RU2307926C1 - Method for bitumen deposit development - Google Patents

Abstract

FIELD: oil production, particularly to produce bitumen with the use of heat along with horizontal well drilling.

SUBSTANCE: method involves drilling heat-transfer wells in reservoir; injecting heat carrier in reservoir via the heat-transfer wells; drilling drain holes below bitumen reservoir bottom; pumping-out reservoir water and producing bitumen in discrete regime. To produce bitumen from elongated deposit having length equal to multiple of deposit widths slanting-horizontal heat-transfer wells are drilled. The slanting-horizontal heat-transfer wells have horizontal sections of sinusoidal type formed in general deposit direction, wherein well azimuth is cyclically changed in horizontal projection so that in the case of 10% well path increase heated area increases by 45-50%. Product is extracted via strings of drain holes.

EFFECT: increased bitumen displacement efficiency and extended area of deposit zone to be heated, which improves bitumen recovery ratio due to direct bitumen reservoir treatment.

3 dwg

Description

The invention relates to the oil industry, and in particular to methods for producing bitumen using heat in combination with the drilling of horizontal wells.

The known method (US patent No. 20159575, publ. 04/26/77), comprising heating the formation using a production string, specially equipped, as well as many peripheral wells drilled in the reservoir near the production well. Peripheral wells reveal only the upper part of the reservoir. The production well is equipped with three columns of pipes that are lowered concentrically one into another. Three columns form three channels of communication with the surface: the first channel - the column of the smallest diameter (tubing) - is lowered to the bottom of the formation and perforated against the producing formation from which the production is made, the second and third channels - the annular space - serve to circulate the coolant.

The displacement efficiency remains low due to the fact that the process of distribution of the coolant in the reservoir is not controlled. The implementation of the method requires large material and energy costs.

Also known is a method using heat in combination with inclined horizontal wells (Russian patent No. 2237804, IPC ⁷ EV 43/24, publ. 10.10.2004). The method includes drilling wells on a specific grid, injecting a displacing agent through injection wells and selecting formation fluids through production wells. Well drilling is carried out on a radial grid. Injection wells are located on the reservoir closer to the upper boundary of the reservoir along the most permeable layers. Production wells are located closer to the lower boundary of the reservoir. At the initial stage of development, all wells conduct thermocyclic treatment of the formation with steam stimulation. Subsequently, they switch to the selection of reservoir fluids through production wells with areal impact on the reservoir through injection wells.

The main technical and technological drawback of the construction of such a heat injection well is that it was conducted in a stable azimuth, which significantly reduced the area and volume of the heated portion of the bitumen formation.

The closest in technical essence and the achieved result to the proposed one is a method of developing bitumen deposits by thermal action on the formation (Russian patent No. 2225942, IPC ⁷ ЕВВ 43/24, publ. March 20, 2004). The method includes determining the optimal size of the production element, in the center of which a central production well is drilled. Injection wells are located at a distance of 10 m from the central and 180 ° from each other. In the immediate vicinity of the central well, a drainage is drilled and equipped with a submersible pump and drained. Steam gas is supplied through the injection well. The formation is heated to the production viscosity of bitumen and bitumen is taken through the production well.

The disadvantage is that the small area of heating the formation and the volume of the heated area of the formation.

The technical result of the invention is to eliminate this drawback, i.e. creating a method for more efficiently displacing bitumen and increasing the volume of the heated section of the formation and thereby increasing the recovery coefficient due to the direct effect on the bitumen formation.

The technical result is achieved by the fact that in the method of developing a bitumen deposit, comprising drilling heat injection wells in the formation, pumping coolant through them, drilling drainage wells below the bottom of the tar sump, pumping formation water and selecting products in discrete mode, according to the invention, when developing extended fields forms, when their length is several times greater than the width, drill directional horizontal heat injection wells with horizontal sections of a sinusoidal type in the direction of the field, while the azimuth of the wells is cyclically changed in horizontal projection so that when the well path is increased by 10%, the heating area is increased by 45-50%, and production is selected through the columns of drainage wells.

The method is illustrated by drawings, where in Fig. 1: 1, a heat injection well. Figure 2: 2 is a horizontal section of a sinusoidal type. Figure 3: 1 - heat injection well; 3 - drainage well; 4 - submersible pump; 5 - drainage column; 6 - production column.

For elongated deposits and deposits, when the length of the deposit is several times greater than the width, the most appropriate is to drill a heat-injection well with a sinusoidal horizontal section relative to the general direction so that the horizontal projection of this well resembles a “snake”.

The method is as follows.

A heat-injection well 1 is drilled to the depth of the bitumen formation, where the horizontal section 2 of the sinusoidal type passes through the formation. For drilling a horizontal-sinusoidal section of a heat injection well, the following layout of the bottom of the drill string (BHA) is required: a bit ⌀151 mm, a downhole screw motor ⌀108 mm with a rigid curved sub, telemetry, drill collar ⌀120 mm. Drilling a heat injection well of this profile is recommended to be drilled with coiled tubing units with continuous flexible pipes. Then, drainage wells 3 are drilled to a depth of 10-15 m below the bitumen formation and equipped with a submersible pump 4 with a capacity of 10 m ³ / h. The bitumen formation is drained within the production element using the drainage column 5. Then, the process of pumping the heat carrier through the heat-injection well 1 is started. After the formation is heated and the production viscosity of bitumen is reached, production is selected by swabbing from the production column 6. In this case, the drainage process occurs in discrete mode . After warming the bitumen to the optimum production viscosity of bitumen, the drainage of the formation is temporarily stopped, which will lead to the rise of groundwater. This, in turn, will increase the displacement of heated bitumen due to the natural energy of pressurized groundwater, which can be 20-30 atm. That is, the idea of in-circuit flooding, widely used in maintaining reservoir pressure, is being implemented.

When heating the bitumen layer with previously applied methods, the main part of the heat was spent on heating the water, whose thermal conductivity is an order of magnitude higher than that of bitumen and the clayey sandstone mineral skeleton. In addition, since bitumen was previously extracted together with water from the production well, and due to the large difference in the filtration coefficients of water and bitumen (more than 5-7 times), a large amount of cold formation water was drawn into the well, which also required a large amount of heat to heat than to warm bitumen itself. In the inventive method, a significant flow of coolant for heating gravity formation water is practically eliminated. In a drained formation, heat transfer and heating of bitumen is carried out with the lowest heat consumption.

Drilling an injection well with a horizontal sinusoidal section increases the heating area by 45-50%, and the length of the route increases by only 10%. The technical and economic efficiency of the proposed method for developing a bitumen deposit is determined mainly by increasing the coverage area of the productive formation, a significant reduction in energy consumption, reducing heat losses, reducing the cost of dewatering the extracted raw materials, and reducing the cost of constructing additional wells.

Claims (1)

A method of developing a bitumen deposit, including drilling heat injection wells in the formation, pumping coolant through them, drilling drainage wells below the bottom of the tar sump, pumping formation water and selecting products in discrete mode, characterized in that when developing fields of elongated shape, when their length several times greater than the width, inclined horizontal heat injection wells are drilled with horizontal sections of a sinusoidal type in the general direction of the field, while the azimuth of the wells is cyclically changed in the horizontal projection in such a way that when the well path is increased by 10%, the heating area is increased by 45-50%, and production is selected through the columns of the drainage wells.

Images