RU2543246C1 - Well formation development device - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: well formation development device includes a swab, a tubing string with a swab limit stop and a filter for interaction with the formation and a packer installed above the formation. The tubing string above the packer, but below the swab limit stop is provided with a row of through holes. When in an initial position, the holes are tightly covered with a hollow sleeve for a discharge shutoff element. The shutoff element has a possibility of leak-proof fit and fixation in the hollow sleeve, as well as a possibility of restricted axial movement together with the hollow sleeve down against stop into an internal annular recess of the tubing string under action of created excess pressure in the tubing string with further fixation of the hollow sleeve with a spring-loaded split stop ring in notches for interaction of the inner space of the tubing string with the above-packer zone after discharge of the shutoff element. Notches are made on the inner surface of the tubing string. The shutoff element is made in the form of a stepped blind cylinder, the upper diameter (Ds) of which is larger than the inner diameter of the hollow sleeve (d), but is less than the inner diameter of the swab limit stop (D).

EFFECT: simpler design of the device and shorter development period of the well.

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Description

The invention relates to the oil and gas industry and can be used in well development in order to clean and improve the filtration characteristics of the bottomhole formation zone.

A device for developing a wellbore by swabbing (Patent RU No. 2432456 IPC E21B 43/25, published in Bulletin No. 30 of 11/27/2011), including a swab, a tubing string with swab limiter and a filter for communication with the reservoir, the packer installed above the reservoir, while the tubing string is equipped with a hollow tip at the bottom, and the filter at the top with a nozzle with an internal cylindrical cavity, and the tip is inserted into the nozzle, from which it is spring-loaded upward and made with the possibility of longitudinal limited movement, while tip The IR is equipped with upper and lower rows of openings, internally separated by a partition and made with the possibility of communication when moving the tip down relative to the filter nozzle through the inner cylindrical cavity of the nozzle, and above the tip and packer, but below the swab stroke limiter in the tubing string, a knockout valve is installed to communicate the tubing string with an overpacker zone after resetting the knocking down element, while the swab is equipped with a safety valve spring-loaded upward with the possibility of opening with a force of 80-90% of the critical and allowable effort.

The disadvantages of this device are:

- firstly, the complexity of the design, due to the large number of nodes and parts (tip, safety valve, swab, nozzle, knockdown valve, knocking element), and, as a result, the high cost and high cost of manufacturing the device;

- secondly, low reliability due to the high probability of failure of the tension-compression spring, which leads to the failure of the device. In addition, during the operation of the device, the tip is constantly moving downward relative to the filter nozzle, which can lead to loss of tightness of the device and, as a result, inability to turn off the under-packer space when swabbing the liquid located in the annulus between the production string and tubing string above the packer;

- thirdly, the long process of well development, due to the limited throughput of the device due to the small passage area of the upper and lower rows of the holes of the tip and filter, respectively.

The closest in technical essence and the achieved result is a device for the development of a wellbore by swabbing (patent RU No. 2440491 IPC E21B 43/25, published in bulletin No. 2 of 01/20/2012), including swab, tubing string ( Tubing) with a swab stroke limiter and a filter for communicating with the reservoir, a packer installed above the reservoir, while the tubing string is equipped with a hollow tip at the bottom and the filter at the top with a nozzle with an internal cylindrical cavity, and the tip is inserted into the nozzle, from which it is spring loaded up and made with cart limited longitudinal movement, while the tip is equipped with upper and lower rows of holes, internally separated by a partition and made with the possibility of communication when moving the tip down relative to the filter nozzle through the inner cylindrical cavity of the nozzle, and the upper row of nozzle openings is made with the possibility of communication with the over-packer zone when moving tip up and fixation relative to the filter nozzle.

The disadvantages of this device are:

- firstly, the complexity of the design, due to the large number of components and parts (tip, safety valve, swab, nozzle, knockdown valve, knocking element) and, as a result, the high cost and high cost of manufacturing the device;

- secondly, low reliability due to the high probability of failure of the tension-compression spring, which leads to the failure of the device. In addition, during the operation of the device, the tip is constantly moving downward relative to the filter nozzle, which can lead to loss of tightness of the device and, as a result, inability to turn off the under-packer space when swabbing the liquid located in the annulus between the production string and tubing string above the packer;

- thirdly, the long process of well development, due to the limited throughput of the device due to the small passage area of the upper and lower rows of the holes of the tip and filter, respectively.

