RU2322574C1 - Method for heavy and highly-viscous hydrocarbon production from underground deposit - Google Patents

Abstract

FIELD: hydrocarbon production, particularly enhanced recovery methods for obtaining hydrocarbons using heat.

SUBSTANCE: method involves drilling wells to oil deposit; consolidating well bore by casing pipe cementing; drilling horizontal end well sections in deposit and preparing injection and producing wells for further operation. Horizontal end sections of producing wells are arranged under that of injection wells. Injection and producing wells are drilled in accordance with one pattern so that specified space between said wells is not less than 5 m. Several horizontal end sections are drilled in injection and producing wells so that the end sections of each well are located in single plane and are uniformly distributed along the full perimeter thereof. Inlet orifices of horizontal injection and producing sections are spaced at least 5 m apart in height direction. Each injection and producing well is correspondingly provided with heat-insulated pipe string for heat-carrier supply and heat-insulated pipe string having pumping installation to produce hydrocarbon. The pipe strings are lowered in branched well end section zones. After that packer to isolate hole annuity between casing pipe and heat-insulated pipe string is arranged over said branched well end section zones to prevent heat action on well section over packer.

EFFECT: increased method simplicity and accuracy of horizontal well section orientation inside oil deposit, as well as extended deposit coverage and decreased heat action on well wall during well operation.

3 dwg

Description

The invention relates to a method for producing hydrocarbons from an underground tar sand deposit or a heavy oil reservoir having a high viscosity. To obtain hydrocarbons from such deposits, their heating is necessary.

There is a method of developing an oil field (patent RU No. 22113857, IPC 7 ЕВВ 43/24, published on 10/10/2003) comprising drilling vertical wells with sidetracks, pumping coolant into the formation through sidetracks and taking oil through them, and vertical wells drilled to the bottom of the lower object with their placement in one of the areal systems, while before the start of areal injection of a working agent, for example water, lateral shafts are drilled into the formation in each vertical well in each production facility of the formation, then Tel'nykh processing sidetracks by feeding them to subsequent selection of coolant through the lateral holes of oil well production to reduce to a minimum viable level, the injection of steam and selection cycles oil repeated until the maximum allowable water cut oil.

The disadvantage of this method is that the selection of products from the well is carried out cyclically, combining it with steam injection to the maximum allowable water cut of the produced product, which reduces the amount of oil produced and leads to significant heat energy costs for heating the formation.

There is also known a method of developing deposits of high viscosity oils and bitumen with horizontal wells (patent RU No. 2237804, IPC 7 ЕВВ 43/24, published on 10/10/2004), including drilling wells on a specific grid, pumping a displacing agent through injection wells and selection formation fluids through production wells, while drilling wells along a radial grid, so that injection wells are located along the productive formation closer to the upper boundary of the formation along the most permeable layers, and production wells are closer to the lower boundary Itza formation, wherein the initial stage of development in all wells is carried thermocyclic treating the formation with steam stimulation, followed by transfer to selection of formation fluids through the production wells with areal influence on the formation through injection wells.

The closest in technical essence is a method of producing hydrocarbons from an underground deposit of tar sand or a heavy oil deposit (patent RU No. 2098613, MKI 6 ЕВВ 43/24, published in bul. 34 from 12/10/1997), containing drilling and preparation for the operation of the injection well, which ends in the reservoir, and the production well, which ends in the reservoir below the level of the injection well, the creation of a permeable zone between the injection and production wells, while drilling and preparation for operation are carried out at least thinking of pairs of wells, where each pair includes an injection well ending in the reservoir, and a producing well ending in the reservoir below the level of the injection well, the second pair of wells facing the first pair of wells, create a permeable zone between the injection well and the producing well of each pair of wells, the injection of water vapor is carried out through injection wells, the simultaneous extraction of hydrocarbons is carried out by producing wells, while the injection pressure in the injection well ine first pair exceeds the injection pressure in the injection well of the second well pair, each injection and production wells have horizontal end sections extending inside the reservoir.

