RU2582529C1 - Development method of layer-by-zonal heterogeneous superviscous oil or bitumen - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry and can be used in development of sandwich-type high-viscosity oil or bitumen accumulation. In development method for layer-by-zonal non-uniform high-viscosity oil or bitumen accumulation, which involves determination of productive formations separated by low permeable interlayers, construction in the lower formation above water-oil contact of horizontal well with additional uprising shafts, opening up upper beds, heat carrier pumping and product extraction, the distance between additional ascending shafts is determined considering technological capabilities of drilling equipment for wiring, as well as with possibility to accommodate filters with adjustable transmission lowered into horizontal well before pumping heat carrier at the pipe string and located opposite additional uprising shafts, as well as packers insulating annular space of horizontal well between additional ascending shafts and above filters. Number of pumped heat carrier and extracted product is determined from the properties of enter formations in each additional ascending shaft due to filters with adjustable transmission, the heat carrier pumping and product extraction is performed successively from the pipe string.

EFFECT: technical result - involvement in development of low-productive formations with thickness less than 10 m, higher efficiency of oil recovery due to more even heating of productive formation, as well as reducing material costs, since it is possible to disconnect mined-out areas of productive formations and reduce volume of pumped heat carrier.

1 cl, 2 dwg

Description

The proposal relates to the oil industry and may find application in the development of a multilayer reservoir of high viscosity oil or bitumen.

A known method of thermal displacement of oil from a horizontal well (patent RU No. 2067168, IPC ⁶ ЕВВ 43/24, published on 09/27/1996), including drilling a well with a horizontal well, installing a casing string and cementing the annulus above a horizontal well, perforating the casing the columns along the annular generators in the end part and at the beginning of the horizontal section immediately before the cement plug, after which the tubing string is lowered, the casing is centered in the casing with the help of a packer The second one is installed behind the first group of perforations, the coolant is supplied through the tubing, and the product is taken through the second group of perforations and transported along the annular annulus.

The disadvantage of this method is the low efficiency of oil recovery, since in the conditions of a layered-zonal-heterogeneous formation, its exposure vertically and in area is extremely small, which leads to a long duration of coverage of the entire volume of the formation by exposure and low rates of selection.

The closest in technical essence and the achieved result is a method of developing a layered-zonal-heterogeneous reservoir of highly viscous oil or bitumen (patent RU No. 2295030, IPC ЕВВ 43/24, published March 10, 2007), including the construction of a producing multi-well horizontal well with additional lateral shafts passing under the clay layer and above it parallel to the producing multi-wellhead horizontal well of the twin-wellhead horizontal well with additional ascending branches mixtures that pass through a clay interlayer, creating a permeable zone between wells by injecting a water coolant into both wells, and at first steam of a low degree of dryness (with a higher gas content) is pumped to increase the injectivity of a multi-mouth horizontal well and the proportion of associated water in the selected product, and then steam with a high degree of dryness (low fat gas) is pumped, the volume of which is determined by increasing the discharge pressure, which is maintained not exceeding the opening pressure vertical cracks, after the creation of the permeable zone, the coolant is supplied only to the injection horizontal wellhead, and the production is taken from the horizontal horizontal wellhead, and the products are taken from the horizontal horizontal wellhead until the reservoir is fully developed; in addition, vertical wells passing through clay interbed, and they are used as a transport channel for filtering steam (gas) above the bed Ia clay seam and create a vapor (gas) oil bath, and supply of products withdrawn downwards.

The disadvantages of this method:

- the inability to engage in the development of low-power productive formations with a thickness of less than 10 m, since it is difficult to conduct a couple of wells in them;

- insufficient oil recovery efficiency, since the probability of a coolant breakthrough through one or more additional ascending branches passing through the most permeable sections of the reservoir is high, while other sections are not sufficiently warmed up;

- the inability to turn off the developed sections of productive formations, which leads to additional material costs, as they continue to pump coolant.

The technical objectives of the proposed method are the involvement in the development of low-power productive formations with a thickness of less than 10 m, increasing the efficiency of oil recovery due to a more uniform heating of the productive formation, as well as reducing material costs, since it is possible to turn off the developed sections of productive formations, while the volume of pumped coolant is reduced.

Technical problems are solved by the method of developing a layer-zonal inhomogeneous reservoir of highly viscous oil or bitumen, including the determination of productive formations in the reservoir separated by low-permeable layers, construction of a horizontal well in the lower layer above the oil-water contact with the ascending trunks that open the upper layers, injection of the coolant and product selection.

New is that the distance between the additional ascending 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, lowered into a horizontal well before pumping the coolant on the pipe string and located opposite the additional ascending shafts, and packers that isolate the annular space of a horizontal well between additional ascending 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 ascending wellbore due to filters with adjustable transmission, while the coolant is injected and the products are selected sequentially from the pipe string.

In FIG. 1 shows the injection of coolant into the formation through a horizontal well with lateral ascending shafts revealing a poorly productive interlayer.

