RU2590171C1 - Packer - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to packers. Packer includes pipe string, sealing element of cylindrical shape, arranged concentrically to pipe string between it and casing pipe, between upper and lower stops. Between the sealing element and lower stop movable element and clamping element made from material with shape memory are installed, wherein sealing element is made of basalt fibre with diameter from 0.5 to 3.5 mqm. Basalt fibre is saturated with metal particles.

EFFECT: technical result is possibility of effective operation of device at high working pressure and temperature.

9 cl, 3 dwg

Description

The invention relates to the oil industry and can be used in the development of deposits of natural bitumen, heavy and highly viscous oils, as well as for the integrated development of oil shale formations.

Specifically, a high-temperature downhole packer for thermal oil recovery enhancement methods (EOR) has been proposed.

According to the World Energy Council, the geological reserves of natural bitumen, heavy and high-viscosity oils in Russia total 55 billion tons, and their deposits in Russia are concentrated mainly in the Volga-Ural (Tatarstan, Udmurtia, Bashkortostan, Samara Region and Perm Territory ), East Siberian (Tunguska basin) and Timan-Pechora oil and gas provinces. The modern concept of in-situ retorting, which involves the in-situ conversion of heavy hydrocarbons to their lighter forms, requires the use of high-temperature thermal effects on productive formations, in which the temperature of the working agent, mainly in the form of superheated steam, can reach 500 ° C.

But, the most significant hydrocarbon reserves of Russia are still concentrated in the Bazhenov Formation, and most of them are concentrated in kerogen - about 383.1 billion tons. The oil content of low-permeability rocks in the productive formations of the Bazhenov Formation does not exceed 22 billion tons. According to industry experts, the development of the Bazhenov Formation, based only on the extraction of low-permeability oil, and without involvement in the active development of kerogen, is unpromising and unprofitable. In turn, involvement in the active development of kerogen also involves the use of high-temperature thermal EOR for its in-situ pyrolysis. In this case, a working agent in the form of water in a supercritical state (SC-water) and having the following thermobaric characteristics must be injected into the reservoir: pressure up to 45 MPa and temperature up to 500 ° C.

The technological scheme of high-temperature thermal effects on reservoirs containing natural bitumen, heavy and high viscosity oils, as well as kerogen, provides for the use of a heat-resistant packer. But there are no such heat-resistant packers capable of operating at temperatures up to 500 ° C either in Russia or abroad. The need for a heat-resistant packer in the presence of high pressures (up to 45 MPa) further aggravates this problem.

For example, Weatherford's heat-resistant ArrowTherm Mechanical-Set Thermal Packer is known, which can be operated at pressures up to 20.68 MPa and temperatures up to 288 ° C. If necessary, Weatherford can make a more advanced modification of the same heat-resistant packer for operation at temperatures up to 343 ° C by special order (“Packers Catalog”, Weatherford, 2005-2010, p. 86).

Also known is the heat-resistant Schlumberger KPR Premium Production Packer, which can operate at very high pressures, up to 103 MPa, but cannot be operated at temperatures above 218 ° C (“Packers Catalog”, Schlumberger, 2009, p. 17).

A known method and device for the development of viscous oil according to the patent of the Russian Federation for the invention No. 2548639, IPC E21B 33/128, publ. 04/20/2015, (prototype).

This device for separating well cavities (packer) is made with radial expansion under the action of axial pressure.

In order to increase the tightness of the packer installation in the well, the supporting mechanical packer contains a barrel telescopically connected by means of cuffs with a support nipple with the possibility of axial movement between them. The barrel is equipped with an annular seal, a connecting sleeve, an adjusting nut with an upper pressure ring stop mounted on the sleeve with the possibility of regulating the position of the annular seal on the barrel between the stops on the adjusting nut and on the sleeve connected to the support nipple. A step surface is made in the sleeve, abutting the step step against the shoulder on the barrel. A groove is made on the shoulder, interacting with shear pins installed in the sleeve. Triangular notches are made on the barrel, interacting with a collet, inside which reciprocal triangular notches and an outer cone are made. The collet is located in the sleeve cavity with an emphasis on the end of the support nipple and is kept from axial movements by a retaining ring with an inner cone interacting with the outer cone of the collet to fix the ring seal in a compressed state, with the possibility of moving along the barrel for a length greater than the compression of the ring seal with the radial expansion to hermetic separation of the well cavity. The circlip is grooved for additional shear pins installed in the sleeve.