The objective of the invention is to simplify the design of the device, reducing the duration of well development, as well as increasing the reliability due to the guaranteed shutdown of the under-packer space when swabbing the fluid located in the annulus between the production string and the tubing string above the packer

The problem is solved by a device for developing a wellbore, including a swab, a tubing string with a swab limiter and a filter for communicating with the reservoir, a packer installed above the reservoir.

What is new is that the tubing string is above the packer, but below the swab stroke limiter, it is equipped with a number of through holes in the initial position, hermetically sealed with a hollow sleeve for a resettable locking element, which has the option of tight fit and fixation in the hollow sleeve, as well as the possibility of limited axial movement together with the hollow sleeve down to the stop in the inner annular selection of the tubing string under the action of the generated overpressure in the tubing string x pipes with subsequent fixation of the hollow sleeve by a spring split retaining ring in the notches made on the inner surface of the tubing string to communicate the inner space of the tubing string with the packer zone after the closure of the shut-off element made in the form of a stepped blind cylinder, the upper diameter is d _s is larger than the inner diameter of the hollow shank - d, but smaller than the inner diameter of the stroke limiter swab - D.

In figures 1, 2, 3 shows schematically the proposed device for the development of the wellbore.

The figure 4 in a section in an enlarged view - I shows a hollow sleeve with a locking element fixed in it.

The device for the development of the reservoir 1 of the well consists of a tubing string (3) lowered into the well 2 (see FIGS. 1 and 2), as well as a packer 5 isolating the annulus 4, installed at a distance of h = 10-15 m above formation 1. A swab 6 on a rope 7 is lowered into the tubing string 3. For example, a tubing string 73 mm in diameter is used as a tubing string 3.

The travel stop 8 of the swab 6 is fixed inside the tubing string 3 by any known method, for example, on a thread. The packer 5 hermetically divides the annulus 4 into a subpacker 9 and a superpacker 10 zone.

At the end of the tubing string 3, a filter 11 is installed, plugged from below and serving to communicate the interior of the tubing string 3 with formation 1.

The tubing string 3 is higher than the packer 5, but below the travel limiter 8, the swab 6 is equipped with a number of through holes 12, in the initial position hermetically closed by the hollow sleeve 13, by means of a shear element 13 '(see Figs. 1, 2 and 4) under the resetting locking element 14 having the ability to tight fit and fixation in the hollow sleeve 13.

A number of through holes 12 in the tubing string 3, for example, are made in the form of eight holes with a diameter of 15 mm, which does not limit the throughput of the device and, compared with the prototype, can reduce the duration of the development of the wellbore.

The locking element 14 with the hollow sleeve 13 (see FIGS. 3 and 4) has the possibility of limited axial movement down to the stop in the inner ring sample 15 of the tubing string 3 with subsequent fixing of the hollow sleeve 13 with a spring split retaining ring 16 located in the outer ring sample 16 'hollow sleeve 13 relative to the notches 17, made on the inner surface of the tubing string 3 under the action of excess pressure generated in the tubing string 3 using a pump unit located at the wellhead (not shown in Figs. 1, 2, 3, 4) for communication the inner space of the tubing string 3 with nadpakery zone 10 after the reset of the locking element 14.

The locking element 14 is in the form of a stepped blind cylinder upper diameter - D _s which is greater than the inner diameter of the hollow shank - d, but less than the inner diameter of the stroke limiter swab - D, i.e. (D> D _s > d).

The locking element in the hollow sleeve 13 is fixed by a locking ring 17 located in the outer annular selection 19 of the locking element 14 under the lower end 20 of the hollow sleeve 13.

The device operates as follows.

The device is mounted in the well 2 (see Fig. 1), while the packer 5 in the well 2 is set 10-15 meters above the top of the formation 1, while the row of through holes 12 of the tubing string 3 in the initial position is sealed by a hollow sleeve 13.

Then, the swab 6 is lowered into the tubing string 3 on the rope to the calculated depth. Next, begin the process of development of the reservoir 1 by swabbing with a ground drive, for example, an aggregate for swabbing (not shown in FIGS. 1, 2, 3).

The fluid is sampled along the tubing string 3 by swabbing from the sub-packer zone 9 through the filter 11 until a stable flow of formation 1 is obtained by periodically lifting the fluid along the tubing string 3 using the swab 6, certain portions of fluid from the well 2 with a sequential stepwise decrease in the fluid level and the corresponding change the depth of descent of the swab 6 at each subsequent stroke. The height of the raised column of liquid and, accordingly, the volume of liquid raised in one cycle, is determined by the immersion of the swab 6 under the liquid level in each cycle.

