blocking of the screen pipe. Moreover, the filter medium is made in a form of
sleeve, and
directly fitted on the base pipe and fixed onto the step, and an annular space
is left between
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the sleeve and the base pipe, so that the screen pipe forms pipe flow during
permeation,
which greatly enhances penetration capacity of the screen pipe and oil
recovery of the oil
well.
[0030] The composite water-controlling and flow-limiting device has a unique
float-type
self-adaptive internal flow control device, which can automatically limit flow
of the fluid
according to the change in viscosity of the fluid.
[0031] The core component of the composite water-controlling and flow-limiting
device is
made of tungsten alloy, and has the advantages of heat resistance, pressure
resistance and
corrosion prevention. In particular, the speed-limiting device is hardened by
special process,
which can prevent sand shock and corrosion of the fluid, and has a long life.
[0032] The composite water-controlling and flow-limiting device has a good
adaptability to
the horizontal well, is convenient in installation, and has simple programs.
[0033] The composite water-controlling and flow-limiting device is advanced in
process,
and strongly targeted. The number of throttle holes on the flow control device
is designed
with numerical simulation software according to actual data of oil and gas
reservoir, and
differential pressure of production of each section is reasonably controlled
to maintain
balance of oil and water interface, prevent earlier water breakthrough, delay
coning of edge
water and bottom water, and achieve the object of earlier liquid control.
During the middle
and late period, the float-type self-adaptive internal flow control device can
suppress water
automatically according to the change in viscosity of the fluid.
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