RU2695478C1 - Method of operating a pair of wells producing high-viscosity oil - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil-producing industry. Method for operation of a pair of wells producing high-viscosity oil includes construction with filter parts in appropriate horizontal shafts of production well and injection well located below and parallel to production well, carrying out in a horizontal borehole of a geophysical survey for determining oil saturation along a horizontal borehole, placing two columns of tubing string in a pressure well ROP, wherein end of column ROP smaller diameter is arranged at the beginning of horizontal shaft, and end of column ROP larger diameter in the zone with oil saturation of more than 60 %, controlled steam injection into the injection well through the columns ROP different diameter, and by means of geophysical studies in the horizontal borehole of the production well, a transition zone with a temperature between larger and smaller heating is determined, from which the electric-centrifugal pump is extracted, wherein when the liquid temperature drops below the maximum allowable at the pump inlet, the steam injection through the injection well is increased, and when the temperature at the pump inlet increases, the injection of steam through the injection well is reduced and/or the pump is switched to periodic operation. Before lowering into injection well in column ROP larger diameter is equipped with one or several couplings with one or two holes arranged along the perimeter evenly. During lowering the holes are arranged near the middle of the filter part to create an additional point or several steam pumping points for uniform heating along the entire horizontal borehole of the well and greater coverage of the formation. At that, couplings with 2 holes are used at volume of steam injection of not less than 120 t/day in ROP of larger diameter. At filter part length of less than 500 m one coupling with orifice or 2 holes of approximately 6 mm is lowered. At length of 500–700 m one coupling with hole or 2 holes is lowered approximately 8 mm. At filter part length of more than 700 m, 2 couplings with hole or 2 holes of 8 mm are lowered and distance between said couplings is not less than 100 m. Pump with shank communicated with pump inlet is lowered into production well. Inlet of shank end is located in transition temperature zone, and pump is located beyond filter part of horizontal shaft of production well.

EFFECT: increased stability of pump operation, creation of a steam chamber more stretched along the horizontal borehole, involvement of a larger formation zone, uniform heating of the formation.

1 cl, 1 dwg, 1 ex

Description

The invention relates to the oil industry and may find application in the development of deposits of high viscosity and bitumen oil.

A known method of developing a reservoir of high viscosity oil using a pair of horizontal injection and producing wells (patent RU No. 2379494, IPC EV 43/24, publ. Bull. No. 2 from 01/20/2010), the horizontal sections of which are placed parallel to one another in the vertical plane of the productive formation, equipped with a string of tubing, allowing simultaneous injection of coolant and selection of products, injection of coolant, heating of the reservoir with the creation of a steam chamber, selection of products through production wells along the tubing and monitoring the technological parameters of the reservoir and the well, while the ends of the tubing strings are located at opposite ends of the conventionally horizontal section of the wells, heating of the reservoir begins with steam injection into both wells, heats the borehole zone of the formation, reduces the viscosity of highly viscous oil and the steam chamber is created by injection of a coolant, propagating to the upper part of the reservoir with an increase in the size of the steam chamber, during the selection process In addition, from time to time, 2-3 times a week, they determine the mineralization of the water being taken in by way, analyze the effect of changes in the mineralization of the water being taken in on the uniformity of heating the steam chamber, and taking into account the changes in the mineralization of the water being taken in, the steam chamber is uniformly heated by adjusting the coolant injection mode or product selection wells until a stable mineralization value of the associated water is reached.

The disadvantage of this method is the lack of temperature control in a horizontal production well, which leads either to overheating of the well and failure of the downhole pumping equipment, or to underheating and loss of oil production.

