RU2625061C1 - Steam cutoff device for underground well in thermal-mining development of oil fields - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: steam cutoff device includes a housing hydraulically connected to the wellhead, a main exhaust valve whose seat is installed in the bottom of the housing, and a float actuator of the exhaust valve. The cutoff device is provided with an additional exhaust valve, the seat of which is also installed in the housing bottom, the valve locking elements being arranged with the possibility to be sequentially opened into the housing by one float actuator. The float actuator of the exhaust valves is made in the form of a console hinged in the housing with the possibility of moving the cantilever in the vertical plane, at the free end of which the float is fixed, wherein the discharge valves are installed on opposite sides of the console. A rod, on which thrusts rigidly connected with the locking elements are freely mounted, is installed and rigidly fixed perpendicular to the console. The thrust length of the additional exhaust valve shutoff element is larger than the thrust length of the main valve shutoff element, each valve shutoff element being made with a guide shank on the bottom, whose length is larger than the full stroke length of the shutoff element.

EFFECT: improved operation reliability of the cutoff device.

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Description

The present invention relates to the oil industry and may find application in thermal mining of a highly viscous oil field.

There is a method of developing solid minerals and highly viscous hydrocarbons, according to which a shut-off device is installed at the mouth of an underground well with the possibility of blocking the well at the time of steam breakthrough and opening (see RF patent No. 2299972, CL ЕВВ 43/00 dated 08/04/2005, published on May 27, 2007). The locking device is a valve that is mounted during the construction of underground wells, while shutting off soaring underground wells is carried out manually.

The disadvantage of using such valves is that when manually closing the soaring underground wells by the operator, it is almost impossible to simultaneously shut off all the soaring wells at the moment of steam breakthrough, which does not prevent steam breakthrough into mine workings and significantly worsens the working conditions in oil mines. Also, the operator cannot simultaneously open all the wells during steam condensation, which leads to a decrease in the rate of extraction of the produced fluid. The use of manual labor of operators does not allow to switch to deserted operation of mine mining blocks.

Also known is a locking device for blocking the channel for condensate drainage in the form of a float valve (see utility model patent No. 64730 of February 6, 2007, class F16T 1/30, publ. July 10, 2007). When the float is in the lower position, the mixture of condensate and steam enters the float, rises between the walls of the housing and the float and is forced into the outlet channel.

However, when this shut-off device is used at the mouths of underground wells in an oil mine, sanding of the device body with sand and jamming of the float will occur, since sand is a constant component of the produced oil-water liquid under any methods of producing highly viscous oil in mine conditions and, as a result, the inability to select well production.

The closest in technical essence, adopted by the authors for the prototype, is a cutoff for an underground well during thermal mining of oil fields (see utility model patent No. 100553 dated 06/17/2009, class E21B 43/24, publ. 12/20/2010), containing a casing hydraulically communicating with the wellhead through a side opening in the casing, an exhaust valve, a seat of which is installed in the bottom of the casing, and a shut-off element connected to the float with the possibility of automatic shut-off of the well at the time of steam breakthrough and opening of the well when ensatsii steam.

A disadvantage of the known cutter is a decrease in the reliability of its operation due to the following factors.

1. The formation of a dead zone in the upper part of the body, in which gas accumulates, restricting the upward movement of the float and, accordingly, reducing the volume of the body filled with the produced well fluid.

2. Failure of the device at high vapor pressures in the reservoir, since the force pressing the locking device to the valve seat exceeds the lifting force of the float.

3. The failure of the device with large flow rates of the well, since the flow rate of the produced well fluid in the device body exceeds the speed of the float.

The technical result achieved by the present invention is to increase the reliability of the cutter.

The specified technical result is achieved by the proposed steam cutoff for an underground well during thermal mining of oil fields, comprising a body hydraulically connected to the wellhead, a main outlet valve, a seat of which is installed in the bottom of the body, and a float valve actuator.

