RU2203385C2 - String disconnector - Google Patents

Abstract

FIELD: extraction of hydrocarbons. SUBSTANCE: string disconnector is designed for connection and subsequent disconnection of string of pipes with packer placed in production or injection wells. String disconnector has shaft with shoulder, radial holes and outer sealing rings. Lower end of shaft carries enclosure with internal sealing rings and rest with shear screws. Enclosure and shaft form upper and lower chambers. On top there is placed body with upper sub and lower cylinder with internal sealing cup and collet. Locking device is positioned on shaft and at least one groove is cut in enclosure to accommodate it. Radial holes in shaft hydraulically communicate its internal space with upper and lower chambers. Enclosure also has radial holes hydraulically communicating correspondingly upper or lower chamber with space behind enclosure, it is linked to collet with the help of shear screws screwed into collet. Sliding bushing with outer locking device and sealing rings tightly insulating radial holes of shaft is put on shaft. Outer locking device comes in the form of snap ring. EFFECT: enhanced functional reliability and efficiency. 3 cl, 5 dwg

Description

 The invention relates to techniques for the production of hydrocarbons (oil, gas and gas condensate) and is intended to disconnect and then connect the pipe string to a packer installed in production or injection wells, as well as to compensate for changes in the length of the pipe string during thermobaric changes in the process of fluid production or pumping environment in the reservoir (s) of the well.

 A known column disconnector (Operating Instructions for the FHH packer of the Baker model "K" sealing sleeve for coupling and uncoupling the product 683-61), comprising a barrel connected to the packer rod, on which a housing is mounted, rigidly connected from above to the sub, and from below - a cylinder with internal sealing cuffs and a collet, over which a casing is mounted, rigidly connected to the anchor of the packer.

 The functioning of the “K” column disconnector is related to the operation of the FHH packer. Its body disengages from the trunk after moving the anchor with the collet cover along the packer rod when creating the calculated (necessary) overpressure in the packer cavity. For this reason, the model “K” column disconnector cannot be used for other types of packers, for example 2PD-YAG. Also, the column disconnector does not allow re-rigid adhesion of its body to the barrel. Therefore, to disrupt and remove the packer from the well, it is first necessary to raise the pipe string with the disconnector body, and then re-lower it into the well with the device for capturing its trunk above the packer.

 Known disconnector columns type 4RK (Catalog. Equipment for gas-lift operation of oil wells. ZINTIKHIMNEFTEMASH, M., 1991), containing a shaft with a shoulder, upper and lower radial openings and external sealing rings, on which a casing with internal sealing rings is installed from below, forming with the barrel the upper and lower chambers, and an emphasis with shear screws, and on top the case with the upper sub and the lower cylinder with internal sealing cuffs and a grip is placed.

 In the process of disconnecting the disconnector of the 4РК column, it is required to install a receiving valve in the landing surface (socket) of the barrel above the lower radial holes, and then create a design excess pressure inside it to cut off the screws on the stop and release the collet. For the 4RK column disconnector to operate in the well, an additional operation is required to lower and remove the receiving valve from its trunk using cable technology and a tool. In the process of disconnecting the disconnector of the 4РК column, there is also a high probability of clogging with sand, salt and other upper radial holes of the barrel after installing a receiving valve in it, since the distance from the landing surface to the upper radial hole is insignificant. If, for this reason, the overpressure does not act on the casing through the upper chamber, then the column disconnector does not disconnect. In addition, the landing seat made in the barrel above the lower radial openings for the receiving valve reduces the diameter of the passage channel 4PK. This, in turn, limits the diameter of the passage of wireline tools and deep tools for lowering into the well below the column disconnector. Also, when reconnecting the disconnector of the 4РК column, its casing with the barrel cannot rigidly engage, therefore, to remove the packer from the well, it is first necessary to lift its casing on the pipe string and then re-lower it with the gripping tool.

 The aim of the invention is to increase the reliability and efficiency of the use of a column disconnector with a packer system in production and injection wells with one or more production facilities (formations).

