RU2398104C2 - Method for development of high-viscosity oil deposits - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention relates to method for development of high-viscosity oil deposits with application of its heating. Concept of the invention is as follows: main well is arranged according to method. For this purpose the main borehole is drilled, afterwards casing pipe string is lowered in it, and cementing is carried out from bottomhole to wellhead to form a cement ring. Then lower part of main well is drilled in the form of horizontal section arranged in payout bed. Over horizontal section of the main well, within this payout bed, side horizontal borehole is drilled. Afterwards packer is installed in the main well below interval of side horizontal borehole cutting with the help of pipe string. Packer seals space between lifting pipe and casing pipe string of the main borehole of the main well. Lifting pipe string (LPS) assembly is started. At the same time it is equipped with tubular filter and nipple with whipstock arranged above, provided with window arranged in wall of lifting pipes over nipple, and bypass channel, inlet of which communicates with over-wedge space of lifting pipe string, and outlet - to under-packer space of lifting pipe string. Afterwards lifting pipe string is lowered into main borehole of main well until nipple tightly interacts with packer with arrangement of tubular filter in horizontal section and arrangement of window opposite to cutting interval of side horizontal borehole above packer. Then perforated string is lowered on process pipe with additional packer via lifting pipe string, whipstock and window into side horizontal borehole until perforated pipe string is located in its horizontal section. Then additional packer is installed between lifting pipes and process pipe over window, but below inlet of bypass channel. Pump is lowered into process string on rod string and is arranged over perforated string. Then well is put in operation, at the same time, pumping of coolant, for instance water steam, into main borehole of main well is carried out along tube space of lifting pipes and process pipes string, bypass channel, under-packer space of lifting pipe string and filter. In side horizontal borehole coolant arrives into payout bed, and as it lifts upwards, it heats payout bed, liquefying high-viscosity oil. Heated high-viscosity oil via perforated string arrives to suction of pump, which pumps high-viscosity oil along process pipe string onto surface. Since coolant is pumped in tube space between process pipe string and lifting pipe string, direct contact of coolant with walls of casing pipe string, and accordingly, with cement ring, is eliminated, which, in its turn, reduces heat losses as coolant is pumped into payout bed.

EFFECT: increased efficiency of method due to reduction of heat losses by coolant in well and direct exposure of well walls to heat in process of deposit development.

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Description

The invention relates to a method for developing highly viscous oil fields. To obtain hydrocarbons from such deposits, their heating is necessary.

There is a method of developing a reservoir of viscous oil or bitumen (patent RU No. 2305762, ЕВВ 43/24, published in Bull. No. 25 of 09/10/2007), including drilling a continuous horizontal well with the placement of the inlet section of the well before the occurrence of the reservoir, conditionally horizontal section of the well along the strike of the reservoir, output section upward with an inclination from the reservoir to the surface, installation of casing, cementing the annulus, installation of tubing with centralizers, heat injection carrier and selection of viscous oil or bitumen, characterized in that they clarify the distribution of productive thicknesses of the reservoir over the area of the reservoir, drill at least one pair of continuous horizontal wells, the horizontal sections of which are placed parallel to each other in a vertical plane at a distance that prevents premature breakthrough condensate to the producing well, casing strings with a filter are installed in the interval of the reservoir, cementing the annulus of the columns is carried out to the roof the reservoir, the coolant is injected through the upper horizontal injection well from the wellhead and the bottom of the well, at the same time, viscous oil or bitumen is taken through the lower horizontal production well from the wellhead and the bottom of the well using a swab, and the trunk path of the producing horizontal well is placed at least at the minimum distance to the soles of the reservoir of viscous oil, or bitumen, or water-bitumen contact, increasing the anhydrous period of operation of wells.

The disadvantages of this method are:

- firstly, the difficulty of pairing continuous horizontal wells, the horizontal sections of which are placed one above the other in a vertical plane at a distance that prevents premature breakthrough of condensate to the producing well;

- secondly, high preparation costs for the coolant, due to the large length of the heated section of the well;

- thirdly, there is no way to extend the well after it is cased by casing strings and cementing their annulus;

- fourthly, oil is produced on a separate trunk.

