RU225901U1 - WELL PUMPING UNIT FOR PRODUCTION OF SUPER-VISCOUS AND BITUMINOUS OIL - Google Patents

Abstract

The utility model relates to the oil industry in the field of steam-thermal methods for extracting super-viscous and bituminous oils from shallow (150...250 m) formations and viscosity up to 10.0 Pa⋅s or more. The technical objective of the proposed utility model is to reduce friction and wear of underground equipment and increase the reliability of its operation. A downhole pumping unit for the production of super-viscous and bituminous oils, including a string of tubing pipes and a string of rods lowered into an inclined section of the wellbore, a surface drive for rotating the string of rods, a centrifugal pump lowered into an inclined section of the wellbore and containing the necessary set of working stages, characterized in that the tubing string contains an intermediate tubing string filled with a lubricating fluid, for example commercial oil with low viscosity, and a string of pumping rods in it with a splined bell at the lower end to drive a centrifugal pump, and in the lower part In the intermediate string of tubing pipes there is an oil seal through which passes an intermediate shaft with a bell at the lower end that engages with the splined end of the centrifugal pump shaft, as well as a splined end of the upper end that engages with the bell of the sucker rod string. 2 ill.

Description

The proposed utility model relates to the oil industry in the field of steam-thermal methods for extracting super-viscous and bituminous oils from shallow (150...250 m) formations and viscosity up to 10.0 Pa⋅s or more. For well production of such oils, a method is used to pump superheated steam into the productive formation, which ensures a reduction in the viscosity of the oil to 0.045...0.055 Pa⋅s and its influx into the inclined part of the wellbore with a pump lowered into it to pump the heated product to the surface. The horizontal part of the wellbore with a length of 750...1000 m or more ensures an oil flow of up to 150 tons/day. To ensure the operation of pumps in an inclined wellbore, a surface drive is used to rotate the sucker rod string. In this case, the temperature of heated oil at the pump intake is 105...115°C.

For the production of super-viscous or bituminous oil, a method is known that involves drilling two horizontal wells in the formation, located parallel to each other (patent RU No. 2287677, E21B 43/24, BI No. 32. November 20, 2006). Steam is injected into the upper well, and product is taken from the lower well by a pump.

The disadvantages of the steam-gravity method are significant heat losses in thin productive formations and the complexity of drilling two parallel horizontal wells.

In addition, there is a known method for producing heavy high-viscosity oil by periodically pumping steam into a production well (for example, A.S. USSR No. 1272788, E21B 43/24. Method for producing heavy high-viscosity oil, application 10.26.84, publ. 07.22.86 G.). During the period of steam injection carried out through the annulus of the well, the pumping equipment is stopped. After the near-wellbore zone of the formation is heated, the downhole pump is put into operation and oil is pumped out until the near-wellbore zone of the formation is significantly cooled.

The disadvantage of this method is significant heat loss into the near-wellbore space when steam is pumped through the annulus.

There is a known method for developing deposits of heavy oils and natural bitumen, based on steam injection, creation of a steam chamber, joint injection of steam and hydrocarbon solvent and selection of products (RF Patent No. 2342955, E21B 43/24, published 10/04/2002). The disadvantage of this method is also the significant loss of heat into the near-well space when coolant is supplied to the bottom hole through the annulus.

A device is known for implementing a method for the extraction of heavy and bituminous oil (RF Patent No. 2399754, E21B 43/24, published on September 20, 2010), which allows steam injection into the productive formation and production selection. A pipe string equipped with an ejector-mixer with a low-pressure chamber is lowered into the well. In the pipe string, water heated to a temperature exceeding the vaporization temperature at reservoir pressure and under a pressure exceeding the vaporization pressure is injected into the space below the packer. The transition of water into a vapor state and mixing it with oil allows the mixture to be pumped into the productive formation with an increase in pressure in the formation by 10...30%. After the steam injection has stopped, they proceed to the selection of formation products using a rod pump, which, thanks to the presence of an additional concentric channel, allows pumping superheated water into the well or withdrawing products from the well.

The disadvantage of the device for implementing the method is the need to construct an additional vertical well into which a 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 is known for implementing a method for developing a deposit of high-viscosity oil or bitumen (RF Patent No. 2339805, E21B 43/24, application March 22, 2007, published November 27, 2008). An additional inclined shaft is inserted into the horizontal trunk of a two-mouth well to select the well's production. A screw pump driven by a rotating rod string with the drive located at the mouth is lowered into this shaft. Injection of water vapor at a temperature of 200°C is carried out alternately from the two extreme mouths. Liquid is withdrawn from the additional middle barrel 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 is destroyed upon contact with the steel rotor.

