RU2455474C1 - Development method of heavy oil or bitumen mine field - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: method includes construction of upper injection well and lower productive well with horizontal areas equipped with filters and located one above the other, heat-transfer medium pumping through horizontal injection well with formation heating, creation of steam chamber and product withdrawal through horizontal productive well with withdrawal reduction in the zones of thermal spikes. Pump shank with temperature valves adjusted depending upon the temperature and located opposite the zones of productive formation is located inside the filter of productive well. Withdrawal reduction is done by means of automatic partial closing to complete closing of valves. The packer in injection well is mounted directly behind the perforated area from mouth side. Tubular annulus above this packer is filled with incombustible gas. After all valves are closed simultaneously they are extracted from the productive well together with string and packer. Heat-transfer medium is pumped into the injection column for increasing the temperature up to 200-250°C, after that heat-insulating compound is pumped, then the string with valves and packer is mounted in productive well. Heat-transfer medium pumping and product withdrawal is resumed in standard mode till closing of all valves, then the treatment of productive well by heat-insulating compound is repeated.

EFFECT: cost decreasing, development effectiveness improvement.

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Description

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

The closest in technical essence is the method of developing a heavy oil or bitumen field using double-mouth horizontal wells (RF patent 2340768, IPC 8 ЕВВ 43/24, published in bulletin 32 dated 12/10/2008), including the injection of coolant through horizontal wellhead injection well, warming up the productive formation with the creation of a steam chamber and selecting products through a two-well horizontal production well, while heating the productive formation begins with the injection of steam into both wells, the cross-hole is heated the formation zone, reduce the viscosity of oil or bitumen, and the steam chamber is created by pumping coolant with the possibility of punching the latter to the upper part of the reservoir and increasing the size of the steam chamber in the process of product selection, in which thermograms of the steam chamber are taken, the state of its heating for uniformity of heating is analyzed and the presence of temperature peaks, and taking into account the obtained thermograms, the steam chamber is uniformly heated by changing the filtration direction and / or the coolant injection modes and ora products, the volume of pumping coolant through the mouth of the injection well and / or selection of products through the mouth of the production well at a ratio change,%: (10-90) :( 90-10).

The disadvantages of this method are:

- firstly, high financial costs for the construction of a double-well well (the cost of building a double-well well is three times more expensive than a single-well well);

- secondly, high material costs associated with the fact that the temperature sensors on the cable are placed along the entire length of the shafts of the double-well wells;

- thirdly, the breakthrough of the coolant into the horizontal section of the producing well is judged by the readings of the temperature sensors, on the basis of which thermograms of the steam chamber are built, their analysis is made, on the basis of which the direction of filtration and / or the modes of pumping the coolant and production selection are changed. This process does not occur automatically and requires constant monitoring of the temperature regime in the steam chamber, as well as time to exclude the breakthrough of the coolant in the horizontal section of the producing well.

The closest in technical essence is the method of developing a heavy oil or bitumen field with regulation of the selection of well production (RF patent 2398103, IPC 8 Е21В 43/24; ЕВВ 34/08, published in bul. 24 from 08/27/2010), including construction of the upper injection well and the lower production well with horizontal sections located one above the other, pumping the heat carrier through the horizontal injection well with heating the formation, creating a steam chamber and taking products through the horizontal producing well by reducing the selection in the areas of temperature peaks, uniformly warming up the steam chamber, and during the construction of wells, their horizontal sections are equipped with filters, inside one of which a pump shank with valves, depending on temperature, located opposite the zones of the reservoir, is selected, reducing the selection produced by automatic shut-off until the valves are completely closed, in the installation zones of which the temperature of the extracted heavy oil or bitumen is 0.5-0.9 etstvenno is the temperature at which the coolant breakthrough in extracting horizontal well.

The disadvantages of this method are:

- firstly, large losses of thermal energy (from 15 to 25%) when the coolant is pumped into a horizontal injection well spent on heating:

- columns of pipes through which the coolant is pumped;

- annular space between the walls of the horizontal injection well and the pipe string, in connection with which the cost of preparing the coolant increases;

- secondly, when the temperature at the inlet openings of the valves located in the horizontal section of the producing well exceeds the calculated temperature (81 ° C), the temperature valves gradually completely shut off, while there is a sharp decrease in the selection of heated heavy oil or bitumen up to full cessation of selection (with complete overlap of all temperature valves), and in order for temperature valves to begin to bypass through at least partially, it is necessary to lower the temperature at the inlet the valve port is below 81 ° C, and with constant injection of coolant into the formation and replacing the pores of the formation with the injected coolant, this is very difficult to achieve, so the temperature valves will be in the closed position, preventing the flow of heated fluid into the horizontal section 4 of the producing well 2. Further field development heavy oil or bitumen becomes ineffective due to a sharp decrease in the volume of production extraction up to its complete cessation (valves are closed).