In FIG. 2 shows the selection of production from the reservoir through a horizontal well with ascending trunks revealing a poorly productive layer. The method is as follows.

Productive formations 1, 2 (Fig. 1, 2) are separated on a layer-zonal heterogeneous reservoir of highly viscous oil or bitumen, separated by a poorly productive layer 3. A well 4 is drilled with a horizontal section 5 below the low-productive layer 3 and above the oil-water contact (in the figures not shown) at 2 m. Posting from the horizontal section 5 additional ascending trunks 6 with the intersection of the poorly productive interlayer 3 are carried out. When choosing the distance between the additional ascending trunks 6 take into account technologically f the capabilities of the drilling equipment (not shown in Fig.) for their wiring, for example, it is necessary to exclude the probability of getting into the next bore when the next bore is drilled by a downhole motor with a skew angle, to exclude the possibility of breaking drill pipes when drilling additional ascending shafts, to ensure that the drill cuttings are washed out when drilling additional ascending trunks and so on. In addition, consider the possibility of placing between them filters 7 with adjustable transmission, for example, RF patent No. 2485290, lowered on a pipe string 8 and located opposite additional ascending shafts 6, as well as packers 9, which isolate the annular space 10 of the horizontal section 5 between the filters 7 and above them.

The coolant 11 is injected (Fig. 1) into the well 4, and the amount of injected coolant 11 is determined from the properties of the exposed formations 1, 2 (the lower the injectivity of the formation and the higher the viscosity of the oil, the more steam is injected, and vice versa) in each additional ascending trunk 6 thanks to the adjustable filters 7. After heating the productive formations 1, 2, the coolant 11 is cut off and the product 12 is sampled (Fig. 2), while the amount of product 12 taken is determined from the properties of the opened formations 1, 2 (the higher the porosity the reservoir, permeability and oil saturation, the more products are taken, and vice versa) in each additional ascending barrel 6 due to adjustable filters 7. Thus, the coolant 11 (Fig. 1) is sequentially injected and production 12 is taken (Fig. 2) to full reservoir formation. In this case, in the case of developing reserves of sections of productive formations 1, 2, opened by additional ascending trunks 6, the corresponding adjustable filters 8 are closed, and from others they continue to select products 12.

Using a hydrodynamic model, a comparative assessment of the effectiveness of the proposed method and the method taken as a prototype. The following parameters are set for the model: the top 1 layer has a temperature of 20 ° C, pressure is 0.5 MPa, oil saturation is 0.77 units, porosity is 30%, permeability is 1.5 μm ² and is saturated with highly viscous oil or bitumen with a density of 956 kg / m ³ and a viscosity of 30,000 mPa · s, and the lower 2 layer - temperature 20 ° С, pressure - 0.5 MPa, oil saturation - 0.6 units, porosity - 30%, permeability - 1.5 μm ² and is saturated with high viscosity oil or bitumen with a density of 956 kg / m ³ and a viscosity of 30,000 mPa · s. The upper 1 and lower 2 productive formations are separated by a poorly productive interlayer 3 of a thickness of 3-5 m, having a temperature of 20 ° C, pressure - 0.5 MPa, oil saturation - 0.6 units, porosity - 17%, permeability - 0.1 μm ² . The sole of the bottom 2 of the productive formation is located at a depth of 90-95 m. In the lower productive layer 2, a well 4 is drilled with a horizontal section 5 of 450-500 m in length, 2 m below the low productivity layer and 2 m above the oil-water contact. In layers 1 and 2 according to the results low-permeable sections are specified through which ascending additional trunks 6 are drilled from a horizontal section 5 of well 4, revealing a low-permeable interlayer 3. The distance between the ascending additional trunks is 40-45 m. As a result, I proposed method can achieve a relative increase oil recovery factor of 14% and a decrease in steam consumption - 9%.

The proposed method for the development of a layer-zonal inhomogeneous reservoir of highly viscous oil or bitumen allows for the involvement of low-power productive formations with a thickness of less than 10 m, increase the efficiency of oil recovery due to more uniform heating of the productive layer, and also reduce material costs, since it is possible to turn off the developed sections of productive layers, while reducing the volume of injected coolant.

Claims (1)

A method for developing a layer-zone-heterogeneous reservoir of highly viscous oil or bitumen, comprising determining in the reservoir productive formations separated by low-permeable layers, constructing a horizontal well in the lower layer above the oil-water contact with additional ascending trunks opening the upper layers, pumping the coolant and product selection, characterized in that the distance between the additional ascending 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, lowered into a horizontal well before pumping coolant on a pipe string and located opposite additional ascending trunks, as well as packers that isolate the annular space of a horizontal well between additional ascending trunks and above the filters, and the amount of injected coolant and selected products are determined from the properties of the exposed formations in each additional ascending wellbore due to filters with re controlled transmission, while the coolant is pumped and the products are selected sequentially from the pipe string.

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