RU2549654C2 - Nitrogen compressor plant to increase bed production rate (versions) - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions is related to oil production industry, in particular, to secondary and tertiary methods of enhanced oil recovery for beds with low oil saturation that envisage use of equipment for production of gaseous nitrogen with high pressure and temperature. Nitrogen compressor plant comprises a multistage piston-type compressor with a power drive unit made as diesel engine, and gas-separating unit. Output of the compressor intermediate stage is coupled to input of gas-separating unit. Output of gas-separating unit is coupled to input of the compressor stage, which follows the intermediate stage. At that nitrogen compressor plant includes heat exchanger, which working medium input is coupled to the compressor output. Input of the compressor heat exchanger is coupled to exhaust output of diesel engine. Gas-separating unit is made as a hollow-fibre membrane unit. Output of the heat exchanger working medium is coupled to input of additional heater. At that output of the additional heater serves as output of the station.

EFFECT: development of more effective means for oil extraction from low-permeable collectors complicated by high paraffin content.

8 cl, 4 dwg

Description

Nitrogen compressor station for enhanced oil recovery (options)

The claimed group of inventions relates to the oil industry, in particular to methods for increasing oil recovery using thermal and gas methods for secondary and tertiary methods for increasing oil recovery (EOR) of formations with reduced oil saturation.

The inventive compressor nitrogen stations can be used to increase the oil recovery factor (ORF) of low-permeability and highly paraffined deposits, due to the production and use of gaseous nitrogen with high pressure and temperature.

The prior art.

In Russia, as in other oil-producing countries of the world, the share of so-called hard-to-recover reserves is increasing (in low-permeability reservoirs, high-viscosity oils, in highly paraffinized fields). The structure of residual oil reserves is complicated due to intensive oil withdrawals mainly from the active part of reserves and incomplete replenishment of the balance of reserves with new volumes of such highly productive reserves.

The actual scale of application in Russia of modern methods of increasing oil recovery (EOR) is insufficient to overcome the trend of a deterioration in the structure of reserves and have a noticeable effect on the dynamics of a deterioration in the structure of reserves and the effective use of the potential of recoverable oil reserves (“The concept of state management of rational use of oil reserves”. RVO “ZARUBEZHNEFT”, Moscow, 2003).

The efficiency of oil recovery from oil reservoirs by modern, industrially developed development methods in all oil-producing countries is today considered unsatisfactory, despite the fact that the consumption of petroleum products is growing from year to year. The average final oil recovery in different countries and regions is from 25 to 40%.

In the prior art, a method for increasing oil recovery is known, including the use of a pack of nitrogen obtained as an oil displacing agent in a formation by injecting aqueous solutions of sodium nitrite and an aqueous solution of an inorganic acid ammonium salt into the formation, adding hydrochloric acid, characterized in that the inorganic ammonium salt acids use ammonium chloride or ammonium sulfate with a ratio of the volume of an aqueous solution of sodium nitrite and the volume of an aqueous solution of ammonium chloride or ammonium sulfate 1: 3, to which th add about 1.25. % hydrochloric acid, then a pack of stable foam is pumped in - a pack of the indicated nitrogen, additionally containing 3-4 vol. % foaming agent - nonionic surfactant. The reaction of nitrogen evolution occurs in reservoir conditions at elevated temperature. The injection is carried out sequentially: a pack of nitrogen - a pack of foam, a pack of nitrogen - a pack of foam, etc. (RF patent No. 2236575, Method for improving oil recovery of low permeability formations, 2004, ЕВВ 43/00 [1]).

The disadvantage of this method [1] is the complicated technology for the preparation of oil-displacing agent, in connection with this, the cost of produced oil increases sharply, which in turn leads to low profitability of this method.

It is known to use a method for producing heavy oils in which a solvent is introduced into water vapor. As a solvent, diesel fuel is introduced into the steam with a temperature of 330-360 K (57-87 ° C) in the range of 0.005 wt. % (Patent 2117756, Method for the recovery of heavy oils, 1998, EV 43/24 [2]). This method [2] has high energy consumption for steam production and unsafe technology.

