阅读说明：本技术 一种基于热采锅炉的蒸汽及烟道气的段塞式注气采油工艺 (Slug type gas injection oil extraction process based on steam and flue gas of thermal recovery boiler ) 是由 张翀 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种基于热采锅炉的蒸汽及烟道气的段塞式注气采油工艺,属于稠油开发工艺技术领域,解决了现有稠油开发工艺方法开采效果不理想的问题,其技术要点是：包括注入井,所述注入井内设置有套管,所述套管用于固定地层,所述套管内设置有油管,所述油管用于间隔注入蒸汽和烟道气,包括如下步骤：步骤(1)：把锅炉排出的烟道气降低温度,锅炉产生蒸汽进入油管；步骤(2)：去除烟道气中的灰尘,防止化学气体腐蚀油管；步骤(3)：去除烟道气中的水分；步骤(4)：为烟道气进入油管提供压力；步骤(5)：对烟道气进行再次除水；步骤(6)：对烟道气进行加压,进行有效回收,减少排放污染,具有能够提高稠油开发效果的优点。(The invention discloses a slug type gas injection oil extraction process based on steam and flue gas of a thermal recovery boiler, belongs to the technical field of thick oil development processes, solves the problem that the existing thick oil development process method is not ideal in recovery effect, and has the technical key points that: including the injection well, be provided with the sleeve pipe in the injection well, the sleeve pipe is used for the fixed formation, be provided with oil pipe in the sleeve pipe, oil pipe is used for interval injection steam and flue gas, includes the following step: step (1): reducing the temperature of the flue gas discharged by the boiler, and enabling the steam generated by the boiler to enter an oil pipe; step (2): dust in the flue gas is removed, and chemical gas is prevented from corroding the oil pipe; and (3): removing moisture from the flue gas; and (4): providing pressure for flue gas to enter the oil pipe; and (5): the flue gas is dewatered again; and (6): the method has the advantages of pressurizing the flue gas, effectively recovering, reducing emission pollution and improving the development effect of the thickened oil.)

1. The slug type gas injection oil extraction process based on steam and flue gas of a thermal recovery boiler is characterized by comprising an injection well, wherein a sleeve is arranged in the injection well, the sleeve is used for fixing a stratum, an oil pipe is arranged in the sleeve, and the oil pipe is used for injecting the flue gas and the steam at intervals, and further comprising the following steps:

step (1): reducing the temperature of the flue gas discharged by the boiler, and enabling the steam generated by the boiler to enter an oil pipe;

step (2): removing dust from the flue gas;

and (3): removing moisture from the flue gas;

and (4): providing pressure for flue gas to enter the oil pipe;

and (5): the gas is dewatered again;

and (6): the flue gas is pressurized.

2. The process of claim 1, wherein the flue gas temperature of the flue gas is reduced to below 40 ℃ by cooling with heat exchange gas in step (1).

3. The process of claim 1, wherein in step (2), the dust containing sulfur and nitrate generated by burning coal is removed.

4. The thermal recovery boiler steam and flue gas based slug gas injection oil recovery process of claim 3 wherein in step (2) dust removal is used to remove corrosive chemical gases.

5. The process of claim 1, wherein in step (3), a micro-pressure freeze dryer is used, and the micro-pressure freeze dryer changes the water vapor in the flue gas from gas to liquid.

6. The thermal recovery boiler based slug type gas injection oil recovery process of steam and flue gas according to claim 1, characterized in that in step (4), a screw compressor is used, which provides pressure for the flue gas.

7. The process of claim 1, wherein a pressure freeze dryer is used in step (5), and the pressure freeze dryer is used to remove water from the pressurized flue gas.

8. The thermal recovery boiler based slug gas injection oil recovery process of steam and flue gas of claim 1 wherein in step (6) a flue gas booster is employed, the flue gas booster being used to pressurize the flue gas into the oil pipe.

Technical Field

The invention relates to the technical field of thick oil development processes, in particular to a slug type gas injection oil extraction process based on steam and flue gas of a thermal recovery boiler.

Background

The task of oil extraction engineering is to enable oil and gas to flow into a well smoothly through a series of engineering technical measures capable of acting on an oil reservoir, and the well is lifted to the ground efficiently to be separated and metered; the goal is to economically and efficiently increase oil wells and oil recovery. For different oil properties, different development modes are adopted for exploitation, wherein the thickened oil has abundant reserves in a plurality of oil fields such as Liaohe, Shengli, Tahe and the like in China, and the main method for developing the thickened oil is to reduce the viscosity and improve the fluidity of the thickened oil, thereby improving the extraction degree and the development effect.

