RU2803347C1 - Method for developing superviscous oil deposits - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: development of deposits of high-viscosity oil or bitumen with an oil-saturated thickness of less than 10 m. In the method for developing a deposit of extra-viscous oil 1, including drilling a vertical well 2, studying the porosity and permeability properties of the formations exposed by drilling, separating bitumen-saturated and water-saturated interlayers, after separating water-saturated and oil-saturated interlayers, the level of water-oil contact of WOC 3 is determined. After that, a pipe string 4 is lowered into a vertical well 2 to a depth of 10 m below the WOC 3 and cemented to form an artificial bottom hole. Next, a lower whipstock is installed in the direction of lower drilling sidetracks 5, 5', a window is cut out. Drilling is carried out from 2 to 4 lower side horizontal tracks 5, 5' 50-100 m long, and in such a way that the lower points of the lower side horizontal tracks 5, 5' are located at a distance of at least 2 m from the WOC 3, and the bottoms of the lower side horizontal tracks 5, 5' were 2 m above the lower points of the lower side horizontal tracks 5, 5'. Then, 5-7 m above the lower whipstock, the upper whipstock is installed in the direction of drilling of the upper sidetracks 6, 6', a window is cut out. Drilling is carried out from 2 to 4 upper side horizontal tracks 6, 6' with a length of 50-100 m parallel to WOC 3 and in such a way that the lower points of the upper side horizontal tracks 6, 6' are located at a distance of 5-7 m from the lower points of the lower side horizontal tracks 5, 5', and the bottoms of the upper side horizontal tracks 6, 6' and the lower side horizontal tracks 5, 5' were at a distance of 3-5 m from each other. A sealing unit 8 is installed at the lower end of the pipe string 7, then a filter string 9 3 m long and a packer 10 are installed. A pipe string 7 is lowered into the vertical well 2 to artificial bottom hole with the location of the filter string 9 opposite the interval of kicking off the lower side horizontal tracks 5, 5', and the packer 10 is between the intervals of kicking off the lower side horizontal tracks 5, 5' and the upper side horizontal tracks 6, 6'. After that, steam is injected into the vertical well 2 between the pipe strings 4 and 7 at an intensity of up to 30 tons/day for 50 days, the steam injection is stopped for thermocapillary impregnation for 20 days. Then, the pump 10 is lowered into the pipe string 7, complete with the filter column 8, to a depth of 3 m above the artificial bottom hole, and the liquid is withdrawn, the steam injection is continued.

EFFECT: increase in the coverage of the deposit development, an increase in the oil recovery of the formation.

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Description

The invention relates to the oil industry, in particular to the development of deposits of high-viscosity oil or bitumen with an oil-saturated thickness of less than 10 m under thermal influence of horizontal wells.

There is a known method for developing high-viscosity oil deposits (patent RU No. 2363839, MPK E21B 43/24, 7/04, 43/10, publ. 08/10/2009, bulletin No. 22), the density of which is lower than the density of the coolant, including drilling the main wellbore, from which a horizontal lateral wellbore is drilled, a perforated string is lowered into it, tubing is lowered into the main wellbore, a packer is installed below the horizontal lateral borehole kickoff interval, which seals the space between the tubing and the main well, coolant is pumped through one borehole and selecting high-viscosity oil or bitumen from another wellbore, and before installing the packer in the lower open part of the main wellbore, a whipstock is lowered on a pipe string, which is oriented with the outlet hole in the direction of the horizontal sidebore and below it within the same productive formation, after which using a flexible pipe with a jet nozzle, a horizontal section is formed, located under a horizontal side well, after which the flexible pipe and pipe string with a whipstock are removed from the well, after installing the packer, but before lowering the tubing, they are equipped with a tubular filter and a nipple located above a diverter equipped with a window made in the wall of the tubing above the nipple, and a bypass channel, the inlet of which is connected with the supra-wedge space of the tubing string, and the outlet with the sub-nipple space of the tubing string, after which the tubing string lowered into the main wellbore until the nipple interacts tightly with the packer, placing a tubular filter opposite the horizontal section and positioning the window opposite the kickoff interval of the horizontal side hole of the packer, then the perforated string on the process pipe string with an additional packer is lowered through the tubing string, whipstock and window into the side horizontal wellbore until the perforated pipe string is placed in its horizontal section, after which an additional packer is installed between the tubing and the technological pipe string above the window, but below the entrance of the bypass channel, the coolant is pumped into the main wellbore through the annulus of the tubing pipes and process pipe string, bypass channel, sub-nipple space of the tubing string and filter, and selection is from a horizontal sidebore through a perforated column along the process pipe string.