The objective of the invention is to reduce the cost of preparing the coolant and the loss of thermal energy of the coolant during its injection into a horizontal injection well with the possibility of increasing the efficiency of the development of a heavy oil or bitumen field by creating a screen of heat-insulating composition opposite the horizontal section of the producing well, in which the valves are located at a sharp decrease volumes of product selection (valve closure).

The problem is solved by the method of developing a heavy oil or bitumen field, including the construction of an upper injection well and a lower production well with horizontal sections located one above the other and equipped with filters and packers, pumping a heat carrier through a horizontal injection well with heating the formation, creating a steam chamber and selecting products through a horizontal production well with a decrease in production in areas of the presence of temperature peaks, providing uniform prog in the steam chamber, and inside the filter of the producing well, a pump shank with valves, depending on the temperature, located opposite the zones of the reservoir, is controlled, the selection is reduced by automatically closing the valves, in the installation zones of which the temperature of the extracted heavy oil or bitumen is respectively 0.5-0.9 of the temperature at which the coolant breaks into the producing horizontal well.

What is new is that the packer in the injection well is installed directly behind the perforated section of the thermally insulated pipe string from the mouth side, and the annulus above this packer is filled with non-combustible gas, after all valves are closed simultaneously, they are removed from the production well with the pipe string and packer and the coolant is pumped into the injection column until the temperature rises 200-250 ° C, after which the heat-insulating composition is pumped with the volume calculated by the formula:

,

,

where V _t - injection volume of the insulating composition, m ³ ;

R ₀ is the radius of the created screen, m;

h is the length of the section of perforations, m;

m - formation porosity, unit

and the value of the insulation radius is determined by the formula:

,

,

where Q is the injectivity of the reservoir, m ³ / day;

after which the pipe string with valves and a packer is installed in the production well, the coolant injection and the selection of well products are resumed in the normal mode until all valves are closed, then the treatment of the well with an insulating composition is repeated.

In figures 1 and 2 schematically presents the proposed method of developing a field of heavy oil or bitumen.

The proposed method is as follows.

First, the construction of the upper injection well 1 (see Fig. 1) and the lower production well 2 with horizontal sections 3 and 4, respectively, located one above the other and revealing the producing formation 5 with heavy oil or bitumen (hereinafter), is carried out injection 1 and producing 2 wells, their horizontal sections 3 and 4, respectively, are equipped with filters 6 and 7.

Injection well 1 is used to pump coolant into formation 5, and production well 2 is used for production from formation 5. Next, injection well 1 is provided with a heat-insulated pipe string 8 with packer 9 and perforated section 10 opposite to filter 6. Packer 9 in injection well 1 is installed directly behind the perforated section 10 of the insulated pipe string 8 from the side of the mouth 11, and the annular space 12 above this packer 9 is filled with a non-combustible gas, for example nitrous oxide.

Filling the annular space 12 above the packer 9 with non-combustible gas allows to reduce the loss of thermal energy (from 10 to 15%) spent on heating the pipe string, through which the coolant is pumped, and the annular space when pumping the coolant into a horizontal injection well.

A pipe string 13 is lowered into the production well 2 with a packer 14 by a submersible pump 15 at the end, in addition, at the end of the pump 15, a shank 16 with temperature-dependent valves 17 placed opposite the filter 7 and zones of the reservoir 5 is placed over the entire horizontal length section 4 of the production well 2 (see figure 1).

Next, they begin to pump coolant (water vapor at a temperature of 180-200 ° C) from a steam generator (CCGT) (not shown in Figs. 1 and 2) into reservoir 5 along the tubing string 8 through its horizontal perforated section 10 and filter 6 of the horizontal section 3 injection wells 1. Depending on the permeability of the formation 5, the injection pressure is selected and, depending on the effective oil-saturated thickness of the formation 5, the volume of injected steam is determined, and the productive formation 5 is heated to create a steam chamber.

