RU199872U1 - Selective hydraulic fracturing assembly in horizontal wells - Google Patents

Abstract

The proposed utility model relates to the oil and gas industry and is intended for hermetic isolation of intervals of oil and gas wells, with the possibility of pumping solutions and maintaining excess pressure in both directions. The objective of the proposed technical solution is to increase the reliability of multistage hydraulic fracturing in wells with horizontal ends due to hermetic isolation separate intervals, with the possibility of injecting solutions for the assembly and maintaining the excess pressure in both directions. The purpose of this utility model is to develop an assembly device for selective hydraulic fracturing in wells with horizontal completion, the activation of which occurs after lowering the tubing on the tubing lift a plug using a transport hub ... Hydraulic fracturing is injected through a transport device that passes directly through the entire body and protects the plug body from the abrasive effect of the gel-proppant mixture. After hydraulic fracturing, the transport device is removed from the plug, and the check valves are closed. Once the adapter has exited BittFrac, re-login is not possible. For the next interval, the working cycle for the trip of the plug, activation and hydraulic fracturing is repeated using a new transport node. Each time the newly stimulated interval remains isolated until the completion of hydraulic fracturing and drilling out of all deflated plugs. Before development, all installed plugs are drilled out. At all stages of the work, it is assumed that workover is used, without the use of a coiled tubing complex. The novelty and innovation consists in the technological solution of delivery to the target interval and the use of easily drilled plugs to ensure the separation of open intervals and perform selective hydraulic fracturing. Potentially candidates can be all wells with lowered assemblies of Ø114 mm with single or multiple-action hydraulic fracturing collars for opening-closing after completing the preparation of the horizontal part of the well (the requirement for a "equal" section - with a 95 mm bit).

Description

The proposed utility model relates to the oil and gas industry and is designed for hydraulic fracturing in wells with horizontal completion.

During operation, the productivity of the well decreases, in particular, due to changes in the conductive characteristics of hydraulic fracturing (HF) fractures due to clogging with mechanical impurities coming from the formation and deformation of the proppant pack ("indentation" of the proppant into plastic rocks). The most effective method for restoring the productivity of wells with multi-stage hydraulic fracturing (MSHF) is re-fracturing. The effectiveness of re-fracturing operations 3-5 years after the previous stimulation has been confirmed in directional wells.

The well-known layout of a small liner for hydraulic fracturing [1. Govzich A.N., Bilinchuk A.V., Faizullin I.G. Experience of multistage hydraulic fracturing in horizontal wells of JSC "Gazprom Neft" // Oil Industry. - 2012. - No. 12. - P. 59–61 .;].

The technology provides for lowering a small-sized layout into the horizontal part of the wellbore. Before re-fracturing, it is required to drill out all the frac sleeves and balls (on coiled tubing (CT) or tubing); the cutter diameter should be as large as possible for the used frac sleeves and the horizontal liner. Then a liner hanger with a diameter of 127 mm with an attached small-size liner with a diameter of 73 mm with hydraulic fracturing sleeves and swellable packers is lowered into the horizontal part of the well, finished with a liner with a diameter of 114 mm. Fracturing sleeves can be activated both by balls and by a reusable coiled tubing tool. Then a new hanger is fitted and a stinger is run for hydraulic fracturing on 89 mm tubing.

The disadvantages include: high metal consumption of the structure; the ability to carry out only one operation of repeated MSF; inability to conduct research in the well after the operation; high risk of getting a complex accident.

The known design of the assembly for hydraulic fracturing with proppant filling [1. Govzich A.N., Bilinchuk A.V., Faizullin I.G. Experience of multistage hydraulic fracturing in horizontal wells of JSC "Gazprom Neft" // Oil Industry. - 2012. - No. 12. - S. 59–61.].

Before re-fracturing, all seats and balls are drilled (on coiled tubing or tubing). A small packer is run into the well using a tubing lift with a diameter of 50 mm in the horizontal part of the wellbore and 89 mm in the main string. During the first re-fracturing operation, the packer is installed between the first and second fracturing sleeves. At the end of the hydraulic fracturing fluid injection, a high concentration proppant pack is supplied to fill the stimulated interval. Thus, the shank section is overlapped, and the machined interval is isolated from those not yet machined. Then the packer is set in the next fracturing interval. The process is repeated.

The disadvantages include: the risk of annular circulation and proppant ingress into the packer equipment; the possibility of stuck assembly after unsuccessful hydraulic fracturing in the horizontal section; the risk of leakage of the proppant plug; loss of control of proppant injection in a certain interval.