The specified goal is achieved through the following solutions:
- a latch is installed on the barrel and, accordingly, at least one groove is made in the casing to fix the position of the casing on the barrel after disconnecting (disengaging) or reconnecting (coupling) the housing with the barrel;
- radial holes on the barrel hydraulically connect its internal cavity to the upper or lower chamber in order to operate (disconnect) the column disconnector from the internal or, conversely, from external pressure;
- radial holes are made on the casing, hydraulically connecting the lower or upper chamber, respectively, with the space behind the casing, in order to connect the casing to the barrel from external or, conversely, from internal pressure;
- the casing can be connected to the collet with shear screws screwed into it for discreteness of the force (pressure) when cutting the screws;
- a sliding sleeve with an external retainer and sealing elements can be installed in the barrel with the possibility of axial movement downward, hermetically insulating its radial holes, in order to prevent the trip of the column disconnector during installation and crimping of the packer in the well, and also, if necessary, with moving the sliding sleeve, ensuring operation (uncoupling) of the column disconnector from hydrostatic pressure in the well;
- the external clamp can be made in the form of a spring ring to simplify the design of the clamp.

 These solutions allow for the disconnection and connection of the column disconnector hydraulically, creating excessive pressure both from inside and outside it, and also provide for its operation from hydrostatic pressure in the well.

 A positive effect from the use of the column disconnector is achieved by increasing the overhaul period of the well, reducing the number of "descent - lifting" of the pipe string and wireline tools, as well as by ensuring the descent, landing, crimping, as well as the separation and removal of each packer from the well separately with simultaneous separate operation of the well.

 Figure 1 shows a schematic view of the disconnector of the column, triggered by internal pressure; figure 2 - column disconnector with a casing connected to the collet shear screws; figure 3 - column disconnector, triggered by external pressure; figure 4 - column disconnector with a sliding sleeve; figure 5 - guide shoe re-entry.

 The column disconnector (Fig. 1) comprises a barrel 1 with a collar 2, radial holes 3 and external sealing elements (rings) 4. On the barrel 1, a casing 5 with internal sealing elements 6, which form with the barrel 1 the upper 7 and / or lower 8 of the chamber, and emphasis 9 with shear screws 10. The casing 5 can be connected to the collet 16 with shear screws 11 screwed into it (Fig. 2). On the barrel 1, a housing 12 with an upper sub 13, a lower cylinder 14 with internal sealing elements (cuffs) 15 and a collet 16 is placed on top. A lock 17 (for example, in the form of a spring ring) and, accordingly, in the casing 5 are mounted on the barrel 1 below at least one groove is made 18. Radial holes 3 on the barrel 1 hydraulically connect its internal cavity to the upper 7 (Figs. 1 and 4) and / or lower 8 (Fig. 3) chamber. In this case, radial holes 19 can also be made on the casing 5 for hydraulic connection, respectively, of the lower 8 or upper 7 of the chamber with the space behind the casing 5.

 In the barrel 1 can be installed with axial downward movement of the sliding sleeve 20 with an external retainer 21 and sealing elements 22, hermetically insulating its radial holes 3 (figure 4). The sliding sleeve 20 can be made removable for installation (before planting and crimping the packer in the well) and removing it from the barrel 1 (after checking the tightness of the packer) using cable technology and tools.

 The disconnector column operates as follows. It as part of the packer equipment is lowered into the well on a pipe string. Then, the pipe cavity under the packer is disconnected (for example, by installing a blank plug or a receiving valve in the seat below the packer), create overpressure in the pipe and install the packer according to its operating instructions. Check the tightness of the installation of the packer bottom and top, and then disconnect the column disconnector in the following way. Create the calculated excess pressure (depending on the number of shear screws 10 and / or 11) in the pipe string or annulus of the well using the unit. This pressure through the internal radial channels 3 of the barrel 1 (Fig. 1, 2) or the outer 19 of the casing 5 (Fig. 3) acts on the inner area of the casing 5. At the same time, the screws 10 and / or 11 are cut off, the casing 5 moves down and releases the petals collet 16, thereby disconnecting the housing 12 from the barrel 1.

