RU2485304C1 - Development method of deposit of high-viscosity oil or bitumen - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: in development method of a high-viscosity oil or bitumen deposit with horizontal wells, which involves drilling of parallel production wells and double-head horizontal wells located above them with arrangement in plan view between production wells, reinforcement of wells with casing strings with secondary drilling of the formation in production wells, pumping of steam or steam-gas mixture to double-head wells and extraction of the product from production wells, in double-head wells there arranged are non-perforated casing strings; at that, double-head wells are connected in series to each other by means of heat-insulated pipelines so that they form a single heating element. Steam or steam-gas mixture is pumped in series through all double-head wells without being released from the casing string to the formation. At that, continuous measurement of temperature of steam or steam-gas mixture is performed at the outlet and the outlet of each double-head horizontal well. When steam or steam-gas mixture temperature is decreased by more than 5-7% of the initial one in rupture of the single heating element there installed is an additional pumping heating station to maintain the temperature and pressure of pumped steam of steam-gas mixture.

EFFECT: increasing high-viscosity oil or bitumen extraction efficiency owing to stable and continuous thermal action on the productive formation, and owing to excluding produced water and condensate in the volume of extracted product; improving environmental situation owing to excluding the possibility of steam penetration via the formation to the surface; reducing material and technical costs.

2 cl, 3 dwg

Description

The invention relates to the oil industry, in particular to the field of development of oil or bitumen deposits, and in particular to methods for producing highly viscous oil or bitumen by producing horizontal wells by thermal exposure to the formation through horizontal steam injectors.

A known method of developing a bitumen deposit (patent RU No. 2307926, IPC ЕВВ 43/24, published on 10/10/2007, bull. No. 28), including drilling heat-injection wells in the formation, pumping coolant through it into the formation, drilling drainage wells below the bottom of the bituminous formation, pumping produced water and sampling in discrete mode.

There is also a known method for developing a highly viscous oil deposit (patent RU No. 2425969, IPC ЕВВ 43/24, published on 08/10/2011, bull. No. 22), which includes the construction of a horizontal production well in the area of the bottom of a productive formation, horizontal injection well above a horizontal production well, injection coolant in the injection well and the selection of formation products from the producing well.

There is also a known method of developing a reservoir of viscous oil or bitumen (patent RU No. 2305762, IPC ЕВВ 43/24, published September 10, 2007, bull. No. 25), which includes drilling a continuous horizontal well with the placement of the inlet section of the well before the formation of a conventionally horizontal section of the well along the strike of the reservoir, the outlet section upward with an inclination from the reservoir to the surface, installation of the casing string, cementing the annulus, installation of tubing with centralizers, filling chku coolant and selection of a viscous oil or bitumen.

The closest in technical essence is the method of developing deposits of highly viscous oil or bitumen (patent RU No. 2287679, IPC ЕВВ 43/24, published November 20, 2006, bull. No. 32), which includes the construction of a number of parallel producing double-well horizontal wells, above a number of parallel producing double-well horizontal wells parallel to it, construction of a series of parallel injection double-well horizontal wells with an arrangement in the plan of injection wells between production wells, injection of water vapor through a series of parallel s dvuhustevyh horizontal injection wells through both the mouth of each injection dvuhustevoy horizontal well, the selection of products through a number of parallel horizontal dvuhustevyh producing wells and the injection wells of flat construction in between the production and injection wells, via which pump solvent heavy oil or bitumen.

The disadvantages of the above analogues are:

- firstly, the low efficiency of extraction of highly viscous oil and bitumen due to the need to pump large volumes of superheated steam into the reservoir, which, when condensed, turns into water, flooding the pumped product, which requires additional costs for its further processing;

- secondly, the implementation of these technologies requires high-performance steam generators;

- thirdly, premature breakthrough of water and condensate from a steam injection well to a production well is possible;

- fourthly, low environmental friendliness of production, if the injection pressure is exceeded, steam breakthrough to the surface can occur.