The closest in technical essence and the achieved result is a method of operating a pair of wells producing highly viscous oil (patent RU No. 2663528, IPC ЕВВ 43/24, publ. Bull. No. 22 of 08/07/2018), including the construction of an injection well and a producing well, located below and parallel to the injection well, the descent into the injection well of two tubing strings - tubing of different diameters with the ends at different intervals of the horizontal wellbore, placement of fiber optic cable to the production well whitewash and tubing with an electric centrifugal pump and temperature sensors at the inlet to the electric motor of the electric centrifugal pump and in the electric centrifugal pump, controlled injection of steam into the injection well through tubing of various diameters, thermobaric measurements in the producing well and using a fiber optic cable to identify the horizontal wellbore of the producing well with various temperature, determination in one of the identified zones of the interval with a change in the angle of set of curvature of not more than 2 degrees by 10 m, an electric centrifugal pump is placed by a otor, and by changing the steam supply through the injection well and the operation of the electric centrifugal pump, the mode of operation of a pair of wells is established, and at a liquid temperature at the inlet equal to the maximum allowable by the operating conditions of the electric centrifugal pump, it is maintained at a constant mode, while in a horizontal barrel injection wells conduct geophysical studies to determine oil saturation along the horizontal wellbore, and then in injection with two tubing strings are placed in an important area, with the end of the smaller diameter column at the beginning of the horizontal well and the end of the larger diameter in the zone with oil saturation of more than 60%, by means of geophysical studies in the horizontal well of the producing well to install the pump, a transition zone with a temperature between large and less warming up, place the electric centrifugal pump in this transition zone, and when the temperature of the liquid drops below the maximum allowable at the pump inlet, the steam injection increases of the injection well, and as the temperature rises at the pump inlet reduce steam injection through the injection well and / or translate periodic pump in operation.

The disadvantages of this method are the decrease in stability and / or failure of the electric submersible pump in cases of significant removal of sand from the rock, achievement of the maximum working temperature at the pump intake, failure of the fiber optic cable due to overheating, as well as uneven heating and creation of a steam chamber due to the presence of only two steam injection points along the injection wellbore.

The technical objectives of the proposed method are to increase the stability of the pump due to the descent of the pump with a shank communicated with the pump inlet, the shank inlet being placed in the transition temperature zone, and the pump outside the filter part of the horizontal wellbore of the producing well, as well as the use in the injection well on the string tubing of larger diameter couplings or couplings with a hole or holes with a diameter of 6-8 mm in the middle of the filter part for uniform heating of horiz the on-line wellbore and the formation, creating a steam chamber more extended along the horizontal wellbore and involving the larger zone of the formation by the steam-gravity effect.

The technical problem is solved by the method of operating a pair of wells producing highly viscous oil, including the construction of filter wells in the respective horizontal wells of the producing well and the injection well located below and parallel to the producing well, conducting geophysical surveys in the horizontal well of the injection well to determine oil saturation along the horizontal well, placement in the injection well of two columns of tubing - tubing, with the end to smaller diameter tubing strings are placed at the beginning of the horizontal wellbore, and a larger diameter tubing string end in the zone with oil saturation of more than 60%, controlled steam injection into the injection well through different diameter tubing strings, and through the geophysical studies in the horizontal well of the producing well, the transition zone with temperature between greater and lesser heating, from which they are selected by an electric centrifugal pump, and when the temperature of the liquid decreases below the maximum allowable at the inlet Asosa increase the steam injection via the injection well, and as the temperature rises at the pump inlet reduce steam injection through the injection well and / or translate periodic pump in operation.

New is that before lowering into the injection well in the tubing string of a larger diameter, equip one or more couplings with one or two holes that are evenly spaced around the perimeter, the holes during the descent are placed in the middle of the filter section to create an additional point or several steam injection points for uniform heating along the entire horizontal wellbore and greater reservoir coverage, while couplings with 2 holes are used with a steam injection volume of at least 120 tons / day in larger tubing moreover, when the length of the filter part is less than 500 m, one sleeve with a hole or 2 holes of 6 mm is lowered, with a length of 500-700 m, one sleeve with a hole or 2 holes of 8 mm is lowered, with a length of the filter part more than 700 m 2 couplings with a hole or 2 holes of 8 mm and a distance between these couplings of at least 100 m, a pump with a shank connected to the pump inlet is lowered into the production well, the shank inlet is placed in the transition temperature zone, and the pump is outside the filter part of the horizontal shaft producing well. The method is as follows.