A device is known for producing high-viscosity oil from a directional well using the method of cyclic steam injection into the formation (RF Patent No. 2436943 C1, E21B 43/24, application 06/03/2010, publ. 12/20/2011). Heat-insulated pump and compressor pipes for supplying steam, as well as an electric centrifugal pump, are lowered into the inclined part of the wellbore. After steam is pumped into a shaft of smaller diameter with an upward trajectory, the heated formation product is pumped out with an electric centrifugal pump. An upward trajectory of the barrel with a smaller diameter and an elevation angle of at least 5-8° is necessary to drain the heated mass of oil to the pump descent zone.

The disadvantage of the device is the low performance of the electric centrifugal pump at high temperatures. The pump components most susceptible to failure are the submersible electric motor with non-metallic elements and its hydraulic protection.

The closest in technical essence to the proposed utility model is a well pumping unit for bituminous oil production (RF Patent No. 2595032. Application 04.29.2015. Publ. 08.20.2016. BI No. 23).

The pumping unit includes a centrifugal pump lowered into the inclined part of the wellbore, driven by a rotating rod string. To increase the rotation speed of the centrifugal pump shaft, an oil-filled multiplier is installed between it and the rod string, which makes it possible to provide a pump pressure sufficient to pump oil to the point of its preparation. The use of a multiplier allows you to increase the pump pressure number to 3.0...4.0 MPa. To avoid cooling of the oil, the oil treatment point is usually located a short distance from the well.

However, the use of a pump speed multiplier is complicated by significant starting loads on the electric drive of rod rotation and rapid wear of rods due to the presence of a large amount of suspended solid particles (SSP) in highly viscous or bituminous oil. The increased torque on the electric motor shaft due to the presence of a pump speed multiplier also leads to frequent rod failures due to gusts and a significant reduction in their operating time.

The technical objective of the proposed utility model is to reduce friction and wear of underground equipment and increase the reliability of its operation.

The solution to the technical problem is achieved by the fact that in a known device, including a string of tubing and a string of rods lowered into an inclined section of the wellbore, a ground drive for rotating the string of rods, a centrifugal pump lowered into an inclined section of the wellbore and containing a set of working stages, characterized in that the tubing string contains an intermediate tubing string filled with a lubricating fluid, for example, commercial oil with a viscosity under normal conditions of no more than 0.030 Pa⋅s and a sucker rod string in it with a splined bell at the lower end for drive of a centrifugal pump, and in the lower part of the intermediate string of tubing pipes there is a seal through which passes the intermediate shaft with a bell at the lower end that engages with the splined end of the centrifugal pump shaft, as well as the splined end of the upper end that engages with the bell sucker rod columns.

In fig. 1 and 2 show diagrams of the utility model. A centrifugal pump 3 with a set of working stages 4 on a shaft 5 is lowered into the inclined wellbore 1 on the main string of tubing (tubing) 2. The shaft 5 has an upper splined end 6, on which a bell 7 with internal splines that engage is located on the outside with splines 6 of shaft 5 of the pump. The bell 7 is the lower part of the intermediate polished shaft 8, passing through the oil seal 9 and also having an upper spline end 10. The oil seal 9 is hermetically placed in the lower part of the intermediate tubing string 11, into which a string of rods 12 with coupling connections 13 and a bell 14 is lowered , engaging with the splined end 10 of the intermediate shaft 8. The diameter of the rod string 12 is selected so that the clearance between the coupling connections 13 and the inner diameter of the intermediate tubing string 11 is minimal.

At the wellhead 1, in the upper part of the intermediate 1 tubing string 11, a gland 15 is installed, through which the upper rod of the string 12 passes, made polished and connected to an electric motor 16. Valves 17 and 18 are connected to the main tubing string 2 and the intermediate tubing string 11 on the day surface. In addition, at the mouth of well 1, a valve 19 is connected to its annulus. Well 1, which opened the productive formation 20, below the centrifugal pump 3 of the pump has a horizontal end of great length (not shown in Figs. 1 and 2) to ensure sufficient oil flow to the well. its inclined part. To reduce the flow of oil from the reservoir together with high-frequency particles, a filter in the form of an elongated shank can be attached to pump 3, extending into the horizontal part of well 1 (not shown in Figs. 1 and 2).