The technical objectives of the invention are:

- increasing the efficiency of development of deposits of high viscosity oil or bitumen due to the stable and continuous thermal effects on the reservoir;

- reduction of produced water along with the exclusion of the share of condensate in the volume of selected products;

- reduction of specific material and technical costs for the production of highly viscous oil or bitumen due to the constant regeneration of the coolant - water vapor or gas mixture, as well as through the use of less powerful and expensive steam generating equipment;

- improving the environmental friendliness of the extraction of high-viscosity oil or bitumen by eliminating the breakthrough of steam (gas-vapor mixture) through the reservoir to the surface.

The problem is solved by the method of developing deposits of highly viscous oil or bitumen, including drilling parallel production wells and horizontal double-well wells located above them with a plan in between the production wells, securing the wells with casing strings with a secondary opening in the production wells, injecting steam or gas mixture into the double-well wells and production selection from production wells.

New is the fact that non-perforated casing strings are placed in double-well wells, and double-well wells are connected in series using heat-insulated pipelines so that they form a single heating element, and steam or gas-vapor mixture is pumped sequentially through all double-well wells without being discharged from the casing into formation, moreover, they constantly measure the temperature of the steam or gas mixture at the inlet and outlet of each two-well horizontal well s, and, by lowering the temperature of the steam or vapor mixture by more than 5.7% of the original, in the rupture of a single heating element mounted heatable additional pumping-station to maintain the temperature and pressure of the pumped vapor or vapor mixture.

Also new is the fact that before taking products into production wells, steam is injected until the temperature of the produced production of the formation is raised from the corresponding well above the melting temperature of highly viscous oil or bitumen.

Figure 1, 2, 3 presents a diagram of the implementation of the proposed method: figure 1 is a longitudinal profile of the reservoir (section A-A of figure 3), figure 2 is a diagram of the location of wells in the field, figure 3 is a transverse reservoir profile.

The proposed method is as follows.

In the field of high viscosity oil or bitumen - productive formation 1 (Fig.1, 2, 3), a number of parallel producing horizontal wells 2 are built in the bottom of the formation 1 (Fig.3). Above a number of producing horizontal wells 2, a series of parallel double-well horizontal wells 3 (FIGS. 1, 2, 3) are built in parallel with it in the central part of the formation 1 (FIG. 3) with a horizontal planar double-well 3 being arranged between horizontal producing wells 2 (FIG. 2).

For example, if a highly viscous oil or bitumen field is represented by a 30 m thick reservoir, then the vertical distance between the row of producing 2 (Fig. 3) and the row of horizontal well borehole 3 should be no more than half the thickness of the reservoir, in this example, 14 m.

The horizontal distance between the nearby two-well wells 3 (Fig. 3) and between the nearby producing horizontal wells 2 should be no more than half the thickness of the reservoir, in this example, 14 m. Moreover, the horizontal distance between the two-well 3 and horizontal producing wells 2 should be half the distance between the wells in a row, in this example, 7 m.

The producing horizontal wells 2 (Fig. 1) are equipped with perforated casing strings and cement the annulus from the mouth 4 to the roof of the producing formation 1, and the double-mouth horizontal wells 3 are equipped with non-perforated casing strings and cement the annular space on both sides from the mouth 5 to the roof of the producing formation 1 .

Double-mouth horizontal wells 3 (figure 2) using thermally insulated pipelines 6 are connected together in series so that they form a single heating element.

The double-mouth horizontal wells 3 (Fig. 1) are equipped on both sides with a column of lift pipes 7 with a packer 8, and the packers 8 are installed at the depth of the entrance of the double-well horizontal wells in the reservoir 3. The producing horizontal wells 2 are equipped with a string of lift pipes 9 equipped with a pump 10 on the bottom the end, moreover, the pump 10 may be a screw, plunger, or any other known construction for pumping highly viscous oil or bitumen.

Using hydrodynamic studies determine the presence of a hydrodynamic connection between the two wellhead 3 (1, 2, 3) and producing horizontal wells 2.

In the absence of hydrodynamic connection, the development of production wells 2 (Figs. 1, 2, 3) is carried out by injecting steam or a gas mixture into reservoir 1 (Figs. 1, 2, 3) with a temperature of 200-250 ° C until the temperature of the produced reservoir products is raised from the corresponding wells exceeding the melting temperature of high viscosity oil or bitumen. At the same time, steam or a gas-vapor mixture begins to be pumped through two-well horizontal wells 3.

