RU2663627C1 - Method of super-viscous oil field development - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to oil industry. Method for developing a super-viscous oil deposit includes constructing a horizontal production well above the water-oil contact or the bottom of the formation above which an injection well is built, drilling additional wellbores from the horizontal section of a well, the distance between the additional wellbores being determined taking into account the technological capabilities of drilling equipment for their wiring, equipping the horizontal section of the production well with a filter, pumping the coolant into both wells prior to heating the interwell space of a reservoir, injection of coolant into an injection well and withdrawal of products from a production well. Hydrodynamic studies are carried out, on the basis of which additional wellbores are drilled upwards sequentially in different directions relatively to the injection well from the production well, to exclude the breakthrough of steam from the injection well, while the bottoms of additional wellbores are located above the producing well by at least 2 m.EFFECT: higher efficiency due to increase in the area of coverage of a super-viscous oil deposit.1 cl, 2 dwg, 1 ex

Description

The invention relates to the oil industry and, in particular, to the development of deposits of super-viscous oil using heat to heat the reservoir.

A known method for the development of deposits of super-viscous oil (patent RU 2531412, IPC ЕВВ 43/24, published on 10/20/2014), comprising drilling a pair of horizontal upper injection and lower producing wells, the horizontal sections of which are placed parallel to each other in a vertical plane, heating the formation by injection steam in both wells with the formation of a steam chamber, heating the inter-well zone of the formation, reducing the viscosity of super-viscous oil, injecting steam into the upper horizontal injection well and taking products from the lower horizontal production borehole. According to the invention, the formation is heated by injecting steam into both wells until the vapor-oil ratio is stabilized. After that, three modes of development of a super-viscous oil deposit are used alternately. The first mode involves injecting steam into the injection well and holding it in the formation for 48-72 hours. The second mode involves the injection of propylene glycol into the production well at the rate of 5 m3 per 100 m of the horizontal section of the production well with a basic substance content of at least 98% with holding in the reservoir for 12-24 hours and simultaneous circulation of water vapor in the injection well. The third regime includes the production of highly viscous oil from a producing well until the steam-oil ratio increases by 1.5 times. 1 ave.

The disadvantage of this method is the narrow scope, as it can be used effectively within lithologically sustained vertically and in the area of the reservoir with uniform oil saturation

Also known is a method of developing a layered-zonal-heterogeneous reservoir of highly viscous oil or bitumen (patent RU 2295030, IPC ЕВВ 43/24, published March 10, 2007), including the construction of a producing multi-mouth horizontal well with additional lateral shafts passing under a clay layer, and above it parallel to the producing multi-mouth horizontal well of the injection two-mouth horizontal well with additional ascending branched shafts that pass through the clay interbed, creating a pron the required zone between the wells by injecting the water coolant into both wells, first, steam of a low degree of dryness (with a higher gas content) is pumped up to increase the injectivity of a multi-well horizontal injection well and the proportion of associated water in the product being taken, and then steam of a high degree of dryness (gas) is pumped low fat content), the volume of which is determined by increasing the injection pressure, which is maintained not exceeding the pressure of the opening of vertical cracks, after creating a permeable zone, the flow of Carrier is produced only in the injection multi-mouth horizontal well, and production is selected from the producing multi-mouth horizontal well, products are selected from the producing multi-mouth horizontal well until the reservoir is fully developed, in addition, vertical wells passing through the clay interlayers are additionally drilled, and they are used as in as a transport channel for filtering steam (gas) above a clay bed and creating a vapor (gas) oil bath, t and to the supply of products withdrawn downwards.

The disadvantages of this method are the high material costs, since multi-well wells are required to be drilled, while the drilling and arrangement of vertical wells is also necessary.

The closest in essence and the achieved result is (patent RU 2582251, IPC ЕВВ 43/24, published on 04/20/2016) a method for developing a layer-zone-heterogeneous reservoir of highly viscous oil or bitumen involves determining two reservoir formations separated by a low-permeable layer in the reservoir . In the lower layer above the oil-water contact, a horizontal production well is built. In the upper producing formation, an injection well is constructed with additional descending shafts, from which additional descending shafts are built through sections of low-permeability formations with opening of a low-permeable interlayer and additional descending shafts through sections of high-permeability formations to hydrodynamic communication or connection with the producing well. The distance between the additional descending shafts is determined taking into account the technological capabilities of the drilling equipment for their wiring, as well as with the possibility of placing filters with adjustable transmission between them, lowered into the injection well on a string of pipes located opposite additional shafts not connected to the producing well, and packers, isolating the annulus of the injection well between the additional shafts and above the filters. The amount of injected coolant and selected products is determined from the properties of the exposed formations in each additional wellbore due to adjustable filters.

The disadvantages of this method are

- a large risk of steam breakthrough along the sidetracks into the production well located in the same plane as the injection well;

- insufficient oil recovery due to the drilling of ascending trunks directly above the main trunk.

The technical task of the proposal is to increase the development efficiency of a super-viscous oil deposit by increasing the coverage area of a super-viscous oil deposit by drilling ascending additional shafts from a producing well that are sequentially multidirectional with respect to the injection well with the exception of the breakthrough of steam from the injection well.

