Device and method for evaluating wax precipitation characteristics and rules of condensate gas reservoir

Abstract

The invention relates to the field of condensate gas reservoirs, and discloses a device and a method for evaluating wax precipitation characteristics and rules of a condensate gas reservoir. The device comprises a reaction kettle, a ring sleeve which is detachably arranged in the reaction kettle and is used for simulating the inner wall environment of a shaft, a temperature control piece arranged on the reaction kettle, a pressure pump communicated with the reaction kettle, an intermediate container arranged between the pressure pump and the reaction kettle, and a microscopic camera, the reaction kettle is provided with an observation window for observation through the microscopic camera, a piston is arranged in the intermediate container, and the pressure pump can drive the piston to reciprocate in the intermediate container so as to drive fluid in the reaction kettle to flow. According to the technical scheme, by means of the intermediate container and the piston, the fluid in the reaction kettle can be driven to flow through the pressure pump, so that the fluid in a flowing state can be more accurately simulated, more accurate wax precipitation characteristics of an oil sample can be obtained, and guidance is provided for wax control and removal measures in field oil and gas production engineering.

Description

Technical Field

[0001] The invention relates to the field of condensate gas reservoirs, in particular to a device for evaluating wax precipitation characteristics and laws in condensate gas reservoirs, and to a method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs. Background Art

[0002] The development of condensate gas reservoirs is becoming increasingly important in the current petroleum industry. However, condensate gas often condenses solid wax during pipeline flow due to changes in temperature and pressure conditions during the development process. Severe wax precipitation can cause wax deposition and even wax blockage in the wellbore and gathering pipelines, resulting in reduced production or even shutdown.

[0003] Condensate gas reservoirs in some areas produce high-wax condensate gas with high wax content and wax precipitation temperature. At the same time, most of the on-site oil and gas pipelines are made of non-insulated materials. The waxy condensate gas gradually drops to ground temperature during pipeline transportation, which is significantly lower than the wax precipitation temperature. Wax is continuously precipitated in this process, attached to the pipe wall and deposited, seriously affecting the safe operation of pipeline transportation and hindering the efficient development of condensate gas reservoirs.

[0004] Therefore, accurately revealing the wax precipitation and wax formation rules in the process of condensate waxy gas reservoir exploitation and solving the problems of wax formation and wax blockage in on-site pipeline transportation are of great significance for guiding the effective production and operation of waxy condensate gas resource development. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of inaccurate analysis results of wax precipitation characteristics of condensate gas reservoirs in the prior art.

[0006] In order to achieve the above-mentioned objectives, the present invention provides, on the one hand, a device for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, which includes a reactor, a detachable annulus sleeve arranged in the reactor for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor, a pressure pump connected to the reactor, an intermediate container arranged between the pressure pump and the reactor, and a microscope camera, wherein the annulus sleeve is used to simulate the inner wall environment of the wellbore, the reactor is provided with an observation window for observation through the microscope camera, a piston is provided in the intermediate container, and the pressure pump can drive the piston to reciprocate in the intermediate container to drive the fluid flow in the reactor.

[0007] In some embodiments, the device comprises two pressure pumps and two intermediate containers respectively connected to two ends of the reactor.

[0008] In some embodiments, the device comprises two reactors connected in series, and a control valve is provided between the two reactors.

[0009] In some embodiments, the reactor is provided with a plurality of sampling holes arranged at intervals along the axial direction of the annulus, and an adsorption rod is provided in each of the sampling holes.

[0010] In some embodiments, the reactor is provided with two observation windows facing each other, the microscope camera is directed toward one of the observation windows, and the device includes a light source directed toward the other observation window.

[0011] In some embodiments, a stirring element is provided in the reaction kettle.

[0012] On the other hand, this solution provides a method for evaluating the wax precipitation characteristics and laws of condensate gas reservoirs, wherein the method uses the device described in the above solution, and the method includes:

[0013] S1, using a cleaning agent to clean the inner cavity of the reactor, and then drying it for later use;

[0014] S2, adjusting the temperature of the reactor to a preset temperature through the temperature control unit and maintaining it for a predetermined time;

[0015] S3, injecting the waxy condensate sample into the reactor, and injecting inert gas so that the pressure in the reactor reaches a preset pressure;

[0016] S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera; and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera; wherein, the piston in the intermediate container is driven to reciprocate by the pressure pump to make the fluid in the reactor flow.

[0017] In some embodiments, in S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor.

[0018] In some embodiments, in S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours.

[0019] In some embodiments, in S3, the inert gas is injected and then left to stand for 1-2 hours, and then excess gas is exhausted to reach the preset pressure.

[0020] In some embodiments, in S4, at a pressure of 15 MPa, the wax precipitation characteristics of the waxy condensate oil sample are observed at 80°C, 60°C, 40°C, and 20°C, respectively; and, at a temperature of 40°C, the wax precipitation characteristics of the waxy condensate oil sample are observed at 15 MPa, 10 MPa, 5 MPa, and normal pressure, respectively.