The disadvantages of this method are:

- insufficient efficiency when using the steam-gravity method for extracting super-viscous oil, since the coolant is pumped into the bottom part of the formation, and production is produced from the top part;

- low efficiency of development coverage of a deposit area due to drilling only one sidetrack.

The closest is the method for developing high-viscosity oils or bitumen (patent RU No. 2289685, MPK E21B 43/24, published June 27, 1996, Bulletin No. 36), including drilling a vertical well, lowering and cementing the production casing, perforating it, lowering the pumping compressor pipes, injection of coolant and selection of high-viscosity oil or bitumen, after drilling a vertical well, the reservoir and thermal properties of the formations exposed by drilling are studied, bitumen-saturated and water-saturated layers are isolated, after which a horizontal lateral trunk is drilled from the vertical well so that it reveals an intermediate aquifer layer in the context of a bituminous formation - half the extent of the local aquifer, the sidebore is cemented to the upper bituminous interlayer, then a perforated casing is lowered into the sidebore, and the perforation is carried out in such a way that the number of perforations increases with distance from the vertical wellbore, and the vertical wellbore wells are perforated in zones exposed by drilling bituminous interlayers, tubing pipes are lowered into a vertical well with a packer, which is installed below the sidetracking interval, coolant is pumped into a horizontal lateral wellbore, and high-viscosity oil or bitumen is withdrawn through a vertical wellbore, while after the productive zone has been developed between the vertical and horizontal lateral wellbore, a slug of polyacrylamide is sequentially pumped into the horizontal lateral wellbore in a volume of 0.1 of the volume of the heated productive zone and water, and water is pumped until polyacrylamide appears in the vertical wellbore, after which the coolant injection into the horizontal lateral wellbore is resumed wellbore, produce high-viscosity oil or bitumen, then proceed to pumping coolant through a vertical wellbore and a horizontal lateral wellbore to ensure the production of high-viscosity oil or bitumen in adjacent production wells.

The disadvantages of this method are:

- large heat losses when pumping coolant, due to the large cross-section of the annular space through which the coolant is pumped, and the direct contact of the coolant with the walls of the well, behind which there is a cement ring, which leads to heating of the latter and, as a consequence, heat absorption, in addition, when heating the cement ring behind the casing deteriorates the quality of adhesion of the cement ring to the casing, which can subsequently lead to behind-the-casing flows;

- the condition for increasing the pressure drop (depression) between the downhole (in the wellbore) and the reservoir (in the “bottom-hole” part of the field adjacent to the well) is not taken into account, which reduces the gravitational flow and, accordingly, the production rate of the wells.

The technical task is to increase the efficiency of development of super-viscous oil deposits in areas of super-viscous oil deposits with a productive reservoir thickness of less than 10 m, as well as to increase the efficiency of production by increasing the coverage of deposit development.

The technical problem is solved by a method for developing a super-viscous oil deposit, including drilling a vertical well, studying the filtration and reservoir properties of the formations exposed by drilling, isolating bitumen-saturated and water-saturated layers, drilling horizontal lateral trunks from a vertical well.

