RU2720850C1 - Development method of super-viscous oil deposit - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and, in particular, to thermal methods for production of ultraviscous oil and/or bitumen. Method includes determination of water-oil contact level, drilling of vertical injection wells and horizontal production wells with opening of sections of these wells located in deposit, pumping of working agent through injection wells and extraction of liquid through production wells. Drilling of horizontal production wells is performed with distances between them in terms of 50–90 m with location in deposit at least by 1 m above foot or level of water-oil contact, equipped with opened sections of wells with filters, vertical pressure wells are drilled between horizontal production wells at distance of 25–45 m from the horizontal well shaft above the beginning of the filter and above the bottom of the production wells, the opened productive intervals in the vertical wells are equipped with filters, according to depth of deposit, maximum pressure is determined, which excludes damage of deposit rock integrity, pumping of working agent through vertical wells is performed in amount of 20–40 t/day, pumping of working agent through horizontal wells is carried out in amount of 60–100 t/day, after heating for two months, horizontal wells are stopped for thermo-capillary impregnation for 1 month, further, horizontal wells are started for liquid extraction till temperature drops down the well shaft below 50 °C and/or oil flow rate to 0.5–1 ton/day at least in one horizontal production well; then, injection and thermo-capillary impregnation are repeated.

EFFECT: higher efficiency of ultraviscous oil deposit development due to enlarging the heating zone of drainage area of the horizontal production well, reduction of the percentage of water cut of the extracted product from the formation due to exclusion of the heat carrier breakthrough into the production well.

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Description

The invention relates to the oil industry and, in particular, to thermal methods for the production of ultra-viscous oil and / or bitumen.

There is a known method of developing a highly viscous oil deposit (patent RU No. 2062865, IPC ЕВВ 43/20, publ. 06/27/1996 in bull. No. 36), in accordance with which vertical injection and horizontal production wells are drilled on a highly viscous oil deposit, the coolant is pumped through injection wells and at the same time periodically through horizontal wells until a coolant breakthrough to vertical production wells. After the coolant breakthrough, a displacing agent is pumped through the injection wells, and sand and formation fluid are selected through horizontal wells.

The disadvantage of this method is that it does not allow to develop an oil reservoir with the achievement of high oil recovery. A quick breakthrough of the coolant from the injection well into the producing well is likely, which reduces its efficiency and increases implementation costs.

Also known is a method of developing a highly viscous oil deposit (patent RU No. 2334095, IPC ЕВВ 43/24, published on 09/20/2008 in bull. No. 26), including drilling vertical injection wells and horizontal production wells, pumping a working agent through injection wells and oil selection through production wells, whereby the horizontal wellbore of the producing well is carried out 1.5-2.5 m above the bottom of the producing formation, the horizontal well is perforated, and the bottom of the vertical injection well is perforated into the horizontal well of the producing well by 3.5-4.5 m the interval of 0.5-1.5 m from the bottom, the vertical injection well is placed from the vertical wellbore of the producing well at a distance greater than 2/3 of the length of the horizontal section of the producing well, up to the end of the horizontal well, while alternating steam is used as a working agent with air.

The disadvantage of this method is the likelihood of a quick breakthrough of the coolant due to the small distance between the bottom of the producing and injection wells (3.5-4.5 m). In this regard, high costs and low efficiency.

Also known is a method of developing a highly viscous oil deposit (patent RU No. 2678739, IPC ЕВВ 43/24, ЕВВ 7/04, Е21В 47/06, published on January 31, 2019 in Bulletin No. 4), including drilling vertical injection wells and horizontal production wells with the opening of sections of these wells located in the reservoir, first, horizontal production wells are drilled with distances between them in the plan of 70-80 m with a location in the reservoir at least 1 m above the bottom or level of the oil-water contact, vertical injection wells are located between the horizontal wells at a distance of 35-40 m from the middle part of the wellbore of producing wells, the maximum pressure is determined by depth, eliminating the violation of the integrity of the reservoir rock, the working agent is injected through injection wells in an amount of 20-40 tons / day, selection through horizontal wells located at the injection well, lead alternately until the temperature decreases along the wellbore below 50 ^o C and / or oil production and up to 0.5-1 t / day in at least one horizontal production well in the reservoir, while the other horizontal production wells are injected with the maximum possible volume at a pressure that excludes the violation of the integrity of the reservoir rock, after which the horizontal wells are stopped for thermocapillary impregnation after which the horizontal wells for injection and selection are changed until the next switchover, then the cycles are repeated.

The disadvantages of the method are the uneven heating of the drainage area of a horizontal well, high material costs for the arrangement of two well sites to accommodate the mouths of horizontal wells.