[0021] In some embodiments, in S4, after the pressure or temperature is changed, the temperature in the reactor is stabilized for 10 minutes before the next observation is performed.

[0022] Through the above technical scheme, with the help of an intermediate container and a piston, the fluid flow in the reactor can be driven by a pressure pump to more accurately simulate the fluid in a flowing state, and a more accurate wax precipitation characteristic of the oil sample can be obtained, providing guidance for wax prevention and elimination measures in on-site oil and gas production projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of the device for evaluating the wax precipitation characteristics and laws of condensate gas reservoirs described in the implementation mode of this scheme.

[0024] Description of Reference Numerals

[0025] 1-reactor, 2-intermediate container, 3-piston, 4-microscope camera, 5-light source, 6-stirring element, 7-control valve, 8-sampling hole, 9-observation window, 10-first pressure gauge, 11-second pressure gauge. DETAILED DESCRIPTION

[0026] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0027] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0028] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0029] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0030] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0031] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0032] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0033] Embodiment 1

[0034] The present solution provides a device for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, which includes a reactor 1, a detachable annulus sleeve arranged in the reactor 1 for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor 1, a pressure pump connected to the reactor 1, an intermediate container 2 arranged between the pressure pump and the reactor 1, and a microscopic camera 4, wherein the annulus sleeve is used to simulate the inner wall environment of the wellbore, the reactor 1 is provided with an observation window 9 for observation through the microscopic camera 4, a piston 3 is provided in the intermediate container 2, and the pressure pump can drive the piston 3 to reciprocate in the intermediate container 2 to drive the flow of fluid in the reactor 1.

[0035] The reactor 1 is a container for containing oil samples, in which a ring sleeve is arranged. The ring sleeve is made of the same material as the simulated wellbore, so that the corresponding wellbore can be simulated.

[0036] The temperature control unit can be arranged outside the reactor 1 to heat the reactor 1 and control its temperature so as to observe the wax precipitation characteristics of the oil sample at a specific temperature.

[0037] The reactor 1 is provided with a transparent observation window 9, and the microscope camera 4 is arranged toward the observation window 9 to collect microscopic image information inside the reactor 1 to obtain wax precipitation characteristics.

[0038] The pressure pump is connected to the reactor 1 through a pipeline to adjust the pressure in the reactor 1. In particular, an intermediate container 2 is provided between the two, and a piston 3 is provided in the intermediate container 2. The parts of the intermediate container 2 located on both sides of the piston 3 are respectively connected to the pressure pump and the reactor 1. When the pressure of the pressure pump changes, the relative position of the piston can change, and the movement of the piston will also cause the fluid in the reactor 1 to flow, so as to more accurately simulate the characteristics of the gas reservoir flowing in the wellbore.

[0039] In this scheme, with the help of an intermediate container and a piston, the fluid flow in the reactor can be driven by a pressure pump to more accurately simulate the fluid in a flowing state, and a more accurate wax precipitation characteristic of the oil sample can be obtained, providing guidance for wax prevention and elimination measures in on-site oil and gas production projects.

[0040] In addition, a first pressure gauge 10 is connected to the pipeline between the intermediate container 2 and the reactor 1, which can be used to measure the pressure in the reactor 1. A second pressure gauge 11 is provided on the pipeline connecting the intermediate container 2 to the pressure pump, which can be used to measure the pressure provided by the pressure pump, that is, the pressures on both sides of the piston 3 of the intermediate container 2 can be measured respectively by the first pressure gauge 10 and the second pressure gauge 11.

[0041] In some embodiments, the device includes two pressure pumps and two intermediate containers 2 respectively connected to the two ends of the reactor 1. Pistons 3 are provided in the two intermediate containers 2, and both ends of the reactor 1 are connected to the pressure pumps. When the fluid in the reactor 1 needs to flow, the pressure of one of the pressure pumps can be increased, and the piston 3 on the corresponding side moves toward the reactor 1, and the pressure of the other pressure pump is reduced, and the piston 3 on the corresponding side moves away from the reactor 1, thereby driving the flow of the fluid in the reactor 1. The two pressure pumps reciprocately increase and decrease pressure, so that the fluid in the reactor 1 can flow back and forth.

[0042] The device comprises two reactors 1 connected in series, and a control valve 7 is arranged between the two reactors 1. The two reactors 1 are connected by a pipeline, and a control valve 7 is arranged on the pipeline to control the connection or disconnection of the two reactors 1. The two reactors 1 can be disconnected from each other, and different pressures and temperatures are set respectively, so that the oil samples in the two reactors 1 can be compared and observed; of course, the two reactors 1 can also be connected to ensure that the reaction conditions therein are the same.

[0043] In addition, the reactor 1 is provided with a plurality of sampling holes 8 arranged at intervals along the axial direction of the annulus, and an adsorption rod is provided in each of the sampling holes 8. The adsorption rod can be made of a material with adsorption properties, which is inserted into the reactor 1 to adsorb the oil sample inside. After the experiment is completed, the adsorption rod can be taken out, the wax sample on it can be extracted, and the component analysis can be performed to obtain the wax precipitation amount and wax precipitation characteristics of the oil sample under different temperature and pressure conditions. The sampling holes 8 are arranged at intervals along the axial direction of the annulus, and wax samples at different positions can be obtained.

