RU2496979C1 - Development method of deposit of high-viscosity oil and/or bitumen using method for steam pumping to formation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: development method of a deposit of high-viscosity oil and/or bitumen using a method for pumping of steam to a formation involves construction of the main horizontal production well and a horizontal injection well located above the horizontal one, steam pumping to horizontal wells, and after a permeable zone is created between wells, steam is pumped to the injection well and the product is extracted from the production well. With that, additional horizontal production wells are built, which are located in series and in parallel to the main one. Besides, horizontal production wells are located above the oil-water contact (OWC), but lower than injection well by 5-8 m. With that, distance between working face of one horizontal production well and the roof inlet of the other one in horizontal projection shall not be less than 5 m. Steam is pumped to production wells before the beginning of extraction in the volume of 2-10 t/m of total length of horizontal sections; after that, controlled extraction of the product from production wells is performed so that bottom-hole pressure in each of the production wells cannot be less than formation pressure of bottom water.

EFFECT: preventing flooding of a production well with bottom water, increasing oil recovery of the deposit, preserving high oil flow rate under real conditions of a non-homogeneous formation underlied with bottom water, and increasing water-free operating period of wells.

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Description

The invention relates to the oil industry, thermal methods for producing highly viscous oil and / or bitumen.

The well-known "Method of thermal impact on a reservoir of highly viscous oil and bitumen" (Pat. RF №2287677, IPC ЕВВ 43/24, publ. 11/20/2006), including drilling a horizontal well, drilling an additional horizontal well under a horizontal well within the same reservoir , coolant injection into the upper horizontal well, production of high-viscosity oil from the lower horizontal well.

The disadvantage of this method is the technical complexity of regulating the mode of fluid withdrawal and steam injection.

Closest to the technical nature of the proposed method is the "Method for the development of oil deposits with water-oil zones" (Pat. RF №2387812, IPC E43 / 16, publ. 04.24.2010), including drilling at least one horizontal production and injection wells, injection displacing agent through injection and product selection through production wells. The producing horizontal well is placed parallel to the oil-water contact (WOC) at a distance that allows the well to be operated with an anhydrous period.

The disadvantages of this method are the low efficiency in the operation of reservoirs with underlying water with an uneven horizontal surface of the OWC, which complicates the horizontal wellbore of the producing well at a safe distance from the bottom water and complicates the installation of a mode of fluid withdrawal from the well to prevent pulling formation water to the bottom of the well.

The technical objectives of the proposed method are to prevent flooding of the producing well with bottom formation water, increasing oil recovery of the reservoir, increasing the efficiency of the development of waterfields with highly viscous oils and / or bitumen developed by steam injection into the reservoir.

The problem is solved by the method of developing deposits of highly viscous oil and / or bitumen by steam injection into the formation, including the construction of a horizontal main production well and located above the horizontal injection well, steam injection into horizontal wells, and after creating a permeable zone between the wells, steam is injected into the injection well and selection of products from the producing well.

New is that they build additional horizontal production wells, place them in series and parallel with the main production well, with horizontal production wells located above the oil-water contact (WOC), but 5-8 m below the injection well, while the distance between the bottom of one horizontal production well wells and the entrance to the roof of the other in horizontal projection should be at least 5 m, steam is injected into production wells before the start of selection in the amount of 2-10 t / m of total length horiz onshore sections, after which regulated production is selected from production wells so that bottomhole pressure in each production well is not less than reservoir pressure of bottom water.

Figure 1, 2 shows the layout of the horizontal injection wells 2 and 3 of the horizontal production wells 1, 3, 4, respectively, a top view and in section of the oil reservoir.

The method is implemented as follows.

When developing a reservoir of highly viscous oil and / or bitumen by steam injection into a formation, a horizontal production well 1 is drilled, according to updated geological data, an injection well 2 is located 5-8 m above it, taking into account all the distances, production wells 3, 4 are successively drilled.

Steam is injected into injection and production wells 1, 2, 3, 4 in a volume of 2-10 t / m of the total length of horizontal sections, after which controlled production is produced from production wells so that bottomhole pressure in each production well is not less than reservoir pressure bottom water.

An example of a specific implementation of the method.

A well system was drilled in a section of the Ashalchinskoye field with an average oil viscosity of 25,000 mPa · s, permeability of 2.6 μm ² , porosity of 30%, and a thickness of oil saturated reservoir of 14 m. Horizontal production well 1 was drilled along the bottom of the formation above the oil-field by 2 m, the length of the horizontal part of the trunk is 220 meters. Above 6 m of the horizontal section of well 1, a horizontal injection well 2 was drilled 2 with a horizontal section length of 760 m and two producing horizontal wells 34 with a horizontal wellbore length of 230 and 300 m, located parallel to the wellbore and 5 m below it.

Steam was injected in an amount of 2600 tons into injection well 2 and 700 tons into each production well 1, 3, 4. After stopping steam injection, leveling and lowering the bottomhole temperature in the producing wells to 90 ° C, each of them was converted to mechanized production with the installation of an electric centrifugal pump (ESP) (not shown in the drawing) with a frequency-controlled drive equipped with an automated thermo-manometric system (TMSP) with a set cut-off threshold for pressure at the pump inlet equal to the reservoir pressure bottom water - 0.5 MPa. In injection well 2 resumed the injection of steam in an amount of 80 tons / day. Production wells 1, 3, 4 launched the ESP to put in fluid selection, the average production rate for wells was: 12 t / day for well 1, 20 t / day for well 3 and 23 t / day for well 4, which amounted to 55 t / days with an average water cut of 82%.

For the comparison base, an option was adopted using two parallel drilled (one above the other) horizontal wells with a horizontal wellbore: injection - 750 m, production - 742 m. The results showed that the proposed method is more effective: the maximum oil recovery coefficient is 11% more The obtained maximum oil production rate was 55 tons / day versus 31 tons / day.

The proposed method allows you to effectively apply heat and steam exposure to the reservoir, to maintain a high oil flow rate in real conditions of a heterogeneous formation, lined with bottom water, to increase the anhydrous period of the wells, which contributes to a higher oil recovery rate.

Claims (1)

A method for developing a reservoir of high-viscosity oil and / or bitumen by the method of steam-thermal treatment, including the construction of a horizontal main production well and located above a horizontal injection well, steam injection into horizontal wells, and after creating a permeable zone between the wells, steam is injected into the injection well and production is selected from a production well, characterized in that they build additional horizontal production wells located in series and parallel flax from the main, and horizontal production wells are located above the oil-water contact - VNK, but 5-8 m below the injection well, while the distance between the bottom of one horizontal production well and the other entrance to the roof in a horizontal projection should be at least 5 m, injection steam to the production wells before the start of the selection is carried out in a volume of 2-10 t / m of the total length of the horizontal sections, after which regulated production is selected from the production wells so that the bottomhole pressure in each production it was well least plantar pressure reservoir waters.

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