RU2439306C1 - Development method of deposits of high-viscosity oils and bitumens - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: according to the method, horizontal two-head or one-head well and inclined vertical injection wells are used as production well to increase the formation coverage area during pumping of reagent, for example steam. They are located above horizontal production well in one vertical plane. Then, geophysical investigations of production well are performed and porosity, permeability and oil saturation is determined. As per permeability parameter the zonal heterogeneities are considered, as per which the distance is determined between the bottom of injection well and shaft of horizontal production well. In the zone with minimum permeability there built is inclined vertical injection well with minimum distance but not less than 5 m in order to prevent the steam breakthrough. The distance from the bottom of the rest injection wells to the shaft of production well is determined as per analytical relationship.

EFFECT: increasing the uniform formation warming-up, increasing its coverage due to construction of inclined vertical injection wells with bottoms close to the shaft of production horizontal well with various distance depending on permeability of non-uniform zones.

2 cl, 1 dwg

Description

The proposal relates to the oil industry, and in particular to methods for developing deposits of high viscosity oils and bitumen.

A known method for the development of deposits of viscous oils and bitumen (RF patent No. 2199656, IPC ЕВВ 43/24, publ. Bull. No. 6, 02.27.2003), including drilling rows of vertical injection wells, drilling horizontal wells along rows of vertical wells, periodic injection of coolant for example, steam into horizontal wells and oil extraction from vertical production wells, while during the period of termination of steam injection, oil is taken from horizontal wells, which are a source of steam breakthrough into vertical wells. After the development of the reservoir in the area of the bottom-hole zones of all wells, they switch to areal injection of a displacing agent, for example, water, into vertical injection wells. At the same time, oil is taken from the remaining wells. Before the areal injection of the displacing agent, horizontal wells located near the vertical injection wells are filled with an insulating composition, for example, a gel-forming one.

The known method allows you to perform coverage by exposure to a large area of the reservoir, however, in this case, undeveloped zones remain in the inter-well space.

The closest in technical essence and the achieved result is a method of developing a highly viscous oil deposit (RF patent No. 2334098, IPC ЕВВ 43/24, published September 20, 2008), including drilling vertical injection wells and horizontal production wells, pumping a working agent through injection wells and selection of oil through production wells. Next, the horizontal trunks of two production wells are placed on the same line towards each other with the placement of faces close to one another, horizontal trunks are carried out 1.5-2.5 m above the bottom of the reservoir and perforated above the bottoms of horizontal trunks of production wells by 3.5- 4.5 m and place the bottom of a vertical injection well, perforated in the range of 0.5-1.5 m from the bottom, parallel to the horizontal line of production wells, horizontal deposits of other horizontal wells with those e parameters and with the same arrangement of the injection well, forming parallel lines of selection and discharge of the working agent, wherein as the working agent vapor is used in alternation with air.

The disadvantages of the method are uneven heating of the reservoir, as well as the incomplete production of reservoir products.

The technical tasks are uniform heating of the formation, increasing its coverage due to the construction of directional-vertical injection wells with faces close to the trunk of the producing horizontal well, with different distances depending on the permeability of heterogeneous zones.

The technical problem is solved by a method, including the construction of a horizontal production well and injection wells, the faces of which are located above the horizontal well, pumping the coolant into the injection wells and selecting production from the production well.

What is new is that during the construction of a horizontal well, zones with a 200 to 1000 mD different permeability are determined, a zone with a minimum permeability is chosen, in which injection wells are built with a face located above the production well at the minimum allowable distance, which excludes coolant breakthrough, and in other areas, injection wells are being built with a face located above the producing one at a distance determined by the formula:

h _x = (K _x · h _min ) / K _min ,

where h _x is the distance from the bottom of the injection well to the producing well in the zone with permeability K _x , m;

h _min - the minimum distance from the bottom of the injection well to the producing well in the zone with minimal permeability, m;

To _x - permeability in the area where the construction of injection wells, MD;

K _min - the minimum permeability in the zone with h _min , MD.

Also new is that injection wells are being constructed in the form of directional wells.

The drawing shows a layout of horizontal production and directional vertical injection wells.