What is new is that after identifying water-saturated and oil-saturated layers, the level of the water-oil contact - the OWC is determined, after which a pipe string is lowered into a vertical well to a depth of 10 m below the OWC and it is cemented to form an artificial bottom, then the lower whipstock is installed in direction of drilling lateral trunks, cut out a window, drill from 2 to 4 lower lateral horizontal trunks with a length of 50-100 m, and in such a way that the lower points of the lower lateral horizontal trunks are located at a distance of at least 2 m from the OWC, and the bottoms of the lower lateral horizontal the trunks were 2 m above the lower points of the lower lateral horizontal trunks, then 5-7 m above the lower whipstock, the upper whipstock was installed in the direction of drilling the upper lateral trunks, a window was cut out, and 2 to 4 upper lateral horizontal trunks were drilled 50-100 m long parallel to the OWC and in such a way that the low points of the upper lateral horizontal shafts are located at a distance of 5-7 m from the low points of the lower lateral horizontal shafts, and the faces of the upper lateral horizontal shafts and the lower lateral horizontal shafts are at a distance of 3-5 m from each other, a sealing unit is first installed at the lower end of the pipe string, then a 3 m long filter column and a packer are installed, a pipe string is lowered into a vertical well to the artificial bottom with the possibility of placing the filter column opposite the kickoff interval of the lower side horizontal trunks, and the packer - between at intervals of kicking off the lower lateral horizontal wells and the upper lateral horizontal wells, after which steam is injected into the vertical well at an intensity of up to 30 tons/day for 50 days, steam injection is stopped for thermocapillary impregnation for 20 days, then into the pipe string combined with a filter column lower the pump to a depth of 3 m above the artificial face and begin withdrawing liquid and continue pumping steam.

In fig. A diagram of the implementation of the proposed method is presented.

The method for developing super-viscous oil deposits is carried out as follows.

In an area of super-viscous oil deposit 1 with an oil-saturated thickness of less than 10 m, a vertical well 2 is drilled, the filtration and reservoir properties of the formations exposed by drilling are studied, bitumen-saturated and water-saturated layers are isolated, and oil saturation is determined.

After identifying water-saturated and oil-saturated layers, the level of water-oil contact is determined - VNK 3 (VNK is isolated) of super-viscous oil deposit 1 (see Fig.). After this, a pipe string 4, for example, with a diameter of 245 mm, is lowered to a depth of 10 m below the VNK 3 and it is cemented to form an artificial face. Next, the lower whipstock (not shown in the figure) is installed in the direction of drilling sidetracks 5 and 5'. Windows are cut out, drilling is carried out (for example, using a jet drilling method) from 2 to 4 lower side horizontal trunks 5 and 5' with a length of 50-100 m (determined by the technical capabilities of the drilling equipment). Drilling is carried out in such a way that the bottom points of the lower lateral horizontal trunks 5 and 5' are located at a distance of at least 2 m from the VNK 3, and the bottoms of the lower lateral horizontal trunks 5 and 5' are 2 m above the low points of the lower lateral horizontal trunks 5 and 5'.

Then, 5-7 m above the installed lower whipstock, an upper whipstock (not shown in the figure) is installed in the direction of drilling the upper sidetracks 6 and 6'. Windows are cut out, drilling is carried out (for example, using a jet drilling method) from 2 to 4 upper lateral horizontal trunks 6 and 6' with a length of 50-100 m parallel to the VNK 3 and in such a way that the lower points of the upper lateral horizontal trunks 6 and 6' are located at a distance of 5-7 m from the lower points of the lower lateral horizontal shafts 5 and 5', and the faces of the upper lateral horizontal shafts 6 and 6' and the lower lateral horizontal shafts 5 and 5' were at a distance of 3-5 m from each other.