A disadvantage of the known invention is the inability to operate the device at high pressures (up to 45 MPa) and temperatures (up to 500 ° C).

The objective of the claimed invention, which coincides with the technical result, is to enable efficient operation of the claimed device at high operating pressures (up to 45 MPa) and temperatures (up to 600 ° C).

The solution to these problems has been achieved in a packer containing tubing, a cylindrical sealing element mounted concentrically between the tubing and the casing pipe, between the upper and lower stops, in that a piston and a clamping element made of shape memory ”, while the sealing element is made of superthin basalt fiber having a diameter of from 0.5 to 3.5 μm, the basalt fiber is saturated with metal particles.

As a metal for saturation, aluminum powder can be used.

The sealing element may be made of metal rubber. The sealing element may be made of graphlex.

The lower tubing can be made of titanium. At the end of the lower tubing pipe, a nozzle coupling can be installed.

The nozzle coupling can be made of tungsten carbide. The clamping element made of a material with a “shape memory" can be made in the form of a spring. A tubing can be coated with a heat-insulating coating.

The invention is illustrated in the drawings of FIG. 1 ... 3, where:

- in FIG. 1 shows a view of the claimed device;

- in FIG. 2 shows the device in operating position;

- in FIG. 3 shows a packer with heat-insulated tubing.

The claimed device (Fig. 1 ... 3) contains from top to bottom: tubing 1 (tubing), couplers 2, the bottom tubing 3, with a cavity 4 inside it. The tubing pipe 1 and the lower tubing pipe 3 are installed inside the casing 5.

The lower tubing 3 is made of titanium, and the tubing 1 is steel.

A sealing element 6 is installed on the bottom pipe of the tubing 3, it is installed concentrically to the bottom pipe of the tubing 3 and divides the cavity inside the casing 5 into two, the upper 7 and the bottom 8. The sealing element 6 contains the upper stop 9 and the lower stop 10, which is rigidly fixed to the lower pipe while the sealing element 6 is installed between them and is made of either basalt fiber or metal rubber or graphlex. A movable element 11 is mounted under the sealing element 6 with the possibility of axial movement, and between it and the lower stop 10, the pressing element 12 is made of “shape memory” material, capable of changing shape with increasing temperature.

Sealing element 6 is preferably made of superthin basalt fiber having a diameter of 0.5 to 3.5 μm to ensure the operability of the device at high temperatures (up to 600 ° C). The basalt fiber can be saturated with metal particles. As a metal for saturation, aluminum powder can be used.

On the bottom pipe of the tubing 3 there is a nozzle coupling 13 with an outlet 14. On the casing 5 in the lower part, perforation 15 is made.

The sealing element 6 is placed inside the casing 6 and forms cavities 7 and 8 between the siege string 5 and the lower tubing tubing 3. The cavities 7 and 8 must be disconnected during operation.

The outlet 14 of the nozzle-coupling 13 communicates the cavity 4 inside the lower tubing tubing 3 with the reservoir 16 and is designed to supply a hot agent to the reservoir 16 to intensify the production of hard to recover oil.

On the pipes of the tubing 1 can be applied insulation coating 17 (Fig. 3). On the lower pipe of the tubing 3 thermal insulation coating 17 is not applied.

DEVICE OPERATION

The claimed device operates as follows (Fig. 1 and 2).

An injection well is drilled to inject the hot agent into the reservoir 16 and the casing 5 is installed in it; the assembly according to FIG. one.

The hot working agent is fed through tubing 1 and through the outlet 14 of the nozzle-coupling 13 into the reservoir 16. The working agent partially enters the cavity 8. The material of the sealing element 6, made of basalt fiber, having a diameter of from 0.5 to 3.5 μm saturated with aluminum powder significantly increases in volume and is compressed in the axial direction, while it expands in the radial direction and covers the gap between the casing 5 and the lower tubing 3.