[0044] In addition, the reactor 1 is provided with two observation windows 9 facing each other, the microscopic camera 4 faces one of the observation windows 9, and the device includes a light source 5 facing the other observation window 9. The observation window 9 can be made of a transparent material, and light can be introduced into the reactor 1 through the light source 5 to illuminate the oil sample therein, so as to facilitate the acquisition of a microscopic image in the reactor 1 by the microscopic camera 4.

[0045] The reactor 1 is provided with a stirring member 6. The stirring member 6 can be used to stir the oil sample in the reactor 1 so that the solid phase, liquid phase, etc. therein are uniformly mixed.

[0046] On the other hand, the present invention also provides a method for evaluating the wax precipitation characteristics and laws of a condensate gas reservoir, wherein the method uses the device described in the above scheme, and the method comprises:

[0047] S1, using a cleaning agent to clean the inner cavity of the reactor 1, and then drying it for later use;

[0048] S2, adjusting the temperature of the reactor 1 to a preset temperature through the temperature control unit and maintaining it for a predetermined time;

[0049] S3, injecting the waxy condensate oil sample into the reactor 1, and injecting an inert gas so that the pressure in the reactor 1 reaches a preset pressure;

[0050] S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera 4; and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera 4; wherein, the piston 3 in the intermediate container 2 is driven to move back and forth by the pressure pump to make the fluid in the reactor 1 flow.

[0051] Among them, the reactor 1 is heated to a preset temperature by a temperature control device and maintained for a preset time to ensure that the temperature at each position is basically consistent; after the waxy condensate oil sample is injected into the reactor 1, it can be stirred by a stirring member 6 to maintain uniformity; an inert gas is injected to adjust the pressure in the reactor 1, for example, nitrogen can be injected to make the pressure in the reactor 1 reach a preset pressure.

[0052] During the observation process, the piston 3 can be driven to move by a pressure pump, thereby driving the fluid in the reactor 1 to flow, so as to simulate the flow of the gas reservoir in the wellbore.

[0053] In S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor 1. Of course, the cleaning operation also includes cleaning of each pipeline. After the cleaning is completed, the device is placed in a cool and dry place to dry for 24 hours for standby use.

[0054] In S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours. The heating temperature of the temperature control unit is set to a certain target value and maintained for a specific time so that the device as a whole reaches the target value and avoids locations where the temperature does not meet the standard.

[0055] In S3, the inert gas is injected and then left to stand for 1-2 hours, and then the excess gas is discharged to reach the preset pressure. After the inert gas is injected, the reactor 1 is kept still, and after the internal environment is stabilized, the excess gas is discharged to reach a stable preset pressure.

[0056] Wherein, in S4, at a pressure of 15 MPa, the wax precipitation characteristics of the waxy condensate oil sample at 80°C are observed respectively; and at a temperature of 40°C, the wax precipitation characteristics of the waxy condensate oil sample at 15 MPa are observed respectively.

[0057] Among them, in S4, after changing the pressure or temperature, wait for the temperature in the reactor 1 to stabilize for 10 minutes before the next observation. After completing the observation under one pressure and temperature condition, it is necessary to change the pressure or temperature, and then the solid phase, liquid phase, etc. therein can be stirred by the stirring member 6, so that the oil sample therein is re-temperatured, and then the wax precipitation therein is observed, so as to avoid the influence of the previous experimental conditions on the next experiment.

[0058] Embodiment 2

[0059] The present solution provides a device for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, which includes a reactor 1, a detachable annulus sleeve arranged in the reactor 1 for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor 1, a pressure pump connected to the reactor 1, an intermediate container 2 arranged between the pressure pump and the reactor 1, and a microscopic camera 4, wherein the annulus sleeve is used to simulate the inner wall environment of the wellbore, the reactor 1 is provided with an observation window 9 for observation through the microscopic camera 4, a piston 3 is provided in the intermediate container 2, and the pressure pump can drive the piston 3 to reciprocate in the intermediate container 2 to drive the flow of fluid in the reactor 1.

[0060] The reactor 1 is a container for containing oil samples, in which a ring sleeve is arranged. The ring sleeve is made of the same material as the simulated wellbore, so that the corresponding wellbore can be simulated.

[0061] The temperature control unit can be arranged outside the reactor 1 to heat the reactor 1 and control its temperature so as to observe the wax precipitation characteristics of the oil sample at a specific temperature.

[0062] The reactor 1 is provided with a transparent observation window 9, and the microscope camera 4 is arranged toward the observation window 9 to collect microscopic image information inside the reactor 1 to obtain wax precipitation characteristics.

[0063] The pressure pump is connected to the reactor 1 through a pipeline to adjust the pressure in the reactor 1. In particular, an intermediate container 2 is provided between the two, and a piston 3 is provided in the intermediate container 2. The parts of the intermediate container 2 located on both sides of the piston 3 are respectively connected to the pressure pump and the reactor 1. When the pressure of the pressure pump changes, the relative position of the piston can change, and the movement of the piston will also cause the fluid in the reactor 1 to flow, so as to more accurately simulate the characteristics of the gas reservoir flowing in the wellbore.