The closest analogue, selected as a prototype for a method of increasing oil recovery, is the invention "Method for the production of oil from wells" (RF patent No. 2212524, 06.20.2003, ЕВВ 43/00) [3]). According to this invention, a carrier gas is used as a working medium, which is precompressed, heated to pressures and temperatures that in the oil layer exceed critical parameters sufficient to dissolve the oil in the carrier gas.

The disadvantage of the prototype [3] is the increased energy intensity of the method in terms of heating the carrier gas.

Known mobile nitrogen compressor station (Russian Federation No. 114490 MPK F04B 41/00, 2011 [4]), which contains the first and second power drives, first and second compressors, gas separation unit, a liquid cooling system with fans. Moreover, the first compressor contains an air cooler at the outlet, the second compressor is multi-stage piston and contains intermediate nitrogen coolers.

The disadvantage of this analogue [4] is the provision of a relatively low temperature of nitrogen, insufficient to obtain the required increase in the oil recovery factor.

Also known is a mobile nitrogen-compressor station (RF patent No. 2187698 for an invention, IPC F04B 41/00, F04B 41/06, 2001 [5]). The station contains an air compressor. The latter is made piston and multi-stage. The output of the second stage of compression of the air compressor through a refrigerator and a water-oil separator is connected to the inlet of the membrane gas separation apparatus through a filter unit. The outlet of the gas separation apparatus is connected to the inlet of the third compression stage of the air compressor.

The specified analogue [5] has an inherent disadvantage of analogue [4].

Known mobile nitrogen compressor station (St.-RF of the Russian Federation No. 38030 for a utility model, IPC F04B 41/00, 2004 [6]), which uses two small-sized reciprocating multi-stage compressors and a gas separation apparatus. The outputs of the third compressor stages are connected to the input of the gas separation apparatus, and the output of the gas separation apparatus is connected to the input of the fourth stage of the first compressor, the output of the fourth stage of the first compressor is connected to the input of the fourth stage of the second compressor. The drive of one compressor through a mechanical clutch and driveshaft is carried out from a diesel engine of the car, the second - from the engine of the chassis of the car.

The specified analogue [6] has the disadvantage of analogue [4].

The specified mobile nitrogen station [6] is the set of essential features the closest device of the same purpose to the claimed invention. Therefore, it is taken as a prototype.

Disclosure of invention

The technical problem to which the claimed inventions are directed is to develop highly efficient devices for increasing the oil recovery coefficient from low-permeability reservoir rocks, highly paraffined deposits.

The use of the claimed inventions ensures, at high temperature and pressure, the guaranteed dissolution of oil in nitrogen and then the displacement of the mixture from low-permeability and highly paraffinized formations.

The technical result provided by the claimed compressor nitrogen stations is to increase the temperature of nitrogen at the outlet of the station and the simultaneous utilization of the heat generated during operation of the station.

The essence of the inventive nitrogen compressor station according to option 1 is that the station contains a multi-stage reciprocating compressor with a power drive made in the form of a diesel engine, and a gas separation unit. The output of the intermediate stage of the compressor is connected to the input of the gas separation unit, and the output of the gas separation unit is connected to the input of the stage of the compressor following the intermediate stage. It differs in that the station also contains a heat exchanger, the input of the working medium of which is connected to the compressor output. In this case, the heat transfer medium inlet of the heat exchanger is connected to the exhaust outlet of the diesel engine.

The essence of the claimed nitrogen compressor station according to option 2 is that the station contains the first and second compressors, the power drives of each of which are made in the form of a diesel engine. The output of the first compressor is connected to the input of the gas separation unit, the output of the gas separation unit is connected to the input of the second compressor. It differs in that the station also contains a heat exchanger, the input of the working medium of which is connected to the output of the second compressor. In this case, the heat transfer medium inlet of the heat exchanger is connected to the exhaust outlet of the said diesel engines.

