RU2455476C1 - Method of heavy oil production - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: method of heavy oil production includes construction of vertical well, exposing of formation from vertical well by method of pressing by casing puller, horizontal injection and production wells. Heat-transfer medium is supplied to the formation, the product is gathered into underground storage tank and pumped to the surface by pumps. The casing puller is made in a form of cylinders temporary coaxially located with centralisers in opposite working chambers equipped with perforated areas and guides at the opposite ends for jointed tubes with perforated areas and end pieces interacting with pistons. The pistons are located inside the cylinders. Note that the cylinders are regularly interconnected by telescopic fitting pipes forming a sealed cavity connected to the hydro-pump. In the course of hydro-pump operation the pistons move in opposite directions together with jointed tubes. All well pairs are constructed according to the project. Note that the jointed tubes together with working chambers form annular cavities connected to the formation and through the corresponding damper valves and manifolds - to the steam pipeline and underground storage tank that are also connected through the corresponding damper valves and manifolds to the steam pipeline and underground storage tank, and their central channels are closed by equal damper valves. Heat-transfer medium is supplied to the formation through steam pipe line, manifold, damper valves, perforated areas of jointed tubes of injection wells and annular cavities of working chambers at other closed damper valves.

EFFECT: increase of heavy oil production efficiency.

6 cl, 3 dwg

Description

The invention relates to the field of the oil industry, and more particularly to methods for producing hydrocarbons by borehole methods with opening a productive formation from a vertical well by underground horizontal wells with subsequent exposure to it by methods that bring its products into a fluid state, and can be used for the production of heavy oil and natural bitumen.

A known method of developing deposits of highly viscous oils and bitumen (patent RU No. 2330950, ЕВВ 43/24, publ. Bull. No. 22 of 08/10/2008), including the construction of a vertical well with the formation of an underground reservoir for products, opening a reservoir from a vertical well horizontal wells by the method of indenting them with the rise from the well, strapping of horizontal wells through the corresponding valves and manifolds with a steam line and underground capacity, preliminary preparation of products in the underground capacity and separate pumping of products ktsii, water and gas to the surface.

The disadvantage of this method is that due to the misalignment of horizontal wells, each of them is built separately, periodically pressing the pipe into the reservoir with the jack up to the design length. In this case, the jack rests on the opposite wall of the vertical well, which must withstand significant loads. Additional strengthening of the walls of a vertical well increases the cost of construction. In addition, due to cramped circumstances in a vertical well, the jack stroke will be small and more time and money will be required for the construction of horizontal wells, which also increases the cost of their construction. Equipping horizontal wells with expensive sand filters also makes construction more expensive. In the underground tank, only preliminary product preparation takes place. It is necessary to build onshore pipelines and product preparation systems.

The closest is the method of oil production by underground horizontal wells (patent RU No. 2354817, ЕВВ 43/24, 7/00, publ. Bull. No. 13 of 05/10/2009) using thermal action on the reservoir, including drilling from the surface vertical shaft shaft and fixing its walls, the construction of an underground working chamber, the construction of two-level horizontal injection and production wells, the mouths of which are located in the working chamber, injection into the reservoir through the injection wells of the coolant supplied from the surface of the steam pipe, the extraction from the reservoir production wells in underground working oil chamber, collecting it in a container at the bottom of the shaft and pumping to the surface. The working chamber is constructed in the form of horizontal conduit pipes symmetrically positioned relative to the axis, which are pushed with a jack into the reservoir, in the directions of the horizontal wells, after releasing the inner cavity of the conductor tubes from the reservoir rock, two-level horizontal injection and production wells are built by pushing the tube filters into the reservoir with telescopic a jack made with the possibility of placement in opposite onduktornyh tubes to increase the working stroke.

The disadvantage of this method is that the jack rests on the opposite wall of the working chamber, which must withstand significant loads. Additional strengthening of the walls of the working chambers increases the cost of construction. In addition, when pumping products with water, gas and mechanical impurities, pumping equipment wears out and works inefficiently, conditions for the formation of stable emulsions are not ruled out. It is necessary to build onshore pipelines and product preparation systems that occupy large land areas.

The technical task of the proposal is to increase the efficiency of heavy oil production by significantly reducing capital, operating costs and production costs by eliminating the construction of surface oil treatment plants and a steam generator, reducing the number of onshore pipelines, reducing the time and cost of building horizontal wells, reducing heat losses and procurement of pumping equipment, increasing flow rate, the use of effective and flexible technologies for impacting the oil reservoir and the quality of Tween preparation of products in the underground capacity, reducing the allotted land and their rational use.

