RU2363839C1 - Procedure for development of high viscous oil deposits - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to procedure of development of high viscous oil deposits. The procedure consists of drilling a main borehole of the well, wherefrom a side horizontal borehole is drilled; in lowering a perforated column into it; in lowering a flow string into the main borehole of the well; in installing a packer below the interval of kickoff of the side horizontal borehole, notably, the said packer seals space between the flow string and the main borehole; in pumping heat carrier through one borehole and in withdrawing high viscous oil or bitumen from another borehole of the well. Before installation of the packer a deflector is lowered on the flow string into a low uncased part of the main borehole of the well; the deflector with its outlet opening is directed to the side horizontal borehole and below it within the boundaries of the same producing reservoir. Located under the side horizontal borehole section is formed by means of a flexible pipe with a jet-head. The flexible pipe and the flow string with the deflector are pulled out from the well. After installation of the packer, but before lowering the flow string the latter is fitted out with a pipe filter and with a nipple mounted above; the nipple is equipped with the deflector furnished with an opening made in the wall of the flow string above the nipple; also the flow string is provided with a bypass. The inlet of the bypass is communicated with above wedge space of the flow string, while its output is connected to under the nipple space of the flow string. The flow string is lowered into the main borehole of the well till nipple pressure tight interacts with the packer; notably, the pipe filter will be arranged opposite to the interval of kickoff of the side horizontal borehole of the packer. Further, the perforated column on the process column with an additional packer is lowered via the flow string, the deflector and the opening into the side horizontal borehole till the perforated column is placed in its horizontal section. An additional packer is installed between the flow string and the process column above the opening, but below the inlet of the bypass. Heat carrier is pumped into the main borehole of the well via annular space of the flow string and process column, the bypass, under the nipple space of the flow string and the filter, while withdrawing of product is performed from the side horizontal borehole through the perforated column along the process column.

EFFECT: increased efficiency of heating high viscous oil deposit with heat carrier, when density of heated oil is below density of heat carrier; also reduced heat losses of heat carrier in well and efficiency of direct effect onto well walls during 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 interlayers, 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 action on the reservoir, including drilling from the day surface of a vertical shaft that reveals the reservoir at its full capacity, construction of an underground working chamber, drilling of horizontal injection and production wells, the mouths of which are located in the underground working chamber, and injection of coolant into the producing formation through injection wells I, 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 full capacity 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 to After the productive formation is over, a ventilation fault occurs from the top of the productive formation between the shaft and the ventilation well, 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 the product the rising oil well using lifting wells, while the mouth of the lifting well on the day surface is equipped with a sealed cover, a support platform is installed in the underground working chamber, and cemented guide casing pipes are installed in its lateral walls, the drilling of 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, moreover, the curled-up casing 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 axial rotation around its axis and connecting the curved part to one or another cemented guide casing pipe, through the bending-guide column into the reservoir a drill pipe is lowered with a downhole diverter with a downhole motor and a bit and a horizontal well is drilled, while the cuttings are lifted to the day surface drive along the annular space between the bending guide and the drill string, and oil is pumped to the day surface by airlift or gas lift lifts mounted in lifting wells.

The disadvantages of this method are:

- firstly, the vertical shaft of the shaft and the presence of ventilation, gas, vapor falling 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, heat absorption, in addition, when the cement ring is heated behind the casing, the adhesion of the cement ring to the casing deteriorates, which can 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 preheated state is lower than the density of the coolant, since all the heat "goes" up.

The objective of the invention is to increase the efficiency of heating the field with highly viscous oil, the density of which in the pre-heated state is lower than the density of the coolant, as well as reducing heat loss by the coolant in the well and direct heat exposure on the walls of the well during field development.

The problem is solved by the method of developing high-viscosity oil fields, the density of which 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, the 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 the coolant one at a time trunk and selection of heavy oil or bitumen from another wellbore.

What is new is that before installing the packer in the lower uncased part of the main well bore, a deflector is lowered onto the pipe string, which is oriented by the outlet in the direction of the horizontal lateral well and below it within the same reservoir, after which they are formed using a flexible pipe with a hydraulic nozzle a horizontal section located under the horizontal lateral shaft, after which the flexible pipe and pipe string with diverter are removed from the well, after installing the packer, but before launching tubing pipes 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 inlet of which communicates with the super-wedge space of the tubing string, and the outlet with the sub-pin space tubing columns, after which the tubing string is lowered into the main wellbore until the nipple and the packer are tightly connected with the tubular filter in the horizontal section and the location of the window opposite the cutoff interval of the lateral horizontal barrel of the packer, then the perforated column on the process pipe string with an additional packer is lowered through the tubing string, the diverter and the window into the horizontal side barrel until the perforated pipe string is placed in its horizontal section, after whereby an additional packer is installed between the tubing and the process pipe string above the window, but below the bypass channel inlet, achku coolant in the main wellbore annulus carried by the tubing and column process tubes, a bypass channel, space podnippelnomu column tubing and filter, and selection - from a lateral horizontal section through the perforated column technology on a pipe string.

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

First, a well is constructed, for this, the main trunk 1 is drilled to the roof 2 of the productive formation 3, then the casing string 4 is lowered into it and cementing is carried out from the roof 2 of the productive formation 3 to the mouth with the formation of a cement ring 5.