The selection of preheated heavy oil or bitumen is carried out using a submersible pump 15, for example a screw pump, moreover, the preheated heavy oil or bitumen from the reservoir 5 first passes through the filter 7 of the horizontal section 4 of the producing well 2 into the horizontal section 4, where the temperature valves 17 are located, which depending on the temperature, the liquids are passed through themselves into the liner 16 and then to the reception of a submersible pump 15, which pumps heavy oil or bitumen to the day surface. The temperature regime of the valves 17 is adjusted before they are lowered into the horizontal wellbore 4 of the producing well 2, depending on the thickness of the formation 5 and the temperature at which the coolant breaks into the horizontal section 4 of the producing well 2. The number of temperature valves 17 installed in the shank 16 in the horizontal the barrel 4 of the production well 2, depends on the length of the horizontal section 4, and also based on the calculation of one valve per 5-10 m of the length of the horizontal section 4 of the production well 2 depending on the volume o Biran products from the production well 2.

In the process, the temperature valves 17 respond to the temperature of the liquid, which they bypass. The device and the principle of operation of the temperature valves 17 are described in the patent of the Russian Federation 2398103, IPC 8 Е21В 43/24; ЕВВ 34/08, publ. in bul. 24 from 08.27.2010

In the process of developing stocks of heavy oil or bitumen from formation 5, the coolant pumped into the formation 5 through the filter 6 of the horizontal section 3 of the injection well 1 replaces the pores of the formation 5 where heavy oil or bitumen was located, and thus in the formation 5 the coolant reaches the horizontal section of the producing well 2, while the temperature of the liquid at the inlet intake (not shown in FIGS. 1 and 2) of the temperature valves 17 is higher than the temperature at which one or all valves 17 are completely closed (depending on the spares of the coolant breakthrough relative to the horizontal section 4 of the production well 2), therefore, the temperature valves 17 are gradually closed, and therefore the volume of production withdrawal from the production well is gradually reduced until the cessation of selection.

Next, the selection of heated products from the horizontal section 4 of the producing well 2 is stopped (the submersible pump 15 is stopped). After that, a pipe string 13 with a packer 14 and a liner 16 with valves 17 are removed from the production well. Before the heat-insulating composition is pumped into the injection well 1, the coolant is pumped, and the temperature of the injected coolant (water vapor) is raised to the CCGT to 200-250 ° С, for example, to a temperature of 230 ° C. Injection of the coolant at a given temperature allows for the advancement of the heat-insulating composition depending on its physicochemical properties into the reservoir 5 and the replacement of the pores of heavy oil or bitumen generated with the creation of a screen from the heat-insulating composition opposite the horizontal section of the production well, in which the valves 17 are located.

Next, calculate the volume of the insulating composition for injection into the reservoir according to the formula:

,

,

where V _t - injection volume of the insulating composition, m ³ ;

R ₀ is the radius of the created screen, m;

h is the length of the section of perforations, m;

m - formation porosity, unit

and the value of the insulation radius is determined by the formula:

,

,

where Q is the injectivity of the reservoir, m ³ / day.

Calculation example:

h = 50 m - the length of the section of perforations;

m = 0.3 - the porosity of the reservoir, d.ed .;

Q = 160 m ³ / day - injectivity of the reservoir.

Then the value of the radius of the created screen (isolation) is determined by the formula:

.

.

Substituting the formula [2]:

R ₀ = -7 + 1.4 ³ √160 = 0.6 m.

Then, substituting the formula [1], we determine the volume of the insulating composition for injection into the well:

V _t = 3.14 · 0.6 ² · 50 · 0.3 = 16.95 m ³ .

As the heat-insulating composition, any composition having good heat-insulating properties, for example, the inorganic gel-forming composition GALA, which is effective for increasing the coverage of the formation when injecting water or steam in the temperature range of 20-350 ° C, is used. The compositions use the ability of the aluminum salt - urea - water - surfactant system to generate inorganic gel and CO ₂ directly in the formation. A homogeneous aqueous solution containing a gelling system is pumped into the formation. Due to the thermal energy of the formation or the pumped coolant, urea is gradually hydrolyzed, forming CO ₂ and ammonia, the pH of the solution increases, hydrolysis of aluminum ions occurs, as a result, after a certain time, a gel is formed almost instantly in the entire solution volume.