The problem is solved by a method of producing heavy oil, including the construction of a vertical well, opening a formation from a vertical well by applying a jack placed in coaxial working chambers, horizontal injection and producing wells, supplying coolant to the formation, collecting products into an underground tank and pumping it to the surface with pumps .

What is new is that the jack is made in the form of cylinders temporarily coaxially placed with centralizers in opposite working chambers, provided with perforated sections and guides for composite pipes with perforated sections and tips interacting with pistons located inside the cylinders connected by a flexible element, moreover, the cylinders are periodically interconnected by telescopic nozzles, forming a sealed cavity connected to the hydraulic pump, during which the piston they move in opposite directions together with composite pipes, build all pairs of wells according to the project, and composite pipes together with working chambers form annular cavities communicating with the formation and through the corresponding valves and collectors with the steam line and underground capacity, which also connect through the corresponding valves and collectors with a steam line and an underground tank, and their central channels are closed with equal bore valves, the coolant is supplied to the formation through a steam pipe, collect torus, valves, perforated sections of the composite pipes of injection wells and annular cavities of the working chambers with the remaining valves closed, the production of the formation from the producing wells enters through the corresponding valves, the collector and the nozzle into an inclined plane equipped with a device for regulating depending on its composition and viscosity the thickness of the stream, where there is a preliminary separation of gas and water from it, which is placed in the upper part of the underground tank, externally radially connected by channels to olnitelnoy borehole pumps connected to the light ends recovery system, wherein the channel bottom is provided with a filter.

New is also the fact that the optimal rate of production from the reservoir into horizontal production wells and its flow through them into the underground tank, at which mechanical impurities are not carried out, is determined by controlling the magnitude of their cross sections.

It is also new that first they build an additional well with a bottom below the bottom of the underground reservoir, while specifying the geological and other parameters of the section and the formation.

Also new is the fact that thermogravitational, thermochemical and electrical methods are used to prepare products in an underground tank.

Also new is the fact that for periodic hydraulic cleaning of an underground tank from mechanical impurities, ground-based equipment with a flexible sleeve with the necessary set of tools and devices is used.

It is also new that the steam generator is placed in a vertical well and associated gas and water from an underground tank are used in its operation.

Figure 1 shows the general arrangement of wells and equipment in the context of the oil reservoir (in the background between the collectors of the mouth of horizontal wells are not conventionally shown).

Figure 2 is a diagram of the construction of horizontal wells, section AA in figure 1.

Figure 3 - diagram of the preliminary preparation of products in an underground tank, leader B of figure 1.

To implement the method of producing heavy oil (oil), first build an additional well 1 (Fig. 1) with a face 2 below the bottom 3 of an underground tank 4, while specifying the geological and other parameters of section 5 and formation 6. If necessary, make changes to the design for the construction of a vertical wells 7. Next, build a vertical sealed well 7, close at the level of the sole 8 of the formation 6 with a horizontal sealed heat-insulated cover 9, forming a container 4 for subsequent product collection. From above, the well 7 is closed with a sealed chamber 10 with a floor 11 in which a working elevator, a ventilation system, and other necessary equipment are placed (not shown in FIG.). In areas above the roof 12 and below the sole 8 of the layer 6, waterproofing is carried out. Horizontal coaxial working chambers 13 are built from a vertical well 7, drilling a formation 6 with known means (for example, a screw), which are surrounded by perforated pipes 14 with guides 15 at opposite ends 16. The required number of working chambers 13 is determined by the design taking into account the parameters of the formation 6 and adopted technology booty. Their number can be eight in one section, several rows in height and more than 10 m in length. Pipes 14 may be integral. The pair of pipes 14 with the wall 17 of the vertical well 7 is sealed by known methods (gaskets). After the construction of all the working chambers 13 is started, horizontal wells 18 begin to be built 18. A jack 19 in the form of cylinders 20 with centralizers (not shown) is placed in the coaxial working chambers 13 (Fig. 2), into the guides 15 of which the composite pipes are introduced and extended to the design length 21 (pipes) with perforated sections 22 and tips 23. Then, pistons 24 are introduced into the cylinders 20 until they contact the pipes 21. At the ends of the cylinders 20, stoppers (not shown) are provided for the pistons 24. Seals are provided on the pistons 24 (not shown) ny) and flexible elements 25 of the estimated length are attached. Next, the cylinders 20 are interconnected by telescopic pipes 26, forming a sealed cavity 27, connected through hoses 28 to a hydraulic pump (not shown). This "charging" of the jack 19 ends.