After obtaining a stable flow of products from the reservoir 1 at 10 and separated nadpakrenoy packer zones 9 by a rope 7 is removed from the tubing 3 swab 6. Produce discharge into the tubing 3 of the locking element 14, made in the form of a stepped blind cylinder diameter D _of the upper upwards, while in the process of moving the locking element 14 down the tubing string 3, it freely passes the travel stop 8 of the swab 6, since the outer diameter D _s is smaller than the inner diameter D of the travel stop 8 of the swab 6 (see figures 1 and 2).

Next, the locking element 14 (see Fig. 4) with the lower stage of a deaf cylinder of smaller diameter d _h tightly enters the passage channel of the hollow sleeve 13, then using a pump unit installed at the wellhead 2, excessive hydraulic pressure is created in the tubing string 3, for example up to 4-5 MPa, with the first locking element 14 is fixed in the hollow sleeve 13, i.e. an additional spring split retaining ring 18, located in the outer annular sample 19 of the locking element 14, is fixed under the lower end 20 of the hollow sleeve 13,

Subsequently, under the influence of excess pressure in the tubing string 3, the shear element 13 'is destroyed and the hollow sleeve 13 together with the locking element 14 are moved down to the stop by the lower end of the hollow sleeve 13 into the inner ring sample 15, after which the hollow sleeve 13 is spring loaded with a split spring retaining ring 16. located in its outer ring sample 16 ', is fixed relative to the notches 17, made on the inner surface of the tubing string 3.

The fixation of the hollow sleeve 13 with the retaining ring 13 in the notches 17 of the tubing string 3 avoids the axial movement of the hollow sleeve 13 upward with the overlapping of a number of through holes 12 during subsequent swabbing of the well 2.

The fixation of the locking element 14 by the locking ring 18 relative to the lower end 20 of the hollow sleeve 13 avoids pumping the liquid out of the under-packer zone 9 when swabbing the liquid from the over-packer zone 10.

The possibility of fixing the hollow sleeve 13 relative to the tubing string and the locking element 14 relative to the hollow sleeve increases the reliability of the device and eliminates the loss of tightness of the device during the development of the wellbore.

As a result, the annular space 4 in the nadpaker zone 10 and the inner space of the tubing string 3 are communicated and the height H ₁ of the liquid column is aligned in them (see Fig. 2).

The pump unit is disconnected from the tubing string 3 at the wellhead 2 and the swab 6 on the rope 7 is again lowered into the tubing string 3.

The fluid is sampled along the tubing string by swabbing from the sub-packer 9 and overpacker 10 zones until the fluid level decreases by ΔН = H ₁ -H ₂ (see FIGS. 2 and 3) in the overpacker zone of the annulus, until the pressure exerted by the hydrostatic the level of H ₂ (see figure 3) of the borehole fluid, will not be lower than the reservoir pressure (R _PL ).

$$P_{Pl}>\rho \times g\times {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="00000004.png"\; state="\{\{state\}\}">H</figure-callout>}}_2,(\mathrm{one})$$

where R _PL - reservoir pressure, MPa;

ρ is the density, kg / m ³ ;

g is the acceleration of gravity, m / s ² ;

H ₂ - the height of the liquid column in the above-packer zone of the annulus and to the top of the reservoir, m;

or $${\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="00000004.png"\; state="\{\{state\}\}">H</figure-callout>}}_2<P_{Pl}/\rho \times g,(2)$$

Then, the packer 5 is unpacked (removed) and removed together with the tubing string 3.

The proposed device for the development of the wellbore has a simple design, allows to reduce the duration of the development of the wellbore and to increase the reliability due to the guaranteed shutdown of the under-packer space when swabbing the fluid located in the annulus between the production string and the tubing string above the packer.

Claims (1)

A device for developing a wellbore, including a swab, a string of tubing with a swab limiter and a filter for communicating with the reservoir, a packer installed above the reservoir, characterized in that the tubing string is higher than the packer, but below the swab limiter it is equipped with a row through holes in the initial position hermetically closed by the hollow sleeve for a resettable locking element having the possibility of tight fit and fixation in the hollow sleeve, as well as the possibility of limited axial movement together with the hollow sleeve down to the stop in the inner annular selection of the tubing string under the action of the generated overpressure in the tubing string with subsequent fixation of the hollow sleeve with a spring split retaining ring in the notches made on the inner surface of the tubing string for communication of the inner space of the tubing string with an over-packer zone after the discharge of the shut-off element, made in the form of a stepped blind cylinder, outer diameter - D _z which is larger than the inner diameter of the hollow sleeve - d, but smaller than the inner diameter of the swab stroke limiter - D.

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