There is also known a method of developing deposits of high viscosity oils or bitumen with horizontal inclined wells (patent RU No. 2237804, ЕВВ 43/24, published in Bull. No. 28 of 10.10.2004), including drilling wells on a specific grid, pumping the displacing agent through injection wells and selection of formation fluids through production wells, while the wells are drilled along a radial grid so that injection wells are located along the productive formation closer to the upper boundary of the formation along the most permeable interlayers, and production wells - closer to the lower boundary of the formation, and at the initial stage of development in all wells, a thermocyclic treatment of the formation with steam stimulation is carried out with the subsequent transition to the selection of formation fluids through production wells with areal exposure to the formation through injection wells.

The disadvantages of this method are:

- firstly, the large financial costs of well construction, due to the fact that injection and production wells are being built separately;

- secondly, it is difficult to predict the selection of highly viscous oils and bitumen from producing wells, since this method is very demanding on the accuracy of well drilling, namely, injection wells are located in the productive formation closer to the upper boundary of the formation along the most permeable layers, and production - closer to the lower boundary of the reservoir, which is almost difficult to achieve;

- thirdly, oil is produced on a separate trunk.

There is also known a method of oil production by underground horizontal wells (patent RU No. 2060377, ЕВВ 43/24, 7/04, 21/00, published in Bull. No. 14 dated 05/20/1996), using thermal effects on the reservoir, including drilling from the day surface of a vertical shaft mine, revealing a productive layer to its entire thickness, construction of an underground working chamber, drilling of horizontal injection and production wells, the mouths of which are located in an underground working chamber, pumping coolant into the producing formation through injection wells supplied from the surface by steam pipe, extracting oil from the reservoir by producing wells into the underground working chamber, collecting it into a tank and pumping it to the surface, characterized in that a ventilation well is drilled parallel to the shaft that opens the reservoir to its entire thickness, and between them a lift, steam supply and gas outlet, a reserve lift well is drilled from the bottom of the ventilation well, while the lift wells are drilled to depths equal to 1.3-1.5 depths of influent of the reservoir, over the roof of the reservoir between the shaft and the ventilation well there is a ventilation fault from which exploration wells are drilled, an underground working chamber is built in the lower part of the reservoir between the shaft and the ventilation well, horizontal injection and production wells are drilled in radial directions in two tiers, the underground working chamber is hermetically isolated from the mine atmosphere, and as a container for collecting effluent from of the oil reservoir, lifting wells are used, while the mouth of the lifting well on the day surface is equipped with an airtight cover, a support platform is installed in the underground working chamber, and cemented guide casing pipes are installed in its lateral walls, drilling horizontal injection and production wells, the mouths of which are located in the underground working chamber, produce a drilling rig located on the day surface, using a bending guide column having a shank and a curved part, and the removed column on the day surface is mounted in a sealed cover, in the underground working chamber on the supporting platform and installed with the possibility of movement in the axial direction, rotation around its axis and connecting the curved part to one or another cemented guide casing pipe, through the bending guide column into the productive the formation on the drill pipes is lowered by a diverter with a downhole motor and a bit and a horizontal well is drilled, while raising the cuttings to the day surface produces odyat by curving the annulus between the guide and drill string and pumping oil to the surface produce mounted in the lifting or gas lift wells airlift lifts.

The disadvantages of this method are:

- firstly, the vertical shaft and the presence of ventilation, gas, steam supply wells, as well as the construction of an underground working chamber lead to high costs for the construction of the well, with which it is necessary to implement this method, that is, this method is very expensive and time-consuming;

- secondly, a complex coolant injection system;

- thirdly, oil is produced on a separate trunk.