Turn on the hydraulic pump and create a working pressure in the cavity 27. In this case, the pistons 24 move in opposite directions and press the pipes 21 with the tips 23 into the reservoir 6. With the same resistance to the pipes 21 with the tips 23, both pistons 24 press them on the stroke length into the reservoir 6. The pressure force is regulated by a change in pressure in the cavity 27 of the hydraulic pump. Next, the cavity 27 is freed from the liquid, the nozzles 26 are extended, and the pistons 24 are pulled out of the cylinders 20 by the flexible elements 25. Then, the jack 19 is again “charged”, and the process is repeated until the horizontal wells 18 reach the design lengths. If during operation only one piston 24 has gone full stroke along cylinder 20 and the other partially, then jack 19 is also “recharged”, etc. Thus, all other pairs of horizontal wells are built 18. To reduce the resistance to pressure of the composite pipes 21 into the formation 6, well-known techniques can be applied (supply of a hot solvent, etc.). If the project provides for the construction of horizontal wells 18 in two tiers in height, then at the same time you can build two pairs of them, etc. At the end of the construction of horizontal wells 18, the composite pipes 21 with the pipes 14 of the working chambers 13 form annular cavities 29 (Fig. 1), communicating with the formation 6 and through the corresponding valves 30 and manifolds 31 with the steam line 32 and the underground capacity 4. Horizontal wells 18 through the corresponding valves 30 and manifolds 31 also communicate with the steam line 32 and the underground tank 4, and their central channels 33 are closed by equal-way valves 34. The mouths of the working chambers 13, horizontal wells 18 and the coupling of the composite pipes 21 with the guides 1 5 are sealed by known methods. The lower collectors 31 through the nozzles 35 communicate with the underground capacity 4, and in its upper part is placed an inclined adjustable plane 36 (FIG. 3), equipped with a device 37 for regulating the thickness of the product flow and a partition 38. The underground tank 4 is connected through channels 39 (FIG. 1) with an additional well 1, which is connected to a ground-based system for trapping light fractions and a steam generator, the lower channel 39 being provided with a filter 40. Pumps 41 are placed in the additional well 1 for pumping products. In the upper part of the well 7, a steam generator 42 is placed connected to the steam line 32. The systems for supplying and preparing gas and water from an underground tank 4 (not shown) are also placed there. Installation of equipment in the well is carried out using a working elevator. The equipment is carried out in explosion-proof quick-assembled modular design, equipped with safety, control and video surveillance devices. Workers are provided with personal protective equipment to work in these conditions.

The proposed method for the production of heavy oil allows you to use various technological methods to reduce the viscosity of the product and bring it into a fluid state. As an example, consider the use of steam gravity drainage technology with the injection of superheated steam with a temperature of about 250 ° C with a two-tier arrangement of horizontal wells. The essence of the technology lies in the fact that the reservoir is heated with superheated steam to reduce the viscosity of the product and bring it into a fluid state. At the first stage of operation, the steam deposits pump the estimated time through the steam line 32 and the upper headers 31 with the upper valves open 30 to all horizontal wells 18 and the cavities 19 of the working chambers 13 for a more complete heating of the formation 6. At this time, the lower valves 30 communicating through the lower collectors 31 and nozzles 35 with a capacity of 4 are closed. After a sufficient warming up of the formation, the lower valves 30 remotely open, communicating cavities 19 of the working chambers 13 and horizontal wells 18 through the lower manifolds 31, pipes 35 with a capacity of 4. At this time, the other valves are closed. In the gravitational mode and under the influence of reservoir pressure, the product enters an inclined plane 36 (figure 3), where it is pre-prepared. Depending on the technology adopted for the deep preparation of products, hot gravity, thermochemical and electrical methods can be applied, depending on its composition. In this case, gas and water are used to operate the steam generator, and marketable oil is pumped out by pumps 41 (Fig. 1) from additional well 1. The optimal rate of production from the formation 6 in the cavity 19 and horizontal production wells 18 and its flow through them into the underground tank 4 , at which mechanical impurities are not carried out, is determined experimentally by adjusting the passage size of the valves 30. With closed valves, the speed is zero. With fully open valves, production speed is at its maximum.

