RU2322576C1 - Method for highly-viscous oil and bitumen production - Google Patents

Abstract

FIELD: hydrocarbon production, particularly highly-viscous oil or bitumen production with the use of double-wellhead wells.

SUBSTANCE: method involves drilling producing double-wellhead well; consolidating thereof with production string having perforated section located in productive reservoir; arranging piston with power pull-rods connected with driving unit at wellheads inside well, wherein the piston may perform reversible sliding inside well; lifting and supplying well product in discharge line to one wellhead of producing well. Injection well having profile parallel to that of producing well is additionally drilled. The injection well is cased with production string having perforation part arranged in the same productive reservoir over producing well. Piston is arranged so that it may directly cooperate with production string of producing well and may perform reversed movement within the limits thereof. Piston movement speed provides viscous oil and bitumen production rate exceeding reverse oil filtration in reservoir from well interior in front of moving piston. Installed on pull-rods are downhole tools for temperature and pressure control during product extraction from producing well and accumulation in discharge line and at the second wellhead of producing well. Heat-carrier is simultaneously injected via two channels of two concentric tubing strings. Tubing string with lesser diameter has length exceeding that of another one.

EFFECT: elimination of sand precipitation and sand plug accumulation in horizontal producing well, increased output and increased efficiency due to instrumental monitoring and control of thermal productive reservoir treatment.

3 cl, 4 dwg

Description

The invention relates to the field of development of hydrocarbon deposits by double-well wells and can be used for the production of highly viscous oil or bitumen.

A known method of developing deposits of viscous oils and bitumen (RF patent No. 2085715, CL EV 43/24, publ. Bull. No. 21 dated 07/27/1997), including drilling a horizontal wellbore, fixing it with production casing, perforation of the production casing section in the zone of the reservoir and the subsequent rise and supply of oil to the flow line.

The disadvantage of this method is the technological complexity of its implementation, associated with the use of high-frequency current for heating the formation and the control circuit reverse ESP double-acting.

A known method of developing deposits of viscous oils and bitumen (RF patent No. 2246001, class ЕВВ 43/24, publ. Bull. No. 4 of 02/10/2005), including drilling a two-well horizontal well, fixing it with a production string dragged from one wellhead along its trunk to another wellhead together with packers for installing the latter in the roof of the producing formation, lifting and supplying oil to the flow line at one of the wellheads. The wellhead sections of the production casing are interconnected by a land section in the form of an arcuate pipeline with an identical inner diameter to form a closed channel, the above-ground section of which is fixed on the support frame of the drive unit, after which an additional casing, which acts as a tubing pipe, is placed in the production casing in the underground part and having perforation channels for communication with the reservoir. A system of cylindrical elements interconnected by means of power rods with the formation of a closed traction system is installed in the cavity of the additional column at equidistant distances from each other. The sections of the underground part of the tubing from the wellhead to the boundaries of the perforation section of the production string together with the aforementioned cylindrical elements form piston pumping pairs. During operation, a system of cylindrical elements is forcedly moved using a drive unit with continuous oil displacement from the tubing by means of the piston pump pairs mentioned above.

The disadvantage of this method is the complexity of the design of the device for its implementation, low productivity of the method, since the fluid is taken along the tubing string, as well as the possibility of the formation of a sand plug in the annulus of the well, which will complicate the flow of bitumen into the tubing string and can lead to sticking of the tubing string in the production string . In addition, it requires sealing the drive of the traction system, which also complicates the design and reduces the reliability of the system. The disadvantage of this method is the lack of the possibility of exploring the well during its operation by depth instruments, which reduces the effectiveness of the method.

Another disadvantage of this method is the lack of interval control of the rate of injection of coolant in the injection well, which leads to undesirable "dagger" breakthroughs of the coolant, uneven heating of the formation, reduces the efficiency of the heat displacement process.

The objective of the invention is to eliminate the possibility of subsidence of sand and the formation of sand plugs in a horizontal production well, increasing the productivity of the method, as well as increasing the efficiency of the method by providing instrumental control and regulation of the heat treatment of the reservoir during the implementation of the method.

The problem is solved by the method of developing deposits of viscous oils and bitumen, including drilling a producing double-well well, securing it with a production string with a perforated section located in the reservoir, placing a piston in the well cavity with power rods that are connected to the drive unit at the wellheads, the piston being made with the possibility of reverse movement in the borehole, lifting and supplying with the help of a piston the borehole products to the flow line at one of the mouths of the producing well.

