RU2287677C1 - Method for extracting oil-bitumen deposit - Google Patents

Abstract

FIELD: oil industry, possible use for extracting a deposit of high viscosity and bituminous oil.

SUBSTANCE: in accordance to method, two-mouth horizontal well is built. Above extractive two-mouth horizontal well in parallel to it, forcing two-mouth horizontal well is built. Penetration zone is formed between wells due to forcing of water steam into both wells. After creation of penetration zone, steam is fed only into forcing two-mouth horizontal well, while product is extracted from extracting two-mouth horizontal well. Dryness degree of steam being forced in is periodically alternated. Firstly, high dryness steam is forced in to increase performance of forcing two-mouth horizontal well and share of steam in product being extracted, then low dryness steam is forced in, volume of which is determined on basis of increase of forcing pressure, which is maintained at level not exceeding opening pressure of vertical cracks. Product is extracted from extracting two-mouth horizontal well until full depletion of productive bed.

EFFECT: increased pace of warming-up, oil extraction and decreased energy costs of thermal effect process.

1 tbl, 3 dwg

Description

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

A known method of operating a two-well horizontal well, which includes opening a productive formation saturated with highly viscous oil or bitumen, a horizontal well and fixing it with a casing production string, wellhead equipment, perforation and well development. After installing the equipment for the selection of hydrocarbons at the second wellhead, the well is developed and production begins from the mouths, and when the waterflood circuit approaches the packer installation site, the in-pipe production casing in the packer installation interval is closed, for example, with a polymer swab, and the mouth located on the side opposite to the direction of movement water flooding, used to inject a liquid or gaseous agent to maintain reservoir pressure, and the opposite mouth - for coal mining hydrogens (RF patent No. 2159317, class E 21 B 43/20, publ. 2000.11.20).

The known method has a low lifting efficiency of viscous oils or bitumen, as it is characterized by a discrete mode of lifting products, which is associated with the use of natural energy of the reservoir.

A known method of developing deposits of highly viscous oil or bitumen, including drilling a two-mouth horizontal well, securing it with a production string, dragged from one wellhead along the trunk to another together with packers for installing the latter in the roof of a productive formation, lifting and supplying oil to a flow line at one of the mouths wells. The wellhead sections of the production casing are interconnected by a ground section in the form of an arcuate pipeline with an identical inner diameter to form a closed channel, the above ground section of which is fixed to the supporting frame of the drive unit. To do this, in the production casing place an additional casing, performing the function of a tubing in the underground part and having perforation channels for communication with the reservoir. A system of cylindrical elements interconnected by means of power rods with the formation of a closed traction system is installed in the cavity of the additional column at equidistant distances from each other. The sections of the underground part of the tubing string from the wellhead to the boundaries of the perforation section of the production string together with the said cylindrical elements form piston pumping pairs. During operation, a system of cylindrical elements is forcedly moved using a drive unit with continuous successive oil displacement from the tubing string by means of the piston pump pairs mentioned above (RF Patent No. 22600600, class E 21 V 43/24, publ. 2005.02.10 )

The known method does not allow to develop a reservoir with high oil recovery due to the small flow of highly viscous reservoir fluids into the well.

Closest to the proposed invention in technical essence is a method of developing an oil field, including drilling a continuous (double-well) well with the formation of its output section upward with an inclination from the reservoir to the surface, installing a casing in the drilled well, cementing the annulus along the entire length, perforation of the casing in the interval of the horizontal section, installation of tubing with centralizers inside the casing, supply of t plonositelya the column tubing with the inlet and outlet sections, the selection of the product at the outlet portion with continued pumping coolant through an input section (RF patent №2211318, Cl. E 21 B 43/24, publ. 27.08.2003).

The main disadvantage of this method is the lack of oil recovery, because when steam is injected and oil is simultaneously withdrawn from one well, steam breaks out quickly, and during cyclic exposure, the steam is unproductive for re-heating the cooled reservoir during the selection period, i.e. high energy consumption.

The proposed method solves the problem of increasing the rate of heating, oil recovery and reducing energy costs for the process of heat exposure.

The problem is solved in that in a method for developing an oil and bitumen deposit, including the construction of a producing double-well horizontal well and product selection, according to the invention, a double-well horizontal horizontal well is built parallel to it, a permeable zone between the wells is built above the producing double-well horizontal well, by creating water vapor in both wells, after creating the permeable zone, steam is supplied only to the injection double-well horizontal well, and along the producing double-well a horizontal well is sampled, while the degree of dryness of the injected steam is periodically alternated, first steam of a high degree of dryness is pumped up to increase the injectivity of the injection double-well horizontal well and the proportion of steam in the selected product, and then steam of low degree of dryness is pumped, the volume of which is determined by the increase in the injection pressure, which is supported not exceeding the pressure of the opening of vertical cracks, and the products are taken along the producing double-mouth horizontal well to the floor Second generation productive formation.