A method of operating a pair of wells producing highly viscous oil involves the construction of a producing well 2 in a producing formation 1 (see Fig. 1) and an injection well 3 located below and parallel to the injection well 3. The horizontal boreholes 2, 3 are cased with a column with slits - slotted filter 4 (filter part). Geophysical studies are carried out in a horizontal well of injection well 3 to determine the oil saturation along the horizontal well, placement of 3 two tubing strings 5, 5 'in the injection well, with the end of the smaller diameter 5 being placed in the production string and the end of the larger diameter 5' in the zone with an oil saturation of more than 60% in the second half of the filter 4. Before lowering into the injection well 3 in the tubing string 5 'of larger diameter, equip one or more couplings 6 with one or two holes (shown in as if) evenly spaced around the perimeter, the holes during descent are placed in the region of the middle of the filter 4 of the injection well to create an additional point or several points of steam injection for uniform heating along the entire horizontal wellbore 3. In this case, couplings 6 with 2 holes are used when steam injection volume of at least 120 tons / day in tubing 5 'of larger diameter. With a filter length of 4 less than 500 m, one sleeve with a hole or 2 holes of about 6 mm is lowered, with a length of 500-700 m one sleeve 4 with a hole or 2 holes of about 8 mm, with a filter length of 4 more than 700 m 2 couplings with a hole or 2 holes of 8 mm and a distance between these couplings 6 of at least 100 m (not shown). This allows you to warm up the horizontal wellbore 3 and reservoir 1 from several points, which leads to more uniform heating. The diameters of the holes 6 ± 1 mm and 8 ± 1 mm are selected empirically.

Geophysical surveys are carried out in the horizontal wellbore of the producing well 2 to determine the transition zone with a temperature between greater and lesser heating, from which the pump 7 is selected.

The pump 7 is lowered onto the tubing 8 in the casing 9 with a shank 10 in communication with the inlet of the pump 7 using the casing 9. The inlet of the shank 10 is placed in the transition temperature zone, and the pump 7 is outside the filter 4 of the horizontal well of the production well 2. Achieve a constant mode of operation pairs of wells 2 and 3 by changing the steam supply through injection well 3 and the rate of pump 7 extraction in production 2, with the temperature of the liquid at the inlet of pump 7 close, but not more than the maximum allowable under the operating conditions of pump 7 (the authors do not claim this). When the temperature of the liquid decreases below the maximum allowable at the inlet of the pump 7, the injection of steam through the injection well 3 is increased, and when the temperature of the inlet of the pump 7 is increased, the injection of steam through the injection well 3 is reduced and / or the pump 7 is put into periodic operation. An example of a specific implementation.

At the Chumachkinskoye super-viscous oil field located at a depth of 95 m, reservoir-reservoir 1 (Fig. 1) is represented by heterogeneous reservoirs with a thickness of about 22 m, reservoir temperature of 8 ° C and pressure of 0.4 MPa, oil saturation of 0.67 units, porosity of 31%, permeability of 0.298 μm2, bitumen density at reservoir conditions of 958 kg / m ³ , viscosity of 13011 mPa⋅s. A couple of horizontal wells were drilled in reservoir 1: production - 2 and injection - 3 at a distance of about 5 m from each other. An injection well 3 with a horizontal well 544 m long at a depth of 109 m was drilled with a bit with a diameter of 244.5 mm. The horizontal well of injection well 3 is cased with a slotted filter 4 — a column with slots. After the construction of wells 2 and 3, we conducted geophysical studies (electrical and radioactive) to determine the oil saturation along the horizontal wellbore of wells 2, 3. Production well 2 with a horizontal well of 592 m in length at a depth of 114 m was drilled with a bit with a diameter of 244.5 mm and cased with another slotted filter 4-column with slots.

Two tubing strings 5 and 5 'were lowered from the mouth into the injection well 3. The end of the first tubing string 5 with a diameter of 60 mm is lowered to the beginning of the horizontal well, to a depth of 448 m. The end of the second string 5 'with a diameter of 89 mm is lowered into the second half of the horizontal wellbore 3, into a zone with oil saturation of 73% at a depth of 870 m, at a depth of 663 m have a sleeve 6 tubing with one hole with a diameter of 8 mm

