A device and method for evaluating the variation of fluid composition of a waxy condensate well

Abstract

This invention discloses an apparatus and method for evaluating the variation law of fluid components in waxy condensate gas wells. The apparatus includes multiple independent component sampling vessels connected in series. The fluid inlet of the first independent component sampling vessel is connected to the outlet of an intermediate container for well fluid and an intermediate container for aqueous solution. The inlets of the intermediate containers for well fluid and aqueous solution are connected to the outlet of a displacement device. The displacement outlet at the bottom of each independent component sampling vessel is connected to the inlet of a pressure-resistant and heat-insulated container. Valves are installed at the fluid inlet, fluid outlet, and displacement outlet of each independent component sampling vessel, as well as at the inlet of the pressure-resistant and heat-insulated container. A heating device and a pressure regulating device are installed outside each independent component sampling vessel. This apparatus can be used to study the variation law of fluid components in waxy condensate gas wells with temperature and pressure, solving the problem of inaccurate determination of the variation law of fluid components in waxy condensate gas wells with temperature and pressure.

Description

Technical Field

[0001] This invention relates to the field of oil and gas engineering technology, specifically to an apparatus and method for evaluating the variation law of fluid composition in waxy condensate gas wells. Background Technology

[0002] Waxing is a common phenomenon in major oilfields across China. The severity of wax buildup varies across different oilfields due to differences in wax content and extraction conditions. As wax gradually accumulates in the wellbore, oil production declines, and in severe cases, well shutdowns can occur. Waxing is a significant factor affecting high and stable oil production, and wax prevention and removal are crucial aspects of oilfield development and management. Oil well wax prevention and removal technologies have long been valued by petroleum producers, and various mechanical, thermal, and chemical methods have been developed and applied. However, with advancements in petroleum technology and increased emphasis on safety, environment, and efficiency, new requirements have been placed on wax prevention and removal technologies.

[0003] With the development of deep / ultra-deep oil and gas resources, especially the continuous exploitation of waxy high-pressure oil and gas, the flow assurance of high-pressure oil and gas is facing severe challenges due to the influence of wellbore sedimentation environment. High-pressure oil and gas reservoirs exhibit varying degrees of solid precipitation, which may cause blockage, leading to fluctuations in oil pressure and production, restricting the production rate of oil and gas wells, and in severe cases, even forcing the shutdown of single wells. Furthermore, the high risk of unblocking further hinders the sustainable and stable production of oil and gas fields.

[0004] Currently, the main methods for evaluating solid phase deposition in waxy condensate gas wells are to determine the critical conditions for solid phase precipitation. However, the commonly used methods cannot clearly define how the composition of the organic solid phase in the condensate gas well fluid changes after precipitation and the critical conditions for the start of component precipitation during temperature and pressure changes. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides an apparatus and method for evaluating the variation law of fluid components in waxy condensate gas wells, which is used to study the variation law of fluid components in waxy condensate gas wells with temperature and pressure, and solves the problem that the variation law of fluid components in waxy condensate gas wells with temperature and pressure cannot be accurately determined.

[0006] This invention is achieved through the following technical solution: an apparatus for evaluating the variation law of fluid components in waxy condensate gas wells, comprising multiple independent component sampling vessels connected in series, wherein the fluid inlet of the first independent component sampling vessel connected in series is connected to the outlet of an intermediate container for well fluid and an intermediate container for aqueous solution, the inlets of the intermediate container for well fluid and the intermediate container for aqueous solution are connected to the outlet of a displacement device, the displacement outlet at the bottom of the independent component sampling vessel is connected to the inlet of a pressure-resistant and heat-insulating container, and valves are provided at the fluid inlet, fluid outlet, displacement outlet of the independent component sampling vessel and the inlet of the pressure-resistant and heat-insulating container, and a heating device and a pressure regulating device are provided outside the independent component sampling vessel.

[0007] Furthermore, a magnetic stirring device is also provided at the bottom of the independent component sampling vessel.

[0008] Furthermore, the pressure regulating device is located at the fluid outlet of the independent component sampling vessel.

[0009] Furthermore, a pressure regulating device is provided at the inlet of the pressure-resistant and heat-insulating container.

[0010] Furthermore, two intermediate containers for the well fluid are provided, one for holding condensate gas single-phase fluid; and one intermediate container for holding pure water is provided.