[0064] In this scheme, with the help of an intermediate container and a piston, the fluid flow in the reactor can be driven by a pressure pump to more accurately simulate the fluid in a flowing state, and a more accurate wax precipitation characteristic of the oil sample can be obtained, providing guidance for wax prevention and elimination measures in on-site oil and gas production projects.

[0065] In addition, a first pressure gauge 10 is connected to the pipeline between the intermediate container 2 and the reactor 1, which can be used to measure the pressure in the reactor 1. A second pressure gauge 11 is provided on the pipeline connecting the intermediate container 2 to the pressure pump, which can be used to measure the pressure provided by the pressure pump, that is, the pressures on both sides of the piston 3 of the intermediate container 2 can be measured respectively by the first pressure gauge 10 and the second pressure gauge 11.

[0066] In some embodiments, the device includes two pressure pumps and two intermediate containers 2 respectively connected to the two ends of the reactor 1. Pistons 3 are provided in the two intermediate containers 2, and both ends of the reactor 1 are connected to the pressure pumps. When the fluid in the reactor 1 needs to flow, the pressure of one of the pressure pumps can be increased, and the piston 3 on the corresponding side moves toward the reactor 1, and the pressure of the other pressure pump is reduced, and the piston 3 on the corresponding side moves away from the reactor 1, thereby driving the flow of the fluid in the reactor 1. The two pressure pumps reciprocately increase and decrease pressure, so that the fluid in the reactor 1 can flow back and forth.

[0067] The device comprises two reactors 1 connected in series, and a control valve 7 is arranged between the two reactors 1. The two reactors 1 are connected by a pipeline, and a control valve 7 is arranged on the pipeline to control the connection or disconnection of the two reactors 1. The two reactors 1 can be disconnected from each other, and different pressures and temperatures are set respectively, so that the oil samples in the two reactors 1 can be compared and observed; of course, the two reactors 1 can also be connected to ensure that the reaction conditions therein are the same.

[0068] In addition, the reactor 1 is provided with a plurality of sampling holes 8 arranged at intervals along the axial direction of the annulus, and an adsorption rod is provided in each of the sampling holes 8. The adsorption rod can be made of a material with adsorption properties, which is inserted into the reactor 1 to adsorb the oil sample inside. After the experiment is completed, the adsorption rod can be taken out, the wax sample on it can be extracted, and the component analysis can be performed to obtain the wax precipitation amount and wax precipitation characteristics of the oil sample under different temperature and pressure conditions. The sampling holes 8 are arranged at intervals along the axial direction of the annulus, and wax samples at different positions can be obtained.

[0069] In addition, the reactor 1 is provided with two observation windows 9 facing each other, the microscopic camera 4 faces one of the observation windows 9, and the device includes a light source 5 facing the other observation window 9. The observation window 9 can be made of a transparent material, and light can be introduced into the reactor 1 through the light source 5 to illuminate the oil sample therein, so as to facilitate the acquisition of a microscopic image in the reactor 1 by the microscopic camera 4.

[0070] The reactor 1 is provided with a stirring member 6. The stirring member 6 can be used to stir the oil sample in the reactor 1 so that the solid phase, liquid phase, etc. therein are uniformly mixed.

[0071] On the other hand, the present invention also provides a method for evaluating the wax precipitation characteristics and laws of a condensate gas reservoir, wherein the method uses the device described in the above scheme, and the method comprises:

[0072] S1, using a cleaning agent to clean the inner cavity of the reactor 1, and then drying it for later use;

[0073] S2, adjusting the temperature of the reactor 1 to a preset temperature through the temperature control unit and maintaining it for a predetermined time;

[0074] S3, injecting the waxy condensate oil sample into the reactor 1, and injecting an inert gas so that the pressure in the reactor 1 reaches a preset pressure;

[0075] S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera 4; and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera 4; wherein, the piston 3 in the intermediate container 2 is driven to move back and forth by the pressure pump to make the fluid in the reactor 1 flow.

[0076] Among them, the reactor 1 is heated to a preset temperature by a temperature control device and maintained for a preset time to ensure that the temperature at each position is basically consistent; after the waxy condensate oil sample is injected into the reactor 1, it can be stirred by a stirring member 6 to maintain uniformity; an inert gas is injected to adjust the pressure in the reactor 1, for example, nitrogen can be injected to make the pressure in the reactor 1 reach a preset pressure.

[0077] During the observation process, the piston 3 can be driven to move by a pressure pump, thereby driving the fluid in the reactor 1 to flow, so as to simulate the flow of the gas reservoir in the wellbore.

[0078] In S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor 1. Of course, the cleaning operation also includes cleaning of each pipeline. After the cleaning is completed, the device is placed in a cool and dry place to dry for 24 hours for standby use.