Depending on the applied technological mode of the reservoir operation, the cavities 19 and horizontal wells 18 in horizontal section and vertical rows can be either steam injection or production wells. For example, steam is pumped into the upper row of all cavities and wells (or to a part of them), and products are produced from the lower row of all cavities and wells (or from a part). Depending on the adopted technology of reservoir operation, there can be any options for the joint operation of cavities 19 and horizontal wells 18. To intensify production, it is possible to use chemical reagents and solvents. For periodic hydraulic cleaning of an underground tank, the well-known ground equipment with a flexible sleeve is used with the necessary set of tools and devices. Technological processes are controlled by the operator from the day surface. After developing a section of a reservoir by a covered well, it can be used in the technological cycle of field development as an underground reservoir (for storing oil, water, industrial waste, etc.).

The technical and economic advantage of the proposed method for the production of heavy oil is as follows. There is the possibility of building simultaneously from a vertical well two coaxial horizontal wells on one tier, four wells on two tiers, etc. At the same time, the forces of the pistons pushing the pipes of horizontal wells into the formation practically do not affect the design of the vertical well. By changing the working pressure in the sealed cavity between the pistons of the hydraulic pump, it is possible to regulate the pressure force of the pipes of horizontal wells into the reservoir over a wide range. The stroke of the piston of the jack is determined by the length of its cylinder and can be more than 10 m. Then, in the favorable case, for the construction of two horizontal wells 700 m long, each jack must be "recharged" 70 times. If it is necessary to build 8 horizontal wells (4 pairs) on one tier of a vertical well, then the jack is "recharged" 280 times. If you spend 4 hours on one “charging” and working strokes of the jack pistons, then it will take 1120 hours — 46.7 days to build 4 pairs of horizontal wells — that is, only 11.7 days for one pair of horizontal wells. The jack has a simple scheme of execution, "recharge" and work. Placing a steam generator in a vertical well and using associated gas and water from an underground tank in its operation precludes the construction of expensive ground-based steam pipelines, water pipelines, light fraction traps and significantly reduces heat loss. The use of the optimal flow rate of products from the reservoir to the underground tank, at which sand removal is excluded, allows not to equip horizontal wells with expensive sand filters and save money. The construction of an additional well for pumps before the construction of a vertical well allows obtaining reliable information about the geological parameters of the section and the formation and, if necessary, promptly making changes to the project, improving the quality of further construction. In addition, it becomes possible to use well-known pumping units, to mount and maintain them, using conventional ground equipment and well-known technological methods, as in conventional wells. The method allows you to open a productive formation with minimal impact on it, apply, depending on the stage of field development, various technological methods of impacting the formation without changing equipment and conduct rational collection of products from various sections of the formation into an underground tank without the use of pumps. Horizontal production wells do not provide backpressure to the reservoir, which improves the flow of products and their collection in an underground tank. The fact that high-quality product preparation takes place in an underground tank using effective devices and technologies, light fractions enter the ground-based collection system or are burned in a steam generator and pump it to the surface in the form of commercial products, eliminating the cost of building expensive land-based processing systems, pipelines and improve environmental conditions. There is an opportunity for commercial products and water to be pumped out of the underground tank separately, and water can be used in the operation of a steam generator.

Here are some estimated parameters for the production of heavy oil using the proposed method. Imagine the volume of the reservoir covered by the wells in the form of a cylinder. At the same time, we believe that the oil in the reservoir is stationary, and the lengths of horizontal wells are the same. Then, to determine the amount of oil that can be extracted from the reservoir, you can write:

Q = πR ² Hpha,

where R is the radius of the base of the cylinder, equal to the length of horizontal wells, m; H is the height of the cylinder, equal to the thickness of the reservoir, m; P is the density of oil, t / m ³ ; h - oil recovery from the reservoir,%; a - oil saturation of the reservoir,%.

If we take R = 700 m, H = 20 m, P = 0.96 t / m ³ , h = 0.9, a = 0.15, then we get:

Q = 3.14 × 700 ² × 20 × 0.96 × 0.9 × 0.15 = 3988051 t.

At the same time, the flow of oil from the boundary zones of the reservoir along the perimeter, which, apparently, will increase this volume of oil, was not taken into account.

The amount of total revenue from oil sales on the domestic market of Russia:

D = QC,

where C is the cost of one ton of oil in the domestic market, rubles.

If we take the cost of oil to 6500 rubles. (tentatively, for evaluation), we obtain:

D = 3988051 × 6500 = 25922331500 rub.