The features of the invention are:

1. construction of a producing double-mouth horizontal well;

2. selection of products;

3. above the producing double-mouth horizontal well parallel to it, the construction of the injection double-mouth horizontal well;

4. creating a permeable zone between the wells by injecting water vapor into both wells;

5. after creating the permeable zone, steam is supplied only to the injection double-well horizontal well;

6. for the production double-wellhead horizontal well, the selection of products;

7. periodic alternation of the degree of dryness of the injected steam;

8. first, the injection of steam with a high degree of dryness to increase the injectivity of the injection double-well horizontal well and the proportion of steam in the selected product;

9. injection of steam of low degree of dryness, the volume of which is determined by increasing the discharge pressure, which is maintained not exceeding the pressure of the opening of vertical cracks;

10. selection of products for a producing two-well horizontal well to the full development of the reservoir.

Signs 1, 2 are common with the prototype, signs 3-10 are the essential distinguishing features of the invention.

SUMMARY OF THE INVENTION

The development of deposits of high-viscosity and bitumen oil is characterized by a low rate of selection and oil recovery. The objective of the invention is to increase the rate of heating of the reservoir, increasing the coefficient of oil recovery and formation coverage by thermal exposure and displacement.

In Fig.1-3 presents a diagram of the implementation of the proposed method: Fig.1 - the operation of post-mouth pairs of wells with access to the surface, Fig.2 - the installation of equipment for heating the reservoir, in Fig.3 - the operation of pumping the coolant and selection product.

Legend: 1 - reservoir; 2 - injection double-well horizontal well; 3 - producing double mouth horizontal well; 4 - conductor; 5 - perforated casing; 6 - centralizer; 7 - column tubing; 8 - packer; 9 - steam generator; 10 - swab pump; 11 - installation of the winding rope of the swab pump.

The method is carried out in the following sequence.

A pair of horizontal well wells is drilled at a high-viscosity oil field (Fig. 1), which consists of an injection well 2 and a production well 3 lying in the formation 1 below the level of the injection well 2, with the formation of output sections upward with an inclination from the productive formation 1 to the day surface . The conductor 4 is installed from the surface to the top of the producing formation 1, the annulus is cemented, the perforated casing 5 with centralizers 6 is lowered, and inside the casing pipe from each wellhead of the tubing 7 with packers 8 is installed. A permeable zone is created between the two-well horizontal injection well 2 and producing double-mouth horizontal well 3 by injecting steam into injection well 2 and producing well 3 through a string of tubing 7 from the input and output sections. Steam is generated by the steam generator 9 at a pressure equal to or greater than the lateral rock pressure at which vertical cracks open. Steam through the cracks enters the zone between wells 2 and 3. Accelerated heating of the formation 1 occurs. After the pressure is removed, the cracks close, the coverage of the formation 1 with heat increases. After creating a permeable zone, the coolant is supplied only to the injection well 2 (figure 2), and the degree of dryness of the injected steam is periodically alternated.

First, a coolant is injected into the formation 1 — steam of a high degree of dryness, which, at the working pressure of injection, due to high mobility mainly enters the highly permeable part of the productive formation 1, covering the formation 1 unevenly.

With an increase in injectivity of injection well 2 and the proportion of steam in the selected products of producing well 3, they switch to injecting steam of a low degree of dryness. Vapor of low degree of dryness with a high content of the liquid phase is introduced into the highly permeable interval of the formation 1 heated by steam of a high degree of dryness and, as the liquid phase, helps to reduce the permeability of this interval for the gas phase, clogging it, resulting in coverage by the influence of other intervals of the formation 1. Required volume steam of a small degree of dryness injected into the well is determined by the change (increase) in the injection pressure, which should not exceed the opening pressure of vertical cracks.

Then they switch to the injection of steam with a high degree of dryness of the steam, which fills the free interval of the formation 1, as a result, a new interval of the formation 1 is involved in the heating, thereby increasing the coverage of the formation by impact and displacement.