[0079] In S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours. The heating temperature of the temperature control unit is set to a certain target value and maintained for a specific time so that the device as a whole reaches the target value and avoids locations where the temperature does not meet the standard.

[0080] In S3, the inert gas is injected and then left to stand for 1-2 hours, and then the excess gas is discharged to reach the preset pressure. After the inert gas is injected, the reactor 1 is kept still, and after the internal environment is stabilized, the excess gas is discharged to reach a stable preset pressure.

[0081] Wherein, in S4, at a pressure of 15 MPa, the wax precipitation characteristics of the waxy condensate oil sample at 60°C are observed; and at a temperature of 40°C, the wax precipitation characteristics of the waxy condensate oil sample at 10 MPa are observed.

[0082] Among them, in S4, after changing the pressure or temperature, wait for the temperature in the reactor 1 to stabilize for 10 minutes before the next observation. After completing the observation under one pressure and temperature condition, it is necessary to change the pressure or temperature, and then the solid phase, liquid phase, etc. therein can be stirred by the stirring member 6, so that the oil sample therein is re-temperatured, and then the wax precipitation therein is observed, so as to avoid the influence of the previous experimental conditions on the next experiment.

[0083] Embodiment 3

[0084] The present solution provides a device for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, which includes a reactor 1, a detachable annulus sleeve arranged in the reactor 1 for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor 1, a pressure pump connected to the reactor 1, an intermediate container 2 arranged between the pressure pump and the reactor 1, and a microscopic camera 4, wherein the annulus sleeve is used to simulate the inner wall environment of the wellbore, the reactor 1 is provided with an observation window 9 for observation through the microscopic camera 4, a piston 3 is provided in the intermediate container 2, and the pressure pump can drive the piston 3 to reciprocate in the intermediate container 2 to drive the flow of fluid in the reactor 1.

[0085] The reactor 1 is a container for containing oil samples, in which a ring sleeve is arranged. The ring sleeve is made of the same material as the simulated wellbore, so that the corresponding wellbore can be simulated.

[0086] The temperature control unit can be arranged outside the reactor 1 to heat the reactor 1 and control its temperature so as to observe the wax precipitation characteristics of the oil sample at a specific temperature.

[0087] The reactor 1 is provided with a transparent observation window 9, and the microscope camera 4 is arranged toward the observation window 9 to collect microscopic image information inside the reactor 1 to obtain wax precipitation characteristics.

[0088] The pressure pump is connected to the reactor 1 through a pipeline to adjust the pressure in the reactor 1. In particular, an intermediate container 2 is provided between the two, and a piston 3 is provided in the intermediate container 2. The parts of the intermediate container 2 located on both sides of the piston 3 are respectively connected to the pressure pump and the reactor 1. When the pressure of the pressure pump changes, the relative position of the piston can change, and the movement of the piston will also cause the fluid in the reactor 1 to flow, so as to more accurately simulate the characteristics of the gas reservoir flowing in the wellbore.

[0089] In this scheme, with the help of an intermediate container and a piston, the fluid flow in the reactor can be driven by a pressure pump to more accurately simulate the fluid in a flowing state, and a more accurate wax precipitation characteristic of the oil sample can be obtained, providing guidance for wax prevention and elimination measures in on-site oil and gas production projects.

[0090] In addition, a first pressure gauge 10 is connected to the pipeline between the intermediate container 2 and the reactor 1, which can be used to measure the pressure in the reactor 1. A second pressure gauge 11 is provided on the pipeline connecting the intermediate container 2 to the pressure pump, which can be used to measure the pressure provided by the pressure pump, that is, the pressures on both sides of the piston 3 of the intermediate container 2 can be measured respectively by the first pressure gauge 10 and the second pressure gauge 11.

[0091] In some embodiments, the device includes two pressure pumps and two intermediate containers 2 respectively connected to the two ends of the reactor 1. Pistons 3 are provided in the two intermediate containers 2, and both ends of the reactor 1 are connected to the pressure pumps. When the fluid in the reactor 1 needs to flow, the pressure of one of the pressure pumps can be increased, and the piston 3 on the corresponding side moves toward the reactor 1, and the pressure of the other pressure pump is reduced, and the piston 3 on the corresponding side moves away from the reactor 1, thereby driving the flow of the fluid in the reactor 1. The two pressure pumps reciprocately increase and decrease pressure, so that the fluid in the reactor 1 can flow back and forth.

[0092] The device comprises two reactors 1 connected in series, and a control valve 7 is arranged between the two reactors 1. The two reactors 1 are connected by a pipeline, and a control valve 7 is arranged on the pipeline to control the connection or disconnection of the two reactors 1. The two reactors 1 can be disconnected from each other, and different pressures and temperatures are set respectively, so that the oil samples in the two reactors 1 can be compared and observed; of course, the two reactors 1 can also be connected to ensure that the reaction conditions therein are the same.