The closest technical solution, chosen for the prototype, is an assembly with a double packer for hydraulic fracturing in wells with horizontal completion [1. Govzich A.N., Bilinchuk A.V., Faizullin I.G. Experience of multistage hydraulic fracturing in horizontal wells of JSC "Gazprom Neft" // Oil Industry. - 2012. - No. 12. - P. 59–61 .; 2. Economides M.J., Nolte K.G. Reservoir Stimulation. - USA: John Wiley Sons, 2006. - 856 p].

Double packer fracturing technology is based on the use of cup packers and a reusable packer. The device can be switched from water jet cutting to hydraulic fracturing and vice versa. The required area is isolated between the top cup and the reusable packer. Before re-fracturing, all seats and balls are drilled out (on coiled tubing or tubing), the assembly is installed in the required interval opposite the open frac sleeve. Then hydraulic fracturing is performed.

The assembly design allows creating new intervals for hydraulic fracturing. To do this, the assembly is moved to the position for perforation followed by pumping of the abrasive mixture. After the completion of the hydraulic fracturing, the assembly is moved to the position for hydraulic fracturing in the new interval.

The disadvantages include: duration of work 25 days or more; the risk of casing circulation and proppant penetration into the packer equipment; sticking a two-packer assembly after a successful hydraulic fracturing in a horizontal section; high injection pressure during hydraulic fracturing due to friction.

The objective of the proposed technical solution is to increase the reliability of multistage hydraulic fracturing in wells with horizontal ends due to hermetic separation of individual intervals with the possibility of pumping solutions for the assembly and maintaining excess pressure in both directions.

The achieved technical result consists in the development of a hydraulic fracturing arrangement, which allows for interval hydraulic fracturing of the formation using a system of poppet check valves.

The set task and the achieved technical result are achieved by the fact that the arrangement for hydraulic fracturing in wells with a horizontal end includes a wellbore with a lower valve assembly, an anchor lower, anti-deflectors, a sealing collar, an upper anchor, a split nut, an upper nut, an upper valve assembly ; the lower anchor is formed of a shoe, grips with inserts and a cone; the grippers are connected to the cone by means of shear screws; the shoe is threaded onto the barrel; the upper anchor is formed of a cone, grips with inserts and an upper nut; the upper anchor is connected to the barrel through a split nut, which is threaded onto the barrel; a split nut, elastically expanding, is capable of jumping along the barrel thread under an external axial force, only in one direction - down; anti-leakage devices are installed on both sides of the rubber cuff and are designed to prevent rubber from flowing into the gap between the assembly and the casing string under the influence of excessive pressure; the lower valve assembly is threaded from the bottom with the barrel and is a poppet check valve; the upper valve assembly is threaded from the top to the barrel and is also a poppet check valve.

The activation of the proposed layout occurs after the plug is lowered on the tubing elevator using the transport unit. Hydraulic fracturing is injected through a transport device that passes directly through the entire body and protects the plug body from the abrasive effect of the gel-proppant mixture. After hydraulic fracturing, the transport device is removed from the plug, and the check valves are closed. Once the adapter has exited BittFrac, re-login is not possible. For the next interval, the working cycle for the trip of the plug, activation and hydraulic fracturing is repeated using a new transport node. Each time, the newly stimulated interval remains isolated until the completion of hydraulic fracturing and drilling out of all deflated plugs.

Before mastering, all installed plugs are drilled out. At all stages of the work, it is assumed to use workover, without using the coiled tubing complex.

The novelty and innovation lies in the technological solution of delivery to the target interval and the use of easily drillable plugs to ensure the isolation of open intervals and hydraulic fracturing. Potentially candidates can be all wells with lowered assemblies of Ø114 mm with single or multiple-action hydraulic fracturing collars for opening-closing after completing the preparation of the horizontal part of the well (the requirement for a "equal" section - with a 95 mm bit).

The essence of the proposed utility model is shown in the drawings (Fig. 1 and 2). FIG. 1 is an arrangement drawing, FIG. 2 - barrel part of the adapter.

The assembly (Fig. 1) includes a barrel 1, on which a lower valve assembly 2, an anchor lower 3, anti-leakage devices 4, a sealing collar 5, an upper anchor 6, a split nut 7, an upper nut 8, an upper valve assembly 9 are installed.

The lower anchor 3 is formed of a shoe, grips with inserts and a cone. The claws are connected to the cone by means of M6 shear screws. The shoe is threaded onto the barrel.

The upper anchor 6 is formed of a cone, grips with inserts and an upper nut 8. The upper anchor is connected to the barrel 1 through a split nut 7, which is threaded onto the barrel. The split nut 7, elastically expanding, is able to jump along the barrel thread under external axial action, exclusively in one direction - down. Moving the split nut upwards is excluded.

Anti-deflectors 4 are installed on both sides of the rubber cuff 5 and are designed to prevent rubber from flowing into the gap between the assembly and the casing under the action of excessive pressure.

