RU2316648C1 - Downhole steam-gas generator - Google Patents

Abstract

FIELD: oil production industry, particularly devices for steam-gas mixture generation directly at well bottom.

SUBSTANCE: steam-gas generator comprises air, water and composite fuel inlet channels, fuel nozzle, ignition unit and combustion chamber provided with outlet nozzle. Steam-gas generator additionally has prechamber and evaporation chamber provided with throttling means on inner surface thereof. Throttling means have water discharge sections. Combustion chamber is made as two coaxially arranged shells, which may slide one relatively another to create cooling jacket. Multiple-flighted auger is formed on outer surface of inner shell included in combustion chamber.

EFFECT: simplified structure and increased operational reliability.

2 dwg

Description

The invention relates to the oil industry, and in particular to devices generating a vapor-gas mixture directly at the bottom.

Known combined-cycle plant containing a compressor, a compressor drive in the form of an internal combustion engine, an exhaust manifold, a water injection device connected to a water supply system, and the installation outlet pipe. The compressor input is in communication with the exhaust manifold of the engine and the water injection device, and the compressor output is connected to the outlet pipe. The water injection device can be made in the form of a nozzle, and the installation is equipped with a superheater located between the compressor outlet and the outlet pipe. The engine can be equipped with a cooling system made in the form of a closed circuit, including an expansion tank, a pump and a refrigerator made in the form of a heat exchanger, the refrigerant supply pipes of which are connected to the storage tank. The water supply system can be equipped with a pump, the input of which is connected to the storage tank (RF Patent No. 2101479).

The disadvantage of this installation is the complexity of the process of obtaining a gas-vapor mixture (on the surface of the earth). The gas-vapor mixture obtained in this way when injecting it into the formation requires equipping the well with a ground steam pipe, heat-resistant fittings, heat-insulated pipes, and heat-resistant packer, which complicates and increases the cost of the thermal effect on the oil reservoir.

Also known is a combined-cycle plant with a downhole steam and gas generator (PGG) (US Patent No. 3456721). In a known installation, the initial components (water, fuel and oxidizing agent) are supplied to the steam and gas generator through independent pipelines, and liquefied propane or hydrogen is used as fuel. The combustion chamber of a steam and gas generator is lined on the inside with a heat-resistant material in the form of a ceramic-metal insert (heat-resistant liner), which helps to reduce heat removal from the combustion zone.

The disadvantages of the known gas generator are:

- the presence of a heat-resistant liner in it leads to a complication of the design of the combustion chamber and an increase in its outer diameter, which leads to technical and technological complications;

- the use of such fuels for the operation of a steam and gas generator requires the presence of cryogenic equipment in the installation, which makes the device rather complicated and requiring increased safety measures during operation in the field.

The closest in technical essence is the bottomhole steam and gas generator, which we have chosen as a prototype and consisting of channels for introducing air, fuel mixture and water, a fuel nozzle, an ignition unit and a combustion chamber.

To protect the wall of the combustion chamber from high temperatures, in its upper part there are tangential channels for water inlet, inclined relative to the axis of the device, and a number of water discharge sectors are installed along its length on the inner wall. An output nozzle is installed in the lower part of the combustion chamber (AS No. 899872).

Downhole steam and gas generator has the following disadvantages:

- the design of the known fuel nozzle with an ignition spark assembly does not provide reliable multiple start-up of a steam and gas generator while supplying simultaneously the operating costs of air, fuel and water;

- the flow of water directly into the combustion zone leads to a decrease in temperature in the parietal layer, which leads to soot formation;

- the stability of the liquid film can be achieved by tangential openings of a sufficiently small diameter, which, in turn, depending on the quality of the supplied water, can lead to their clogging, overheating of the wall of the combustion chamber, and exit from the operating state of the gas generator.

The aim of the invention is to simplify the design and increase the reliability of the bottomhole gas and steam generator.

The goal is achieved in that the downhole steam and gas generator, including channels for introducing air, fuel mixture and water, a fuel nozzle, an ignition unit and a combustion chamber with an outlet nozzle, according to the invention is additionally equipped with a pre-chamber and an evaporation chamber, on the inner surface of which narrowing devices with sectors are made water discharge, and the combustion chamber is made in the form of two coaxially located shells with the ability to move relative to each other and the formation of a cooling jacket, while on uzhnoy surface of the inner shell of the combustion chamber is made multistart screw.

Figure 1 shows the bottomhole steam and gas generator.

Figure 2 shows a diagram of a combined cycle plant with a downhole steam and gas generator.

The bottomhole gas and gas generator contains a transition compartment (1) that commutes the life support system with the corresponding channels of the steam and gas generator, a prechamber (2) equipped with an ignition unit, a combustion chamber (3) with a cooling jacket arranged between the inner (4) and outer (5) shells of the chamber. The inner (4) and outer (5) shells of the combustion chamber are arranged to move relative to each other and form a cooling chamber. A multi-auger screw (6) for introducing water into the evaporation chamber (7) is made on the outer surface of the inner shell (4), and narrowing devices with discharge sectors (8) are installed along its length on the inner surface of the wall. An outlet nozzle (9) is installed in the lower part of the steam and gas generator.

Ground equipment includes compressor (11) and technological (12) blocks, water and fuel consumables (13), borehole fittings (14), pipelines (15) connecting all ground blocks, the compressor block is an independent technological unit, which is completed by order (figure 2). The technological unit includes systems for supplying fuel and water to the steam and gas generator, control devices and automatic control of the process of generating the gas mixture, shut-off and control valves and pipelines of water, fuel, air for fastening the steam and gas generator in the transport position; downhole equipment: pipelines for supplying steam (gas) to the gas generator (16), fuel (17), water (18), a voltage supply cable to the ignition device of the prechamber and thermometry (19), a gas and gas generator (20), and a heat-resistant packer (21).

Downhole steam and gas generator works as follows.

At the treated well, surface equipment is mounted (11, 12, 13, 14, 15). The gas and steam generator (20) is lowered into the well on tubing (16) and installed in the formation perforation zone using a heat-resistant packer (21). Air is supplied to the PHG combustion chamber (3) through the tubing, and fuel and water are supplied through pipelines (17), (18). Ignition of the working flow rates of fuel and air supplied to the combustion chamber (3) through the nozzle head (10) takes place using a prechamber (2), where the starting flow rates of fuel and air are preliminarily ignited.

Water is piped (18) from the surface of the earth (from the annular space) into cooling jackets arranged between the inner and outer shells of the combustion chamber, and then through a multi-auger screw (6) into the evaporation chamber (7). In this case, water is heated and partial evaporation occurs. When water enters the narrowing device with a discharge sector (8), water is introduced into the high-temperature flow of combustion products, which contributes to a more complete evaporation of water and an increase in the vapor content in the vapor-gas mixture. The combined-gas mixture thus obtained enters through the nozzle (9) into the producing formation, warming it and facilitating a more complete extraction of oil from the formation. The presence of the output nozzle (9) ensures reliable start-up and a stable mode of operation of the SGP in conditions of increased backpressure.

Claims (1)

Downhole gas and gas generator, including channels for the introduction of air, fuel mixture and water, a fuel nozzle, an ignition unit and a combustion chamber with an outlet nozzle, characterized in that it is additionally equipped with a pre-chamber and an evaporation chamber, on the inner surface of which narrowing devices with sectors of water discharge are made, and the combustion chamber is made in the form of two coaxially located shells with the ability to move relative to each other and the formation of a cooling jacket, while on the outer surface of the inner shell ki combustion chamber formed multistart screw.

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