Automatic regulation and control exploitation experiment method and device for heavy oil reservoir

Abstract

The invention provides an automatic regulation and control exploitation experiment method and device for a heavy oil reservoir. A physical model of the heavy oil reservoir is designed according to reservoir physical property parameters and well pattern distribution; the fireflood dynamic process and effect of the heavy oil reservoir are simulated through the designed physical model, the temperature in a cavity of the physical model is monitored in real time through a temperature measuring well in the experiment process, and the gas-liquid output dynamic state of each production well is monitored in real time; according to the temperature monitoring data in the designed physical model cavity and the monitoring data of the liquid production capacity and the gas concentration of each production well, the fireflooding development effect of the target oil reservoir under different gas injection schemes and regulation measures is evaluated. According to the device, the dynamic evolution law of the fire cavity of the heterogeneous oil reservoir can be researched, and heavy oil reservoirs under different heterogeneous conditions can be simulated; the dynamic change of fire line development in the fireflooding process and the influence of different regulation and control schemes on the advancing speed and the swept volume of the fire line can be detected in real time, and finally a development scheme of the maximum recovery rate of fireflooding is given.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas production, and in particular to an automated control and production experimental method and device for heavy oil reservoirs. Background Art

[0002] The exploitation of heterogeneous oil reservoirs is difficult, mainly reflected in the following aspects:

[0003] 1. Large permeability differences: Heterogeneous reservoirs have large permeabilities in different injection and production directions. In areas with high permeability, the average pore size is large and the fluid flow resistance is small. The injected water, gas and other displacement fluids can easily and quickly pass through, forming a "cross-flow" channel; while in areas with low permeability, the pores are small, the fluid flow is difficult, and the displacement fluid is difficult to reach, resulting in the crude oil in this part of the reservoir being difficult to extract, and the overall recovery rate is limited. For example, the local permeability of some oil layers can reach thousands of millidarcy, while others are only a few millidarcy. When injecting water, the water will preferentially flow to the high permeability area and bypass the low permeability area.

[0004] 2. Difficulty in predicting fluid flow paths: Due to the complex geological structure, numerous faults and fractures, and volatile permeability of heterogeneous reservoirs, it is difficult to accurately predict the direction of injected fluids. This makes it easy for the injected fluids to fail to displace crude oil as expected during the production process, and instead flow ineffectively, wasting resources and failing to achieve the expected recovery rate.

[0005] 3. Complex distribution of remaining oil: Heterogeneity creates a complex distribution pattern of remaining oil. After a period of exploitation, the remaining oil may be scattered in low-permeability areas, tiny pores, dead oil areas, or areas separated by faults and barriers. It is difficult to accurately locate and implement targeted exploitation measures. Conventional exploitation methods are difficult to extract these scattered remaining oil.

[0006] 4. Difficulty in adapting mining technology: A single mining technology often cannot meet the needs of heterogeneous oil reservoirs. For example, water injection mining may only be effective in some high-permeability areas; although thermal oil recovery can improve the fluidity of heavy oil, it is difficult to diffuse to all oil-bearing areas due to the complex permeability differences in the reservoir and uneven heat distribution; chemical agents for chemical flooding oil recovery will also be injected unevenly and have insufficient reaction effects with crude oil due to the heterogeneity of the reservoir. It is necessary to integrate multiple mining technologies, which are faced with the challenges of high costs and difficult process coordination.

[0007] At present, most heavy oil reservoirs have entered the late stage of steam injection development. The oil-water distribution is complex and the remaining oil is dispersed. They are facing problems such as low heat utilization rate in the reservoir, high water content in the output fluid, and low crude oil recovery, which leads to the economic benefits of steam development decreasing year by year. Therefore, there is an urgent need for a method to evaluate the recovery effect of heterogeneous reservoirs (especially heavy oil reservoirs) to determine the optimal recovery method for heterogeneous reservoirs. Summary of the invention

[0008] This specification provides an automated control and exploitation experimental method and device for heavy oil reservoirs, which are used to evaluate the fire drive development effect of target oil reservoirs under different gas injection schemes and control measures.