Both analogues and prototypes to one degree or another have common disadvantages:

firstly, the complex process of the method;

secondly, the small coverage area of the reservoir in horizontal sections, and, as a result, the low efficiency of reservoir development;

thirdly, the difficulty of orienting horizontal sections of injection and producing wells in the reservoir;

fourthly, in the process of pumping coolant, a thermal effect is exerted on the walls of the well, and this has a negative effect on the strength of the fastening (cement stone) of the casing of the well and leads to premature destruction of the cement stone behind the casing of the well.

An object of the invention is to simplify the process of implementing the method and increase the accuracy of orientation of horizontal sections of wells in the reservoir, as well as increase the efficiency of developing deposits by increasing the coverage area of the reservoir of heavy and highly viscous hydrocarbons in horizontal sections and reduce the thermal effect on the walls of the well during operation.

The stated technical problem is solved by a method of producing heavy and highly viscous hydrocarbons from an underground deposit, comprising drilling to the reservoir, strengthening the barrel by cementing the casing, drilling horizontal end sections located in the reservoir, and preparing for operation injection and producing wells, with horizontal end sections of producing wells below the horizontal end sections of the injection wells.

What is new is that the injection and production wells are drilled using one of the areal systems with a certain distance of at least 5 meters between them, and several horizontal end sections located in each well at the same level and evenly distributed throughout the injection and production wells are drilled perimeter, and the inlet holes of the horizontal sections of injection and production wells are spaced at least 5 meters apart in height, with each injection and production well being Before preparation for operation, they equip respectively a thermally insulated pipe string for supplying a coolant and a thermally insulated pipe string with a pumping unit for hydrocarbon production, which are lowered into the branching area of the end sections, after which a packer is installed above the branching of the end sections of each well, which insulates the annular space between the casing and the thermally insulated pipe string to eliminate thermal effects on the well above the packer.

New is that the number of injection and producing wells is at least one pair.

Figure 1 in a longitudinal section schematically shows an image of an underground deposit of heavy and high viscosity hydrocarbons with producing and injection wells.

Figure 2 in section AA shows a schematic image of an underground deposit of heavy and high viscosity hydrocarbons with producing and injection wells.

Figure 3 schematically shows one of the options for placement on the surface of production and injection wells.

The essence of the method is as follows:

First, the construction of one pair of wells is carried out, consisting of production 1 (see Fig. 1) and injection 2 wells, for example, first the construction of production well 1 is carried out, which, after drilling, is cased and cemented.

Further, in the production well 1, they are drilled in any known manner (see patents RU No. 2259457, 2265711, 2269633, 2269632, 2268982) several (for example, four) branched horizontal end sections 3; 3 ′; 3 ′ ′; 3 ′ ′ ′, located at the same level 4 and evenly distributed around the entire perimeter of the production well 1.

Then, in the same way, on the same areal system with the production well 1, an injection well 2 is constructed with branched horizontal end sections 5; 5'; 5''; 5 ′ ′ ′, located at the same level 6 and evenly distributed around the entire perimeter of injection well 2, the height being N (see FIG. 1) between the level 4 of the inlet openings of the producing well 1 and the level 6 of the inlet openings of the injection well 2 determined by calculation , but should be at least 5 meters to exclude the breakthrough of the coolant during its injection from the branched horizontal end sections 3; 3 ′; 3 ′ ′; 3 ′ ′ ′ of production well 1 into branched horizontal end sections 5; 5'; 5''; 5 ″ ″ injection well 2, and for the same purpose as indicated above, the distance L (see FIG. 2) between the axes of the producing 1 and injection 2 wells should also be at least 5 meters.

Next (e.g., staggered) within one system produce areal construction of the following pairs of wells (see. Figure 3) consisting of producing 1 ... ⁿ 1 and injection 2 '... 2 ⁿ wells, respectively, while respecting the above distance is L between the axes of nearby wells.