The product is taken through a production well 3 by transporting it with a piston to the surface along a casing 5 having two exits to the surface. The selection of products lead to the complete development of the reservoir 1. An example of a specific implementation

The Ashalchinskoye bitumen oil field is being developed. At the Ashalchinskoye field, located at a depth of 90 m, represented by heterogeneous formations 1 with a thickness of 20-30 m with a temperature of 8 ° C, a pressure of 0.5 MPa, oil saturation of 0.70 units, a porosity of 30%, and a permeability of 0.265 μm ² , s oil, having a density of 956 kg / m ³ and a viscosity of 12206 MPa · s, drill a couple of wells (Fig. 1), which consists of an injection well 2 and a production well 3, which lies in a deposit below the level of an injection well 2, with the formation of output sections up with a slope from the reservoir 1 to the surface, set to nduktor 4 from the surface to the producing formation roof. Then the annulus is cemented, the perforated casing 5 with centralizers 6 is lowered and installed inside the casing from each mouth of the tubing string 7, centered by packers 8. Injection is carried out along the tubing string 7 from the inlet and outlet sections (Fig. 2 ) coolant - steam at a pressure of 2.1 MPa, which is equal to the lateral mountain pressure. In this case, vertical cracks open, through which steam enters the zone between wells 2 and 3. An accelerated heating of the formation 1 occurs. After the pressure is removed, the cracks close, the coverage of the formation 1 with heat increases, thereby creating an extensive permeable zone. Next, the coolant is supplied only to the injection well 2 (figure 3), and the degree of dryness of the injected steam is periodically alternated.

First, a coolant is injected into the reservoir 1 — steam of a high degree of dryness equal to 0.8-0.9 units, which, at the working pressure of 0.8 MPa, due to its high mobility, mainly enters the highly permeable part of the reservoir 1, covering the formation unevenly one.

With an increase in injectivity of injection well 2 and the proportion of steam in the selected products of producing well 3, they switch to injecting steam with a low degree of dryness equal to 0.2-0.4 units. Steam of low degree of dryness with a high content of the liquid phase is introduced into the highly permeable interval of the formation 1 heated by steam of a high degree of dryness and clogs it. The injection of steam with a low degree of dryness is stopped when the pressure rises to 2.1 MPa and they are transferred to the injection of steam with a high degree of dryness of steam equal to 0.8-0.9 units, which fills the free interval of the formation 1.

After creating a permeable zone, products are selected for production well 3 by transporting it to the surface using a piston along the casing 5, which has two exits to the surface. The selection of products lead to the complete development of the reservoir 1.

Due to the flow of coolant from the input and output sections of the producing 3 and injection 2 wells at a pressure equal to or greater than the lateral mountain, heating of the formation 1 is accelerated; due to a periodic change in the degree of dryness of the supplied steam, the coverage of formation 1 by exposure increases, formation 1 is uniformly produced and, as a result, oil recovery is significantly increased. The rate of selection of bitumen oil due to the acceleration of heating the reservoir increased from 1.3% to 5.9% of the recoverable oil reserves, the cost of steam for heating the reservoir decreased by 35% compared with the prototype.

Comparison of the effectiveness of the proposed method is shown in the table. From the table it follows that the proposed method allows to obtain an additional 162.5 thousand tons oil.

Application of the proposed method will increase the rate of heating, oil recovery and reduce energy costs for the process of heat exposure.

Technical and economic effectiveness of the proposed method Indicators Prototype The proposed method Balance reserves, thousand tons 590 590 The average oil flow rate, t / day 8 17 The coefficient of coverage of the reservoir impact, unit 0.40 0.70 The coverage coefficient of the formation by water flooding, d.ed. 0.55 0.80 The displacement factor, unit 0.50 0.68 Oil recovery ratio, unit 0.11 0.38 Recoverable oil reserves, thousand tons 65 224 Additional oil production, thousand tons - 162.5 The value of additional oil production, million rubles - 1055 Costs, million rubles - 44.0 National economic effect, million rubles - 1011.0

Claims (1)

A method for developing an oil and bitumen deposit, including the construction of a production double-well horizontal well and production selection, characterized in that an injection double-well horizontal well is built parallel to it above the producing double-well horizontal well, creating a permeable zone between the wells by injecting water vapor into both wells, after creating the permeable zone steam is supplied only to the injection double-well horizontal well, and through the producing double-well horizontal well production is taken, while the degree of dryness of the injected steam is periodically alternated, first, steam of a high degree of dryness is pumped up to increase the injectivity of an injection double-well horizontal well and the proportion of steam in the selected product, and then steam of a low degree of dryness is pumped, the volume of which is determined by the increase in the injection pressure, which is maintained not exceeding the pressure of the opening of vertical cracks, and the products are taken along the producing two-mouth horizontal well until the full production of formation.

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