Salient features of the claimed invention are:

- the cutter is equipped with an additional exhaust valve, the seat of which is also installed in the bottom of the housing;

- locking elements of the valves are installed with the possibility of their sequential opening into the body using one float actuator;

- the float actuator of the exhaust valves is made in the form of a console pivotally mounted in the housing with the possibility of moving the console in a vertical plane;

- a float is fixed on the free end of the console;

- exhaust valves are installed on opposite sides of the console;

- locking elements of the exhaust valves are rigidly connected to the rods freely mounted on the rod;

- the bar is rigidly attached perpendicular to the console;

- the thrust length of the locking element of the additional exhaust valve is greater than the thrust length of the locking element of the main valve;

- each locking element of the valve is made bottom with a guide shank, the length of which is greater than the stroke length of the locking element;

- the distance from the hinge of the console to the middle of the perpendicular rod is determined by the formula:

,

,

where l ₁ is the distance from the hinge of the console to the center of the float, m;

l ₂ is the distance from the hinge of the console to the middle of the perpendicular rod, m;

ρ _W - the density of the working fluid, kg / m ³ ;

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

ρ _pop - density of the float and console, m;

V is the volume of the float and console, m;

P _slave. - pressure of the medium in the case of the steam cutoff, Pa;

S _holes - the area of the outlet of the saddle of the exhaust valve, m ² .

The claimed combination of essential features improves the reliability of the proposed cutter, namely the design of the device prevents the formation of a dead zone in the upper part of the body, in which gas accumulates, restricting the upward movement of the float and, accordingly, reducing the volume of the body filled with produced well fluid. The design of the body eliminates the dependence of the flow rate of the produced well fluid in the body on the ascent rate of the float, while the design of the shut-off element, for example, in the form of a cone, allows you to adjust the flow rate of the produced well fluid when the fluid level in the body changes. The operability of the shut-off device at high vapor pressures in the formation is ensured by the selection and calculation of the shut-off parameters: float volume, cantilever arm lengths, sizes and number of exhaust valves.

The design of the inventive cutter also prevents clogging of the device body with sand, which is a constant component of the produced well fluid under any methods of producing highly viscous oil in mine conditions, which is an important field factor affecting the operation of the device. Thus, the design of the cutter significantly increases the reliability of its operation, ensuring trouble-free operation under various operating conditions of production wells during thermal mining of oil fields, preventing steam breakthrough into production galleries.

The claimed combination of essential features is not known to us from the prior art, therefore, the present invention is new. The claimed features of the invention are not obvious to the average person skilled in the art. In this regard, we believe that the claimed invention has an inventive level. The invention is industrially applicable, since the equipment manufactured by the industry used in the claimed invention allows to realize the device in full.

The essence of the invention is illustrated in FIG. 1, which shows a schematic diagram of a cutter; FIG. 2, which shows a cutaway section along AA; FIG. 3, which shows an embodiment of rods in the form of plates rigidly fixed with locking elements of the exhaust valves and freely mounted on a perpendicular rod.