[0009] In a first aspect, the present specification provides an automated control method for a heavy oil reservoir, comprising: obtaining reservoir physical property parameters and well pattern distribution of a heavy oil reservoir; designing a physical model of the heavy oil reservoir according to the reservoir physical property parameters and well pattern distribution, wherein the physical model is a simulated model of the actual well pattern distribution of the heavy oil reservoir in proportion, and the shell of the physical model forms a cavity with injection wells, production wells, and temperature measurement wells; the cavity of the physical model is filled with heterogeneous oil sands according to the reservoir physical property parameters and sealed to simulate a heterogeneous reservoir; simulating the fire drive development effect of a target reservoir under different gas injection schemes and control measures of the heavy oil reservoir through the physical model, monitoring the temperature in the cavity of the physical model in real time through the temperature measurement well during the experiment, and monitoring the gas and liquid production dynamics of each production well; and evaluating the fire drive development effect of the target reservoir under different gas injection schemes and control measures according to the temperature monitoring data in the cavity of the physical model, the liquid production of each production well, and the output gas concentration monitoring data.

[0010] In some embodiments, the cavity of the physical model is filled with heterogeneous oil sands in the following manner: a heavy oil reservoir is divided into a plurality of permeability areas with different permeability differences, and a partition is set inside the cavity of the physical model according to the division result to divide the cavity into a plurality of permeability areas; the oil sand mixing ratio corresponding to each permeability area is determined according to the reservoir physical property parameters of the heavy oil reservoir, and quartz sand, crude oil and alkaline land are mixed according to a predetermined oil sand mixing ratio and then filled into the corresponding permeability area; the mixing ratios and compaction degrees corresponding to adjacent permeability areas are different to make the permeability different.

[0011] In some embodiments, during the fire flooding experiment, the following operations are intermittently performed during the fire cavity expansion stage after ignition: gas injection, hot water injection, and water vapor injection to improve the fire flooding recovery rate.

[0012] In some embodiments, after evaluating the fire drive development effect of the target oil reservoir under different gas injection schemes and control measures according to the temperature monitoring data in the physical model cavity, the liquid production and gas concentration monitoring data of each production well, it also includes: on the basis of the fire drive production scheme, adjusting at least one of the following parameters to form an extended fire drive scheme: adjusting the depth of the injection well in the physical model cavity, the setting position of the production well on the surface of the physical model, and the depth of the production well in the physical model cavity; simulating the implementation process of each extended production scheme for the heavy oil reservoir through the physical model, during the implementation of the extended production scheme, real-time monitoring the temperature in the physical model cavity through the temperature measuring well, and monitoring the liquid production and output gas concentration of each production well, evaluating the production effect of the extended production scheme, and selecting the plan with the highest recovery rate as the final implementation production plan according to the evaluation results.

[0013] In some embodiments, the physical model is further provided with a first pressure gauge and a second pressure gauge, the first pressure gauge collects the injection pressure of the injection well, and the second pressure gauge collects the internal pressure of each production well when the recovery end is connected; during the fire drive experiment, after the regulation time is reached, each production well is closed, and the following S1 and S2 are executed cyclically: S1: When the production pressure difference reaches the upper limit pressure, the production well corresponding to the low permeability area is opened, and the opening is kept at the maximum; the production well corresponding to the high permeability area is opened, and the opening is kept at the minimum; the production pressure difference is the difference between the pressures collected by the first pressure gauge and the second pressure gauge; S2: When the production pressure difference is reduced to the target pressure range, each production well is closed.

[0014] In some embodiments, the method further includes: during the experiment, automatically controlling the switch status of the production wells in each area according to the advancement status of the fire line during the fire drive process in the following manner: if the advancement progress of the front edge of the fire line in the first area exceeds that of the second area, increasing the opening and frequency of the production wells corresponding to the first area, and reducing the opening and frequency of the production wells corresponding to the second area.

[0015] In some embodiments, each production well has multiple opening levels; the opening of the production well is periodically adjusted according to the actual production situation; the method also includes: adjusting the opening of the production well during the experiment in the following manner: if the progress of the hotline advancement in the high permeability area is greater than the preset progress, and the current opening of the production well in the high permeability area is the first opening level, and it is currently necessary to reduce the opening of the production well, then in the next cycle the opening of the production well will be reduced to the next opening level, and when it is necessary to reduce the opening of the production well again, the production well will be further adjusted to the next opening level or a fully closed state until there is no need to reduce the opening of the production well.

[0016] In some embodiments, the method further includes: when the rate of change of the cumulative liquid production rate of each production well decreases to a preset liquid production rate, and / or when the oxygen concentration (rising rate) in the produced gas concentration reaches a preset threshold, determining that the target control timing is reached.