To determine the daily production rate of a vertical well, you can write:

Q _cit. = qn,

where q is the daily production rate of the producing horizontal well, t / day; n is the number of producing horizontal wells.

Suppose that eight pairs of horizontal wells were constructed from a vertical well, of which half are producing. Oil production rate of existing producing inclined horizontal wells at the Ashalchinskoye field, the horizontal part of which is about 300 m, passes through the reservoir - more than 30 tons / day. If a horizontal production well operates under the same conditions, but its length passing through the formation is more than twice as long and it operates in a depressed mode, then it can be assumed that its production rate will increase. There is evidence that in Canada and Venezuela from horizontal wells with a length of 500-700 m produce highly viscous products of about 150 tons / day. We accept a daily production rate of a producing horizontal well of 75 tons / day. Then the daily rate will be:

Q _cyt = 75 × 8 = 600 t / day.

To determine the annual oil production, you can write:

Q _year. = 365 × Q _cyt = 365 × 600 = 219000 t,

where 365 is the number of days in a year.

Annual revenue from the sale of this oil:

D year. = 219000 × 6500 = 1,423,500,000 rubles.

Proposed number of years of well operation:

N years. = Q: Q _year. = 3988051: 219000 = 18 years.

Thus, the application of the proposed method improves the efficiency of heavy oil production by a significant reduction in capital, operating costs and production costs due to the exclusion of the construction of ground-based oil treatment plants and a steam generator, a significant reduction in the number of land pipelines, a reduction in the timing and cost of constructing horizontal wells, reduction in heat losses and pumping purchases equipment, filters, increase flow rate, use effective and flexible technologies They will be supplied to the oil reservoir without re-adjustment of underground equipment and preparation of products in the underground capacity, reduction of allotted land and their rational use. Due to the fact that there are no ground-based oil treatment facilities, the number of land-based steam supply and production pipelines has been reduced, the mouths of horizontal wells are compactly and hermetically tied in a vertical well underground, and the underground tank is connected to a ground-based system for trapping light fractions of products and a steam generator are most fully implemented environmental requirements.

Claims (6)

1. A method of producing heavy oil, including the construction of a vertical well, opening a formation from a vertical well by pressing the jack in coaxial working chambers, horizontal injection and producing wells, supplying coolant to the formation, collecting products into an underground tank and pumping it to the surface with pumps, characterized in that the jack is made in the form of cylinders temporarily coaxially placed with centralizers in opposite working chambers, provided with perforated sections and against the supporting ends of the guides for composite pipes with perforated sections and tips interacting with pistons located inside the cylinders connected by a flexible element, and the cylinders are periodically connected to each other by telescopic pipes, forming a sealed cavity connected to the hydraulic pump, during which the pistons move in opposite directions together with composite pipes, all pairs of wells are built according to the project, and composite pipes together with working chambers form annular e cavities communicating with the formation and through the corresponding valves and collectors - with the steam line and underground capacity, which also connect through the corresponding valves and collectors with the steam line and underground capacity, and their central channels are closed with equal passage valves, the coolant is supplied to the formation through the steam pipe, collector , valves, perforated sections of composite pipes of injection wells and annular cavities of working chambers with the remaining valves closed, production of a formation from production wells flows through the corresponding valves, the collector and the nozzle into an inclined plane, depending on its composition and viscosity, equipped with a device for regulating the flow thickness, where gas and water are preliminarily separated from it, which is placed in the upper part of the underground tank externally radially connected by channels with an additional well for pumps connected to a trapping system for light fractions, and the lower channel is equipped with a filter. 2. The method according to claim 1, characterized in that the optimal rate of production from the reservoir into horizontal production wells and its flow through them into the underground tank, at which mechanical impurities are not carried out, is determined by adjusting the magnitude of their cross sections. 3. The method according to claim 1, characterized in that first they build an additional well with a bottom below the bottom of the underground reservoir, while specifying the geological and other parameters of the section and the formation. 4. The method according to claim 1, characterized in that for the preparation of products in an underground tank, thermogravitational, thermochemical and electrical methods are used. 5. The method according to claim 1, characterized in that for periodic hydraulic cleaning of the underground tank from mechanical impurities, ground equipment with a flexible sleeve with the necessary set of tools and devices is used. 6. The method according to claim 1, characterized in that the steam generator is placed in a vertical well and associated gas and water from the underground tank are used in its operation.

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