A method and apparatus for monitoring inter-well connectivity in a steam flood of heavy oil

Abstract

The application provides a method and device for monitoring interwell communication condition of thick oil steam flooding, the method comprises the following steps: installing several temperature and pressure monitoring devices at the wellhead of a production well for continuously monitoring temperature and pressure values at the wellhead of the production well, then calculating mass flow rate and heat content of output fluid of each production well based on the temperature and pressure values and heat balance principle, and finally analyzing interwell communication degree of injection and production wells based on the mass flow rate and heat content of output fluid of the production well, and evaluating the interwell communication condition of the injection and production wells. The application improves the interwell monitoring technology of steam flooding injection and production wells, calculates the dynamic change of the mass flow rate and heat content of output fluid of the production well, and obtains the heat distribution between each production well and the steam injection well in real time, so that the quantitative evaluation of the interwell communication condition of the steam flooding injection and production wells is realized.

Description

Technical Field

[0001] This invention belongs to the field of reservoir development technology, and specifically relates to a method and equipment for monitoring the inter-well connectivity of heavy oil steam drive wells. Background Technology

[0002] Steam drive is a commonly used method for developing heavy oil reservoirs. Heavy oil steam drive typically involves one injection well and multiple production wells; that is, one injection well may affect multiple production wells. In multi-well groups, a single production well may be affected by multiple injection wells. Therefore, the relationship between injection and production wells in heavy oil steam drive is complex, and accurately analyzing and understanding the relationships and connectivity between injection and production wells is quite challenging.

[0003] Currently, the main methods for evaluating the connectivity between steam-driven wells in heavy oil production include tracer methods, microseismic methods, and production dynamic data analysis. High-temperature well-to-well tracing technology has seen some application in recent years, using gaseous tracers to track fluid flow lines in formations with steam. However, due to complex formation conditions and phase transitions in steam, the monitoring results are directly affected, limiting the application of high-temperature well-to-well tracing technology. In microseismic monitoring, the reliability of surface monitoring data inversion is poor due to formation absorption and complex propagation paths, limiting its application. Currently, understanding the connectivity between steam-driven wells mainly relies on analyzing development dynamic data. This involves using wellhead production, temperature, and water cut data to directly analyze the connectivity between injection and production wells for a rough qualitative assessment. On the other hand, the method of inter-well interference is adopted, which involves adjusting the steam injection well discharge rate, recording the temperature and pressure data of the production well, and evaluating the connectivity between the injection and production wells based on the data response patterns and magnitudes. At the same time, a mathematical model is established to quantitatively divide the steam intake of the production wells in combination with the production volume and water content, so as to achieve quantitative analysis of the connectivity between the injection and production wells. The production volume data used in this method is production report data, not real-time dynamic production data, which has a certain impact on the analysis results. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method and device for monitoring the connectivity between steam-driven wells in heavy oil production. Based on the aforementioned steam-driven well interference monitoring technology, this invention obtains real-time production volume by recording temperatures at two points, constructing a mathematical model, and developing a calculation method. This production volume, along with water cut, is then used to quantitatively analyze the steam absorption of the production wells, enabling quantitative analysis of the connectivity between injection and production wells. This invention represents an improvement upon the aforementioned steam-driven well interference monitoring technology.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for monitoring inter-well connectivity in heavy oil steam drive includes the following steps:

[0007] Several temperature and pressure monitoring devices are installed at the wellhead of the production well to continuously monitor the temperature and pressure values ​​at the wellhead.

[0008] The mass flow rate and heat content of the produced fluid for each production well were calculated based on temperature and pressure values ​​and the principle of heat balance.

[0009] Based on the mass flow rate and calorific value of the produced fluid from the production well, the degree of connectivity between the injection and production wells is analyzed, and the connectivity status between the injection and production wells is evaluated.

[0010] Preferably, the formula for calculating the mass flow rate is:

[0011] ;

[0012] in, This represents mass flow rate, in kg / s. This indicates the specific heat capacity of crude oil, expressed in J / kg·℃. The specific heat capacity of water is expressed in J / kg·℃. This represents the heat transfer coefficient of the pipeline, in W / m. 2 ·℃; This represents the average temperature of the first and second points, expressed in °C. —Ambient temperature, °C; Indicates the water content of the fluid. Indicates the inner radius of the pipeline, in meters (m). The first point is the wellhead temperature; d represents the temperature at the wellhead of the second point; d represents the distance between the first and second points at the wellhead, where both the first and second points are monitoring points at the wellhead.