The steam cutter includes a housing 1, hydraulically connected with the wellhead in the upper part, and a main exhaust valve, a seat 2 of which is installed in the bottom of the housing, and a float actuator for the exhaust valve. The cutter is equipped with an additional exhaust valve, a seat 3 of which is also installed in the bottom of the housing, and the shut-off elements 4, 5 of the exhaust valves are installed with the possibility of their sequential opening into the housing by one float actuator. The float actuator of the exhaust valves is made in the form of a console 6 fixed in the housing with a hinge 7 with the possibility of moving the console in a vertical plane. The console can be made in the form of a metal beam, rod, etc. The float 8 is rigidly fixed on the free end of the console. The float can be made of metal or other material that can withstand temperatures up to 200 ° C. A rod 9 is rigidly attached perpendicular to the console, which can be made in the form of a bar, pole, strap, etc., while the rod can be rigidly attached to the console, both above and below or inside the console body. It is advisable to fix the perpendicular rod to the console with equal shoulders relative to the console to prevent unbalancing of the exhaust valves, which are installed on different sides relative to the console. On a perpendicular rod 9, on opposite sides of the console 6, the thrust of the main valve 10 and the thrust of the additional valve 11 are freely mounted, the lower end of which is rigidly fixed with the corresponding locking element 4 and 5 of the exhaust valves. Each locking element of the exhaust valve is made with a guide shank, respectively 12 and 13, the length of which is greater than the stroke length of the corresponding locking element. Rods can be made, for example, in the form of metal plates, rods, tubes, etc. All parts of the steam cutoff are made of heat-resistant metal or alloy, such as steel. When performing traction, for example, in the form of a metal plate in the center of the upper part of the plate, a hole 14 with a diameter is provided, providing a free nozzle of the traction and its movement along the perpendicular rod. It is advisable to perform the length of the main valve rod corresponding to the distance at which the locking element completely covers the valve seat and the float is in a horizontal position. The thrust of the locking element of the additional exhaust valve is longer than the thrust of the locking element of the main valve. When performing rods, for example, in the form of plates, the elongation of the additional valve rod is carried out by vertically extending the holes 15 in the center of the upper part of the plate with a diameter providing a free nozzle of the rod and its movement along the perpendicular rod. It is advisable to extend the length of the thrust of the additional valve by half the full stroke length of the locking element of the main valve. In this case, the full stroke length of the auxiliary valve corresponds to half the stroke length of the main valve. The operability of the shut-off device is maintained with a slight increase or decrease in the length of the valve rods. In this case, the stroke length of the shut-off elements of the exhaust valves accordingly changes. An embodiment of the rods of the locking elements of the exhaust valves is possible, for example, in the form of rods of different lengths that freely pass through the holes in the perpendicular rod 9 with limiters for the vertical movement of the rods over the perpendicular rod, for example, in the form of a nut. Seats 2, 3 of the exhaust valves can be equipped with nozzles 16, 17 of various shapes to increase the throughput of the exhaust valves. Nozzles are made with the possibility of closing them with plugs to check the tightness of the cutter. A possible embodiment of the shut-off device, in which several exhaust valves are installed in the housing of the device, successively opening into the housing with a single float actuator.

The distance from the hinge of the console to the middle of the perpendicular rod is determined by the formula:

where l ₁ is the distance from the hinge to the center of the float, m;

l ₂ - the distance from the hinge to the perpendicular rod, m;

ρ _W - the density of the working fluid, kg / m ³ ;

ρ _pop - density of the float and console, m;

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

V is the volume of the float and console, m;

P _slave. - pressure of the medium in the case of the steam cutoff, Pa;

S _holes - the area of the outlet of the saddle of the exhaust valve, m ² .

Based on the specific operating conditions clipper with the operating pressures and the productivity of wells under the condition ensuring the passage of the locking elements throughout inflowing from the wellbore into the housing clipper fluid predetermined value ρ _Pople, V, S _holes, and l _1, wherein it is advisable to reduce the distance l ₂ - from the hinge to the perpendicular bar by at least 20%.

Steam cutoffs are installed in production galleries at the mouth of each underground production well with the formation of a hydraulic connection between the well and the upper part of the body, while to prevent direct exposure to liquid flow on the float, a guide element is installed in the upper part of the body, for example, in the form of a chipper (the position in the diagram does not shown).

The operation of the cutter is as follows. Consider installing two exhaust valves in the housing. The exhaust valves are in the closed position, the shut-off elements 4 and 5 are tightly pressed to the seats 2 and 3 when the steam breaks into the well. The liquid level in the housing 1 of the cutter is below the mark at which the Archimedean force acting on the float 8 is less than the weight of the float in the liquid. The opening and closing of the locking elements 4 and 5 is carried out only due to the Archimedean force acting on the float 8. When the condensation of steam in the well and filling the well and the shutter body with the produced fluid, the float 8 is immersed in the liquid, the Archimedean force grows and at a certain moment the float floats, when this console together with the perpendicular rod 9 also rises up and through the rod 10 is the lifting of the locking element 4 and the opening of the main exhaust valve. With the further emergence of the float 8, when the locking element 4 of the main exhaust valve rises to a distance of more than half of its full stroke, the locking element 5 of the additional exhaust valve will begin to rise. When the float reaches its extreme upper position, both outlet valves open and the borehole fluid flows out of the cutter body outward, and the rods 10 and 11 move freely along the perpendicular rod 9. When the borehole fluid level in the cutter body decreases, the float 8 is lowered by its own weight, locking elements 4 and 5 overlap the seats 2 and 3, while the shanks 12, 13 of the locking elements provide a fixed movement of the locking elements inside the seats. The fluid selection process continues until a new cycle of steam breakthrough into the wells. In this case, the shut-off elements work again, closing the exhaust valves, block the mouth of the underground well, and, as a result, steam is prevented from entering the mine workings. It is possible for the cutter to work when a certain dynamic level of the borehole fluid is established in the housing, i.e., the inflow of fluid into the cutter is equal to its outflow, in this case the float remains stationary, and the level of the borehole fluid in the housing locks the vapor accumulated above it.