The method of developing deposits of viscous oils and bitumen is carried out in the following way.

At the sole of the reservoir 1 (drawing), a single well or double mouth horizontal production well 2 is drilled through which the production will go. Next, geophysical surveys are conducted along well 2, and porosity, permeability, and oil saturation are determined. According to the permeability parameter, we take into account zonal inhomogeneities, which will determine the distance h (drawing) between the bottom of injection wells 3 and the horizontal well of production well 2. In the zone with the lowest permeability above production well 2, we construct an inclined vertical injection well 3 with the smallest distance h, but at least 5 m to avoid steam breakthrough.

Further, from the obtained data, a formula can be derived that determines the distance from the bottom faces of inclined-vertical injection wells 3 to the trunk of the producing well 2:

h _x = (K _x · h _min ) / K _min ,

where h _x is the distance from the bottom of the injection well to the producing well in the zone with permeability Kx, m;

h _min - the minimum distance from the bottom of the injection well to the producing well in the zone with minimal permeability, m;

To _x - permeability in the area where the construction of injection wells, MD;

To _min - the minimum permeability in the zone with h _min , MD.

Using this formula, we find for the remaining injection wells 3 the distance from the bottom to the trunk of the producing well 2.

The implementation of this method will consider a specific example. A horizontal production well 2 was drilled from the roof of the formation 1 to the entire depth, zones with different permeability were brought out. Studies have shown that the site consists of three zones with average permeability for each zone K ₁ = 500 mD, K ₂ = 750 mD and K ₃ = 1000 mD (drawing). The permeability K _{2 of the} second zone and K _{1 of the} first zone differs 1.5 times, the permeability K _{3 of the} third zone differs from K _{1 of the} first zone by 2 times, therefore, the distance from the bottom of the injection wells for uniform heating of the formation should be different.

In the zone with the lowest permeability of 500 mD, we take the distance from the bottom of the injection well 3 to the trunk of the producing horizontal well 2 equal to h ₁ = 5 m to reduce the heating time of the formation in the area of the barrel of the producing well 2.

For the other two deviated vertical injection wells 3, using the formula (see above), we find h ₂ and h ₃ .

h ₂ = (K ₂ · h _min ) / K ₁ = (750 mD · 5 m) / 500 mD = 7.5 m.

For injection well 3, the operation of which will be carried out in an area with a permeability of 750 mD, the distance from the bottom will be 7.5 m.

h ₃ = (K ₃ · h _min ) / K ₁ = (1000 mD · 5 m) / 500 mD = 10 m.

For injection well 3, the work of which will be carried out in an area with a permeability of 1000 mD, the distance from the bottom will be equal to 10 m

Thus, using this method, we determined the distances from all faces of deviated vertical wells to the trunk of the producing horizontal well, which ensured uniform heating of the formation in each heterogeneous zone of the site in terms of permeability, and increased the coverage of the impact of injection wells.

The application of this method makes it possible to uniformly warm up the formation and increase its coverage due to the construction of directional vertical injection wells with faces close to the trunk of the producing horizontal well with a different distance depending on the permeability of inhomogeneous zones.

Claims (2)

1. A method of developing deposits of high viscosity oils and / or bitumen, including the construction of a horizontal production well and injection wells, the faces of which are located above the horizontal well, pumping coolant into the injection wells and selecting production from the production well, characterized in that during the construction of a horizontal well determine zones with 200–1000 mD permeability differing from each other, a zone with a minimum permeability is chosen in which an injection well is built with a bottom hole, located above the production with the minimum permissible distance, excluding the breakthrough of the coolant, and in other areas, injection wells are built with a face located above the production at a distance determined by the formula:
_{h x = (K x · h} min) / K min,
where h _x is the distance from the bottom of the injection well to the producing well in the zone with permeability K _x , m;
h _min - the minimum distance from the bottom of the injection well to the producing well in the zone with minimal permeability, m;
To _x - permeability in the area where the construction of injection wells, MD;
K _min - the minimum permeability in the zone with h _min , MD. 2. The method according to claim 1, characterized in that the injection wells are built in the form of directionally directed.

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