[0093] In addition, the reactor 1 is provided with a plurality of sampling holes 8 arranged at intervals along the axial direction of the annulus, and an adsorption rod is provided in each of the sampling holes 8. The adsorption rod can be made of a material with adsorption properties, which is inserted into the reactor 1 to adsorb the oil sample inside. After the experiment is completed, the adsorption rod can be taken out, the wax sample on it can be extracted, and the component analysis can be performed to obtain the wax precipitation amount and wax precipitation characteristics of the oil sample under different temperature and pressure conditions. The sampling holes 8 are arranged at intervals along the axial direction of the annulus, and wax samples at different positions can be obtained.

[0094] In addition, the reactor 1 is provided with two observation windows 9 facing each other, the microscopic camera 4 faces one of the observation windows 9, and the device includes a light source 5 facing the other observation window 9. The observation window 9 can be made of a transparent material, and light can be introduced into the reactor 1 through the light source 5 to illuminate the oil sample therein, so as to facilitate the acquisition of a microscopic image in the reactor 1 by the microscopic camera 4.

[0095] The reactor 1 is provided with a stirring member 6. The stirring member 6 can be used to stir the oil sample in the reactor 1 so that the solid phase, liquid phase, etc. therein are uniformly mixed.

[0096] On the other hand, the present invention also provides a method for evaluating the wax precipitation characteristics and laws of a condensate gas reservoir, wherein the method uses the device described in the above scheme, and the method comprises:

[0097] S1, using a cleaning agent to clean the inner cavity of the reactor 1, and then drying it for later use;

[0098] S2, adjusting the temperature of the reactor 1 to a preset temperature through the temperature control unit and maintaining it for a predetermined time;

[0099] S3, injecting the waxy condensate oil sample into the reactor 1, and injecting an inert gas so that the pressure in the reactor 1 reaches a preset pressure;

[0100] S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera 4; and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera 4; wherein, the piston 3 in the intermediate container 2 is driven to move back and forth by the pressure pump to make the fluid in the reactor 1 flow.

[0101] Among them, the reactor 1 is heated to a preset temperature by a temperature control device and maintained for a preset time to ensure that the temperature at each position is basically consistent; after the waxy condensate oil sample is injected into the reactor 1, it can be stirred by a stirring member 6 to maintain uniformity; an inert gas is injected to adjust the pressure in the reactor 1, for example, nitrogen can be injected to make the pressure in the reactor 1 reach a preset pressure.

[0102] During the observation process, the piston 3 can be driven to move by a pressure pump, thereby driving the fluid in the reactor 1 to flow, so as to simulate the flow of the gas reservoir in the wellbore.

[0103] In S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor 1. Of course, the cleaning operation also includes cleaning of each pipeline. After the cleaning is completed, the device is placed in a cool and dry place to dry for 24 hours for standby use.

[0104] In S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours. The heating temperature of the temperature control unit is set to a certain target value and maintained for a specific time so that the device as a whole reaches the target value and avoids locations where the temperature does not meet the standard.

[0105] In S3, the inert gas is injected and then left to stand for 1-2 hours, and then the excess gas is discharged to reach the preset pressure. After the inert gas is injected, the reactor 1 is kept still, and after the internal environment is stabilized, the excess gas is discharged to reach a stable preset pressure.

[0106] Wherein, in S4, the wax precipitation characteristics of the waxy condensate oil sample at 40°C are observed under a pressure of 15 MPa; and the wax precipitation characteristics of the waxy condensate oil sample at 5 MPa are observed at a temperature of 40°C.

[0107] Among them, in S4, after changing the pressure or temperature, wait for the temperature in the reactor 1 to stabilize for 10 minutes before the next observation. After completing the observation under one pressure and temperature condition, it is necessary to change the pressure or temperature, and then the solid phase, liquid phase, etc. therein can be stirred by the stirring member 6, so that the oil sample therein is re-temperatured, and then the wax precipitation therein is observed, so as to avoid the influence of the previous experimental conditions on the next experiment.

[0108] Embodiment 4

[0109] The present solution provides a device for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, which includes a reactor 1, a detachable annulus sleeve arranged in the reactor 1 for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor 1, a pressure pump connected to the reactor 1, an intermediate container 2 arranged between the pressure pump and the reactor 1, and a microscopic camera 4, wherein the annulus sleeve is used to simulate the inner wall environment of the wellbore, the reactor 1 is provided with an observation window 9 for observation through the microscopic camera 4, a piston 3 is provided in the intermediate container 2, and the pressure pump can drive the piston 3 to reciprocate in the intermediate container 2 to drive the flow of fluid in the reactor 1.

[0110] The reactor 1 is a container for containing oil samples, in which a ring sleeve is arranged. The ring sleeve is made of the same material as the simulated wellbore, so that the corresponding wellbore can be simulated.

[0111] The temperature control unit can be arranged outside the reactor 1 to heat the reactor 1 and control its temperature so as to observe the wax precipitation characteristics of the oil sample at a specific temperature.

[0112] The reactor 1 is provided with a transparent observation window 9, and the microscope camera 4 is arranged toward the observation window 9 to collect microscopic image information inside the reactor 1 to obtain wax precipitation characteristics.