4590 tons of steam are pumped through injection well 3 with a flow rate of 67 tons / day in tubing 5 'and 28 tons / day in tubing 5, and 3535 tons of steam into production well 2 with a flow rate of 76 tons / day. In production well 2, geophysical studies are carried out to determine the distribution of pressure and temperature along the horizontal wellbore 2. Through these studies, in the horizontal well of production well 2, a transition zone is detected with a temperature between greater than 129 ° C (at a depth of 480 m) and less than 105 ° C ( at a depth of 660 m) by heating, in which the input of a liner 10 with a diameter of 60 mm and a length of 182 m, connected to an electric centrifugal pump 7 of the ETsNA5A-125-400 brand in a casing 9, lowered to a depth of 423 m, is placed using a tubing string 8. Pump 7 udovan temperature sensors at the inlet of the pump motor electrocentrifugal (shown in phantom) and an electric centrifugal pump 7. Along extractive borehole 2 is placed an optical fiber cable for temperature control during the operation. Steam injection at a flow rate of 65 tons / day in tubing 5 'and 30 tons / day in tubing 5 through injection well 3 is resumed, and formation products from production well 2 are selected by an electric centrifugal pump 7 through a shank 10 with a withdrawal mode of 110 tons / day. Measure the temperature at the inlet of the electric centrifugal pump 7. The admissible temperature at the reception of this electric centrifugal pump 7 is 130 ° C, while the temperature in the region where the end of the shank 10 can be placed can be 5-10 ° C higher, which does not interrupt the operation of the pump.

At a temperature of 115 ° C at the reception of this electric centrifugal pump 7, it is operated in a constant mode, and steam injection through injection well 3 is increased by 20 t / day (by 10 t / day in tubing 5 and by 10 t / day in tubing 5 ' ) Achieve a constant mode of operation of the electric centrifugal pump 7 with the necessary flow rate to maintain the temperature of the liquid at the reception of the electric centrifugal pump 7 close, but not more than 130 ° C.

The stability of the pump 7 in the conditions of a higher value of the heating of the reservoir 1 is confirmed by an increase in the overhaul period by 23% compared with the neighboring wells of the site. Placing in the middle of the filter part of an additional point of steam injection into the tubing 5 'of a larger diameter allows for more uniform heating along the entire horizontal wellbore 3 and to stretch the created steam chamber over the producing well 2 along the entire horizontal wellbore. At the same time, a large area of formation 1 is covered by steam-gravity action, which is also confirmed by oil production rates that are 15-17% higher than the same values for the wells of the site working without shanks, according to the technology described in the closest analogue.

The proposed method of operating a pair of wells that produce highly viscous oil can improve the stability of the pump by lowering the pump with a liner in communication with the pump inlet, the liner inlet being placed in the transition temperature zone, and the pump outside the filter part of the horizontal wellbore of the producing well, and create a steam chamber that is more extended along the horizontal wellbore and engage a large formation zone by means of steam gravity by using the injection well in the injection well it is not tubing pipes (tubing) of larger diameter couplings or couplings with a hole or holes with a diameter of 6-8 mm in the region of the middle of the filter part, ensuring uniform heating of the horizontal wellbore and formation.

Claims (1)

A method of operating a pair of wells producing highly viscous oil, including the construction of filter wells in the respective horizontal shafts of a producing well and an injection well located below and parallel to the producing well, conducting geophysical surveys in a horizontal well of an injection well to determine oil saturation along a horizontal well, placement in an injection well two tubing strings - tubing, with the end of the tubing string being a smaller diameter they place at the beginning of the horizontal wellbore, and the end of the tubing string of a larger diameter in the zone with oil saturation of more than 60%, controlled steam injection into the injection well through the tubing string of various diameters, and through geophysical studies in the horizontal wellbore of the producing well, the transition zone with a temperature between large and smaller heating, from which the selection is carried out by an electric centrifugal pump, and when the liquid temperature drops below the maximum allowable at the pump inlet, steam injection is increased through the injection well, and when the temperature at the inlet of the pump rises, steam injection through the injection well is reduced and / or the pump is switched to a periodic mode of operation, characterized in that before lowering into the injection well in the tubing string of a larger diameter, one or more couplings are equipped with one or two openings evenly spaced around the perimeter, the holes during the descent are placed in the middle of the filter part to create an additional point or several points of steam injection for uniform heating and along the entire horizontal wellbore and greater reservoir coverage, couplings with 2 holes are used with a steam injection volume of at least 120 tons / day in larger tubing, and with a length of the filter part of less than 500 m, one sleeve with a hole or 2 - with holes of about 6 mm, with a length of 500-700 m, one sleeve with a hole or 2 holes of about 8 mm is lowered, with a length of the filter part of more than 700 m, 2 couplings with a hole or 2 holes of 8 mm and the distance between the data couplings not less than 100 m into the production well of descent The pump is equipped with a liner in communication with the pump inlet, the liner inlet is placed in the transitional temperature zone, and the pump is outside the filter part of the horizontal wellbore of the producing well.

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