[0017] The second aspect of the present specification provides an experimental device for a heavy oil reservoir, comprising: a physical model for simulating a heavy oil reservoir: the physical model is a simulated model of the actual well network distribution of the heavy oil reservoir in a proportional manner, the shell of the physical model forms a cavity with an injection well, a production well, and a temperature measurement well; the cavity of the physical model is filled with heterogeneous oil sands according to the reservoir physical property parameters of the heavy oil reservoir and sealed to simulate the heterogeneous reservoir; an injection and production subsystem is used to inject gas from the injection well into the cavity of the physical model, and collect and measure the output gas and output liquid of each production well; the injection and production subsystem The system measures and separates the produced liquid at the production end of each production well separately; the monitoring subsystem is used to monitor the gas pressure, temperature and gas concentration during the simulation of the production plan of the heavy oil reservoir; the control subsystem includes a valve body and a controller arranged in each production well, the controller observes the production situation of the production wells in different permeability areas in real time according to the metering results of the injection and production subsystem, judges the production degree of different permeability areas, sends control instructions to the valve body according to the liquid production speed of each production well to adjust the progress of the fire line expansion, and sends control instructions to the valve body to realize the automatic control and exploitation experimental method of heavy oil reservoirs described in any one of the first aspects.

[0018] The automated control experimental method and device for heavy oil reservoirs provided in this specification can use the physical model of heavy oil reservoirs to carry out a one-injection-multiple-recovery production scheme experiment, so as to study the dynamic evolution law of the fire cavity in heterogeneous oil reservoirs; the heterogeneity of the model body can be optimized and adjusted according to actual formation parameters, and the model can simulate formation heterogeneity of any parameters; the simulation system can solve the problems of time-consuming and labor-intensive manual control, untimely control and inaccurate control, and achieve the technical effect of "precisely determining the combustion state of fire drive and accurately controlling the fire drive oil production process"; the influence of different control schemes on the fire line advancement speed and swept volume can be studied, the dynamic changes of the fire line development in the fire drive process can be detected in real time, the direction of the fire line can be controlled and pulled in real time, and the swept volume of the fire cavity can be controlled and increased, thereby improving the reservoir utilization degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 A schematic diagram of a process flow of an automated control experimental method for a heavy oil reservoir provided in this specification;

[0021] Figure 2 is a schematic diagram of the physical model of a heavy oil reservoir;

[0022] Figure 3 A schematic diagram of another process of an automated control experimental method for a heavy oil reservoir provided in this specification;

[0023] Figure 4 A flow chart of a control method for a fire drive mining scheme;

[0024] Figure 5 A flow chart of another control method for fire flooding mining scheme;

[0025] Figure 6 Schematic diagram of various structures for controlling the opening of production wells;

[0026] Figure 7 This is a schematic diagram of an automated control experimental device for heavy oil reservoirs;

[0027] Figure 8 It is a structural diagram of the proportional solenoid valve. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0029] In order to improve the recovery rate of heterogeneous oil reservoirs, this specification provides an automated control and exploitation experimental method for heavy oil reservoirs, such as Figure 1 As shown, the method includes the following S10 to S40.

[0030] S10: Obtain reservoir physical property parameters and well pattern distribution of heavy oil reservoirs.

[0031] Reservoir physical parameters may include porosity, permeability, content saturation, pore structure parameters (such as pore radius, pore throat ratio), compressibility (such as rock compressibility, fluid compressibility), etc.

[0032] Well network distribution refers to the distribution of oil wells on the reservoir plane, which may include the location of production wells, the relative orientation between injection wells and production wells, etc.

[0033] S20: Designing a physical model of a heavy oil reservoir according to the reservoir physical property parameters and the well network distribution, wherein the physical model is a simulated model of the actual well network distribution of the heavy oil reservoir in a proportional manner, and the shell of the physical model forms a cavity with injection wells, production wells, and temperature measurement wells; the interior of the cavity of the physical model is filled with heterogeneous oil sands according to the reservoir physical property parameters and sealed to simulate a heterogeneous reservoir.

[0034] The physical model of heavy oil reservoir is a solid model. Figure 2 As shown, G represents a chimney well, N1, N2, and N3 represent horizontal production wells, H represents a gas injection well, and P represents a pressure gauge for measuring gas pressure. The physical model includes a shell, which can be made of high-temperature and high-pressure resistant Hastelloy alloy and can withstand a high temperature of 700°C. The shell encloses an open cavity, and an end cover and a flange are provided at the opening of the cavity. The material of the flange can be high-temperature resistant stainless steel, and the shell and the end cover are connected by a flange. A closed cavity is formed by the shell, the end cover, and the flange to simulate the actual high temperature and high pressure environment in the heavy oil reservoir.

