RU2273729C1 - Method for highly-viscous oil or bitumen deposit development - Google Patents

Abstract

FIELD: hydrocarbon deposit development with double-head wells.

SUBSTANCE: method involves drilling double-head well; casing thereof with production string and extracting product from well alternately with heat carrier injection. Heat carrier is injected through the first well head up to heat carrier appearance through the second well head. Product is extracted from the first head up to temperature reduction to 20-40°C. Then heat carrier is injected through the second head up to heat carrier appearance from the first head and product is extracted through the second well head up to temperature reduction to 20-40°C. Above operations are repeated up to full recovery of deposit reserves.

EFFECT: increased oil recovery.

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Description

The invention relates to the field of development of hydrocarbon deposits by double-well wells and can be used for the production of highly viscous oil or bitumen.

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 mastered and production starts from the mouths, and when the waterflood circuit approaches the packer installation site, the in-pipe production casing in the packer installation interval is blocked, for example, with a polymer swab and the mouth located on the side opposite to the direction of the circuit movement water flooding, used to inject a liquid or gaseous agent to maintain reservoir pressure, and the opposite mouth for coal mining odorodov (. Russian Patent №2159317, 21 cl E 43/20, published 2000.11.20 -. prototype).

The known method provides an increase in hydrocarbon production by increasing the flow area of the production casing, at least twice. However, the 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.

Closest to the proposed invention in technical essence is a method of developing deposits of highly viscous oil or bitumen, including drilling a two-well 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 the reservoir, lifting and feeding oil in the flow line at one of the wellheads. 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, the system of cylindrical elements is forcedly moved using a drive unit with continuous sequential oil displacement from the tubing string by means of the piston pump pairs mentioned above (RF Patent No. 22246001, class E 21 V 43/24, publ. 2005.02.10.10 - prototype).

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.

The proposed method solves the problem of increasing oil recovery deposits.

The problem is solved in that in a method for developing a highly viscous oil or bitumen deposit, including drilling a double-well well, securing it with a production casing, selecting products from the well, according to the invention, the products are selected alternately with the coolant being pumped, for which the coolant is pumped through the first wellhead until the coolant exits through the second wellhead, products are taken through the first wellhead until the temperature drops to 20-40 ° C, the coolant is pumped through the second wellhead until the coolant comes out of the first wellhead selected products via the second wellhead temperature to decrease to 20-40 ° C, injecting and selection in this mode is continued until the production of reserves deposits.

The features of the invention are:

1) drilling a double-well well;

2) securing the well with a production casing;

3) selection of products from the well;

4) selection of products alternately with the injection of coolant;

5) coolant injection through the first wellhead until the coolant exits through the second wellhead;

6) selection of products through the first wellhead until the temperature drops to 20-40 ° C;

7) coolant injection through the second wellhead until the coolant exits through the first wellhead;

8) selection of products through the second wellhead until the temperature drops to 20-40 ° C;

9) injection and selection before the development of reserves of deposits.

Signs 1-3 are common with the prototype, signs 4-9 are the essential features of the invention.

SUMMARY OF THE INVENTION

When developing a reservoir of highly viscous oil or bitumen, the task of increasing the oil recovery of a deposit is especially urgent. The solution to the problem is complicated by the high viscosity of formation fluids and the complexity of heat supply to productive formations. The use of double-well wells allows the coolant to be pumped and products taken in a cyclic mode, which determines the achievement of high oil recovery.

A two-well well is secured with a production casing. The production string is perforated in the interval of the reservoir. Through the first mouth, a string of tubing is lowered into the well to the roof of the reservoir. A coolant - water vapor with a temperature of 150-200 ° C is pumped into the well through a tubing string. Steam injection is continued until water appears at the second wellhead. Stop the steam injection, lower the tubing string to the bottom of the well, and take the product along the tubing string through the first wellhead. Initially, the temperature of the product is high. Gradually, as the reservoir cools down, the temperature of the product decreases. When the temperature drops to 20-40 ° C, the selection of products is stopped. Raise the tubing string from the well. The tubing string is lowered into the well through the second wellhead to the top of the reservoir and steam is pumped through it until water appears at the first wellhead. The steam injection is stopped, the tubing string is lowered to the bottom of the well, and the products are taken along the tubing string through the second wellhead until the temperature drops to 20-40 ° C. In this mode, injection and selection are continued until reserves are depleted.

This technology allows you to select products directly from the heated place of the reservoir, which increases the oil recovery of the reservoir.

Concrete example

A highly viscous oil reservoir is developed with the following characteristics: average depth - 200 m, initial reservoir temperature - 8 ° C, reservoir pressure - 0.1 MPa, reservoir thickness - 26 m, reservoir porosity - 26%, permeability - 3 μm ² , oil saturation - 87%, oil viscosity -12000 mPa · s, oil density - 933 kg / m ³ .

A two-mouth well is drilled into the deposits with a distance between the mouths of 100 m. The main part of the well is drilled at the bottom of the productive formation at a depth of 213 m. The well is fixed with a production casing. The production string is perforated in the interval of the reservoir. A column of tubing is lowered into the well through the first wellhead to the top of the reservoir at a depth of 187 m. A coolant — water vapor at a temperature of 200 ° C — is pumped into the well along the tubing string. Steam injection is continued for 50 days, i.e. before the appearance of water at the second wellhead. The steam injection is stopped, the tubing string is lowered to the bottom of the well at a depth of 213 m, and the products are taken from the tubing string through the first wellhead. Initially, the product temperature is 90 ° C. When the temperature drops to 20 ° C, the selection of products is stopped. Raise the tubing string from the well. The tubing string is lowered into the well through the second wellhead to the top of the reservoir at a depth of 187 m and steam is injected through it at a temperature of 200 ° C until water appears at the first wellhead. The steam injection is stopped, the tubing string is lowered to the bottom of the well at a depth of 213 m, and the products are taken along the tubing string through the second wellhead until the temperature drops to 20 ° C. In this mode, injection and selection is continued for 5 years before the development of reserves.

As a result of the development of the reservoir area, the achieved oil recovery is 93%, while the evaluation of oil recovery from the prototype is 50%.

The application of the proposed method will improve oil recovery deposits of highly viscous oil or bitumen.

Claims (1)

A method for developing a reservoir of high-viscosity oil or bitumen, including drilling a double-well well, securing it with a production casing, selecting products from the well, characterized in that the selection of products is carried out alternately with the injection of coolant, for which the coolant is pumped through the first wellhead until the coolant exits through the second wellhead, the products are taken through the first wellhead until the temperature drops to 20-40 ° C, the coolant is pumped through the second wellhead until the coolant exits through the first wellhead, from production is taken through the second wellhead until the temperature drops to 20-40 ° C, injection and selection in this mode continue until the reservoir is depleted.