The device operates as follows. First, a centrifugal pump 3 is lowered into well 1 on the tubing string 2 to the calculated depth. After securing the tubing 2 at the wellhead, the intermediate tubing string 11 is lowered into it, assembled with an intermediate shaft 8, a bell 7 and an oil seal 9. When lowering, the bell 7 engages with the splined end 6 of the shaft 5 of the centrifugal pump 3. Next, a string of rods 12 with couplings 13 and a bell 14 at the lower end, which engages with the splined end 10 of the intermediate shaft 8, is lowered into the intermediate tubing string 11. At the wellhead 1 upper polished rod the sucker rod strings 12 are passed through the gland 15 in the intermediate tubing string 11. The upper end of the rod string 12 is articulated with the electric motor 16.

After this, through valve 18, the intermediate tubing column 11 is filled with a low-viscosity lubricating fluid, for example, commercial oil from another field with a viscosity under normal conditions of no more than 0.030 Pa⋅s and freed from high-frequency particles to commercial concentrations. Filling the tubing column 11 with such oil will prevent high values of friction and equipment wear from rotation of the rod string 12 inside the intermediate tubing column 11. To compensate for the temperature expansion of the filled liquid, the latter is not partially added to the pipes.

When high-temperature products from the oil reservoir 20 with a temperature of about 105...115°C enter the inclined wellbore 1, the electric motor 16 drives the rotation of the rod string 12 with a rotation speed of up to 1400...1500 rpm. The rotation of the rod column 12 is transmitted through the intermediate shaft 8 to the shaft 5 of the pump 3 and ensures its pressure in accordance with the size characteristics. The extracted products are pumped through the annular space between the main 2 and intermediate 11 tubing columns. The product exits to the wellhead through valve 17. In the operating position, valve 18 remains closed.

For deposits of super-viscous or bituminous oil, it is necessary to provide pump 3 pressure of the order of 3.0...4.0 MPa, sufficient to pump the hot product through heat-insulated pipes to the point of its collection and preparation. The presence of seals 9 and 15 prevents leaks of lubricating fluid (commercial oil) pumped into the tubing column 11. If small volumes of leakage occur, the tubing column 11 is replenished with liquid through valve 18.

The number of revolutions of the pump shaft 3 prevents excessively high power values to drive the rod string, friction and wear. The small gap between the coupling connections of rods 13 and tubing 11 prevents runout during radial movements of rotating rods in the tubing string 11. The modern range of tubing pipes produced by the industry of the Russian Federation in accordance with GOST 31825-2012 (sucker rods) and GOST 31446-2017 (tubing pipes) allows you to select their required standard sizes. The rod diameter of 22 mm corresponds to the diameter of the intermediate tubing string 11 - with an outer diameter of 60.3 mm and an inner diameter of 50.3 mm. The rod coupling with a diameter of 46 mm thus freely passes into the intermediate tubing string 11 with a small gap. At the same time, the intermediate tubing string 11 with couplings with a diameter of 73 mm enters the tubing string 2 with an internal diameter of 88.6 mm and an outer diameter of 101.6 mm.

In cases where the liquid level in the annulus is high, a packer is installed on the tubing string 2 in close proximity to pump 3, which reduces heat transfer from the pumped product to the surrounding rocks (not shown in Figs. 1 and 2). Otherwise, the presence of liquid in the annulus will significantly increase heat transfer to the surrounding rocks and more intensive cooling of the heated product.

For better fit on spline shafts 6 and 10, bells 7 and 14 are made with conical nozzles.

During repair work, equipment is removed from well 1 in the opposite direction.

The technical and economic advantage of the proposed utility model is the reduction of friction and wear of the rotating rod string and increased reliability of well equipment.

Claims (1)

A downhole pumping unit for the production of super-viscous and bituminous oils, including a string of tubing pipes and a string of rods lowered into an inclined section of the wellbore, a surface drive for rotating the string of rods, a centrifugal pump lowered into an inclined section of the wellbore and containing a set of working stages, different in that the tubing string contains an intermediate tubing string filled with a lubricating fluid, for example, commercial oil with a viscosity under normal conditions of no more than 0.030 Pa⋅s, and a sucker rod string in it with a splined bell at the lower end for drive of a centrifugal pump, and in the lower part of the intermediate string of tubing pipes there is a seal through which passes the intermediate shaft with a bell at the lower end that engages with the splined end of the centrifugal pump shaft, as well as the splined end of the upper end that engages with the bell sucker rod columns.