The gas separation unit of the stations according to both options is preferably made in the form of a hollow fiber membrane unit. The output of the working medium of the heat exchanger can be connected to the input of an additional heater. The output of the additional heater is the output of the station. The input of the working medium of the heat exchanger can be connected to the output of the working medium of the heat exchanger through the first control valve, and the input of the heat transfer medium of the heat exchanger can be connected to the output of the heat transfer medium of the heat exchanger through the second control valve.

A brief description of the drawings.

Figures 1 and 2 show a generalized diagram of a nitrogen compressor station according to options 1 and 2, in FIG. 3 - scheme of the station according to option 1, Fig. 4 - scheme of the station according to option 2.

The implementation of the invention.

The method of increasing oil recovery, implemented by the stations in both options, is as follows.

At the first stage, nitrogen gas is obtained from the air, preferably compressed to a pressure of 400 atm. In this case, use:

- at least one compressor, the power drive of which is a diesel engine;

- gas separation unit.

To obtain compressed nitrogen, additional compressors can be used, the power drives of which can be diesel engines, electric motors or other power plants.

At the second stage, compressed nitrogen is heated by exhaust gases of at least one of the mentioned diesel engines.

In the third stage, if necessary, carry out additional heating of nitrogen to a temperature of 180-500 ° C.

Then nitrogen, heated to a temperature of 180-500 ° C under a pressure of about 400 atm., Is fed into the oil reservoir.

The nitrogen compressor station for enhanced oil recovery according to embodiment 1 comprises a nitrogen preparation unit (1) (Fig. 3), which in turn contains a reciprocating multistage compressor (2) and a gas separation unit (3) with hollow fiber membranes. The nitrogen preparation unit (1) is designed to receive nitrogen from the air and compress it to a pressure of about 400 atm. The power drive of said compressor (2) is a diesel engine (4).

The compressor (2) is designed to compress atmospheric air and supply it to the gas separation unit (3). The gas separation unit (3) is designed to separate air into a gas with a high nitrogen content (hereinafter referred to as nitrogen) and permeate - the rest of the gas with a high oxygen content.

The output (11) of one of the intermediate stages of the compressor (1) is connected to the input of the gas separation unit (3).

The output of the gas separation unit (3) is connected to the input (12) of the compressor stage (1) following the aforementioned intermediate stage.

The output (13) of the last stage of the compressor (2) (it is the nitrogen output of the nitrogen preparation unit (1)) is connected to the input of the working medium (5) of the heat exchanger (6). Moreover, between the mentioned output (13) of the compressor (2) and the heat exchanger (6) there are no coolers installed at the output of known analogue stations.

The heat exchanger (6) is a device in which heat is transferred from the coolant to the working medium. In this case, the coolant is isolated from the working medium. The inlet of the heat carrier (7) of the heat exchanger (6) is connected to the exhaust outlet of the diesel engine (4). The coolant outlet (8) communicates with the atmosphere.

If additional heating of the obtained nitrogen is not required, then the outlet of the working medium (9) of the heat exchanger (6) is the outlet of the station.

To obtain a higher temperature of nitrogen at the outlet of the station than that which can be provided with exhaust gases of a diesel engine (4), the outlet of the working medium (9) of the heat exchanger (6) is connected to an additional heater (10). In this case, the output of the station is the output of an additional heater (10).

The design of the station provides nitrogen at its outlet with a pressure of about 400 atm. and a temperature of 180-500 ° C.

Nitrogen compressor station according to option 1 operates as follows.

At the inlet of the nitrogen preparation unit (1), air enters, which is compressed by compressors (2) and is divided into nitrogen and permeate in the gas separation unit (3). Nitrogen can then be further compressed. Then nitrogen is supplied to the heat exchanger (6).

In the heat exchanger (6), nitrogen is heated by the exhaust gases of diesel engines (4). If the heat exchanger (6) has bypass lines, the nitrogen temperature at the outlet of the heat exchanger is changed by means of control valves.

