RU2395677C1 - Thermal stimulator for heavy and bituminous oil reservoir - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: stimulator accommodates a wellhead, a pipe string with a packer mounted above a reservoir, and a lift valve at the bottom, an auxiliary pipe string equipped with centering skids and laterals at the bottom, concentrically inserted into the pipe string, sealed at the bottom above the laterals and interacting with the lift valve. According to the invention, over the hermetic sealing, the auxiliary pipe string has a ring restrictor for an inserted plunger pump to be lowered on the pump rods in the auxiliary string and tightly mounted in the ring restrictor after injection of the heat-carrier is completed. The auxiliary pipe string is equipped with a valve unit covering the laterals of the auxiliary pipe string and opening it when interacting with the lift valve.

EFFECT: enhancement of the device due to combination of repeating injection of the heat-carrier in the reservoir with withdrawal of the heated heavy and bituminous oil from the reservoir of the greater coverage radius.

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Description

The invention relates to the oil industry and is intended for thermal effects on the bottomhole zone and the oil reservoir with heavy and bituminous oil, and may also find application for the prevention or heating of paraffin hydrate deposits.

A well-known device for steam and thermal treatment of the reservoir (Reference book on oil production, M .: Nedra, 1974, pp. 127-131), where the coolant is pumped through a tubing string. The wellhead is equipped with an unloading stand, wellhead seal and lubricator, and the tubing string is equipped with a stuffing box, centering lights and a heat-resistant packer to seal the annulus above the formation roof.

The disadvantages of this device are:

- firstly, when the coolant is pumped through the tubing string, large heat losses occur along the wellbore as a result of the heat exchange process between the tubing - production string (EC) - surrounding rocks;

- secondly, it is impossible to achieve the required coolant temperature at the bottom of the well and even at a depth of 600 meters, since the temperature of the coolant does not exceed the natural temperature of the well, and therefore the efficiency of the device decreases sharply.

The closest in technical essence is a borehole device for pumping coolant into the formation (patent RU No. 2334093, IPC 8 ЕВВ 43/24, 36/00, published in Bulletin No. 26 of 09/20/2008), containing wellhead piping, injection a column of hollow tubing of smaller diameter concentrically located in the tubing of larger diameter with a heat-resistant packer overlapping the production string above the formation, while the string of tubing of larger diameter in the lower part is sequentially from top to bottom the cylinder and the nozzle, which is equipped with a poppet valve, a self-sealing packer and a safety casing with a transverse rod passing through the longitudinal windows of the nozzle, the shoe of the discharge column is equipped with a hollow plunger in the form of a nipple with o-rings and is placed in the inner cavity of the cylinder with the possibility of interaction with the poppet valve and the poppet valve stem through a transverse stem with a safety casing of the self-sealing packer, while the lower muffled end of the hollow plunger The era is made conical with side openings, and the injection column is equipped with centralizers from non-heat-conducting material.

The disadvantages of this device are:

firstly, the limited functionality of the device, because after pumping the coolant into the reservoir, the device does not allow to extract the heated heavy and bituminous oil from the reservoir;

secondly, low work efficiency due to the fact that extensive heating of the formation with heavy and bituminous oil is not ensured in a zone remote from the well;

thirdly, in the case of repair of downhole equipment (for example, replacing the sealing rings of the nipple of the injection string), it becomes necessary to remove the injection string, while the liquid inside the additional column enters the annular space, so there is a need for additional work on pumping the liquid out of the aforementioned annular space for subsequent operation of the device.

An object of the invention is to expand the functionality of the device by combining the periodic injection of coolant into the reservoir with the selection of heated heavy and bituminous oil from the reservoir, as well as increasing the efficiency of the device, which allows for extensive heating of the reservoir with heavy and bituminous oil, increasing the radius of coverage and providing an inflow of heated heavy and bituminous oil to the well from a zone remote from the well with the possibility of exclusion The fluid in the annular space during repair downhole equipment.

The stated technical problem is solved by a device for thermal impact on a formation with heavy and bituminous oil, including wellhead piping, a pipe string with a packer installed above the reservoir, and a poppet valve installed at the bottom, an additional pipe string with centralizers and side channels below, concentrically inserted into a pipe string with a seal in the lower part above the channels and with the possibility of interaction with a poppet valve.