In addition, the pressing element 12 changes shape (increases in the axial direction) and additionally creates an axial pressing force through the piston 11 to the sealing element 6. As a result, the cavities 7 and 8 are disconnected by the sealing element 6.

Removing the claimed device from the well is carried out after the cessation of the supply of the hot agent. The clamping element 12 again changes shape (decreases axial size), the compression of the sealing element 6 is reduced. In addition, when cooling, the volume of the sealing element 6 decreases and the sealing density decreases. Then carry out the lifting of tubing 1 up.

One of the main distinguishing functional features of the claimed invention is that the claimed device is a self-regulating device. This is expressed in the fact that the higher the pressure of the working agent at the bottom of the well in the sub-packer zone, the denser and less permeable the sealing element 6 becomes and the denser the friction surface of the sealing element 6 is pressed against the inner surface of the casing 5.

Since the sealing element 6 is made of pre-pressed superthin basalt fiber having an average diameter of 0.002 mm (or in the range from 0.5 to 3 μm) It is the diameter of the fiber in the base that determines the permeability of the sealing element. The smaller it is, the higher the efficiency of the sealing element. So, for example, if the diameter of any fiber used is relatively large, for example, 0.1 mm, then a sealing element made of such a material will have a high permeability comparable to that of fine-grained sandstone having a grain size from 0.1 to 0.25 mm The ultrafine basalt fiber used is small in diameter and made of it and finally pressed into the well under the action of the pressure of the working agent, the sealing element has an ultra-low permeability comparable to that of fine-grained calcareous dolomite rocks with grain sizes from 0.001 to 0.01 mm. Only a colloid-grained calcareous dolomite rock having a grain size of less than 0.001 mm can be less permeable to fluids.

The sealing element 6 in the process of its manufacture and prior to its preliminary compression is saturated with particles of various metals, such as: aluminum, zinc, zirconium, tungsten, etc. In a preferred embodiment of the invention, PAP-2 aluminum powder is used having an average linear particle size of 0.02 to 0.03 mm. When a high-temperature working agent is supplied to the bottom of the well, the sealing element is heated and due to the thermal expansion of the ultrafine basalt fiber and aluminum particles, its density increases, and the permeability, on the contrary, decreases even more. The degree of pressing of the sealing element to the inner surface of the casing also increases. In this process, aluminum particles play a more significant role, since the coefficient of thermal expansion (KTP) of aluminum (KTP = 0.000024 m / (m · ° C)) is 3.69 times higher than the coefficient of thermal expansion of basalt (KTP = 0.0000065 m / (m ° C)). Note: KTP dimension, m / (m · ° C) or 1 / ° C - shows how much (in meters) the material will elongate when its temperature increases by 1 degree ° C. It should also be noted that superthin basalt fiber begins to sinter only at temperatures exceeding 1100 ° C. As a result of the above-mentioned process of thermal action on the sealing element, its permeability at the micro level is markedly reduced.

Metal rubber is a sealing element made of thin pressed stainless steel wire with a diameter of 0.1 ... 0.2 mm.

Graphlex is a combination of gaskets and gaskets made of thermally expanded graphite (TRG), low-temperature carbon fiber, expanded fluoroplastic and aramid yarn. During the manufacturing process, all of these ingredients can be combined with various other impregnations and additives.

Modern scientific developments allow us to develop new technologies for the production of sealants of varying complexity. The graphlex series materials are based on natural graphite - a layered mineral that is an allotropic modification of carbon. Graphite has unique chemical properties that allow it to produce materials used for sealing in any temperature environment. The production process of Graphlex products is based on nano-technologies, when molecules of various chemical elements are embedded in the crystal lattice of graphite. Then the resulting compound is cleaned of impurities and subjected to thermal foaming. The result is products of the Graflex group.

To date, sealing materials made of thermally expanded graphite are widely used all over the world. Such gaskets and seals withstand various temperatures and pressures, are designed for an unlimited service life and are immune to wear.

