RU2773651C1 - Borehole pumping unit for the extraction of bituminous oil - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry and can be used in the steam-gravity method for extraction of bituminous oils. A borehole pumping unit for the extraction of bituminous oil for a well with an inclined part, with a lower main 1 and an upper additional 2 horizontal trunks turns on a centrifugal pump 6, lowered on a tubing string 5 into an inclined section of wells, the shaft of which is articulated with a rod string 8 using a cone 7 mounted at its lower end, a packer 11 mounted on the tubing string above the pump 6, the upper drive for rotating the rod string 8. The pipe string-shank 12 from the pump reception is located in the upper additional 2 horizontal borehole and is blocked from the outside by a packer 13 in the initial section of the horizontal borehole. In the area between the packer 13 and the pump 6 intake, spring-loaded check valves 16 and 17 are located inside the pipe string-shank. The upper spring-loaded check valve 17 is connected to the borehole space in the deflector wedge 3 installation zone.

EFFECT: increase in the efficiency of the production of bituminous oil reserves with the steam-gravity method for its extraction.

1 cl, 3 dwg

Description

The present invention relates to the oil industry and can be used in the steam gravity method for the extraction of bituminous oils.

For the extraction of bituminous oil, a method is known that includes drilling two horizontal wells in the formation, located parallel to each other (patent RU No. 2287677, E21B 43/24, publ. Bull. No. 32 of 20.11.2006). Steam is injected into the upper well, and products are taken from the lower well.

The known method has disadvantages due to heat loss in productive formations and production wells, as well as the complexity of drilling two parallel horizontal wells with two mouths.

A known method for the production of heavy high-viscosity oil by periodic injection of steam into a production well (for example, AS USSR No. 1272788, E21B 43/24. Method for the production of heavy high-viscosity oil, declared 26.10.84, publ. 22.07.86) . For the period of steam injection, carried out through the annulus of the well, the pumping equipment is stopped. After warming up the bottomhole formation zone, the downhole pump is put into operation and oil is pumped out until the bottomhole formation zone is substantially cooled. The disadvantage of this method is the significant heat loss in the borehole environment.

In addition, there is a known method for the development of deposits of heavy oils and natural bitumen, based on the injection of steam, the creation of a steam chamber, the joint injection of steam and a hydrocarbon solvent and the selection of products (RF Patent No. 2342955, E21B 43/24, publ. 04.10.2002) . The disadvantage of this method is a significant loss of heat in the near-wellbore space when the coolant is supplied to the bottomhole through the annulus.

Also known is a device for implementing a method for the production of heavy and bituminous oil (RF Patent No. 2399754, E21B 43/24, publ. 20.09.2010), which allows steam to be injected into the reservoir and product selection. A string of pipes is lowered into the well, equipped from below with an ejector-mixer with a low-pressure chamber. Water heated to a temperature exceeding the vaporization temperature at reservoir pressure and at a pressure exceeding the vaporization pressure is produced into the pipe string in the under-packer space. The transition of water into a vapor state and its mixing with oil make it possible to pump the mixture into the reservoir with an increase in pressure in the reservoir by 10 ... 30%. After the steam injection is stopped, the production of the formation is taken off using a rod pump, which allows, due to the presence of an additional concentric channel, to pump superheated water into the well or take products from the well.

The disadvantage of the device for implementing the method is the need to build an additional vertical well into which the rod pump is lowered, since the operation of such a pump in a horizontal or inclined well with a large zenith angle is impossible.

A device for implementing a method for developing deposits of high-viscosity oil or bitumen is known (RF Patent No. 2339805, E21B 43/24, applied on March 22, 2007, published on November 27, 2008). An additional inclined shaft is inserted into the horizontal wellbore of a double-headed well to take well production. A screw pump is lowered into this shaft, driven by a rotating rod string with the drive located at the wellhead. The injection of water vapor with a temperature of 200°C is carried out alternately from the two extreme mouths. The selection of fluid from the additional middle shaft is performed continuously.

The disadvantage of the device for implementing the method is the low reliability of the screw pump at high temperatures. The elastomer of the screw pump stator loses its elasticity and collapses upon contact with the steel rotor.

Also known is a device for implementing a method for the production of high-viscosity oil from a directional well by the method of cyclic injection of steam into the reservoir (RF Patent No. 2436943 C1, E21B 43/24, declared 03.06.2010, publ. 20.12.2011). Heat-insulated tubing for steam supply, as well as an electric centrifugal pump, are lowered into the inclined part of the wellbore. After injection of steam into a shaft of smaller diameter with an ascending trajectory, the heated production of the formation is pumped out by an electric centrifugal pump. An ascending wellbore trajectory with a smaller diameter and an elevation angle of at least 5-8° is necessary for the flow of the heated oil mass to the pump descent zone.

The disadvantage of the device for implementing this method is the low efficiency of the electric centrifugal pump at high temperatures. The most failure-prone pump components are the submersible motor with non-metallic elements and its hydraulic protection.

The closest in technical essence is a downhole pumping unit for the production of bituminous oil (RF Patent No. 2595032 C1, E21B 43/00, applied on April 29, 2015, published on August 20, 2016, BI No. 23). The unit includes a centrifugal pump, a speed multiplier, tubing and rod strings, a bell at the lower end of the rod string, a packer, a wellhead drive for rotating the rod string with a pump, a liner lowered into the horizontal part of the well, rod centralizers.