[0113] The pressure pump is connected to the reactor 1 through a pipeline to adjust the pressure in the reactor 1. In particular, an intermediate container 2 is provided between the two, and a piston 3 is provided in the intermediate container 2. The parts of the intermediate container 2 located on both sides of the piston 3 are respectively connected to the pressure pump and the reactor 1. When the pressure of the pressure pump changes, the relative position of the piston can change, and the movement of the piston will also cause the fluid in the reactor 1 to flow, so as to more accurately simulate the characteristics of the gas reservoir flowing in the wellbore.

[0114] In this scheme, with the help of an intermediate container and a piston, the fluid flow in the reactor can be driven by a pressure pump to more accurately simulate the fluid in a flowing state, and a more accurate wax precipitation characteristic of the oil sample can be obtained, providing guidance for wax prevention and elimination measures in on-site oil and gas production projects.

[0115] In addition, a first pressure gauge 10 is connected to the pipeline between the intermediate container 2 and the reactor 1, which can be used to measure the pressure in the reactor 1. A second pressure gauge 11 is provided on the pipeline connecting the intermediate container 2 to the pressure pump, which can be used to measure the pressure provided by the pressure pump, that is, the pressures on both sides of the piston 3 of the intermediate container 2 can be measured respectively by the first pressure gauge 10 and the second pressure gauge 11.

[0116] In some embodiments, the device includes two pressure pumps and two intermediate containers 2 respectively connected to the two ends of the reactor 1. Pistons 3 are provided in the two intermediate containers 2, and both ends of the reactor 1 are connected to the pressure pumps. When the fluid in the reactor 1 needs to flow, the pressure of one of the pressure pumps can be increased, and the piston 3 on the corresponding side moves toward the reactor 1, and the pressure of the other pressure pump is reduced, and the piston 3 on the corresponding side moves away from the reactor 1, thereby driving the flow of the fluid in the reactor 1. The two pressure pumps reciprocately increase and decrease pressure, so that the fluid in the reactor 1 can flow back and forth.

[0117] The device comprises two reactors 1 connected in series, and a control valve 7 is arranged between the two reactors 1. The two reactors 1 are connected by a pipeline, and a control valve 7 is arranged on the pipeline to control the connection or disconnection of the two reactors 1. The two reactors 1 can be disconnected from each other, and different pressures and temperatures are set respectively, so that the oil samples in the two reactors 1 can be compared and observed; of course, the two reactors 1 can also be connected to ensure that the reaction conditions therein are the same.

[0118] In addition, the reactor 1 is provided with a plurality of sampling holes 8 arranged at intervals along the axial direction of the annulus, and an adsorption rod is provided in each of the sampling holes 8. The adsorption rod can be made of a material with adsorption properties, which is inserted into the reactor 1 to adsorb the oil sample inside. After the experiment is completed, the adsorption rod can be taken out, the wax sample on it can be extracted, and the component analysis can be performed to obtain the wax precipitation amount and wax precipitation characteristics of the oil sample under different temperature and pressure conditions. The sampling holes 8 are arranged at intervals along the axial direction of the annulus, and wax samples at different positions can be obtained.

[0119] In addition, the reactor 1 is provided with two observation windows 9 facing each other, the microscopic camera 4 faces one of the observation windows 9, and the device includes a light source 5 facing the other observation window 9. The observation window 9 can be made of a transparent material, and light can be introduced into the reactor 1 through the light source 5 to illuminate the oil sample therein, so as to facilitate the acquisition of a microscopic image in the reactor 1 by the microscopic camera 4.

[0120] The reactor 1 is provided with a stirring member 6. The stirring member 6 can be used to stir the oil sample in the reactor 1 so that the solid phase, liquid phase, etc. therein are uniformly mixed.

[0121] On the other hand, the present invention also provides a method for evaluating the wax precipitation characteristics and laws of a condensate gas reservoir, wherein the method uses the device described in the above scheme, and the method comprises:

[0122] S1, using a cleaning agent to clean the inner cavity of the reactor 1, and then drying it for later use;

[0123] S2, adjusting the temperature of the reactor 1 to a preset temperature through the temperature control unit and maintaining it for a predetermined time;

[0124] S3, injecting the waxy condensate oil sample into the reactor 1, and injecting an inert gas so that the pressure in the reactor 1 reaches a preset pressure;

[0125] S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera 4; and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera 4; wherein, the piston 3 in the intermediate container 2 is driven to move back and forth by the pressure pump to make the fluid in the reactor 1 flow.

[0126] Among them, the reactor 1 is heated to a preset temperature by a temperature control device and maintained for a preset time to ensure that the temperature at each position is basically consistent; after the waxy condensate oil sample is injected into the reactor 1, it can be stirred by a stirring member 6 to maintain uniformity; an inert gas is injected to adjust the pressure in the reactor 1, for example, nitrogen can be injected to make the pressure in the reactor 1 reach a preset pressure.

[0127] During the observation process, the piston 3 can be driven to move by a pressure pump, thereby driving the fluid in the reactor 1 to flow, so as to simulate the flow of the gas reservoir in the wellbore.