The lower valve assembly 2 is connected to the barrel 1 from the bottom along the thread and is a poppet check valve. It holds pressure in one direction from bottom to top.

The upper valve assembly 9 is connected to the barrel 1 from above along the thread and is also a poppet check valve. It holds pressure in one direction from top to bottom.

The adapter is designed to connect the layout to the installation module. In general, a barrel part can be distinguished in the adapter, which is connected to the barrel of the assembly and the output rod of the installation module and the outer part, which transmit the force of the installation module to the assembly parts movably mounted on the barrel.

The stem part of the adapter (Fig. 2) consists of a sleeve 10, into which a rod 16 is screwed. A clip 11 with radial holes in the amount of 4 pieces is screwed onto the sleeve 10 along the external thread. The support of the collet 14 is screwed into the holder 11, on which the collet 13 is previously put on.

The collet is inserted into the cage 11 and is secured from movement by shear pins 12 in the amount of 4 pieces inserted into the radial holes on the cage 11. On top of the cage a cover of pins 15 is put on, which protects the shear pins 12 from falling out. Cover 15 is fixed with a locking screw 22.

There is a knock-off valve on the bottom of the stem 16. Seat 18 with ball 24 is inserted into stem 16.

The saddle is kept from falling out by the collet 18, which in turn is fixed on the rod 16 by shear screws 21 in the amount of 4 pieces. The collet 18 is kept from opening the petals by the sleeve 20, which is fixed against movement by shear screws 21 in the amount of 2 pieces.

The knock-off valve is designed to shut off the inner cavity of the tubing when creating excess pressure inside and activating the setting module.

The outer part of the adapter is represented by a pusher 17, which is threaded onto the lower sleeve of the installation module. The assembly is connected to the adapter by means of a collet 13, on the petals of which there is a left-hand thread. To prevent spontaneous opening of the assembly, it is fixed with two M6 shear screws, screwed in at the upper end of the assembly between the collet petals.

The assembly also includes a valve collet 19, a locking screw 23, rings 25 and 26.

The layout works as follows.

The assembly is connected to the installation module by means of an adapter. Then this arrangement is lowered into the well on the tubing string. When a given depth is reached, a ball is thrown into the tubing and overpressure is created in the tubing. Under the action of hydraulic pressure, the cylinders of the installation module move downward relative to the stationary barrels and exert a force effect on the moving parts of the assembly.

Under the action of the pusher, the M6 shear screws on the anchors are sheared and the parts move on the assembly barrel. As a result of axial movement of the assembly details, the grippers engage with the casing, the collar expands and compresses the casing, hermetically separating the intervals before and after assembly.

When the pressure in the tubing reaches 18 MPA, the pins on the adapter are sheared, as evidenced by pressure fluctuations (but does not fall to zero) and the collet disengages from the assembly. As a result, the adapter is able to move upward, within the stroke (400 mm) of the adapter to the knock-off valve. Then the pressure in the tubing is released and the suspension is tensioned to no more than 2 tons. As a result, the seat and ball are pushed out of the stem, thereby tearing off the bore. Further, it is checked that the through hole is open by unloading onto assemblies weighing up to 2 tons and creating pressure in the tubing. If the pressure does not increase and there is no circulation through the annulus, then the valve is installed and the orifice is open. Injection is performed for the assembly.

After carrying out work under the assembly, the suspension is tensioned more than 400 mm and weighing more than 3 ... 4 tf. before a sharp drop in weight to its own. As a result, the collet 10 flies off the rod 7 and allows the adapter

After carrying out work under the assembly, the suspension is tensioned more than 400 mm and weighing more than 3 ... 4 tf. before a sharp drop in weight to its own. As a result, the collet flies off the stem and allows the adapter to exit the assembly. The lower and upper check valves are closed. Circulation appears along the annulus. Work on the layout.

Claims (1)

An assembly for hydraulic fracturing in wells with a horizontal end, characterized in that it includes a wellbore on which a lower valve assembly is installed, an anchor lower, anti-deflectors, a sealing collar, an upper anchor, a split nut, an upper nut, an upper valve assembly; the lower anchor is formed of a shoe, grips with inserts and a cone; the grippers are connected to the cone by means of shear screws; the shoe is threaded onto the barrel; the upper anchor is formed of a cone, grips with inserts and an upper nut; the upper anchor is connected to the barrel through a split nut, which is threaded onto the barrel; a split nut, elastically expanding, is capable of jumping along the barrel thread under an external axial force, only in one direction - down; anti-leakage devices are installed on both sides of the rubber cuff and are designed to prevent rubber from flowing into the gap between the assembly and the casing string under the influence of excessive pressure; the lower valve assembly is threaded from the bottom with the barrel and is a poppet check valve; the upper valve assembly is threaded from the top with the barrel and is a poppet check valve.

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