If there is an additional heater (10), the nitrogen coming from the heat exchanger is additionally heated.

In the inventive station according to option 1, the claimed technical result: "reducing the energy consumption of increasing oil recovery in low-permeable formations" is achieved due to the fact that the station contains a multi-stage reciprocating compressor with a power drive, made in the form of a diesel engine, and a gas separation unit. The output of the intermediate stage of the compressor is connected to the input of the gas separation unit, and the output of the gas separation unit is connected to the input of the stage of the compressor following the intermediate stage. It differs in that the station also contains a heat exchanger, the input of the working medium of which is connected to the compressor output. In this case, the heat transfer medium inlet of the heat exchanger is connected to the exhaust outlet of the diesel engine. The achievement of the technical result is facilitated by the production of nitrogen from the air, and the utilization of heat from the exhaust gases of the diesel power drive to heat this nitrogen.

The nitrogen compressor station for enhanced oil recovery in option 2 contains a nitrogen preparation unit (1) (Fig. 4), which in turn contains the first (2) and second (14) compressors and a gas separation unit (3) with hollow fiber membranes. The nitrogen preparation unit (1) is designed to receive nitrogen from the air and compress it to a pressure of about 400 atm. The power drive of the first compressor (2) is a diesel engine (4), and the power drive of the second compressor (14) is a diesel engine (15).

The first compressor (2) is designed to compress atmospheric air and supply it to the gas separation unit (3). Therefore, the output of the first compressor

(2) connected to the inlet of the gas separation unit (3). Gas separation unit

(3) is designed to separate air into a high nitrogen gas (hereinafter referred to as nitrogen) and permeate, the rest of the high oxygen gas.

The output of the gas separation unit (3) (aka the nitrogen output of the nitrogen preparation unit (1)) is connected to the input of the second compressor (14). The output of the second compressor (14) is connected to the input of the working medium (5) of the heat exchanger (6). Moreover, between the mentioned output of the second compressor (14) and the heat exchanger (6) there are no coolers installed at the output of known analogue stations.

The heat exchanger (6) is a device in which heat is transferred from the coolant to the working medium. In this case, the coolant is isolated from the working medium. Exits of exhaust gases of both diesel engines (4, 15) are connected to the input of the heat agent (7) of the heat exchanger (6). The coolant outlet (8) communicates with the atmosphere.

If additional heating of the obtained nitrogen is not required, then the outlet of the working medium (9) of the heat exchanger (6) is the outlet of the station.

To obtain a higher temperature of nitrogen at the outlet of the station than that which can be provided with exhaust gases of a diesel engine (4), the outlet of the working medium (9) of the heat exchanger (6) is connected to an additional heater (10). In this case, the output of the station is the output of an additional heater (10).

The design of the station provides nitrogen at its outlet with a pressure of about 400 atm and a temperature of 180-500 ° C.

For the purpose of regulating the temperature of nitrogen at the outlet of the station, the inputs and outputs of the heat exchanger (6) are covered by two bypass lines of the paths, respectively, of the working medium and heat agent. In this case, the inlet of the working medium (5) is connected to the outlet of the working medium (9) through the first control valve (16), and the inlet of the heat agent (7) is connected to the outlet of the heat agent (8) through the second control valve (17). The first (16) and second (17) control valves can be connected to the automation system.

Nitrogen compressor station according to option 2 operates as follows.

At the inlet of the nitrogen preparation unit (1), air enters, which is compressed by compressors (2) and is divided into nitrogen and permeate in the gas separation unit (3). Nitrogen can then be further compressed. Then nitrogen is supplied to the heat exchanger (6).

In the heat exchanger (6), nitrogen is heated by the exhaust gases of diesel engines (4). If the heat exchanger (6) has bypass lines, the nitrogen temperature at the outlet of the heat exchanger is changed by means of control valves.

If there is an additional heater (10), the nitrogen coming from the heat exchanger is additionally heated.