Next, select a pipe string 7, for example, with a diameter of 168 mm. First, a sealing unit 8 is installed at the lower end of the pipe string 7, then, as part of the pipe string 7, a filter column 9 3 m long, then a packer 10. A pipe string 7 is lowered into the vertical well 2 to the artificial bottom (with the bottom-up arrangement installed: sealing unit 8, filter column 9, packer 10) with the possibility of placing the filter column 9 opposite the kickoff interval of the lower lateral horizontal wellbores 5, 5', and the packer - between the kickoff intervals of the lower lateral horizontal wellbores 5 and 5' and the upper lateral horizontal wellbores 6 and 6'. The sealing unit 8 at the lower end of the pipe string 7 is installed to prevent sand infestation (located 1-2 meters above the artificial bottom), the packer is installed to prevent steam breakthrough down the wellbore 2.

After this, steam is injected into the vertical well 2 between the columns of pipes 4 and pipes 7 at an intensity of up to 30 tons/day (determined by the injectivity of the well; with increasing injectivity, the intensity of steam injection increases) for 50 days. Next, steam injection is stopped for thermocapillary impregnation for 20 days. Then, pump 10 is lowered into the pipe string 7 together with the filter column 9 to a depth of 3 m above the artificial bottom of the vertical well 2 and liquid selection begins; steam injection continues into the interval between the pipe strings 4 and 7.

The proposed method makes it possible to increase the efficiency of development of super-viscous oil deposits in areas of super-viscous oil deposits with a productive formation thickness of less than 10 m, as well as to increase production by increasing the development coverage of the deposit and increasing the flow rate.

Examples of specific implementation.

Example 1

In the Arkhangelsk deposit of super-viscous oil, located at a depth of 205 m, reservoir temperature 8 ° C, pressure 0.4 MPa, oil saturation 0.65 units, porosity 29%, permeability 1.34 μm ² , oil density in surface conditions 944 kg/m ³ , oil viscosity in reservoir conditions is 11820 mPa*s, a section of the deposit with an oil-saturated thickness of less than 10 m was identified. A vertical well was drilled, and the filtration and reservoir properties of the formations exposed by drilling were studied. Based on the data obtained, bitumen-saturated and water-saturated layers were identified and oil saturation was determined.

After identifying the water-saturated and oil-saturated layers, the level of the oil-water contact was determined - the OWC of the deposit (210 m). After this, a pipe string with a diameter of 245 mm was lowered into a vertical well to a depth of 10 m (220 m) below the reservoir OWC and cemented, thus forming an artificial bottom.

Next, we installed the lower whipstock (not shown in the figure) in the direction of drilling the sidetracks. We cut out windows and drilled two lower lateral horizontal trunks with a length of 50 m and 55 m. The lower points of the lower lateral horizontal trunks were located at a distance of 2 m and 2.5 m from the OWC, and the faces of the lower lateral horizontal trunks were 2 m above the lower points of the lower lateral horizontal trunks.

Then, 5 m above the installed lower whipstock, the upper whipstock was installed, windows were cut out and two upper side shafts 50 m and 55 m long were drilled parallel to the OWC and in such a way that the lower points of the upper side horizontal shafts were located at a distance of 5 m from the bottom points of the lower lateral horizontal shafts, and the faces of the upper lateral horizontal shafts and the lower lateral horizontal shafts were at a distance of 3 m from each other.

Next, on a pipe string with a diameter of 168 mm, a sealing unit, a filter column 3 m long and a packer were preliminarily installed from the bottom up, then the pipe string was lowered to the artificial bottom with the filter column placed opposite the kickoff interval of the lower lateral horizontal trunks, and the packer - between the kickoff intervals of the lower lateral horizontal trunks and upper lateral horizontal trunks.

After this, steam was injected into a vertical well between pipe strings with a diameter of 168 mm and 245 mm at an intensity of up to 28 tons/day for 50 days. Next, the injection was stopped for thermocapillary impregnation for 20 days. Then, a pump was lowered into a pipe string with a diameter of 168 mm, combined with a filter column, to a depth of 3 m above the artificial bottom of the vertical well and liquid was started to be withdrawn, and steam injection continued into the interval between the pipe strings with diameters of 168 mm and 245 mm.