The closest in technical essence is the method of developing high-viscosity oil or bitumen deposits (patent RU No. 2289685, ЕВВ 43/24, publ. Bull. No. 35 dated 12/20/2006), including drilling a vertical well, launching and cementing the production string, its perforation, descent of tubing, injection of coolant and selection of highly viscous oil or bitumen, while after drilling a vertical well, the reservoir and thermal properties of the layers uncovered by drilling are studied, bitumen-saturated and water saturated interlayers, after which a horizontal well is drilled from a vertical well so that it reveals an intermediate aquifer in the context of the bitumen formation — half the distribution of the local aquifer, the lateral well is cemented to the upper bituminous well, then a perforated casing is lowered into the lateral well, and perforation is carried out so that the number of perforations increases with distance from the vertical wellbore, and the vertical wellbore we perforate in the zones exposed by drilling the bituminous layers, the tubing is lowered into a vertical well with a packer, which is installed below the sidetracking interval, the coolant is injected into the horizontal sidetrack, and the selection of highly viscous oil or bitumen is performed along the vertical wellbore, after the development of a productive zone between the vertical and lateral horizontal trunk, the polyacrylamide rim in a volume of 0.1 from the volume ma of the heated productive zone and water, and water is pumped until polyacrylamide appears in the vertical wellbore, then the coolant is pumped back into the lateral horizontal well, high-viscosity oil or bitumen is produced, then the coolant is pumped through the vertical well and horizontal lateral well to ensure production of high viscosity oil or bitumen in neighboring producing wells.

The disadvantages of this method are:

- firstly, large heat losses during the injection of the coolant, due to the large cross-section of the annular space through which the coolant is pumped and direct contact of the coolant with the walls of the well, behind which the cement ring is located, which leads to heating of the latter and, as a result, to heat absorption, except in addition, when the cement ring is heated behind the casing, the adhesion of the cement ring to the casing deteriorates, which may subsequently lead to annular flows;

- secondly, the producing section of the well is vertical, and the injection section is horizontal, which leads to inefficient heating of the field with highly viscous oil or bitumen by the coolant, since the horizontal section of the injection well is directed from the vertical section of the producing well;

- thirdly, the low efficiency of the method in the case when the density of highly viscous oil in a heated state is lower than the density of the coolant, because all the heat "goes" upstairs.

The objective of the invention is to increase the efficiency of heating with a coolant field of highly viscous oil, as well as reducing heat loss by the coolant in the well and direct thermal effects on the walls of the well during the development of the field.

The problem is solved by the method of developing high-viscosity oil fields, the density of which in a preheated state is lower than the density of the coolant, including drilling the main wellbore, from which the horizontal sidetrack is drilled, the perforated string is lowered into it, the tubing is lowered into the main wellbore, the installation is lower kickoff interval of the lateral horizontal bore of the packer, which seals the space between the tubing and the main well, injection one coolant bore and the selection of highly viscous oil of different borehole.

What is new is that the lower part of the main wellbore is drilled in the form of a horizontal section located in the reservoir, and the lateral horizontal well is drilled above the horizontal section of the main well within the reservoir, after installation of the packer, but before the tubing they are equipped with a tubular filter and a nipple located above with a deflector equipped with a window made in the wall of the tubing above the nipple and a bypass channel, the input of which is in communication with above the wedge-shaped space of the tubing string, and the outlet with the under-packer space of the tubing string, after which the tubing string is lowered into the main wellbore until the nipple engages with the packer with a tubular filter placed in a horizontal section and the window is opposite the interval cut-offs of the lateral horizontal trunk of the packer, then the perforated column on the process pipe string with an additional packer is lowered through the pump-com string spring pipes, a diverter and a window in the lateral 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 process pipe above the window, but below the bypass channel inlet, the coolant is pumped into the main wellbore along the annulus of the tubing and the string of process pipes, the bypass channel, the under-pack space of the tubing string and the filter, and about assembly - from a lateral horizontal trunk through a perforated column along the technological pipe string.

The drawing shows a diagram of an implementation of the proposed method for the development of high-viscosity oil fields.

First, the construction of the main well 1 is carried out, for this the main trunk 1 is drilled, after which the casing string 2 is lowered into it and cementing is carried out from the bottom to the mouth with the formation of a cement ring 3.

Then, the lower part of the main well 1 is drilled in the form of a horizontal section 4 located in the reservoir 5. Further, above the horizontal section 4 of the main well 1 within the given reservoir 5, a horizontal lateral trunk 6 is drilled.

Then, in the main well below the cutoff interval of the lateral horizontal barrel 6, using the pipe string (not shown), the packer 7 is installed.