The technical problem is solved by the method of developing a super-viscous oil reservoir, including the construction of a horizontal oil well in the reservoir above the oil-water contact or the sole of the reservoir, above which an injection well is built, drilling additional trunks from the horizontal section of the well, and the distance between the additional trunks is determined taking into account the technological capabilities of the drilling equipment for their wiring, equipment of the horizontal section of the producing well with a filter, pumping coolant into both wells before heating the inter-well space of the reservoir, pumping the coolant into the injection well and taking products from the producing well.

What is new is that hydrodynamic studies are carried out, on the basis of which additional shafts are drilled ascending sequentially multidirectional relative to the injection well from the producing well so that steam breakthrough from the injection well is avoided, while the faces of the additional shafts are positioned at least 2 m above the producing well.

In FIG. 1 shows the location of injection and production wells (top view).

In FIG. 2 shows a longitudinal arrangement of injection and production wells.

A horizontal injection well 1 (FIGS. 1 and 2) located one above the other and a production well 2 with sidetracks 3 in an oil reservoir 4 (FIG. 2) are drilled. In this case, the horizontal sections of the upper injection well 1 and production well 2 are located in the formation 4 in parallel one above the other in a vertical plane. Before drilling additional shafts 3 (FIGS. 1 and 2) from production well 2, hydrodynamic studies determine the distance at which steam breakthrough from injection well 1 to production 2 is least likely. Based on these studies, from a horizontal section of production well 2, they are drilled sequentially in different directions from injection well 1 (Fig. 1) ascending additional trunks 3 (Fig. 2) so that the faces of additional trunks 3 are located at least 2 meters above the producing well. After that, the horizontal section of the production well 2 is equipped with a sand filter (not shown in FIGS. 1 and 2).

Steam is injected into production 2 (Fig. 1) and injection 1 wells and a steam chamber is created in formation 4, the inter-well zone of the formation is heated between the horizontal sections of the upper injection 1 and lower production 2 wells, and water vapor injected into the formation due to the difference in density tends to the upper part of the oil saturated interval of the reservoir 4, creating an increasing in size steam chamber. Heating the formation 4 leads to a decrease in the viscosity of the oil, and it acquires mobility. Heat exchange occurs at the interface between the steam chamber and the cold zones of oil-saturated thicknesses, as a result of which steam condenses into water, which, together with the heated oil, moves to production well 2 with additional shafts 3. The presence of additional shafts 3 of production well 2 allows increasing the filtration area of well 2 and coverage of formation 4, involving additional zones of formation 4 in the selection, which leads to an increase in the extracted products from the formation 4. After creating the steam chamber, the selection is super-viscous minute through a production well 2, and the steam is injected only into the injection well: 1. Develop viscous oil reservoir in this mode is carried out to stabilize the magnitude relationship paroneftyanogo: 3-3.5. The oil-steam ratio is defined as the volume of steam injected to produce one ton of high-viscosity oil.

An example of a specific implementation of the method

In the Ashalchinsky bitumen deposit, located at a depth of 90 m, heterogeneous formations 4 (Fig. 2) with a thickness of 20-30 m, a reservoir temperature of 8 ° C, a pressure of 0.5 MPa, an oil saturation of 0.7 units, a porosity of 30 units are located %, with a permeability of 2.65 μm ² , a density of bitumen under reservoir conditions of 960 kg / m ³ , a viscosity of 22,000 MPa, a pair of horizontal wells were drilled at a distance of 5 m from each other: production 2 and injection 1. When analyzing geophysical data, it was revealed that production well 2 was drilled in a clay interlayer (not shown). As a result of this, at the stage of exploration of the studies, a low flow rate (less than 1 t / day) was noted for liquid and oil, there was no thermo-hydrodynamic connection with injection well 1. We determined the optimal distance to exclude steam breakthrough between wells 1 and 2, which is at least 3 m. As a result of these studies, it was decided to drill from the existing production casing of the production well 2 of two differently directed lateral branches (trunks) 3 (Fig. 2) relative to the injection well 1 (Fig. 2) with a rise to the side 2.5 m higher than production well 2. As a result of drilling, a good hydrodynamic relationship was obtained between injection 1 and production 2 wells, and an increase in injectivity from 22 to 85 tons / day was observed. After the well was transferred to production, the oil production rate was 15 tons / day.

The proposed method for the development of a super-viscous oil deposit allows increasing efficiency by increasing the coverage area of a super-viscous oil deposit by drilling ascending additional shafts from a producing well that are sequentially multidirectional with respect to the injection well with the exception of steam breakthrough from the injection well.

Claims (1)

A method for developing a super-viscous oil reservoir, including constructing a horizontal production well in the reservoir above the oil-water contact or the sole of the reservoir, above which an injection well is built, drilling additional trunks from a horizontal section of the well, the distance between the additional trunks being determined taking into account the technological capabilities of the drilling equipment for their installation, equipping the horizontal section of the producing well with a filter, pumping coolant into both wells before heating important space of the reservoir, pumping the coolant into the injection well and selecting products from the producing well, characterized in that hydrodynamic studies are conducted, on the basis of which additional shafts are drilled ascending sequentially multidirectional relative to the injection well from the producing well so as to prevent steam breakthrough from the injection well, at the same time, the bottoms of the additional trunks are located at least 2 m above the producing well.

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