After the equipment is lowered into the well, steam is pumped into the pipe string from the wellhead, which enters the liner through the intensifier and impellers of the centrifugal pump. The steam heats up the near-wellbore area of the productive formation and the heated mass of oil through the perforations enters the liner cavity and further to the pump intake. After the formation is warmed up, the pumping unit is put into operation.

The most significant drawback of the pumping unit is the impossibility of implementing the steam-gravity mode of well operation. Extraction of oil from the heated lower zone of the near-wellbore space of the well in the conditions of one wellbore is impossible.

The technical objective of the invention is to increase the efficiency of the development of reserves of bituminous oil in the steam-gravity method of its production.

The solution of the technical problem is achieved by the fact that in a downhole pumping unit for the production of bituminous oil, including a centrifugal pump lowered on a tubing string into an inclined section of the well, the shaft of which is articulated with the rod string using a bell installed at its lower end, the pipe string at the pump intake, lowered into the horizontal section of the well, a packer installed on the tubing pipes above the pump, the top drive for rotating the rod string, according to the invention, the liner string from the pump intake is located in the upper additional horizontal wellbore with an inclined part, the main and additional horizontal wells and is blocked from the outside by a packer in the initial section of the horizontal well, and in the area between the packer and the pump intake inside the liner there are spring-loaded check valves, the upper of which is in communication with the well space in the area of the whipstock installation.

In FIG. 1, 2 and 3 shows a diagram of a downhole pumping unit. In deposits with bituminous oil, the main wellbore 1 with inclined and horizontal parts was drilled. Above the horizontal main shaft 1, an additional horizontal shaft 2 is inserted into its inclined part using a whipstock 3 with a through channel 4. A centrifugal pump 6 with a splined upper end is lowered into the inclined part of the wellbore on a string of tubing 5 (tubing). a shaft connected by means of a bell 7 with internal slots to a column of rods 8. Technological valves 9 and 10 are installed at the wellhead. The output upper end of the rod string 8 is connected to a drive for its rotation (not shown in Fig. 1). Above the pump 6, a packer 11 is installed on the pipe string 5.

The receiving part of the pump 6 is connected to the liner 12, passing into the horizontal shaft 2. In the horizontal shaft 2, a packer 13 and a centralizer 14 are installed on the liner 12. Holes 15 are made in the horizontal part of the liner 12 behind the packer 13. Directly in front of the packer, a spring-loaded reverse valve 16, and directly under the pump 6 in the shank there is also a spring-loaded check valve 17, which communicates with the outer side of the shank 12.

The operation of the downhole pumping unit is as follows. After drilling the main shaft 1, a whipstock 3 with a through channel 4 is lowered into the inclined section. overlap. After fixing the wellbore 2, the passage channel 4 is opened, and the pump 6 is lowered into the well on the tubing string 5 together with the liner 12 and packers 11 and 13. Due to the presence of the whipstock 3, the liner 12 will enter the horizontal wellbore 2. Next, a string of rods 8 is lowered into the pipe string 5 in such a way that the bell 7 with its internal splines engages with the splines of the pump shaft 6.

Next, steam is injected through the valve 9 into the tubing string. Steam under pressure passes through the working bodies of the pump 6, the outer side of the valve 17 and, pressing the valve 16, enters the horizontal part of the shank 12. Through the hole 15, steam is injected into the horizontal shaft 2 and heats the near-well space. Heated oil of low viscosity will flow down into the open hole 1 and accumulate in it.

After that, the steam injection is stopped and the pump 6 is put into operation by rotating its shaft with a string of rods 8 using a bell 7. The pressure of the centrifugal pump 6 is created only by rotating its shaft with a string of rods 8. In this regard, a submersible electric motor is not required to drive the pump. From the moment the steam injection stops and the pump 6 is turned on, the return flow of steam and its condensate from the barrel 2 through the liner 12 becomes impossible due to the presence of the check valve 16.

During the same period, the accumulated heated oil from the shaft 1 under the influence of rock pressure will flow to the intake of the pump 6 through the channel 4 of the whipstock 3 and the check valve 17, squeezing its spring.

Oil pump 6 will be pumped to the wellhead through the tubing string 5. Packer 11 allows you to keep the heat of the heated fluid due to the absence of its contact with the well wall above the packer.

In order to facilitate the entry of the liner 12 into the shaft 2, centralizers 14 are installed to prevent the collision of the coupling joints of the pipes.

After sufficient cooling of the extracted oil and an increase in its viscosity, its extraction is stopped and steam is re-injected into the horizontal well 2.

In FIG. 1, 2 and 3 cycles of oil extraction and steam injection are illustrated by solid and dotted lines, respectively.

The technical and economic advantages of a downhole pumping unit are the reduction in the volume of well construction for the steam-gravity method of extracting bituminous oil, the reduction of heat losses during steam injection, the absence of round-trip operations during cyclic steam injection and the selection of heated oil.

Claims (1)

A downhole pumping unit for the production of bituminous oil, including a centrifugal pump lowered on a tubing string into an inclined section of the well, the shaft of which is articulated with the rod string by means of a bell installed at its lower end, a pipe string at the pump intake lowered into a horizontal section wells, a packer installed on the tubing above the pump, an upper drive for rotating the rod string, characterized in that the liner string from the pump intake is located in the upper additional horizontal wellbore with an inclined part, the main and additional horizontal wellbore and is blocked from the outside the packer in the initial section of the horizontal wellbore, and in the section between the packer and the pump intake inside the liner pipes there are spring-loaded check valves, the upper of which is in communication with the well space in the area of the whipstock installation.

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