[0013] Preferably, the formula for calculating the heat transfer coefficient of the pipeline is:

[0014] ;

[0015] in, Pipeline thermal resistance, m·℃ / W; Let be the inner radius of the pipeline, in meters (m). Let be the outer radius of the pipeline, in meters (m). is the thermal conductivity of the pipeline, W / m·℃.

[0016] Preferably, the formula for calculating the calorific value of the produced liquid is:

[0017] ;

[0018] in, This indicates that the produced liquid contains heat.

[0019] Preferably, the analysis of the inter-well connectivity between the injection and production wells, and the evaluation of the inter-well connectivity status, includes the following steps:

[0020] Collect data on oil well production and total heat of injected steam;

[0021] Draw the mass flow rate separately and the heat content of the produced liquid A curve that changes over time;

[0022] Based on the calorific value of the produced liquid The time it takes for steam injection to take effect is determined by the curves that change over time and the production status of the oil wells;

[0023] Based on the calorific value of the produced liquid The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

[0024] A device for monitoring the inter-well connectivity of heavy oil steam drive wells includes a temperature and pressure monitoring module, a calculation module, and an analysis module;

[0025] The temperature and pressure monitoring module includes several pressure monitoring devices installed at the wellhead of the production well, which are used to continuously monitor the temperature and pressure values ​​at the wellhead of the production well.

[0026] The calculation module calculates the mass flow rate and heat content of the produced fluid for each production well based on temperature and pressure values ​​and the principle of heat balance.

[0027] The analysis module analyzes the degree of connectivity between injection and production wells based on the mass flow rate and calorific value of the produced fluid, and evaluates the connectivity status between injection and production wells.

[0028] Preferably, a control module is also provided, which includes a main valve, a dewaxing valve, and several oil production valves.

[0029] Preferably, the wellhead of the production well is cross-shaped, the main valve is installed in the lower section of the production well, the wax removal valve is installed in the upper wellhead of the production well, and the oil production valve is installed in the wellheads on both sides of the production well.

[0030] Preferably, a sucker rod is provided in the production well along the vertical direction.

[0031] Preferably, the formula for calculating the mass flow rate by the calculation module is:

[0032] ;

[0033] in, Indicates mass flow rate; This indicates the specific heat capacity of crude oil, expressed in J / kg·℃. The specific heat capacity of water is expressed in J / kg·℃. This represents the heat transfer coefficient of the pipeline, in W / m. 2 ·℃; This represents the average temperature of the first and second points, expressed in °C. —Ambient temperature, °C; Indicates the water content of the fluid. Indicates the inner radius of the pipeline, in meters (m). The first point is the wellhead temperature; d represents the temperature at the wellhead of the second point; d represents the distance between the first and second points at the wellhead, where both the first and second points are monitoring points at the wellhead.

[0034] Preferably, the formula used by the calculation module to calculate the heat transfer coefficient of the pipeline is:

[0035] ;

[0036] in, Pipeline thermal resistance, m·℃ / W; Let be the inner radius of the pipeline, in meters (m). Let be the outer radius of the pipeline, in meters (m). is the thermal conductivity of the pipeline, W / m·℃.

[0037] Preferably, the formula used by the calculation module to calculate the calorific value of the produced liquid is:

[0038] ;

[0039] in, This indicates that the produced liquid contains heat.

[0040] Preferably, the analysis module analyzes the connectivity between the injection and production wells and evaluates the connectivity status between the injection and production wells, including the following steps:

[0041] Collect data on oil well production and total heat of injected steam;

[0042] Draw the mass flow rate separately and the heat of the produced liquid A curve that changes over time;

[0043] Based on the calorific value of the produced liquid The time it takes for steam injection to take effect is determined by the curves that change over time and the production status of the oil wells;

[0044] Based on the calorific value of the produced liquid The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

[0045] The beneficial effects of this invention are:

[0046] This invention improves the monitoring technology between steam-driven injection and production wells, calculates the dynamic changes in the mass flow rate of the production well and the heat content of the produced fluid, and obtains the heat distribution between each production well and the steam injection well in real time, thereby realizing a quantitative evaluation of the connectivity status of steam-driven injection and production wells.

[0047] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 A flowchart of a method for monitoring inter-well connectivity in heavy oil steam drive is shown.

[0050] Figure 2 A schematic diagram of a continuous monitoring device at the wellhead of a production well is shown.

[0051] Figure 3 A schematic diagram of a steam-driven inverse nine-point well group is shown.

[0052] Figure 4 Mass flow rate is shown and the heat of the produced liquid A curve that changes over time.