The use of this technology made it possible to obtain a hydrodynamic connection between the lower and upper side trunks of a vertical well and made it possible to increase the flow rate by 7 tons/day.

Example 2

In the Arkhangelsk deposit of super-viscous oil, located at a depth of 205 m, reservoir temperature 8 ° C, pressure 0.4 MPa, oil saturation 0.65 units, porosity 29%, permeability 1.34 μm ² , oil density in surface conditions 944 kg/m ³ , oil viscosity in reservoir conditions is 11820 mPa*s, a section of the deposit with an oil-saturated thickness of less than 10 m was identified. A vertical well was drilled, and the filtration and reservoir properties of the formations exposed by drilling were studied. Based on the data obtained, bitumen-saturated and water-saturated layers were identified and oil saturation was determined.

After identifying the water-saturated and oil-saturated layers, the level of the oil-water contact was determined - the OWC of the deposit (214 m). After this, a pipe string with a diameter of 245 mm was lowered into a vertical well to a depth of 10 m (224 m) below the OWC of the deposit and cemented, thus forming an artificial bottom.

Next, we installed the lower whipstock (not shown in the figure) in the direction of drilling the sidetracks. We cut out windows and drilled two lower lateral horizontal trunks with a length of 78 m and 81 m. The lower points of the lower lateral horizontal trunks were located at a distance of 2.1 m and 2.4 m from the OWC, and the bottoms of the lower lateral horizontal trunks were 2 m above the lower points of the lower lateral horizontal trunks.

Then, 6 m above the installed lower whipstock, the upper whipstock was installed, windows were cut out and two upper side shafts 80 m and 82 m long were drilled parallel to the OWC and in such a way that the lower points of the upper side horizontal shafts were located at a distance of 6 m from the bottom points of the lower lateral horizontal shafts, and the faces of the upper lateral horizontal shafts and the lower lateral horizontal shafts were at a distance of 4 m from each other.

Next, on a pipe string with a diameter of 168 mm, a sealing unit, a filter column 3 m long and a packer were preliminarily installed from the bottom up, then the pipe string was lowered to the artificial bottom with the filter column placed opposite the kickoff interval of the lower lateral horizontal trunks, and the packer - between the kickoff intervals of the lower lateral horizontal trunks and upper lateral horizontal trunks.

After this, steam was injected into a vertical well between pipe strings with a diameter of 168 mm and 245 mm at an intensity of up to 19 tons/day for 50 days. Next, the injection was stopped for thermocapillary impregnation for 20 days. Then, a pump was lowered into a pipe string with a diameter of 168 mm, combined with a filter column, to a depth of 3 m above the artificial bottom of the vertical well and liquid was started to be withdrawn, and steam injection continued into the interval between the pipe strings with diameters of 168 mm and 245 mm.

The use of this technology made it possible to obtain a hydrodynamic connection between the lower and upper side trunks of a vertical well and made it possible to increase the flow rate by 6 tons/day.

Example 3

In the Arkhangelsk deposit of super-viscous oil, located at a depth of 205 m, reservoir temperature 8 ° C, pressure 0.4 MPa, oil saturation 0.65 units, porosity 29%, permeability 1.34 μm ² , oil density in surface conditions 944 kg/m ³ , oil viscosity in reservoir conditions is 11820 mPa*s, a section of the deposit with an oil-saturated thickness of less than 10 m was identified. A vertical well was drilled, and the filtration and reservoir properties of the formations exposed by drilling were studied. Based on the data obtained, bitumen-saturated and water-saturated layers were identified and oil saturation was determined.

After identifying the water-saturated and oil-saturated layers, the level of the oil-water contact was determined - the OWC of the deposit (216 m). After this, a pipe string with a diameter of 245 mm was lowered into a vertical well to a depth of 10 m (226 m) below the OWC of the deposit and cemented, thus forming an artificial bottom.