The main development modes of the thick oil comprise steam huff and puff, steam drive, in-situ combustion and the like, but with the extension of development time, stratum energy is lacked, and difficultly-used reserves are difficult to extract, so that the problems of small steam swept area, weak steam displacement force, high difficulty in implementing the in-situ combustion process, difficulty in controlling underground combustion and the like exist, and the development effect of the thick oil is restricted.

On the basis of the original steam injection, flue gas is injected into the same oil pipe at intervals. The main components of the flue gas are carbon dioxide and nitrogen, and the thick oil is heated and subjected to viscosity reduction by injecting steam for a period of time in a slug injection mode, so that the thick oil has certain fluidity. In addition, carbon dioxide in the flue gas can be dissolved in the thick oil, so that the thick oil expands and becomes large in volume, and the viscosity is reduced again. The nitrogen in the flue gas is inert gas, is insoluble in water and oil, and can lift the viscosity-reduced thick oil, thereby improving the development effect.

Disclosure of Invention

In view of the defects in the prior art, an object of the embodiments of the present invention is to provide a slug type gas injection oil extraction process based on steam and flue gas of a thermal recovery boiler, so as to solve the above problems in the background art.

In order to achieve the purpose, the invention provides the following technical scheme:

the slug type gas injection oil extraction process based on steam and flue gas of a thermal recovery boiler comprises an injection well, wherein a sleeve is arranged in the injection well, the sleeve is used for fixing a stratum, an oil pipe is arranged in the sleeve, and the oil pipe is used for injecting the flue gas and the steam at intervals, and further comprises the following steps:

step (1): reducing the temperature of the flue gas discharged by the boiler, and enabling the steam generated by the boiler to enter an oil pipe;

step (2): dust in the flue gas is removed, and chemical gas is prevented from corroding the oil pipe;

and (3): removing moisture from the flue gas;

and (4): providing pressure for flue gas to enter the oil pipe;

and (5): the gas is dewatered again;

and (6): the flue gas is pressurized, so that the flue gas can be effectively recovered, and the emission pollution is reduced.

As a further proposal of the invention, in the step (1), the temperature of the flue gas above 200 ℃ is effectively reduced to below 40 ℃ by adopting heat exchange gas for temperature reduction.

As a further proposal of the invention, in the step (2), dust such as sulfur, nitre and the like generated by coal burning is removed.

As a further proposal of the invention, in the step (2), dust removal is used for removing corrosive chemical gases such as sulfur.

As a further scheme of the invention, in the step (3), a micro-pressure freeze-drying machine is adopted, and the micro-pressure freeze-drying machine changes the water vapor in the flue gas from a gaseous state to a liquid state.

As a further proposal of the invention, in the step (4), a screw compressor is adopted, and the screw compressor provides pressure for the flue gas, so as to prevent the damage caused by no pressure gas entering the subsequent equipment.

As a further aspect of the present invention, a pressurized freeze dryer is used in step (5), and the pressurized freeze dryer is used to remove water from the pressurized flue gas again.

As a further proposal of the invention, in the step (6), a flue gas booster is adopted, and the flue gas booster is used for pressurizing the flue gas and entering the oil pipe.

In summary, compared with the prior art, the embodiment of the invention has the following beneficial effects:

the invention injects steam and flue gas into the oil pipe at intervals, not only adopts a flue gas-steam slug injection mode, but also has obvious development effect compared with the traditional pure steam injection mode, no matter in steam huff and puff or steam drive. The main components of the flue gas are carbon dioxide and nitrogen, and the thick oil is heated and subjected to viscosity reduction by injecting steam for a period of time in a slug injection mode, so that the thick oil has certain fluidity. In addition, carbon dioxide in the flue gas can be dissolved in the thick oil, so that the thick oil expands and becomes large in volume, and the viscosity is reduced again. The nitrogen in the flue gas is inert gas, is insoluble in water and oil, and can lift the viscosity-reduced thick oil, thereby improving the development effect.

To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the invention.

Reference numerals: 1-casing pipe, 2-oil pipe, 3-injection well, 4-steam injection boiler, 5-heat exchanger cooling, 6-purification and dust removal, 7-micro-pressure cold dryer, 8-screw compressor, 9-pressure cold dryer, 10-flue gas booster.

Detailed Description

In the description of the present invention, it is to be understood that the terms "longitudinal," "lateral," "upper," "lower," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and thus are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Specific implementations of the present invention are described in detail below with reference to specific embodiments.