[0053] In the diagram: 1. Production well; 2. Temperature and pressure monitoring device; 3. Dewaxing valve; 4. Oil production valve; 5. Main valve; 6. Sucker rod. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] A method for monitoring inter-well connectivity in heavy oil steam drive, such as Figure 1 As shown, it includes the following steps:

[0056] Several temperature and pressure monitoring devices 2 are installed at the wellhead of production well 1 to continuously monitor the temperature and pressure values ​​at the wellhead of production well 1.

[0057] The mass flow rate and heat content of the produced fluid for each production well 1 were calculated based on temperature and pressure values ​​and the principle of heat balance.

[0058] Based on the mass flow rate and calorific value of the produced fluid from production well 1, the degree of connectivity between injection and production wells is analyzed, and the connectivity status between injection and production wells is evaluated.

[0059] It should be noted that the temperature and pressure monitoring device 2 is preferably two sets.

[0060] It should be noted that the present invention mainly adopts the method of installing two sets of temperature and pressure monitoring devices 2 at the wellhead of the production well 1 of the steam-driven well group. By adjusting the steam injection rate of the steam injection well, a formation energy (temperature and pressure) pulse is established, thus forming an interference well test system with the steam injection well as the excitation well and the production well 1 as the observation well. Considering the heat balance, the mass flow rate and heat content of the produced fluid of each production well 1 are calculated by using the temperature values ​​of two points of the continuously monitored production well 1. In this way, the thermal connectivity between the injection and production wells can be obtained, and the connectivity status of the injection and production wells can be evaluated.

[0061] It should be noted that during the steam drive process, a temperature and pressure monitoring device 2 is simultaneously installed at the wellhead of production well 1 in the steam drive well group. By monitoring the temperature and pressure values ​​of each production well 1, the mass flow rate and calorific value of the produced fluid of each production well 1 are calculated using the principle of heat balance. Based on the changes in the mass flow rate and calorific value of production well 1, the degree of connectivity between injection and production wells is analyzed, and the connectivity status between injection and production wells is evaluated.

[0062] The calculation is performed using a reverse nine-point well group consisting of one steam injection well and eight production wells as a unit, such as... Figure 3 As shown, the design involves monitoring for n days, assuming the monitoring data is as follows:

[0063] Production Well 1:

[0064] First point: Wellhead temperature ( =1, 2, ..., 8), ℃;

[0065] Second point: Wellhead temperature: ( =1, 2, ..., 8), ℃;

[0066] The distance between the first and second points: d, m;

[0067] Where d is the distance between the two monitoring points at the wellhead of production well 1, and m is the distance unit meter.

[0068] Assuming the mass flow rate of production well 1 (kg / s) and the water content of the produced fluid (decimal), the formula can be obtained using the principle of heat balance:

[0069] (1)

[0070] In the formula: is the specific heat capacity of crude oil, J / (kg·℃); is the specific heat capacity of water, J / (kg·℃); The heat transfer coefficient of the pipeline is W / (m²). 2 ·℃); The first point temperature and the average of the first point temperatures, in °C; The ambient temperature is in °C.

[0071] Furthermore, the formula for calculating the pipeline heat transfer coefficient is as follows:

[0072] (2)

[0073] in, Pipeline thermal resistance, m·℃ / W; Let be the inner radius of the pipeline, in meters (m). Let be the outer radius of the pipeline, in meters (m). The thermal conductivity of the pipeline is W / (m·℃).

[0074] Furthermore, by combining formulas (1) and (2), the formula for calculating the mass flow rate is:

[0075] (3)

[0076] in, Indicates mass flow rate; The specific heat capacity of crude oil is expressed in J / (kg·℃). The specific heat capacity of water is expressed in J / (kg·℃). This represents the heat transfer coefficient of the pipeline, W / (m²). 2 ·℃); This represents the average temperature of the first and second points, expressed in °C. —Ambient temperature, °C; Indicates the water content of the fluid. Indicates the inner radius of the pipeline, in meters (m). The first point is the wellhead temperature; d represents the temperature at the wellhead of the second point; d represents the distance between the first and second points at the wellhead, where both the first and second points are monitoring points at the wellhead.

[0077] Furthermore, the mass flow rate calculated according to formula (3) The calorific value of the produced liquid at the first monitoring point can be calculated. The formula for calculating the calorific value of the produced liquid is:

[0078] (4)

[0079] in, This indicates that the produced liquid contains heat.