Next, we installed the lower whipstock (not shown in the figure) in the direction of drilling the sidetracks. We cut out windows and drilled four lower lateral horizontal trunks with lengths of 94 m, 97 m, 99 m and 100 m. The lowest points of the lower lateral horizontal trunks were located at a distance of 2 m, 2.1 m, 2.3 m and 2.5 m, respectively from the OWC, and the faces of the lower lateral horizontal shafts were 2 m above the low points of the lower lateral horizontal shafts.

Then, 7 m above the installed lower whipstock, the upper whipstock was installed, windows were cut out and four upper lateral horizontal shafts with lengths of 94 m, 97 m, 99 m and 100 m were drilled parallel to the OWC and in such a way that the lower points of the upper lateral horizontal the shafts were located at a distance of 7 m from the bottom points of the lower lateral horizontal shafts, and the faces of the upper lateral horizontal shafts and the lower lateral horizontal shafts were at a distance of 5 m from each other.

Next, on a pipe string with a diameter of 168 mm, a sealing unit, a filter column 3 m long and a packer were preliminarily installed from bottom to top, after which the pipe string was lowered to the artificial bottom with the filter column placed opposite the kickoff interval of the lower side horizontal trunks, and the packer between the kickoff intervals lower lateral horizontal trunks and upper lateral horizontal trunks.

After this, steam was injected into a vertical well between pipe strings with a diameter of 168 mm and 245 mm at an intensity of up to 29 tons/day for 50 days. Next, the injection was stopped for thermocapillary impregnation for 20 days. Then, a pump was lowered into a pipe string with a diameter of 168 mm, combined with a filter column, to a depth of 3 m above the artificial bottom of the vertical well and liquid was started to be withdrawn, and steam injection continued into the interval between the pipe strings with diameters of 168 mm and 245 mm.

The use of this technology made it possible to obtain a hydrodynamic connection between the lower and upper side trunks of a vertical well and made it possible to increase the flow rate by 9 tons/day.

Claims (1)

A method for developing a super-viscous oil deposit, including drilling a vertical well, studying the filtration and reservoir properties of the formations exposed by drilling, isolating bitumen-saturated and water-saturated layers, drilling horizontal lateral trunks from a vertical well, characterized in that after isolating the water-saturated and oil-saturated layers, the level of oil-water contact is determined - VNK , after that, a pipe string is lowered into a vertical well to a depth of 10 m below the OWC and it is cemented to form an artificial bottom, then the lower whipstock is installed in the direction of drilling the lateral trunks, a window is cut out, and 2 to 4 lower horizontal laterals are drilled shafts 50-100 m long, and in such a way that the lower points of the lower lateral horizontal shafts are located at a distance of at least 2 m from the OWC, and the faces of the lower lateral horizontal shafts are 2 m above the low points of the lower lateral horizontal shafts, then 5- 7 m above the lower whipstock, install the upper whipstock in the direction of drilling the upper lateral trunks, cut out a window, drill 2 to 4 upper lateral horizontal trunks 50-100 m long parallel to the OWC and in such a way that the lower points of the upper lateral horizontal shafts were located at a distance of 5-7 m from the lower points of the lower lateral horizontal shafts, and the faces of the upper lateral horizontal shafts and lower lateral horizontal shafts were at a distance of 3-5 m from each other, first a sealing unit was installed at the lower end of the pipe string, then a filter a 3 m long column and a packer, a pipe string is lowered into a vertical well to the artificial bottom with the possibility of placing a filter column opposite the kickoff interval of the lower lateral horizontal trunks, and a packer - between the kickoff intervals of the lower lateral horizontal trunks and upper lateral horizontal trunks, then into the vertical well steam is injected at an intensity of up to 30 tons/day for 50 days, the steam injection is stopped for thermocapillary impregnation for 20 days, then the pump is lowered into the pipe column with a filter column to a depth of 3 m above the artificial bottom and liquid withdrawal begins, injection continues pair.