The list of modern sealing materials of the new generation, which are known under the general name - Graflex, includes:

- stuffing box for flange connections, fittings and pumps;

- various gaskets;

- graphite foil;

- braided packing;

- graphite rings;

- graphite sheets reinforced and unreinforced.

To maintain the high quality of products, a full production cycle is practiced. The process begins with the processing of raw materials to the formation and production of finished products.

Stuffing box packing, packing and gaskets are the most common products among soft packings. There are about 40 types of these products. The temperature range of packing use ranges from -200 ° C to + 560 ° C. Graphlex gaskets are used to seal pipelines, pumps, fittings and components of various equipment used in the oil refining, gas and chemical industries.

Graphlex products significantly reduce the consumption of sealants on a particular stuffing box and reliably maintain its sealing. Previously, from 8 to 18 rings were used for packing in the stuffing box, today their use has decreased to 4-6 pieces. A decrease in the number of seal rings led to a significant reduction in the depth of the stuffing box, which led to a decrease in the metal consumption of the reinforcement. The manufactured new fittings received the design of the stuffing box themselves, intended for use with Graflex seals. This method involves installing a special sleeve in the chamber - a spacer. Thus, a smaller number of rings in the stuffing box was achieved, the excess of which would not allow them to be compressed qualitatively. Not fully clamped rings can lead to displacement of the stem and weakening of the stuffing box packing, which can damage the sealing.

When installing the claimed device (packer) at the bottom of the well and after applying to the bottom of the well a high-temperature working agent of high pressure, which is water in a supercritical state, a chemical reaction is oxidized of a certain part of the aluminum particles in supercritical water. During the reaction, alumina nanoparticles that have a size of from 0.00002 to 0.0004 mm (from 20 to 400 nm) are synthesized from a certain part of aluminum particles having a size from 0.02 to 0.03 mm. The result of the above-mentioned chemical process for the synthesis of aluminum nanoparticles in SC water is a decrease in the permeability of the sealing element at the nanoscale.

Thus, the maximum possible low permeability of the sealing element is achieved by the following three main processes:

- preliminary mechanical compression of the sealing element in the manufacturing process and its final compression at the bottom of the well under the action of pressure of the working agent;

- thermal expansion of superthin basalt fiber and metal particles with which the sealing element is saturated; and

- the synthesis of nanosized particles of metal oxides from a certain part of the metal particles with which the sealing element is saturated.

To ensure even more tight pressing of the sealing element to the walls of the well, the clamping elements creating an axial force on the annular sealing elements are made of material “Shape memory” in the working position (when heated, they take the shape of a cone), which when compressing the annular sealing elements creates an additional effect wedging. Due to significant power loads in the presence of high temperatures, part of the elements of the claimed device, in the preferred embodiment, are made of titanium. The result of using the claimed device is a reliable disconnection of individual sections of the wellbore during the use of thermal EORs at pressures up to 70 MPa and temperatures up to 600 ° C.

Despite the fact that the present invention is described in the presented example, various modifications are possible, not contradicting the basic principles of the invention. Therefore, the present invention should be construed as relating to any such modifications within the spirit of the invention.

Claims (9)

1. A packer containing tubing tubing, a cylindrical sealing element mounted concentrically to the tubing tubing between it and the casing between the upper and lower stops, characterized in that a movable element and a clamping element made of material with shape memory are installed between the sealing element and the lower stop ", While the sealing element is made of basalt fiber having a diameter of from 0.5 to 3.5 μm, and the basalt fiber is saturated with metal particles. 2. The packer according to claim 1, characterized in that aluminum powder is used as a metal for saturation. 3. The packer according to claim 1, characterized in that the sealing element is made of metal rubber. 4. The packer according to claim 1, characterized in that the sealing element is made of graphlex. 5. The packer according to claim 1, characterized in that the lower tubing pipe is made of titanium. 6. The packer according to claim 1, characterized in that a nozzle coupling is installed at the end of the lower tubing pipe. 7. The packer according to claim 6, characterized in that the nozzle coupling is made of tungsten carbide. 8. The packer according to claim 1, characterized in that the clamping element is made of a material with "shape memory" in the form of a spring. 9. The packer according to claim 1, characterized in that the tubing is coated with a heat-insulating coating.

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