[0011] Furthermore, a single-flow valve is installed at the outlet of the well fluid intermediate container and the aqueous solution intermediate container, and a multi-port valve is installed at the fluid inlet of the first independent component sampling vessel connected in series to achieve communication with the well fluid intermediate container and the aqueous solution intermediate container respectively.

[0012] Furthermore, valves are installed at the outlet of the displacement device, the inlet and outlet of the well fluid intermediate container and the aqueous solution intermediate container.

[0013] Furthermore, the fluid outlet of the last independent component sampling vessel in the series is connected to the inlet of the separation device.

[0014] Furthermore, the independent component sampling vessel is also equipped with a temperature controller and a pressure gauge.

[0015] The present invention also provides a method for using the above-mentioned device, the specific steps of which are as follows: S1 sets the temperature and pressure inside each independent component sampling vessel, opens the fluid inlet and fluid outlet of each independent component sampling vessel, closes the displacement valve at the bottom of the independent component sampling vessel, and injects the well fluid in the intermediate container into multiple series-connected independent component sampling vessels through the displacement device. S2 closes the fluid inlet and fluid outlet of each independent component sampling vessel, and injects the aqueous solution in the intermediate container into the independent component sampling vessel for displacement through the displacement device. Then, it opens the displacement valve at the bottom of the independent component sampling vessel and injects the wax-containing condensate gas into the pressure-resistant and heat-insulated container while maintaining heat and pressure. S3 adjusts the pressure or temperature of the independent component sampling vessel, measures the components of the wax-containing condensate gas well fluid in the pressure-resistant and heat-insulated container, and obtains the variation law of the wax-containing condensate gas well fluid components with pressure or temperature.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an apparatus for evaluating the variation law of fluid components in waxy condensate gas wells, comprising multiple independent component sampling vessels connected in series. Each independent component sampling vessel is equipped with a valve at its fluid inlet, fluid outlet, and displacement outlet. The independent component sampling vessels are externally equipped with a heating device and a pressure regulating device. The independent component sampling vessels can be used to determine the variation law of fluid components in waxy condensate gas wells with temperature and pressure under constant pressure or constant temperature. This invention introduces wax-containing condensate gas well fluid into multiple interconnected independent component sampling vessels via an intermediate well fluid container. The composition of the wax-containing condensate gas well fluid in these multiple independent sampling vessels is consistent, avoiding unnecessary experimental errors caused by repeated sampling. Furthermore, it can be used to determine the temperature-dependent changes in the composition of wax-containing condensate gas well fluid during the development of high-temperature, high-pressure gas wells and wellbore flow. This invention enables the evaluation of the temperature and pressure-dependent changes in the composition of wax-containing condensate gas well fluid, which is of great significance for the study of wax formation rules in wax-containing condensate gas wells. It can also guide the formulation of on-site condensate gas well operating procedures and wax removal and prevention processes.

[0017] When the device of the present invention is used, the displacement device injects the well flow material in the intermediate container into the series of independent component sampling vessels, and then the displacement device injects the aqueous solution in the intermediate container into the independent component sampling vessels for displacement. The aqueous solution keeps the wax-containing condensate gas in the vessel warm and pressurized and injects it into the pressure-resistant and heat-insulating container to avoid errors caused by changes in fluid composition due to temperature and pressure changes during the sampling process.

[0018] This invention allows for the simultaneous determination of a large number of wax-containing condensate gas well fluid components in independent component sampling vessels under various temperature and pressure conditions by setting different pressure or temperature variations for different independent component sampling vessels. By comparing and analyzing the wax-containing condensate gas well fluid components, the variation law of wax-containing condensate gas well fluid components with temperature and pressure can be evaluated. Attached Figure Description

