RU1805212C - Process of development of oil fields - Google Patents

Abstract

The invention relates to the oil industry, to the development of oil fields by a mine method using thermal action on the formation. The goal is to increase oil recovery in heterogeneous formations with vertical and steeply inclined fractures. To do this, it passes below the bottom of the oil reservoir; - a mine shaft, Horizontal mine workings pass from the mine shaft, in which drill chambers are constructed at equal distances, From each drill chamber, from the bottom up, they drift fan-shaped sloping, steeply inclined and vertical wells, evenly positioning them over the cross section of the developed reservoir. Break all the wells into groups. The coolant is pumped into separate groups of wells. The entire volume of the developed reservoir is evenly heated. At the same time, oil is taken from the remaining groups of wells. After the formation is heated to a temperature characterized by a minimal decrease in oil viscosity, a displacing agent is pumped into vertical and steep-hole wells with the lowest productivity. In order to increase the rate of oil recovery from the reservoir, the displacing agent is injected at a pressure exceeding the pressure of the coolant. 1 s.p. f-ly, 4 ill. ate

Description

The invention relates to the field of oil field development using a shaft method using thermal action on a formation, in particular to methods for developing heterogeneous fractured formations containing high viscosity oil or mobile bitumen.

An object of the present invention is to enhance oil recovery by applying a method in heterogeneous fractured formations. due to a more complete coverage of its impact process.

Figure 1 shows a section of the reservoir with mine workings and wells.

The vertical shaft 1 extends below the bottom of the oil reservoir 2. From

a shaft mine 1 underneath the oil reservoir 2 runs a horizontal mine 3, in which drill chambers 4 are constructed at equal distances. From each drill chamber, they are drilled fan-shaped half-inclined 5, circular-inclined 6 and vertical wells 7, evenly spaced across them the developed reservoir and their equipment for steam injection and oil recovery. After that, all wells are divided into groups so that the wells of each group uniformly cover the formation.

One of the possible options for dividing wells into groups is shown in Figs. 2 and 3.

Yu

The most optimal is the option (see Fig. 2), in which the wells are divided into two groups a and b.

In this embodiment, the above principle is read in the best manner — the uniform coverage of the formation by heating. In FIG. 3, three groups a, .- are broken.

The amount of rpyrrrt for the injection of heat transfer fluids in each particular case depends on the injection rate, whereas the amount of heat transfer pumped is determined experimentally. .

. After dividing the wells into groups, coolant (steam) is injected with a pressure of 0.2-0.3 MPa in turn into each group of wells. At the same time, wells that are not under injection are used as production wells. As the formation warms up, the duration of the injection cycles is reduced as well. oil production cycles - increase.

Wells in which the temperature has risen to a value above which the viscosity of the oil does not significantly decrease are used only as production wells. .After heating the formation, within the developed area to the indicated temperature, it proceeds to displace the oil remaining in the formation by some displacing agent: produced water, air, water-air mixture, cold water with additives of chemical reagents, etc. - its vertical wells 7 at a pressure of 0.4-0.6 MPa (pressure higher than the pressure of the coolant, which contributes to the most efficient displacement of oil from porous blocks into cracks and wells), while producing oil from other wells, B qual TBE .nagnetatelnyh.ispolzuyut wells with imenschim flow rate, i.e., with minimal productivity,; ,

..Example. The claimed method can be implemented at the Yarega field of the Komi ASSR. The reservoir of this field with an average thickness of 20 m is underlain with bottom water and contains oil with a viscosity of 15 thousand, MPa1 s. The oil-containing reservoir is divided by two mutually perpendicular systems of tectonic disturbances, located on average 20-25 m. The permeability of these zones significantly exceeds the permeability of the pore part of the formation. At the Yaregskoye field, a mine method of oil production is used. -.

Mine shafts 1 are passed up to a tuff horizon located 20-30 m above the top of the oil reservoir (see Fig. 4).

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In the tuffite horizon, horizontal mine workings 2

In order to implement the method under such conditions, it is necessary to pass an inclined projection of 5 to 3 5-6 m below the oil reservoir. A horizontal working mine 4 is constructed under the oil reservoir, from which drilling chambers 5 are built every 60 m. 9 wells are drilled from the chamber, incl.

40 four half-bladed 6, four steeply inclined 7 and one vertical boreholes 8 with a length of 30 to 130 m. All wells to the bottom of the oil reservoir are cased with pipes with a diameter of 14 mm, which are cemented with heat-resistant cement. To pump the heat carrier of the well at 2/3 of the length, a tubing-compressor is equipped. pipes with a diameter of 50-60 mm and are divided into two groups (similar to Figure 2). Then start

.20 injection of steam with a pressure of 0.2-0.3 MPa into five wells of the fan through one, the remaining four wells are used for oil extraction. 30 days later. the steam injection is stopped and the remaining four 25-inch fans are injected, and the steam-treated wells are used for oil production.

After 30 days, the first group of wells is transferred again for steam injection, and the second group of wells is used for the extraction of oil

30 tees. As the formation warms up, the duration of steam injection cycles is reduced from 30 to 10 days, and the production cycles are increased, from 30 to 50 days, Wells in which the temperature has risen to 60-70 ° C are used only as mining ones. .After increasing the average temperature of the reservoir within the developed area to 6Q-70 ° C, steam injection is stopped and about 30% of vertical wells

40

and steeply inclined, they are injected with hot water at a pressure of 0.4-0.6 MPa. For injection use water, simultaneously produced from the reservoir, which is previously separated from the oil in special tanks

5 located in the mine workings. As injection wells, the lowest production wells are used which are least associated with fractures. From the remaining wells selected

0 oil, Development is carried out to increase water cut to 99% .:

. Using the method allows to increase the rate of oil extraction from the reservoir from 11 to 14% and oil recovery from 40 to 47%

5 in comparison with the basic technology currently used at the Yaregskoye field of the Komi Autonomous Soviet Socialist Republic, due to a more complete coverage of the formation by thermal influence, and an increase in the discharge pressure of the displacing agent.

Claims (2)

1. A method of developing oil fields, including pumping coolant into the formation and extracting oil from it through directional and steep-hole wells drilled from a mine located beneath the oil reservoir, so that, with In order to increase oil recovery in heterogeneous formations with vertical and steeply inclined fractures, vertical wells are additionally drilled, all wells are divided into groups, each of which covers the entire volume of the developed formation, the coolant is injected into 0 individual groups of wells evenly heat the entire volume of the developed formation, simultaneously taking oil from the remaining groups of wells, and after heating the formation to a temperature characterized by a minimal decrease in oil viscosity, the displacing agent is pumped into vertical and steep wells with the lowest productivity. 2. A method according to claim 1, characterized in that, in order to increase the rate of oil extraction from the formation, the injection of the displacing agent is carried out at a pressure exceeding the pressure of the coolant injection. firm Option 2 x fig.Z