New is that above the sealing in the additional pipe string an annular narrowing is made under the plug-in plunger pump, which is lowered on the sucker rods into the additional column and hermetically installed in the annular restriction after the coolant has stopped pumping, while the additional pipe string is equipped with a valve assembly configured to overlap lateral channels of an additional pipe string and their opening when interacting with a poppet valve.

Figure 1 shows a diagram of a device in the process of pumping coolant.

On. figure 2 shows a diagram of a device in the process of selecting heated oil.

A device for thermal treatment of a formation with heavy and bituminous oil includes a wellhead piping 1 (lowered in FIGS. 1 and 2) lowered into a production casing of a well 1 pipe string 2 (for example, an additional pipe string with a diameter of 114 mm) with a packer 3, installed above the reservoir 4 with heavy and bituminous oil. A poppet valve 5 is installed at the bottom of the pipe string 2. An additional pipe string 6 (for example, a tubing string 73 mm in diameter) with centralizers 7 made of non-conductive material is installed inside the pipe string 2. Centralizers 7 are made of non-conductive material to reduce heat loss during the injection of the coolant and the selection of heated heavy and bituminous oil.

The additional pipe string 6 is concentrically inserted into the pipe string 2 with a seal 8 in the lower part, made in the form of a hermetically inserted into the cylinder 9 and the hollow plunger 10, and the cylinder 9 is placed as part of the pipe string 2, and the plunger 8 is installed on the lower end of the additional pipe string 6 provided with side channels 11 below. The additional pipe string 6 is capable of interacting with the poppet valve 5. Above the sealing 8, the additional pipe string 6 has an annular restriction 12 under the plug-in plunger pump 13, which is lowered on the sucker rods 14 into the additional pipe string 5 and is hermetically installed in the annular restriction 9 after pumping is stopped coolant.

The additional pipe string 6 is equipped with a valve assembly 15 configured to overlap the side channels 11 of the additional pipe string 6 and open them when interacting with the poppet valve 5. The valve assembly 15 is made similar to the RF patent for utility model RU No. 55017, publ. in bull. No. 21 of July 27, 2006, in which the annular groove of the nipple, equipped with radial channels, has the ability to tightly overlap the pipe when moving up.

The device operates as follows.

The pipe string 2 is lowered into the production casing of the well 1 in an arrangement with the cylinder 9, the packer 3 and the poppet valve 5 from the bottom, while during the descent of the pipe string 2 the poppet valve 5 is in the closed position (not shown in Figs. 1 and 2).

As the pipe string 2 is lowered into the production casing of the well 1, the hydrostatic pressure force acting under the poppet valve 5 increases, and therefore the tightness of the shut-off unit increases, therefore the pipe string 2 with the above arrangement and the absence of the borehole fluid in its internal cavity is lowered to the roof of the productive formation 4.

Packer 3 is planted. Next, an additional pipe string 6 with centralizers 7 of non-conductive material is lowered into the pipe string 2 until the lower muffled end of the hollow plunger 10 rests on the poppet valve 5 (see Fig. 1), while the hollow plunger 10 is located in the inner cavity cylinder 9, that is, sealing 8 occurs due to the sealing rings of the hollow plunger 10, while the lower end of the valve assembly 15 located at the lower end of the hollow plunger 10 of the additional pipe string 6 interacts with the poppet valve 5 and due to The dead weight of the additional pipe string 6 opens the poppet valve 5, while the holes of the valve assembly 15 (see Figs. 1 and 2) are aligned with the side holes 11 of the additional pipe string and the under-packer space of the well 1 communicates with the space inside the additional pipe string 6.

If the additional weight of the additional pipe string 6 is not enough to open the poppet valve 5, the coolant is pumped and pressure is created above the poppet valve 5 above the hydrostatic pressure of the liquid under the poppet valve 5. In this case, the valve 5 opens and the pressure under and above it is equalized, and in the future, the position of the valve 5 is “open” is maintained due to the dead weight of the additional pipe string 6 and the weight of the coolant column in it.

Next, from the wellhead 1, the coolant (hot water, steam) heated by any known method is pumped. To do this, from the wellhead 1 (see Fig. 1) through an additional pipe string 6 using any known pump, the coolant is pumped in the calculated volume V _s , while the coolant heats the heavy and bituminous oil in the interval of the reservoir 4.