[0128] In S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor 1. Of course, the cleaning operation also includes cleaning of each pipeline. After the cleaning is completed, the device is placed in a cool and dry place to dry for 24 hours for standby use.

[0129] In S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours. The heating temperature of the temperature control unit is set to a certain target value and maintained for a specific time so that the device as a whole reaches the target value and avoids locations where the temperature does not meet the standard.

[0130] In S3, the inert gas is injected and then left to stand for 1-2 hours, and then the excess gas is discharged to reach the preset pressure. After the inert gas is injected, the reactor 1 is kept still, and after the internal environment is stabilized, the excess gas is discharged to reach a stable preset pressure.

[0131] Wherein, in S4, the wax precipitation characteristics of the waxy condensate oil sample at 20°C are observed under a pressure of 15 MPa; and the wax precipitation characteristics of the waxy condensate oil sample at normal pressure are observed at a temperature of 40°C.

[0132] Among them, in S4, after changing the pressure or temperature, wait for the temperature in the reactor 1 to stabilize for 10 minutes before the next observation. After completing the observation under one pressure and temperature condition, it is necessary to change the pressure or temperature, and then the solid phase, liquid phase, etc. therein can be stirred by the stirring member 6, so that the oil sample therein is re-temperatured, and then the wax precipitation therein is observed, so as to avoid the influence of the previous experimental conditions on the next experiment.

[0133] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0134] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A device for evaluating the wax precipitation characteristics and laws of condensate gas reservoirs, characterized in that: The invention comprises a reactor (1), a detachable annular sleeve arranged in the reactor (1) for simulating the inner wall environment of a wellbore, a temperature control unit arranged on the reactor (1), a pressure pump connected to the reactor (1), an intermediate container (2) arranged between the pressure pump and the reactor (1), and a microscopic camera (4), wherein the annular sleeve is used to simulate the inner wall environment of the wellbore, the reactor (1) is provided with an observation window (9) for observation through the microscopic camera (4), a piston (3) is arranged in the intermediate container (2), and the pressure pump can drive the piston (3) to move back and forth in the intermediate container (2) to drive the flow of fluid in the reactor (1).

2. The device for evaluating wax precipitation characteristics and laws of condensate gas reservoirs according to claim 1, characterized in that: The device comprises two pressure pumps respectively connected to the two ends of the reaction kettle (1) and two intermediate containers (2).

3. The device for evaluating wax precipitation characteristics and laws of condensate gas reservoirs according to claim 2, characterized in that: The device comprises two reaction kettles (1) connected in series, and a control valve (7) is arranged between the two reaction kettles (1).

4. The device for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 1, characterized in that: The reaction kettle (1) is provided with a plurality of sampling holes (8) arranged at intervals along the axial direction of the ring sleeve, and an adsorption rod is arranged in each of the sampling holes (8).

5. The device for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 1, characterized in that: The reactor (1) is provided with two observation windows (9) facing each other, the microscope camera (4) is facing one of the observation windows (9), and the device includes a light source (5) facing the other observation window (9).

6. The device for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 1, characterized in that: The reaction kettle (1) is provided with a stirring element (6).

7. A method for evaluating the characteristics and laws of wax precipitation in condensate gas reservoirs, characterized in that: The method adopts the device according to any one of claims 1 to 6, and the method comprises: S1, using a cleaning agent to clean the inner cavity of the reaction kettle (1), and drying it after cleaning for later use; S2, adjusting the temperature of the reactor (1) to a preset temperature through the temperature control unit and maintaining it for a predetermined time; S3, injecting the waxy condensate sample into the reactor (1), and injecting an inert gas so that the pressure in the reactor (1) reaches a preset pressure; S4. Under a specific pressure, the wax precipitation characteristics of the waxy condensate oil sample at different temperatures are observed by the microscopic camera (4); and, under a specific temperature, the wax precipitation characteristics of the waxy condensate oil sample at different pressures are observed by the microscopic camera (4); wherein the piston (3) in the intermediate container (2) is driven to move back and forth by the pressure pump to allow the fluid in the reactor (1) to flow.

8. The method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 7, characterized in that: In S1, ultrapure water and ethanol are used to clean the inner cavity of the reactor (1).

9. The method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 7, characterized in that: In S2, the heating temperature of the temperature control unit is set to 70-80°C and maintained for 3-4 hours.

10. The method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 7, characterized in that: In S3, the inert gas is injected and then left to stand for 1-2 hours, and then excess gas is exhausted to reach the preset pressure.

11. The method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 7, characterized in that: In S4, under a pressure of 15 MPa, the wax precipitation characteristics of the waxy condensate oil sample at 80°C, 60°C, 40°C, and 20°C are observed respectively; and, at a temperature of 40°C, the wax precipitation characteristics of the waxy condensate oil sample at 15 MPa, 10 MPa, 5 MPa, and normal pressure are observed respectively.

12. The method for evaluating wax precipitation characteristics and laws in condensate gas reservoirs according to claim 7, characterized in that: In S4, after the pressure or temperature is changed, the temperature in the reactor (1) is stabilized for 10 minutes before the next observation is performed.

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