The closest is a method of developing a highly viscous oil deposit (patent RU No. 2506417, IPC EVB 43/16, published on 02/10/2014 in bull. No. 4), including drilling vertical injection wells and inclined horizontal production wells, pumping a working agent through injection wells and the selection of fluid through the producing wells, while determining the level of water-oil contact - the OWC, producing an inclined horizontal well from the mouth to the bottom, are drilled with a location at least 2-3 m above the level of the OWC, a vertical injection well is drilled with the bottom located above the bottom of the producing well 5-8 m higher, the production well is perforated along the entire length of the inclined section, the vertical injection well is perforated in the formation zone in the direction of the production well mouth, stage by stage, as the working agent breaks out or the product is flooded above 95%, the bottom of the production inclined horizontal well is cut off above the zone breakthrough or flooding, and the opening area of the injection well the springs are cut off from the bottom by 1 / 3-1 / 2 of its entire length; when developing the entire developed zone, the mouth of the producing inclined horizontal well is transferred to pump the working agent.

The disadvantages of the method are the uneven heating of the drainage area of the horizontal production well, the likelihood of a quick breakthrough of the steam injected into the vertical injection well to the bottom of the producing horizontal well.

The technical objectives of the method are to increase the development efficiency of a super-viscous oil deposit by increasing the heating zone of the drainage area of a horizontal producing well, reducing the percentage of water cut of produced products from the reservoir by eliminating the breakthrough of the coolant into the producing well.

Technical problems are solved by the method of developing an extra-viscous oil deposit, including determining the level of water-oil contact, drilling vertical injection wells and horizontal production wells with opening sections of these wells located in the deposits, pumping a working agent through injection wells and taking fluid through production wells.

What is new is that horizontal production wells are drilled with distances between them of 50-90 m in plan with a location at least 1 m above the bottom or level of the oil-water contact, open sections of the wells are equipped with filters, vertical injection wells are drilled between horizontal production wells at a distance of 25-45 m from the horizontal wellbore above the start of the filter and above the bottom of the producing wells, the opened productive intervals in vertical wells are equipped with filters, the maximum pressure is determined by the depth of the reservoir, eliminating the violation of the integrity of the reservoir rock, the working agent is injected through vertical wells 20-40 tons / day, the working agent is pumped through horizontal wells in an amount of 60-100 tons / day, after heating for two months, horizontal wells are stopped for thermocapillary impregnation for one month, then horizontal wells foreigners start the selection of fluid until the temperature in the wellbore drops below 50 ° C and / or the oil production rate reaches 0.5-1 t / day in at least one horizontal production well, then the injection and thermocapillary impregnation cycles are repeated.

In FIG. 1 shows a diagram of the location of wells in the reservoir (top view).

In FIG. 2 shows a layout of horizontal and vertical wells in a reservoir (side view).

The method is implemented as follows.

According to geological data, choose reservoir 1 (Fig. 1) super-viscous oil. Horizontal wells 2 are drilled (Fig. 2) and 2 'with distances between them in the plan of 50-90 m with an arrangement in reservoir 1 of at least 1 m (to prevent steam breakthrough) above the sole 3 (Fig. 1) or level 3 oil-water contact (WOC). The open sections of horizontal wells 2 (Fig. 1) and 2ꞌ (Fig. 2) are supplied with filters 4 (Fig. 1). Vertical injection wells 5 (Fig. 2) and 5ꞌ are drilled between horizontal production wells 2 and 2 'at a distance of 25-45 m from the trunk of horizontal wells 2 and 2' at the beginning of filter 4 (Fig. 1) and closer to the bottom of production wells 2 (Fig. 2) and 2 '. In this case, the opened production interval in vertical wells 5 and 5ꞌ is equipped with filters 4 (Fig. 1). The depth of occurrence of reservoir 1 determines the maximum pressure, eliminating the violation of rock integrity of reservoir 1. The working agent is pumped through vertical wells 5 (Fig. 2) and 5ꞌ in the amount of 20-40 tons / day (the maximum possible amount for vertical wells is 5 and 5ꞌ in deposits 1 superviscous oil), the injection of the working agent through horizontal wells 2 and 2 'is carried out in an amount of 60-100 tons / day.

After warming up by injecting a working agent (for example, steam) for two months, horizontal wells 2 and 2 'are stopped for thermocapillary impregnation for a period of one month. Next, horizontal wells 2 and 2 'are launched to take fluid until the temperature in the wellbore drops below 50 ° C and / or the oil production rate reaches 0.5-1 t / day in at least one horizontal production well 2. When fixing the temperature drop by the wellbore below 50 ° C and / or oil production up to 0.5-1 t / day in a horizontal well, for example, horizontal well 2, it is stopped and transferred to the injection of the working agent for two months, then stopped for thermocapillary impregnation of one the month after which the horizontal well 2 is transferred under fluid sampling until the next cycle. Next, the cycles are repeated.

An example of a specific implementation.