After pumping the coolant of the estimated volume V _s close the valve of the wellhead harness (not shown in FIGS. 1 and 2), intended for pumping the coolant, and install the plunger of the plug-in plunger pump 13 (see FIG. 2) in the annular restriction 12 made in an additional column pipes 6, and the drive is put into operation (not shown in FIGS. 1 and 2) by means of sucker rods 14 connected to the plug-in plunger pump 13, and heated heavy and bituminous oil are selected by an additional pipe string 6 from the productive formation 4 of well 1.

After a certain period of time, when the calculated volume of heated heavy and bituminous oil is taken from the well 1 by the plug-in plunger pump 13, the drive of the plug-in plunger pump 13 is turned off and the plug of the plug-in plunger pump 13 is lifted by means of sucker rods 14 from the annular restriction 12 of the additional pipe string 6 on the length L = 1-2 m (see figure 1).

The valve of the wellhead harness intended for pumping coolant is opened, and coolant is pumped from the wellhead 1 through an additional pipe string 6 into the reservoir 4 in a design volume V _s1 greater than V _s , i.e. (V _s1 > V _s ), while the heat carrier penetrates even deeper into the reservoir 4 compared with the originally injected volume V _z .

After pumping the calculated volume V _{s1 of the} coolant into the reservoir 4 (see Fig. 2), close the wellhead valve intended for pumping the coolant and install the plunger of the plug-in plunger pump 13 in the annular restriction 12 made in an additional pipe string 6.

The drive is put back into operation (not shown in FIGS. 1 and 2), and by means of sucker rods 14 connected to the plug-in plunger pump 13, the heated heavy and bituminous oil is selected through an additional pipe string 6 from the producing formation 4 of well 1.

In the future, the above cycle is repeated until the maximum permissible pressure of the coolant is injected into the reservoir 4. With each subsequent injection of the coolant into the reservoir 4, the depth of penetration (coverage radius) of the coolant into more distant zones of the reservoir 4 for heating heavy and bituminous oil is increased, and, accordingly, with each subsequent injection, the injection pressure increases.

Injection pressure P _{P1 P1} volume V into the reservoir 4 exceeds the injection pressure P _of the volume V _s, i.e. _P1 P> P _s, which is caused by deeper penetration of the coolant in the reservoir 4.

As a result, with each cycle of selection of heated heavy and bituminous oil and coolant injection, the radius of heating of the productive formation 4 increases and the influx of heated heavy and bituminous oil flows to well 1 from the zone farthest from well 1.

If it is necessary to repair the sealing 8, for example, replacing the sealing rings on the hollow plunger 10, an additional pipe string 6 is removed from the well, while the valve assembly 15 of the additional pipe string 6 seals the side channels 11 of the additional pipe string 6, since the holes of the valve assembly 15 are lower side holes 11 of the additional pipe string 6. Due to this, the coolant or the heated heavy and bituminous oil do not fall into the annular space between the pipe string 2 and the additional pipe pipes 6, where there are centralizers 7 made of non-heat-conducting material, which excludes additional work on pumping liquid from the aforementioned annular space.

The proposed device for thermal impact on the reservoir with heavy and bituminous oil has enhanced functionality, as it allows you to combine periodic injection of coolant into the reservoir with the selection of heated heavy and bituminous oil from the reservoir.

In addition, increasing the efficiency of the device is due to the fact that it allows for extensive heating of the reservoir with heavy and bituminous oil due to a gradual increase with each cycle of the volume of coolant pumped into the reservoir, providing an inflow of heated heavy and bituminous oil to the well remote from the well zones.

Claims (1)

Device for thermal impact on a formation with heavy and bituminous oil, including wellhead piping, a pipe string with a packer installed above the reservoir and a poppet valve installed below, an additional pipe string with centralizers and side channels at the bottom, concentrically inserted into the pipe string with sealing in the lower part above the channels and with the possibility of interaction with a poppet valve, characterized in that an annular narrowing under a plunger plunger pump that can be lowered onto the sucker rods into an additional column and sealed in an annular restriction after the coolant has stopped pumping, while the additional pipe string is equipped with a valve assembly that can block the side channels of the additional pipe string and open them when interacting with a poppet valve .

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