The packer 7 seals the space between the tubing 8 and the casing string 2 of the main trunk 1 of the main well.

Next, they begin to install the tubing string (tubing) 8, while equipping it with a tubular filter 9 and a nipple 10 located above with a deflector 11 provided with a window 12 made in the wall of the tubing 8 above the nipple 10 and the bypass channel 13 the input of which is in communication with the super-wedge space 14 of the column of tubing 8, and the output 15 is with the sub-packer space 16 of the column of tubing 8.

After that, the tubing string 8 is lowered into the main wellbore 1 of the main well until the nipple 10 is tightly connected with the packer 7 with the tubular filter 9 placed in the horizontal section 4 and the window 12 is located opposite the cutoff interval of the lateral horizontal barrel 6 above the packer 7.

Then, the perforated column 17 on the production pipe 18 with an additional packer 19 is lowered through the tubing string 8, the diverter 11 and the window 12 into the lateral horizontal barrel 6 until the perforated pipe string 17 is placed in its horizontal section, and the technological pipe string 18 enters the window 12 diverters 11 are produced by geophysical surveys or using marks made on the pipes of the process column 18.

Then an additional packer 19 is installed between the tubing 8 and the process pipe string 18 above the window 12, but below the entrance of the bypass channel 13.

Next, the pump 21, which is placed above the perforated column 17, is lowered into the production string 18 on the string of pump rods 20.

Then the well is put into operation, while the coolant (for example, water vapor) is injected into the main trunk 1 of the main well through the annulus 22 of the tubing 8 and the tubing string 18, the bypass channel 13, the under-tubing space 16 of the tubing string 8 and filter 9.

In the horizontal lateral barrel 6, the coolant enters the reservoir 5 and, rising upward, heats the reservoir 5, diluting highly viscous oil, while its viscosity decreases.

Heated high-viscosity oil through a perforated column 17 is fed to a pump 14, which pumps high-viscosity oil through a process pipe string 18 to the surface.

Since the coolant is injected through the annular space 22 between the process pipe string 18 and the tubing string 8, direct contact of the coolant with the walls of the casing string 2 and, accordingly, with the cement ring 3 is excluded, and this, in turn, reduces thermal losses during the injection of coolant into the reservoir.

The proposed method for the development of high-viscosity oil fields, the density of which in the preheated state is lower than the density of the coolant, allows to increase the efficiency of heating the high-viscosity oil field by heating the productive layer from the bottom up, as well as to reduce the heat loss of the coolant in the main well when it is pumped into the reservoir by eliminating direct thermal effects on the casing string of the well.

Claims (1)

A method for developing highly viscous oil fields, the density of which in the preheated state is lower than the density of the coolant, including drilling the main wellbore, from which the horizontal sidetrack is drilled, the perforated string is lowered into it, the tubing pipes are lowered into the main wellbore, installation is lower than the lateral cutoff interval horizontal trunk of the packer, which seals the space between the tubing and the main well, pumping coolant along one trunk selection of highly viscous oil from another wellbore, characterized in that the lower part of the main wellbore is drilled in the form of a horizontal section located in the reservoir, and the lateral horizontal well is drilled above the horizontal section of the main well within this reservoir, after which the packer is installed, but before lowering the tubing, they are equipped with a tubular filter and a nipple located above with a deflector equipped with a window made in the wall of the tubing e of the nipple, and a bypass channel, the input of which is in communication with the super-wedge space of the tubing string, and the outlet is with the sub-packer space of the tubing string, after which the tubing string is lowered into the main wellbore until the nipple interacts with the packer with by placing a tubular filter in a horizontal section and arranging a window opposite the cutoff interval of the lateral horizontal trunk of the packer, then a perforated column on the process pipe string with additional The packer is lowered through the tubing string, the diverter and the window into the horizontal lateral trunk until the perforated tubing string is placed in its horizontal section, after which the additional packer is installed between the tubing and the tubing string above the window, but below the bypass channel entrance, the coolant is injected into the main wellbore through the annulus of the tubing and the tubing string, the bypass channel, the under-packer stvu column tubing and filter, and selection - from a lateral horizontal section through the perforated column technology on a pipe string.

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