On the Averyanovskoye deposit of super-viscous oil, located at a depth of 141 m, with an average oil-saturated thickness of 10.2 m, reservoir temperature of 9 ° C, pressure of 0.95 MPa, oil saturation of 0.66 units, porosity of 32%, and permeability of 2.9 μm2, with a density of bitumen under surface conditions of 949 kg / m3, viscosity of 15303 MPa, horizontal wells 2, 2 ', 2' ', 2' '' and 2 '' '' were drilled (Fig. 2) with distances between them in plan 50 m, 70 m, 80 m, 90 m, respectively, with a location in reservoir 1 (Fig. 1) at least 1 m above the sole 3 or level 3 of the oil-water contact (WOC). They supply open sections of horizontal wells 2, 2 ', 2' ', 2' '' and 2 '' '' (Fig. 2) with filters 4 (Fig. 1). Vertical injection wells 5 and 5ꞌ, 6 and 6ꞌ, 7 and 7ꞌ, 8 and 8ꞌ (Fig. 2) were drilled between horizontal production wells 2 and 2 ', 2' and 2 '', 2 '' and 2 '' ', 2 '' 'and 2' '' ', respectively, at a distance of 25 m (between production wells 2 and 2'), 35 m (between production wells 2 'and 2' '), 40 m (between production wells 2' 'and 2' ''), 45 m (between production wells 2 '' 'and 2' '' ') from the horizontal wells 2, 2', 2 '', 2 '' 'and 2' '' 'at the beginning of filter 4 (Fig. . 1) and closer to the bottom of production wells 2, 2 ', 2' ', 2' '' and 2 '' '' (Fig. 2). At the same time, the opened production interval in vertical wells 5, 5ꞌ, 6, 6ꞌ, 7, 7ꞌ, 8, 8ꞌ (Fig. 2) was equipped with filters 4 (Fig. 1). The maximum pressure was determined from the depth of occurrence of deposit 1, which excludes the violation of the rock 1. Deposit of the working agent through vertical wells 5 and 5 через, 6 and 6ꞌ, 7 and 7ꞌ, 8 and 8ꞌ (Fig. 2) was carried out in an amount of 20 t / day ( for vertical wells 5 and 5ꞌ, 6 and 6ꞌ), 30 t / day (for vertical wells 7 and 7ꞌ), 40 t / day (for vertical wells 8 and 8ꞌ). The working agent was pumped through horizontal wells 2, 2 ', 2' ', 2' '' and 2 '' '' in the amount of 60 t / day (for horizontal wells 2, 2 ꞌ), 85 t / day (for horizontal wells 2ꞌꞌ, 2ꞌꞌꞌ), 100 t / day (for a horizontal well 2ꞌꞌꞌꞌ).

After warming up with the injection of the working agent for two months, horizontal wells 2, 2 ', 2' ', 2' '' and 2 '' '' were stopped for thermocapillary impregnation lasting one month. Then, horizontal wells 2, 2 ', 2' ', 2' '' and 2 '' '' 'were launched for fluid selection until the temperature in the wellbore dropped below 50 ° C and the oil production rate reached 0.5-1 t / day horizontal wells 2 ', 2' '', 2 '' '' '. In the 2 'well, the temperature decreased to 47 ° С, the flow rate to 1 t / day, in the 2' 'well the temperature decreased to 45 ° С, the flow rate to 0.8 t / day, in the 2' 'well the temperature dropped to 38 ° C, flow rate to 0.7 t / day, in the 2 '' '' well, the temperature decreased to 39 ° C, flow rate to 0.5 t / day. After fixing the temperature drop along the wellbore and / or oil production rate, horizontal wells 2 ', 2' ', 2' '', 2 '' '' were stopped and transferred to steam injection for two months, after which horizontal wells 2 ' , 2``, 2 '' ', 2' '' 'stopped for thermocapillary impregnation lasting one month, after which they started to take the liquid. Next, the cycles were repeated.

The proposed method for the development of a super-viscous oil deposit increases the efficiency of developing a super-viscous oil deposit by increasing the heating zone of the drainage area of a horizontal producing well, and reduces the percentage of water cut of produced products from the reservoir by eliminating the breakthrough of the coolant into the producing well.

Claims (1)

A method for developing a super-viscous oil deposit, including determining the level of water-oil contact, drilling vertical injection wells and horizontal production wells with opening sections of these wells located in the deposits, pumping a working agent through injection wells and taking fluid through production wells, characterized in that the drilling is horizontal producing wells are produced with distances between them in the plan of 50-90 m with a location in the reservoir at least 1 m above the bottom or level of the oil-water contact, they supply open sections of the wells with filters, vertical injection wells are drilled between horizontal production wells at a distance of 25-45 m from the well horizontal wells above the start of the filter and over the bottom of production wells, opened production intervals in vertical wells are equipped with filters, the maximum pressure is determined by the depth of the reservoir, eliminating the violation of the integrity of the reservoir rock, injection of the working agent Without vertical wells, they are carried out in an amount of 20-40 tons / day, the working agent is injected through horizontal wells in an amount of 60-100 tons / day, after heating for two months, the horizontal wells are stopped for thermocapillary impregnation for one month, then the horizontal wells are launched to take fluid to reduce the temperature in the wellbore below 50 ° C and / or oil production to 0.5-1 t / day in at least one horizontal production well, then the injection and thermocapillary impregnation cycles are repeated.

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