In one embodiment, a process for producing oil by slug gas injection based on steam and flue gas of thermal recovery boiler, referring to fig. 1, comprises an injection well 3, a casing 1 is arranged in the injection well 3, the casing 1 is used for fixing the stratum, an oil pipe 2 is arranged in the casing 1, the oil pipe 2 is used for injecting steam and flue gas at intervals, and is characterized by comprising the following steps:

step (1): reducing the temperature of the flue gas discharged by the boiler, and enabling the steam generated by the boiler to enter an oil pipe;

step (2): dust in the flue gas is removed, and chemical gas is prevented from corroding the oil pipe;

and (3): removing moisture from the flue gas;

and (4): providing pressure for flue gas to enter the oil pipe;

and (5): the gas is dewatered again;

and (6): the flue gas is pressurized, so that the flue gas can be effectively recovered, and the emission pollution is reduced.

In this embodiment, steam is injected into the oil pipe 2 first, a period of time is injected, then flue gas is injected into the oil pipe 2, the situation is repeated, the steam and the flue gas are injected into the oil pipe 2 in sections, the steam is injected first, then the flue gas is injected, then the steam is injected, the effect of the steam is that the oil extraction efficiency is improved, the oil extraction speed is increased, the well is closed for a period of time, then the exploitation is performed, the hot steam can reduce the viscosity of thick oil in the stratum, but the steam is changed into water along with the increase of time, the swept area is limited, the carbon dioxide is added to dissolve the steam with the water in the steam, the swept area is increased, the viscosity of the thick oil is effectively reduced, the flue gas contains non-condensable gases such as nitrogen, the stratum pressure can be supplemented, the steam heat carrying capacity is enhanced, the steam trend is controlled, the heat exchange process of the steam and the crude oil in the stratum is enhanced, and the utilization rate of the injected heat energy is improved, thereby improving the oil recovery effect.

Through section plug type oil recovery, can realize two kinds of viscous crude development modes, firstly the mode of handling in, realize gas injection and oil recovery simultaneously in a well, just inject a certain amount of steam and flue gas into oil pipe 2 earlier, close the well for a period of time, treat that the heat energy of steam is to the oil reservoir diffusion back, open the well production again, this kind of mode injection well also is the extraction well, is applicable to single-well exploitation. And the other is a steam flooding mode, steam and flue gas are injected from an injection well, high-temperature steam heats underground thick oil, and the thick oil is extracted from an extraction well. Compared with the traditional huff and puff or steam flooding method, the method only injects the steam generated by heating the boiler into the bottom of the well, and the development effect of the thickened oil is obviously not ideal.

The main components of the flue gas are carbon dioxide and nitrogen, and the thick oil is heated and subjected to viscosity reduction by injecting steam for a period of time in a slug injection mode, so that the thick oil has certain fluidity. In addition, carbon dioxide in the flue gas can be dissolved in the thick oil, so that the thick oil expands and becomes large in volume, and the viscosity is reduced again. The nitrogen in the flue gas is inert gas, is insoluble in water and oil, and can lift the viscosity-reduced thick oil, thereby improving the development effect. The traditional method of huff and puff or steam flooding is to inject the steam generated by heating the boiler to the bottom of the well.

In one embodiment, referring to FIG. 1, in step (1), heat exchange gas cooling 5 is used to effectively cool the flue gas above 200 ℃ to below 40 ℃ and steam is injected into steam boiler 4 to generate steam.

In this embodiment, the flue gas is through heat transfer gas cooling 5, can drop the temperature of flue gas to 40 degrees to let the steam temperature in the flue gas also drop, be close to the normal atmospheric temperature, make things convenient for follow-up cooling dewatering. Water in the flue gas is subjected to dehydration twice and pressurization once, a dry environment and a certain pressure are provided for the flue gas adding machine, the requirement of the working environment of the flue gas adding machine is met, a pure external environment is provided for the injection of carbon dioxide and nitrogen, and therefore the efficiency of steam displacement and viscosity reduction of gas in a well is improved.

In one embodiment, referring to fig. 1, in step (2), dust such as sulfur and nitrate generated from coal burning is removed by using a clean dust removal 6.

Further, referring to fig. 1, in step (2), the clean dust 6 is used to remove corrosive chemical gases such as sulfur.

In one embodiment, referring to fig. 1, in step (3), a micro-pressure freeze dryer 7 is used, and the micro-pressure freeze dryer 7 changes the water vapor in the flue gas from a gaseous state to a liquid state.

In one embodiment, referring to fig. 1, in step (4), a screw compressor 8 is employed, the screw compressor 8 providing pressure to the flue gas for preventing damage caused by no pressurized gas entering the subsequent equipment.

In one embodiment, referring to fig. 1, a pressure freeze dryer 9 is employed in step (5), the pressure freeze dryer 9 being used to remove water from the flue gas under pressure again.

In one embodiment, referring to FIG. 1, in step (6), a flue gas booster 10 is employed, the flue gas booster 10 being used to pressurize the flue gas entering the oil pipe.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.