[0019] Figure 1 A schematic diagram of an apparatus for evaluating the variation law of fluid composition in waxy condensate gas wells provided by the present invention; In the diagram, 1. Displacement device; 2. Valve; 3. Well flow intermediate container; 4. Aqueous solution intermediate container; 5. One-way valve; 6. Multi-way valve; 7. Independent component sampling vessel; 8. Temperature controller; 9. Pressure gauge or pressure sensor; 10. Pressure gauge; 11. Magnetic stirring device; 12. Pressure regulating device; 13. Pressure-resistant and heat-insulated container. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0021] like Figure 1 As shown, the present invention provides an apparatus for evaluating the variation law of fluid components in waxy condensate gas wells, comprising a displacement device 1, a well fluid intermediate container 3, an aqueous solution intermediate container 4, and multiple independent component sampling vessels 7 connected in series. The outlet of the displacement device 1 is connected to the inlet of the well fluid intermediate container 3 and the aqueous solution intermediate container 4 respectively through valves 2. The outlets of the well fluid intermediate container 3 and the aqueous solution intermediate container 4 are connected to the fluid inlet of the first independent component sampling vessel 7 connected in series through multi-port valves 6. The fluid outlet of the last independent component sampling vessel 7 connected in series is connected to the inlet of the separation device. The independent component sampling vessels 7 have the same structure. The external heating device and pressure regulating device 11 of the independent component sampling vessels 7 are installed to regulate the temperature and pressure in the independent component sampling vessels 7. The displacement outlet at the bottom of the independent component sampling vessels 7 is connected to a pressure-resistant and heat-insulated container 12 through a valve 2. The pressure-resistant and heat-insulated container 12 is used for sampling. A magnetic stirring device 10 is installed at the bottom of the independent component sampling vessels 7. The independent component sampling vessels 7 are also equipped with a temperature controller 8 and a pressure gauge 9. The temperature controller 8 is used to control the heating temperature of the heating device, and the pressure gauge 9 is used to display the pressure in the independent component sampling vessels 7. Preferably, the number of independent component sampling vessels 7 is selected and determined based on the temperature and pressure data of a single well shaft.

[0022] Preferably, the number of independent component sampling vessels 7 is selected according to the wellbore pressure stabilization gradient.

[0023] Preferably, the pressure regulating device 11 is located at the fluid outlet of the independent component sampling vessel 7.

[0024] A pressure regulating device 11 is provided at the inlet of the pressure-resistant and heat-insulating container 12.

[0025] The independent component sampling vessel 7 is equipped with valves 2 at both the fluid inlet and the fluid outlet to prevent changes in the fluid of the entire system during the sampling process, which facilitates subsequent data processing and comparative analysis. Preferably, the intermediate container 3 of the well flow material includes two containers. The intermediate container 3 of the well flow material is used to hold the single-phase fluid of condensate gas. The single-phase fluid of condensate gas in the intermediate container 3 of the well flow material is injected into the sampling vessel 7 of each independent component through the displacement device 1. Only one intermediate container 3 of the well flow material is opened during the experiment, and the other is kept as a backup to facilitate the displacement temperature during the experiment.

[0026] Preferably, the intermediate aqueous solution container 4 is used to hold pure water. The pure water in the intermediate aqueous solution container 4 is injected into the sampling vessels 7 of each independent component through the displacement device 1. Through displacement, the aqueous solution heats and pressurizes the wax-containing condensate gas in the vessel and injects it into the pressure-resistant and heat-insulating container 12, so as to avoid errors caused by changes in fluid composition due to temperature and pressure changes during the sampling process.

[0027] Preferably, the magnetic stirring device 10 consists of two parts: a power unit outside the independent component sampling vessel and a stirring device inside the vessel. The bottom power unit is driven by electric energy to rotate the stirring device inside the vessel to achieve sample mixing.

[0028] Preferably, a check valve 5 is provided at the outlet of both the intermediate container 3 for well fluid and the intermediate container 4 for aqueous solution to prevent fluid backflow.

[0029] The specific steps for using the device of the present invention for evaluating the variation law of fluid composition in waxy condensate gas wells are as follows: 1) First, set the temperature and pressure inside each independent component sampling vessel 7, open the fluid inlet and fluid outlet of each independent component sampling vessel 7, close the displacement valve at the bottom of the independent component sampling vessel 7, and inject the well fluid in the intermediate container 3 into each independent component sampling vessel 7 through the single-flow valve 5 via the displacement device 1, and turn on the magnetic stirring device at the bottom of the independent component sampling vessel 7. 2) After the well fluid has stabilized sufficiently, close the fluid inlet and outlet of the independent component sampling vessel 7, open the displacement valve at the bottom of the independent component sampling vessel 7, and inject the aqueous solution in the intermediate container 4 into the independent component sampling vessel 7 through the displacement device 1 for displacement. The aqueous solution will keep the wax-containing condensate gas in the vessel warm and pressurized and inject it into the pressure-resistant and heat-insulating container 12 to avoid errors caused by changes in fluid composition due to temperature and pressure changes during the sampling process.