The gelation time depends on the temperature of the formation and the ratio of the components. So, a solution of the GALKA-Thermogel-C composition forms a gel at 200-250 ° C in 10-40 minutes. As a result of gel formation, the permeability of the formation to water is reduced. The degree of permeability reduction is higher, the greater the initial water saturation and permeability of the formation rock. In 2000 IHN SORAN together with AURAT OJSC and HIMECO-GANG CJSC organized the production of a solid commercial form of the GALKA-thermogel composition according to TU 2163-015-00205067-01: GALKA-thermogel-C for temperatures above 70 ° C. The ability of inorganic gel-forming compounds GALKA-thermogel to withstand temperatures of 300-350 ° C allows you to use them to increase the coverage of the reservoir.

As an additional insulating composition, we can give an example of an aqueous solution of polymer mixtures prepared on the basis of HIPAN (hydrolyzed polyacrylonitrite) of the VRP-VO-44-60 grade, which are temperature resistant up to 350 ° C with a polymer concentration in the aqueous solution of 0.5%.

Then, by any known method, for example, (see Fig. 2), the calculated volume of the heat-insulating composition is pumped through the column of casting pipes 18 using the technological packer 19, units CA320, AN500, AN600 or others (not shown in figures 1 and 2) the aforementioned volume of V _t through the column of filling pipes 18 (see figure 2) using buffer fluid through the perforation section 20 of the filling pipes 18 and the filter 7 of the horizontal section 4 of the producing well 2 into the formation 5, and since the conditions for advancement have been previously created heat-insulating composition deep into the formation 5, depending on its physico-chemical properties, the heat-insulating composition fills the pores of the formation 5 opposite the filter 7 and creates a screen 21 of the heat-insulating composition opposite the horizontal section 4 in the production well 2. Then the pipe string 13 (see Fig. 1) with a pump 15 and a shank 16, equipped with valves 17 and a packer 14, are installed in the production well 2. The pump 15 is started and the selection is started from the production well 2. The presence of the screen 21 prevents the breakdown of the coolant in the horizontal section 4 of the production well 2 and resume operation of the temperature valves 17 in the normal temperature mode due to the isolation of heat in the formation 5. At the same time, the coolant begins to be pumped into the injection well 1 (water vapor at a temperature of 180-200 ° C) from the CCGT to the formation 5 along the tubing string 8 through its horizontal perforated section 10 and the filter 6 of the horizontal section 3 of the injection well 1 in the normal mode until all valves 17 located in the liner 16 in the horizontal section 4 of the producing well 2 are closed.

Then, the treatment of the production well 2 with an insulating composition is repeated. The application of this method allows to reduce the cost of preparation of the coolant and heat energy losses of the coolant (by 10-15%) during its injection into a horizontal injection well through the use of heat-insulated pipes, through which steam is injected and the annulus filling the heat-insulated pipes with non-combustible gas, at the same time, the financial costs of preparing the coolant (energy costs for CCGT) are also reduced.

In addition, the proposed method allows to increase the efficiency of the development of a heavy oil or bitumen deposit by creating a screen of a heat-insulating composition opposite the horizontal section of the producing well, in which the valves are placed with a sharp decrease in production volumes (closing the valves), which allows for optimal development of the field with gradual production stocks of heavy oil or bitumen from the reservoir.

Claims (1)

A method of developing a heavy oil or bitumen field, including the construction of an upper injection well and a lower production well with horizontal sections located one above the other and equipped with filters and packers, pumping a heat carrier through a horizontal injection well with heating the formation, creating a steam chamber and taking products through a horizontal producing well with a decrease in selection in areas of the presence of temperature peaks, providing uniform heating of the steam chamber, and inside the filter of the producing well is placed the pump shank with valves depending on the temperature, located opposite the zones of the reservoir, the selection is reduced by automatically closing until the valves are completely closed, in the installation zones of which the temperature of the produced heavy oil or bitumen is 0.5-0, 9 the temperature at which the coolant breaks into the producing horizontal well, characterized in that the packer in the injection well is installed directly just behind the perforated section from the mouth side, and the annular space above this packer is filled with non-combustible gas, after all the valves are closed simultaneously, they are removed from the production well with the pipe string and packer, and the coolant is pumped into the injection column to raise the temperature to 200-250 ° C, after which the insulating composition is pumped in with the volume calculated by the formula

where V _T is the injection volume of the insulating composition, m ³ ;
R ₀ is the radius of the created screen, m;
h is the length of the section of perforations, m;
m - formation porosity, unit
and the value of the insulation radius is determined by the formula

where Q is the injectivity of the reservoir, m ³ / day;
after which the pipe string with valves and a packer is installed in the production well, the coolant injection and production selection of the well are resumed in the normal mode until all valves are shut off, then the treatment of the production well with an insulating composition is repeated.

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