Then, from the cemented part of the main trunk 1, the lateral horizontal trunk 6 is cut (drilled) into the reservoir 3. Next, before installing the packer 7, the main trunk 1 is extended (drilled) down within the reservoir 3.

In the lower uncased part 8 of the main wellbore 1, a deflector (not shown) is lowered onto the pipe string, which is oriented with an outlet in the direction of the lateral horizontal wellbore 6 (the deflector is oriented in the well by geophysical surveys) and below it within the same reservoir 3, after which using a flexible pipe with a hydraulic nozzle (not shown) form a horizontal section 9 located under the horizontal horizontal barrel 6, after which the flexible pipe and a pipe string with a diverter is removed from the well. Work on the descent and installation of the deflector, its orientation and the formation of a horizontal section using a flexible pipe with a jet nozzle are made according to US patent No. 5413184, EV 7/08, publ. May 9, 1995.

Then, in the main well 1 below the cutoff interval of the lateral horizontal wellbore 6, a packer 7 is installed using a pipe string (not shown).

The packer 7 seals the space between the tubing 10 and the casing string 4 of the main wellbore 1.

Next, they begin to install the tubing string 10, while equipping it with a tubular filter 11 and a nipple 12 located above with a deflector 13 provided with a window 14 made in the wall of the tubing 10 above the nipple 12 and the bypass channel 15, the input of which communicated with the super-wedge space 16 of the tubing string 10, and the outlet 17 is connected with the sub-pin space 18 of the tubing string 10.

After that, the tubing string 10 is lowered into the main bore 1 of the well until the nipple 12 is tightly connected with the central channel 7 'of the packer 7 with the tubular filter 11 opposite the horizontal section 9 and the window 14 opposite the cutoff interval of the lateral horizontal barrel 6 above the packer 7 when help geophysical exploration.

Then, the perforated string 19 on the pipe production string 20 with an additional packer 21 is lowered through the tubing string 10, the diverter 13 and the window 14 into the lateral horizontal barrel 6 until the perforated pipe string 19 is placed in its horizontal section, whereby the pipe pipe string is placed and placed 20 to the window 14 of the deflector 13 is controlled using marks (not shown) made on the pipes of the process string 20.

Then, an additional packer 21 is installed between the tubing 10 and the process pipe string 20 above the window 14, but below the entrance of the bypass channel 15. Next, the pump 23 is lowered into the process string 20 on the string of pump rods 22, which is placed over the perforated string 17.

Then, the well is put into operation, while the coolant (for example, water vapor) is injected into the main wellbore 1 through the annulus 24 of the tubing 10 and the tubing string 20, the bypass channel 15, the sub-tubing space 18 of the tubing string 10 and the filter 11 and further, the coolant through the horizontal section 9 enters the reservoir 3 and, rising upwards, heats the reservoir 3, diluting highly viscous oil, while its viscosity decreases.

Heated high-viscosity oil through a perforated column 19 is fed to a pump 23, which pumps high-viscosity oil through a process pipe string 20 to the surface.

Since the coolant is injected along the annulus 24 between the process pipe string 20 and the tubing string 10, direct contact of the coolant with the walls of the casing string 4 and, accordingly, with the cement ring 5 is excluded, and this, in turn, reduces heat losses during the injection of coolant into the reservoir 3.

The proposed method for the development of high-viscosity oil fields, whose density 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 the coolant by heating the productive formation from the bottom up and from the open part of the main trunk. This method also allows to reduce the heat loss of the coolant in the main well when it is injected 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 whose density is lower than the density of the coolant, including drilling the main wellbore, from which the horizontal sidetrack is drilled, perforated columns are lowered into it, tubing pipes are lowered into the main wellbore, the packer is set below the cutoff interval of the lateral horizontal wellbore , which seals the space between the tubing and the main well, the injection of coolant along one barrel and the selection of highly viscous tee or bitumen from another wellbore, characterized in that before installing the packer in the lower uncased part of the main wellbore, a deflector is lowered onto the pipe string, which is oriented by the outlet in the direction of the horizontal lateral wellbore and below it within the same reservoir, after which using a flexible pipe with a hydraulic nozzle, a horizontal section is formed, located under the lateral horizontal barrel, after which the flexible pipe and pipe string with a diverter 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, 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 the super-wedge space of the tubing string compressor pipes, and the outlet - with sub-nipple space of the tubing string, after which the tubing string is lowered into the main wellbore until the nipple and packer are tightly connected with the placement of a tubular filter opposite the horizontal section and the location of the window opposite the cutoff interval of the lateral horizontal barrel of the packer, then the perforated column on the process pipe string with an additional packer is lowered through the tubing string, the diverter and the window into the side horizontal barrel until the perforated pipe string is placed in it horizontal section, after which an additional packer is installed between the tubing and the tubing string e windows, but below the inlet of the bypass channel, the coolant is injected into the main wellbore through the annulus of the tubing and the tubing string, the bypass channel, the sub-nipple of the tubing string and the filter, and the selection is from the horizontal lateral trunk through a perforated the column on the technological pipe string.