[0030] 3) Evaluate the variation of fluid composition with temperature and pressure in waxy condensate gas wells. After setting an experimental pressure for each independent component sampling vessel 7, the independent component sampling vessel 7 was cooled to determine the change law of the fluid components of the wax-containing condensate gas well with temperature. After setting an experimental temperature for each independent component sampling vessel 7, the pressure of the independent component sampling vessel 7 is adjusted to determine the change law of the fluid composition of wax-containing condensate gas well with pressure. This invention unifies the composition of the wax-containing condensate gas well fluid in multiple independent component sampling vessels 7, avoiding unnecessary experimental errors caused by repeated sampling. By setting different pressure or temperature changes for different independent component sampling vessels 7, a large number of wax-containing condensate gas well fluid components in independent component sampling vessels 7 under various temperature and pressure conditions can be measured at once. By comparing and analyzing the wax-containing condensate gas well fluid components, the variation law of wax-containing condensate gas well fluid components with temperature and pressure can be evaluated.

Claims

1. An apparatus for evaluating the variation law of fluid composition in waxy condensate gas wells, characterized in that, The system includes multiple independent component sampling vessels (7) connected in series. The fluid inlet of the first independent component sampling vessel (7) is connected to the outlet of the intermediate container (3) for well fluid and the intermediate container (4) for aqueous solution. The inlets of the intermediate container (3) for well fluid and the intermediate container (4) for aqueous solution are connected to the outlet of the displacement device (1). The displacement outlet at the bottom of the independent component sampling vessel (7) is connected to the inlet of the pressure-resistant and heat-insulating container (12). Valves (2) are provided at the fluid inlet, fluid outlet, and displacement outlet of the independent component sampling vessel (7) and at the inlet of the pressure-resistant and heat-insulating container (12). A heating device and a pressure regulating device (11) are provided outside the independent component sampling vessel (7). A magnetic stirring device (10) is also provided at the bottom of the independent component sampling vessel (7). Two intermediate containers (3) for well flow material are provided, which are used to hold condensate gas single-phase fluid; one intermediate container (4) for aqueous solution is provided, which is used to hold pure water; A single-flow valve (5) is provided at the outlet of the intermediate container (3) for well fluid and the intermediate container (4) for aqueous solution. A multi-way valve (6) is provided at the fluid inlet of the first independent component sampling vessel (7) connected in series to achieve communication with the intermediate container (3) for well fluid and the intermediate container (4) for aqueous solution respectively. The independent component sampling vessel (7) is also equipped with a temperature controller (8) and a pressure gauge (9).

2. The apparatus for evaluating the variation law of fluid components in waxy condensate gas wells according to claim 1, characterized in that, The pressure regulating device (11) is located at the fluid outlet of the independent component sampling vessel (7).

3. The apparatus for evaluating the variation law of fluid components in waxy condensate gas wells according to claim 1, characterized in that, A pressure regulating device (11) is provided at the inlet of the pressure-resistant and heat-insulating container (12).

4. The apparatus for evaluating the variation law of fluid components in waxy condensate gas wells according to claim 1, characterized in that, Valves (2) are provided at the outlet of the displacement device (1), the inlet and outlet of the well fluid intermediate container (3) and the aqueous solution intermediate container (4).

5. The apparatus for evaluating the variation law of fluid components in waxy condensate gas wells according to claim 1, characterized in that, The fluid outlet of the last independent component sampling vessel (7) in series is connected to the inlet of the separation device.

6. The method of using the apparatus according to any one of claims 1-5, characterized in that, The specific steps are as follows: S1 sets the temperature and pressure inside each independent component sampling vessel (7), opens the fluid inlet and fluid outlet of each independent component sampling vessel (7), closes the displacement valve at the bottom of the independent component sampling vessel (7), and injects the well fluid in the intermediate container (3) into multiple series-connected independent component sampling vessels (7) through the displacement device (1). S2 closes the fluid inlet and fluid outlet of each independent component sampling vessel (7), and injects the aqueous solution in the intermediate container (4) into the independent component sampling vessel (7) for displacement through the displacement device (1). Open the displacement valve at the bottom of the independent component sampling vessel (7), and inject the wax-containing condensate gas into the pressure-resistant and heat-insulating container (12) while maintaining heat and pressure. S3 adjusts the pressure or temperature of the independent component sampling vessel (7), measures the components of the wax-containing condensate gas well fluid in the pressure-resistant and heat-insulating container (12), and obtains the variation law of the wax-containing condensate gas well fluid components with pressure or temperature.

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