 To reduce the number of screws 10 and / or 11 and, accordingly, reduce the effort (pressure) of their shear, as well as to prevent clogging of the radial holes 3 and premature operation of the column disconnector in the well, a sliding sleeve 20 is installed in the barrel 1 (Fig. 4) (on the surface or in a well using cable technology and tools). In this case, the disconnection of the column disconnector is ensured by first moving the sliding sleeve 20 in the barrel 1, hydraulically - after installing the receiving valve in the sleeve 20 or by mechanical shock at its end, after which excessive pressure is created in the pipe string to cut off the screws 10 and / or eleven.

 If necessary, in order to ensure that the column disconnector is activated from hydrostatic pressure in the well, radial holes 19 are isolated (excluded) on its casing 5, then a sliding sleeve 20 is installed on the surface of the barrel 1, thereby sealing the chamber 8 hermetically, keeping atmospheric pressure in it . After moving the sliding sleeve 20 in the barrel 1, hydrostatic pressure acts on the casing 5 through the radial holes 3, as a result of which the disconnector of the column is disconnected.

 The reconnection of the disconnector of the column to remove the packer is achieved by creating excess pressure in the annulus of the well (Figs. 1, 2, 4) or in the pipe string (Fig. 3), while the casing 5 is moved up and locked by the latch 17, going to the collet petals 16, thereby providing adhesion of its petals to the shoulder 2 of barrel 1. If necessary, by tightening the pipe string, the packer is torn off and removed from the well together with the column disconnector.

 In the process of pumping the working medium into the formation (s) of the well (injection of cold water, cyclic impact, hydraulic fracturing, treatment of the bottomhole zone, etc.), the thermobaric conditions change, leading to a change (lengthening or shortening) of the length of the pipe string, which can lead to spontaneous release the packer or break the pipe string. In order to prevent these consequences, the column disconnector is made with a telescopic stroke.

 To enter the telescopic stroke, a pipe string with a housing 12 is removed from the well after disconnecting the disconnector, then the collet 16 is turned out of the cylinder 14 and a reentry guide shoe 23 is installed instead of it (Fig. 5). Again, the housing 12, the cylinder 14 with the guide shoe 23 are lowered into the well on the pipe string and are hermetically connected to the barrel 1 above the packer, providing the necessary axial load. Then the axial load is removed and the pipe string with the casing 12 is lifted to 0.5 m and the tightness of the connection of the casing 12 with the barrel 1 is checked by creating excessive pressure in the pipe and / or annulus of the well. When the isolation device is tight, the well is put into operation.

 The telescopic stroke of the column disconnector to extend the pipes (move down) or to shorten the pipes (move up) is regulated by changing the location of its body 12 with the shoe 23 on the barrel 1.

 Depending on the operating conditions, a blank plug or a receiving valve can be installed on top of the barrel 1 of the column disconnector for crimping the pipe string and / or eliminating the flow of fluid from the formation into the well.

 Stalling and lifting the packer from the well can also be carried out using a special extraction tool. To do this, raise the housing 12 with the shoe 23 and re-lower the pipe string with the extraction tool to capture the rod 1 above the packer.

Claims (4)

 1. A column disconnector comprising a barrel with a collar, radial holes and external sealing rings, on which a casing with internal sealing rings is mounted on the bottom, forming the upper and lower chambers with the barrel, and an abutment with shear screws, and a housing with an upper adapter and a lower one is placed on top a cylinder with internal sealing cuffs and collets, characterized in that a latch is installed on the barrel and, accordingly, at least one groove is made in the casing, with radial holes on the barrel hydraulically connect its inner cavity with the upper or lower chamber, wherein on the housing is also provided with radial openings fluidly interconnecting respectively lower or upper chamber with the space of the housing.  2. The column disconnector according to claim 1, characterized in that the casing is connected to the collet with shear screws screwed into it.  3. The column disconnector according to claim 1 or 2, characterized in that a sliding sleeve with an external retainer and o-rings is installed in the barrel with the possibility of axial movement downward, hermetically insulating its radial holes.  4. The disconnector of the column according to claim 3, characterized in that the external retainer is made in the form of a spring ring.

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