In the inventive station according to option 2, the claimed technical result: "reducing the energy consumption of increasing oil recovery of low-permeability formations" is achieved due to the fact that the station contains the first and second compressors, the power drives of each of which are made in the form of a diesel engine. The output of the first compressor is connected to the input of the gas separation unit, the output of the gas separation unit is connected to the input of the second compressor. It differs in that the station also contains a heat exchanger, the input of the working medium of which is connected to the output of the second compressor. In this case, the heat transfer medium inlet of the heat exchanger is connected to the exhaust outlet of the said diesel engines. The achievement of the technical result is facilitated by the production of nitrogen from the air, and the utilization of heat from the exhaust gases of the diesel power drive to heat this nitrogen.

Industrial applicability

The inventive nitrogen compressor stations to increase oil recovery can be implemented with the present development of the prior art and are effectively used in the oil industry, in particular to increase oil recovery using thermal and gas methods for secondary and tertiary methods of increasing oil recovery (EOR) of reservoirs with low oil saturation reservoirs, in order to increase the oil recovery factor (ORF) of low-permeability and highly paraffined deposits.

INFORMATION SOURCES

1. RF patent No. 2236575, Method for improving oil recovery of low permeability formations, 2004, ЕВВ 43/00.

2. Patent 2117756, Method for the extraction of heavy oils, 1998, EV 43/24.

3. RF patent No. 2212524, “Method for the production of oil from wells”, 06/20/2003, ЕВВ 43/00.

4. RF patent No. 1144490 for the utility model "Mobile nitrogen-compressor station", IPC F04B 41/00, 2011.

5. RF patent No. 2187698 for an invention, Mobile nitrogen-compressor station, IPC F04B 41/00, F04B 41/06, 2001.

6. RF patent No. 38030 for utility model, Mobile nitrogen compressor station, IPC F04B 41/00, 2004.

Claims (8)

1. A nitrogen compressor station comprising a multistage reciprocating compressor with a power drive in the form of a diesel engine and a gas separation unit, wherein the output of the intermediate stage of the compressor is connected to the input of the gas separation unit, and the output of the gas separation unit is connected to the input of the compressor stage following the intermediate stage characterized in that the station also contains a heat exchanger, the input of the working medium of which is connected to the output of the compressor, while the input of the heat transfer medium is a heat exchanger ka is connected to the exhaust of a diesel engine. 2. Nitrogen compressor station according to claim 1, characterized in that the gas separation unit is made in the form of a hollow fiber membrane unit. 3. The nitrogen compressor station according to claim 1, characterized in that the outlet of the working medium of the heat exchanger is connected to the input of the additional heater, while the output of the additional heater is the output of the station. 4. The nitrogen compressor station according to claim 1, characterized in that the input of the working medium of the heat exchanger is connected to the output of the working medium of the heat exchanger through the first control valve, and the input of the heat transfer medium of the heat exchanger is connected to the output of the heat transfer medium of the heat exchanger through the second control valve. 5. A nitrogen compressor station containing the first and second compressors, the power drives of each of which are made in the form of a diesel engine, while the output of the first compressor is connected to the input of the gas separation unit, the output of the gas separation unit is connected to the input of the second compressor, characterized in that the station also contains a heat exchanger, the input of the working medium of which is connected to the output of the second compressor, while the input of the heat carrier of the heat exchanger is connected to the exhaust outlet of the said diesel engines . 6. The nitrogen compressor station according to claim 5, characterized in that the gas separation unit is made in the form of a hollow fiber membrane unit. 7. The nitrogen compressor station according to claim 5, characterized in that the outlet of the working medium of the heat exchanger is connected to the input of the additional heater, while the output of the additional heater is the output of the station. 8. The nitrogen compressor station according to claim 5, characterized in that the input of the working medium of the heat exchanger is connected to the output of the working medium of the heat exchanger through the first control valve, and the input of the heat transfer medium of the heat exchanger is connected to the output of the heat transfer medium of the heat exchanger through the second control valve.

Images