When the conditions for raising the temperature of the produced products of the formation 1 from the corresponding well exceeding the melting temperature of high-viscosity oil or bitumen are met, the injection of steam or gas mixture into the producing wells 2 is stopped and the selection of products begins. At the same time, through a series of parallel double-well horizontal wells 3 (Fig. 2), using a steam generating installation 11, steam or a gas-vapor mixture is continuously pumped at a temperature of 200-250 ° C, and steam is pumped sequentially through all double-well wells without discharge from the casing into layer 1 (Fig.1, 2, 3).

In this case, a constant measurement of the temperature of the steam or vapor-gas mixture at the inlet and outlet of each two-mouth horizontal well 3 is made (Figs. 1, 2).

When lowering the temperature of the steam or gas mixture by more than 5-7% of the initial, in the gap of a single heating element, an additional pumping and heating station 12 (Fig. 2) is installed to maintain the temperature and pressure of the steam (gas mixture) at the level of the initial values.

If there is a hydrodynamic connection between the two wellhead 3 (Figs. 1, 2, 3) and producing horizontal wells 2, the development of producing wells 2 by injection of steam or a gas mixture into the formation 1 is not carried out, but they directly proceed to the selection of products, through a series of parallel two-mouth horizontal wells 3 (figure 2) using a steam generating installation 11 in a continuous mode pump steam or a gas mixture with a temperature of 200-250 ° C, and steam is pumped sequentially through all two-well wells without release of the casing 1 into the reservoir (1, 2, 3), thus producing a constant measurement temperature steam or steam-gas mixture at the inlet and outlet of each horizontal well dvuhustevoy 3 (1, 2).

When lowering the temperature of the steam or gas mixture by more than 5-7% of the initial, in the gap of a single heating element, an additional pumping and heating station 12 (Fig. 2) is installed to maintain the temperature and pressure of the steam (gas mixture) at the level of the initial values.

Heat from the pumped overheated steam or gas-vapor mixture through the double-mouth horizontal wells 3 (Figs. 1, 2, 3) is transmitted through the casing walls to the formation 1, the formation is heated, the heated, highly viscous oil or bitumen flows to the producing horizontal wells 2 and, being received pump 10 (figure 1), is pumped through a column of elevator pipes 9 to the surface.

Using the proposed method allows to increase the efficiency of production of highly viscous oil or bitumen due to the stable and continuous thermal effects on the reservoir, as well as by eliminating incidentally produced water and condensate in the volume of selected products. In addition, the proposed method, in contrast to the steam-cycle method of pumping coolant into the formation, is more environmentally friendly by eliminating the possibility of steam breaking through the formation to the surface. It allows to reduce the specific material and technical costs for the production of highly viscous oil or bitumen due to the constant regeneration of the coolant - water vapor or gas mixture, as well as through the use of less powerful and expensive steam generator equipment. There is no need to produce and prepare large volumes of water to generate steam.

Claims (2)

1. A method of developing a highly viscous oil or bitumen deposit by horizontal wells, including drilling parallel production wells and horizontal dual-well wells located above them with a plan in between the production wells, securing the wells with casing strings with a secondary opening in the production wells, injecting steam or a gas mixture into double-well wells and production selection from production wells, characterized in that non-perforated casing strings are placed in double-well wells, etc. why do two-well wells with the help of heat-insulated pipelines be connected together in series so that they form a single heating element, moreover, steam or a gas-vapor mixture is pumped sequentially through all double-well wells without being discharged from the casing into the formation, and steam or gas-vapor mixture is continuously measured at the outlet and exit from each two-well horizontal well, with a decrease in the temperature of the steam or gas mixture by more than 5-7% of the initial in the gap of a single heating element, an additional pump-heating station is installed to maintain the temperature and pressure of the pumped steam or gas-vapor mixture. 2. The method according to claim 1, characterized in that prior to the selection of products in the producing wells, steam is injected until the temperature of the produced production of the formation is raised from the corresponding well above the melting point of high viscosity oil or bitumen.

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