New is that they additionally drill an injection well with a profile parallel to the profile of the production well, fix it with a production string with a perforated section located in the same reservoir above the production well, the piston is installed to interact directly with the production string of the production well and reverse its limits, the speed of movement of the piston provide the selection of viscous oil and bitumen at a speed exceeding the rate of reverse filtration and oil from the well cavity in front of the moving piston into the reservoir, deep rods are installed on the power rods on both sides of the piston to control temperature and pressure during the selection from the production well of products that are taken into the flow line and at the second wellhead of the production well, while the coolant is injected lead simultaneously through the channels of two at least concentrically placed tubing - tubing, of which smaller in diameter perform longer.

In addition, new is also that:

- the drive unit is made in the form of two traction devices located at each wellhead of the producing well, connected to the power rods of the piston and working synchronously alternately in antiphase;

- the coolant is injected into the double-well injection well with separately controlled flow rates from both wellheads through the openings from each wellhead to a predetermined section of the exposed part of the tubing string formation.

The invention is illustrated by drawings, where figure 1 shows a diagram of the construction and operation of injection and production wells of the proposed method; figure 2 shows the downhole equipment of the producing well; figure 3 and 4 - embodiments and equipment injection wells.

The method of developing deposits of viscous oils and bitumen is as follows.

A two-wellhead production well 1 is drilled (see FIG. 1), fixed with a production casing 2 with a perforated section 3 located in the reservoir 4. An injection well 5 with a profile parallel to the profile of the production well 1 is drilled, fixed with a production casing 6 with a perforated section 7 located in the same reservoir 4 above the production well 1. A piston 8 (see FIG. 2) with power rods 9 and 10 connected to it is installed in the production well 1 with the possibility of direct interaction with the expl atatsionnoy string 2 and reverse travel within it. Power rods 9 and 10 are connected to the traction devices 11 and 12 (see figure 1) located on the mouths 13 and 14 of the producing well 1. On the power rods 9 and 10 (see figure 2), deep devices 15 with transmission means are installed information to the surface.

In the injection well 5 (see Fig. 3) two columns of tubing 16 and 17 of different diameters are placed, and the string of pipes 16 of smaller diameter is made of a greater length.

During the operation of the deposit, the piston 8 placed in the borehole (see FIG. 2) by means of a power rod 10 (which can be used as a steel rope), which is wound on the winch drum 18 of the traction device 12, moves from the mouth 13 to the mouth 14. In this case, the power rod 9 (see Fig. 1) is wound off the winch drum 19 of the traction device 11. The fluid located in the cavity 20 of the production casing 2 in front of the piston 8 is moved by it to the mouth 14, from where the liquid flows through the check valve 21 into the discharge line 22 onwards to the collection system 23. When this m a cavity 24 (see FIG. 2) for the production casing 2 is filled with the piston 8 coming from the reservoir 4 with bitumen, with which there is supplied and a certain amount of sand.

The control of the traction devices 11 and 12 (see Fig. 1) is carried out automatically, which is achieved by installing control units 25 and 26 on them, associated, for example, with sensors 27 of the piston 8 approaching the mouths 13 and 14 of the producing well 1 and power relaxation sensors 28 rods 9 and 10. The control units 25 and 26 are also interconnected, for example, using the communication line 29.

The winding of the power traction 10 on the drum of the winch 18 of the traction device 12 is made until the piston 8 approaches the mouth 14, as indicated by the sensor 27 mounted on the mouth 14, the signal from which is fed to the interconnected control units 26 and 25, while the rotation of both drums of the winch 18 and 19 traction devices 11 and 12 stops. Then the traction device 11 is turned on. The piston 8, by means of a power rod 9, which is wound on the winch drum 19 of the traction device 11, is now moved in the direction from the mouth 14 to the mouth 13. In this case, the power rod 10 is wound from the winch drum 18 of the traction device 12. Bitumen and all the sand entering the production well 1 is moved by the piston 8 to the mouth 13, wherefrom all the production enters the flow line 30 and then to the collection system 23.

In the process, the rotation speed of the winch drum 18, from which the power link 10 is being rewound, may exceed the speed of the power link 10 descending into the well 1. In this case, the tension of the power link 10 decreases, the sensor 28 for loosening the power link 10 of the linkage device 12 , the signal from which is supplied to the control unit 26, including the braking of the rotation of the winch drum 18. When the tension of the power rod 10 is stabilized, the braking is disabled. This allows for synchronous alternate operation of the traction devices 11 and 12 in antiphase, that is, when the piston 8 is pulled to one traction device 11 or 12, the other traction device 12 or 11 ensures that the traction 10 or 9 converges into the production well 1.

Further work cycles are repeated.