Upon completion of the construction of wells, they begin their preparation for operation. For this purpose, each production well 1 ... 1 ⁿ column equipped with a heat-insulated pipe 7 ... 7 ⁿ (see FIG. 1) with a pump unit 8 ... 8 ^n, respectively, of any known construction, in the run-flat region 9 ... 9 ⁿ branching of the end sections of the producing well 1 ... 1 ⁿ .

Each injection well 2 ... 2 ^{n is} equipped with a heat-insulated string of pipes 10 ... 10 ⁿ for supplying a coolant deflated to the branching region 11 ... 11 ^{n of the} end sections of the wells.

Next, above the branching of the end sections of each of the producing 1 ... 1 ⁿ and injection 2 ... 2 ⁿ wells, a packer 12 ... 12 ^n, respectively, is installed that insulates the annulus 13 ... 13 ^{n of the} wells between the casing and the heat-insulated pipe string to exclude thermal effects on the walls of the well above the packer 12 ... 12 ⁿ .

Then, from the mouth of injection wells 2 ... 2 ^n, coolant (hot water vapor) is pumped into a heat-insulated pipe string 10 ... 10 ⁿ , which, having reached the areas of 11 ... 11 ⁿ branching of the end sections of injection wells 2 ... 2 ⁿ falls into the horizontal end sections 5; 5';5''; 5 ′ ′ ′ along which deep into the reservoir of heavy and highly viscous hydrocarbons 14. They then start the pumps 8 ... 8 ⁿ into operation.

Heating takes place over the entire height of the reservoir of heavy and highly viscous hydrocarbons 14 radially directed from each horizontal end portion 5; 5';5''; 5 ′ ′ ′ level 6 injection wells 2 ... 2 ⁿ .

The heated product (heavy viscous oil) deposits of heavy and highly viscous hydrocarbons 14 fall into the horizontal end sections 3; 3 ′; 3 ′ ′; 3 '''level 4 in the production wells 1 1 ... ^n, respectively, and enters them into the production wells 1 1 ... ⁿ into the area 9 ... 9 ⁿ at the pump intake 8 ... 8 ⁿ respectively, which is pumped heated heavy viscous oil to the surface.

The use of heat-insulated columns of pipes 7 ... 7 ⁿ and 10 ... 10 ⁿ , as well as packers 12 ... 12 ^n, can significantly reduce the negative impact of thermal effects on the fastening of the walls of the well during operation.

The proposed method allows to increase the accuracy of the orientation of horizontal sections of wells in the deposits, as well as the efficiency of the development of the deposits by increasing the coverage area of the deposits of heavy and highly viscous hydrocarbons in horizontal sections, and the simplification of the process of the method allows to save material and financial costs. In addition, reducing the thermal effect on the walls of the well during operation will extend the life of the well until overhaul.

Claims (1)

A method for producing heavy and highly viscous hydrocarbons from an underground deposit, comprising drilling wells to deposits, reinforcing the barrel by cementing the casing, drilling horizontal end sections located in the reservoir, and preparing for operation injection and producing wells, the horizontal end sections of producing wells being located below the horizontal end ones sections of injection wells, characterized in that the drilling of injection and production wells, at least one pair, produce one of flare systems with a defined distance of at least 5 m between them; moreover, several horizontal end sections located in each well at the same level and evenly distributed along the entire perimeter are drilled in injection and production wells, and the inlet holes of the horizontal sections of injection and production wells are spaced not less than 5 meters in height, while each injection and production well is equipped with a thermally insulated pipe string to supply coolant and heat insulation bath tubing with a pumping unit for the production of hydrocarbons, which are lowered into the branching region of the end sections, after which a packer is installed above the branching of the end sections of each well, isolating the annular space between the casing and the heat-insulated pipe string to prevent thermal effects on the well above the packer.

Images