Example. The proposed cutter can be used in the Yaregskoye field of high-viscosity oil with the following characteristics: depth - 200 m, initial reservoir temperature - 8 ° C, reservoir pressure - 0.1 MPa, reservoir thickness - 26 m, porosity - 26%, permeability - 3 μm ² , oil saturation - 87%, oil viscosity - 12000 MPa · s, oil density - 933 kg / m ³ . As the heat carrier water saturated steam is used. In the 4th quarter of 2015, 4 prototypes of the steam cutter were manufactured and installed at the mouths of production wells in the Severny block of oil mine No. 2. Dimensions of the cutter body: the bottom of the housing 537 * 124 (mm), the height of the side walls 324 and 130 (mm). The length of the float is 280 mm, the diameter of the float is 115 mm. The distance from the console hinge to the center of the float is 336 mm. The distance from the bottom of the body to the bottom of the float when it is horizontal is 15 mm, and from the bottom of the body to the center of the console is 75 mm. The thrust length of the main exhaust valve is 75 mm. The traction length of the additional exhaust valve is 87 mm. The distance between the axes of the valves is 36 mm. Prior to the installation of steam cutoffs, the wells were operated by periodically manually opening the wellhead valve to drain the well fluid. The fluid temperature in the wells was 97-98 ° C. During periodic operation of the wells, the production rate of the wells ranged from an average of 1.4 tons per day for oil. up to 1.7 tons / day., and water from 0.8 tons / day. up to 1.6 t / day. After the liquid was discharged from the wells, steam was released at a pressure of about 1 kg / cm ² . After installing the inventive steam cutoffs in the wells, the produced fluid flowing from the wellhead passed through the device body and flowed through the exhaust valves into the mine workings. During steam breakthrough, the valves were closed, holding the steam inside the housing until it condensed. In the process of testing steam cutoffs, well production rates increased approximately 2 times. At the same time, in the process of operation of the cut-outs, automatic ejection of sand accumulated at the seats of the exhaust valves was carried out. The inventive cut-offs have been working steadily from the day the pilot field work began to the present, having proved their operability and reliability of operation.

Claims (10)

Steam cutoff for an underground well during thermal mining of oil fields, comprising a housing hydraulically connected to the wellhead, a main exhaust valve, a seat of which is installed in the bottom of the housing, and a float actuator of an exhaust valve, characterized in that the shutoff valve is equipped with an additional exhaust valve, the seat of which is also installed in the bottom of the housing, and the locking elements of the exhaust valves are installed with the possibility of their sequential opening into the housing using a single float of the drive, which is made in the form of a console pivotally mounted in the housing with the possibility of moving the console in a vertical plane, on the free end of which a float is fixed, while the exhaust valves are installed on opposite sides of the console, and their shut-off elements are rigidly connected to rods freely mounted on a rod rigidly attached perpendicular to the console, while the length of the thrust of the locking element of the additional exhaust valve is greater than the length of the thrust of the locking element of the main valve, each locking element ent valve is formed below the guide shank whose length is longer than the full stroke of the locking element and the distance from the middle console of the hinge perpendicular to the rod determined by the formula:

, where l ₁ is the distance from the hinge of the console to the center of the float, m; l ₂ is the distance from the hinge of the console to the middle of the perpendicular rod, m; ρ _W - the density of the working fluid, kg / m ³ ; q is the acceleration of gravity, m / s ² ; ρ _pop - density of the float and console, m; V is the volume of the float and console, m; P _slave. - pressure of the medium in the case of the steam cutoff, Pa; S _holes - the area of the outlet of the seats of the exhaust valves, m ² .

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