During the selection process, when moving the piston 8 at a certain speed along the perforated section 3 of the production string 2, for example, from the mouth 14 to the mouth 13, the reservoir pressure may decrease, and the fluid pressure in the cavity 24 (see figure 2) in front of the piston 8 s an increase in the height of the liquid column when the liquid rises to the mouth 13 in combination with the pressure in the flow line 30 can exceed the reservoir pressure. At the same time, the rate of fluid outflow from the producing well 1 back to the producing formation 4 can be compared with the rate of liquid withdrawal from the producing well 1, that is, all the fluid moved by the piston 8 will go through the perforated holes of the perforated section 3 from the producing well 1 back to the producing formation 4, without entering the collection system 23 (see figure 1), which implies that the speed of movement of the piston 8 in the perforated section 3 of the production casing 2 of the producing well 1 should be selected from the provision from ora bitumen on the surface at a rate exceeding the reverse filtration speed of the bitumen production well 1 into the reservoir 4.

The inflow of viscous products into the producing well 1 is ensured by heating of the producing formation 4, which is carried out by pumping the coolant into the producing formation 4 through the perforated section 7 of the production casing 6 of the injection well 5. The coolant is injected from the heat supply source 31 with separately adjustable, for example, using 32 valves (see Fig. 3), the flow rate simultaneously for two columns of tubing 16 and 17 of different diameters installed on the mouth 33 of the injection well 5. The execution of the column 16 with smaller diameter longer allows, ceteris paribus, with greater speed, and therefore with less heat loss, bring the coolant to a given section of the reservoir 4, located at a greater distance from the mouth of the injection well 5. In addition, the location of the column 16 of smaller diameter inside columns 17 of tubing of larger diameter reduces heat loss of the coolant in the inner column 16 due to the fact that the outer surface of the column 16 is heated by the coolant driven along the column 17.

The efficiency of heat treatment of the productive formation 4 (see FIG. 4) will further increase the heat carrier injection with separately controlled flow rate from both mouths 33 and 34 of injection well 5 through tubing pipes 16, 17, 35 and deflected from each mouth 33 and 34 36 to predetermined sections of the exposed part of the reservoir 4, which will double the number of heat exposure zones on the reservoir 4 and more evenly cover it with thermal exposure.

The installation of deep devices 15 (see Fig. 2) on power rods 9 and 10 on both sides of the piston 8 allows, when moving it along the production well 1 between the mouths 13 and 14, to control the temperature and pressure of the liquid along the length of the barrel of the producing well 1 before and behind the piston 8 in the process of selecting products from the producing well 1, have an idea of the temperature of the products according to the profile of the producing well 1, which will allow you to adjust the location of the zones of heating of the productive formation 4 and the rate of injection of coolant in them.

Using the proposed method eliminates the possibility of settling of sand and prevents the formation of a sand plug in the production casing of the producing well due to the fact that the sand entering the well with bitumen is brought to the surface with each movement of the piston, and it is also possible to heat the producing formation with high efficiency.

The selection of bitumen by the piston along the production casing of the producing well can significantly increase the productivity of the method, since when moving the piston at a speed of, for example, 0.5 m / s along the production casing with an inner diameter of 150 mm, the theoretical productivity of the method, taking into account the fact that the products are supplied alternately on both mouths, that is, in the method there is no unproductive stroke of the piston, is 31.6 m ³ / hour.

Claims (3)

1. The method of developing deposits of viscous oils and bitumen, including drilling a producing double-wellbore, securing it with a production string with a perforated section located in the reservoir, placing a piston in the well cavity with power rods that are connected to the drive unit at the wellheads, the piston being made with the possibility of reverse movement in the well, lifting and supplying with the help of a piston the well products to the flow line at one of the mouths of the producing well, characterized in that The injection well with a profile parallel to the profile of the production well is drilled, fixed with its production string with a perforated section located in the same reservoir above the production well, the piston is installed to interact directly with the production string of the production well and reverse movement within it, the speed of movement pistons provide the selection of viscous oil and bitumen at a speed exceeding the rate of reverse oil filtration from the well cavity per a moving piston into the reservoir, on power rods on both sides of the piston, deep devices are installed to control temperature and pressure during the selection of products from the production well that are taken to the flow line and at the second mouth of the production well, while the coolant is pumped simultaneously through the channels of two at least concentrically placed tubing - tubing, of which smaller in diameter perform longer. 2. The method according to claim 1, characterized in that the drive unit is made in the form of two traction devices located at each mouth of the producing well, connected to the power rods of the piston and working simultaneously alternately in antiphase. 3. The method according to claim 1, characterized in that the coolant is injected into the double-well injection well with separately adjustable flow rates from both wellheads through the openings from each wellhead to a predetermined section of the exposed part of the productive tubing string string.

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