[0080] Furthermore, the degree of connectivity between injection and production wells is analyzed, and the connectivity status between injection and production wells is evaluated, including the following steps:

[0081] Collect data on oil well production and total heat of injected steam;

[0082] Draw the mass flow rate separately and the heat of the produced liquid A curve that changes over time;

[0083] Based on the calorific value of the produced liquid The time it takes for steam injection to take effect is determined by the curves that change over time and the production status of the oil wells;

[0084] Based on the calorific value of the produced liquid The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

[0085] It should be noted that the mass flow rate can be plotted according to formulas (3) and (4). and the heat of the produced liquid A curve showing how the heat of the produced liquid changes over time. Generally, this represents the heat of the produced liquid. It changes over time, through The changes in these parameters, combined with oil well production data, can help determine the timing of steam injection effectiveness; through... The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

[0086] It should be noted that the production status of an oil well mainly refers to its fluid production, oil production, water cut, and fluid temperature. The effective time of steam injection can determine the connectivity between injection and production wells; a short effective time generally indicates good connectivity between wells. The total heat of injected steam is the total heat of the injection well, which can be directly calculated based on the steam injection parameters.

[0087] In summary, this invention proposes a technical method for evaluating the degree of inter-well connectivity during steam injection in heavy oil wells by simultaneously and continuously monitoring the temperature and pressure values ​​at two points at the wellhead of production well 1, calculating the mass flow rate and heat content of the produced fluid, quantitatively dividing the steam absorption, and assessing the inter-well connectivity. Furthermore, this monitoring method is based on thermal reservoir engineering calculation methods and inter-well interference monitoring technology for steam-driven injection and production wells.

[0088] A device for monitoring the inter-well connectivity of heavy oil steam drive wells includes a temperature and pressure monitoring module, a calculation module, and an analysis module;

[0089] The temperature and pressure monitoring module includes several pressure monitoring devices installed at the wellhead of production well 1, which are used to continuously monitor the temperature and pressure values ​​at the wellhead of production well 1.

[0090] The calculation module calculates the mass flow rate and heat content of the produced fluid for each production well based on temperature, pressure values ​​and the principle of heat balance.

[0091] The analysis module analyzes the connectivity between injection and production wells based on the mass flow rate and calorific value of the produced fluid from production well 1, and evaluates the connectivity status between injection and production wells.

[0092] It should be noted that the present invention continuously monitors the temperature and pressure at the wellhead of production well 1. Two sets of devices are installed at the wellhead of each well, with equal intervals. The monitoring devices are powered by high-energy batteries and can continuously monitor for more than 3 months.

[0093] Furthermore, the monitoring equipment is also equipped with a control module, such as... Figure 2 As shown, the control module includes a main valve 5, a wax removal valve 3, and several oil production valves 4. The wellhead of production well 1 is shaped like a cross. The main valve 5 is installed in the lower section of production well 1, the wax removal valve 3 is installed in the upper wellhead of production well 1, and the oil production valves 4 are installed in the wellheads on both sides of production well 1.

[0094] It should be noted that the wax removal valve 3 is used to control the valve gate for the test instrument to move in and out of the internal channel of the production tubing; the left and right oil production valves 4 are used to control the inflow and outflow of fluids from the left and right directions; and the main valve 5 is used to control the overall opening and closing of the inflow and outflow of fluids.

[0095] Furthermore, a sucker rod 6 is installed vertically inside production well 1.

[0096] It should be noted that sucker rod 6 is a slender rod in production well 1 (pumping unit well). It connects to the power components of the pumping unit at the top and the pump at the bottom, serving to transmit power. Simply put, the up-and-down movement of sucker rod 6 drives the pump plunger to lift the fluid from the bottom of the well to the surface.

[0097] It should be noted that, as Figure 4 As shown, when the cumulative testing time is around 300 hours, the heat of the produced fluid begins to increase, indicating that steam injection begins to take effect. This helps determine the time when steam injection begins to take effect and whether the wells are connected. If the heat of the produced fluid does not increase during the monitoring period, it indicates that the wells are not connected. Based on the identification of connected wells, the degree of connection between injection and production wells is evaluated according to the ratio of the heat of the produced fluid in each connected well to the total heat of the injected steam.

[0098] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring inter-well connectivity in heavy oil steam drive wells, characterized in that, Includes the following steps: Several temperature and pressure monitoring devices (2) are installed at the wellhead of the production well (1) to continuously monitor the temperature and pressure values ​​at the wellhead of the production well (1). The mass flow rate and heat content of the produced fluid of each production well (1) were calculated based on temperature and pressure values ​​and the principle of heat balance. The formula for calculating the mass flow rate is: ； in, This represents mass flow rate, in kg / s. The specific heat capacity of crude oil is expressed in J / (kg·℃). The specific heat capacity of water is expressed in J / (kg·℃). This represents the heat transfer coefficient of the pipeline, W / (m²). 2 ·℃); This represents the average temperature of the first and second points, expressed in °C. —Ambient temperature, °C; Indicates the water content of the fluid. Indicates the inner radius of the pipeline, in meters (m). The first point is the wellhead temperature; The temperature at the wellhead is the second point; d represents the distance between the first and second points at the wellhead, where both the first and second points are monitoring points at the wellhead. The formula for calculating the calorific value of the produced liquid is: ； in, This indicates that the produced liquid contains heat; Based on the mass flow rate and calorific value of the produced fluid from the production well (1), the degree of connectivity between the injection and production wells is analyzed, and the connectivity status between the injection and production wells is evaluated, including: Collect data on oil well production and total heat of injected steam; Draw the mass flow rate separately and the heat content of the produced liquid A curve that changes over time; Based on the calorific value of the produced liquid The time it takes for steam injection to take effect is determined by the curves that change over time and the production status of the oil wells; Based on the calorific value of the produced liquid The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

2. The method for monitoring inter-well connectivity in heavy oil steam drive according to claim 1, characterized in that, The formula for calculating the heat transfer coefficient of the pipeline is: ； in, Pipeline thermal resistance, m·℃ / W; Let be the inner radius of the pipeline, in meters (m). Let be the outer radius of the pipeline, in meters (m). The thermal conductivity of the pipeline is W / (m·℃).

3. A device for monitoring the inter-well connectivity in heavy oil steam drive wells, characterized in that, It includes a temperature and pressure monitoring module, a calculation module, and an analysis module; The temperature and pressure monitoring module includes several pressure monitoring devices (2) installed at the wellhead of the production well (1) for continuously monitoring the temperature and pressure values ​​at the wellhead of the production well (1). The calculation module calculates the mass flow rate and heat content of the produced fluid for each production well (1) based on temperature and pressure values ​​and the principle of heat balance. The formula for calculating the mass flow rate by the calculation module is as follows: ； in, Indicates mass flow rate; The specific heat capacity of crude oil is expressed in J / (kg·℃). The specific heat capacity of water is expressed in J / (kg·℃). This represents the heat transfer coefficient of the pipeline, W / (m²). 2 ·℃); This represents the average temperature of the first and second points, expressed in °C. —Ambient temperature, °C; Indicates the water content of the fluid. Indicates the inner radius of the pipeline, in meters (m). The first point is the wellhead temperature; The temperature at the wellhead is the second point; d represents the distance between the first and second points at the wellhead, where both the first and second points are monitoring points at the wellhead. The formula used by the calculation module to calculate the calorific value of the produced liquid is as follows: ； in, This indicates that the produced liquid contains heat; The analysis module, based on the mass flow rate and calorific value of the produced fluid from the production well (1), analyzes the connectivity between the injection and production wells and evaluates the connectivity status between them, including: Collect data on oil well production and total heat of injected steam; Draw the mass flow rate separately and the heat of the produced liquid A curve that changes over time; Based on the calorific value of the produced liquid The time it takes for steam injection to take effect is determined by the curves that change over time and the production status of the oil wells; Based on the calorific value of the produced liquid The degree of connectivity between injection and production wells is evaluated by the proportion of the total heat of injected steam.

4. The device for monitoring the inter-well connectivity of heavy oil steam drive according to claim 3, characterized in that, It is also equipped with a control module, which includes a main valve (5), a wax removal valve (3) and several oil production valves (4).

5. The device for monitoring the inter-well connectivity of heavy oil steam drive according to claim 4, characterized in that, The wellhead of the production well (1) is shaped like a cross. The main valve (5) is installed in the lower section of the production well (1). The wax removal valve (3) is installed in the upper wellhead of the production well (1). The oil production valve (4) is installed in the wellheads on both sides of the production well (1).

6. The device for monitoring the inter-well connectivity of heavy oil steam drive according to claim 3, characterized in that, A sucker rod (6) is installed vertically inside the production well (1).

7. The device for monitoring the inter-well connectivity of heavy oil steam drive according to claim 3, characterized in that, The formula used by the calculation module to calculate the heat transfer coefficient of the pipeline is as follows: ； in, Pipeline thermal resistance, m·℃ / W; Let be the inner radius of the pipeline, in meters (m). Let be the outer radius of the pipeline, in meters (m). The thermal conductivity of the pipeline is W / (m·℃).

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