[0035] A layer of high-temperature resistant fire-retardant paint can be evenly applied to the inner wall of the cavity to reduce heat loss, and a constant temperature insulation sleeve can be installed on the outside of the shell to compensate for heat loss.

[0036] The shell is equipped with injection wells, production wells, chimney wells, and temperature measurement wells. An electric igniter can be embedded in the injection well, and the electric igniter is installed in the liner. There are multiple air holes at the bottom of the liner for injecting air. Both the injection well and the production well are equipped with high-temperature resistant stainless steel screens to prevent sand from clogging the pipeline.

[0037] The number and location of production wells and chimney wells can be determined according to the actual distribution of the well network in the heavy oil reservoir. Multiple temperature measuring wells can be set (for example, one temperature measuring well is set every 10 cm or so), and the temperature measuring wells can extend from the bottom of the cavity to the top, and each temperature measuring well can be set in parallel. Multiple thermocouples at different heights are set in each temperature measuring well to form multiple temperature measuring layers with different distances from the production plane. In other words, the temperature of multiple planes inside the cavity and multiple positions on each plane can be measured through the temperature measuring wells.

[0038] The interior of the cavity of the physical model is filled with heterogeneous oil sands in the manner described in S21 and S22 below.

[0039] S21: Dividing the heavy oil reservoir into a plurality of permeable areas with different permeability differences, and setting a partition inside the cavity of the physical model according to the division result to divide the cavity into a plurality of permeable areas.

[0040] After obtaining the reservoir physical property parameters of the heavy oil reservoir, multiple permeability areas with different permeability differences can be divided according to the reservoir physical property parameters of the heavy oil reservoir. The specific division into several permeability areas and the permeability value range of each permeability area can be determined according to actual conditions. The permeability value spans of different permeability differences can be different.

[0041] S22: Determine the mixture particle size and oil sand mixing ratio corresponding to each permeability area according to the reservoir physical property parameters of the heavy oil reservoir, mix quartz sand, crude oil and kaolin according to the predetermined oil sand mixing ratio and then fill them into the corresponding permeability area; the mixing ratios and compaction degrees corresponding to adjacent permeability areas are different to make the permeability different.

[0042] The particle size of the mixture and the oil sand mixing ratio can be determined based on the permeability combined with various reservoir physical parameters such as porosity, permeability, saturation, pore structure parameters, etc. For example, quartz sand with different particle sizes can be mixed with crude oil and kaolin to obtain three mixed filling materials corresponding to the permeability difference.

[0043] S30: Using the temperature measuring well of the physical model to monitor the temperature in the cavity of the physical model in real time, and to monitor the liquid production and produced gas concentration of each production well.

[0044] The fire drive experiment process may specifically include the following steps: opening a high-pressure nitrogen bottle, injecting nitrogen into the cavity of the physical model through a pressure stabilizing device, and opening a back pressure valve to adjust the pressure in the cavity of the physical model; when the back pressure of the physical model remains stable, preheating the physical model to a preset temperature through a heating rod; after the preheating reaches the preset requirements, opening each production well, opening a high-pressure air bottle, injecting air into the cavity of the physical model and igniting it to simulate a fire drive mining plan.

[0045] In some embodiments, during the fire chamber expansion phase of the fire drive experiment, the following operations may be intermittently performed: gas injection, hot water injection, and water vapor injection. The intermittent execution of A and B means that B is executed after A is executed for a period of time, and A is executed after B is executed for a period of time, and so on, A, B, B, A...are executed alternately.

[0046] By injecting hot water and using water vapor to regulate the oil, the viscosity of crude oil can be reduced and its fluidity can be enhanced. In addition, the seepage conditions of the oil layer can be improved and the recovery rate of crude oil can be increased.

[0047] S40: Evaluate the fire drive development effect of the target oil reservoir under different gas injection schemes and control measures according to the temperature monitoring data in the physical model cavity, the liquid production and output gas concentration monitoring data of each production well.

[0048] The fire drive production effect can be evaluated based on the gas and liquid production dynamics of each production well. At the same time, it is also necessary to combine the temperature changes in the physical model cavity to determine whether the expected fire drive production level has been achieved. For example, if the maximum temperature of most areas inside the cavity of the physical model reaches a certain high temperature value, but the maximum temperature of one area is far from the high temperature value, then it can be determined that the front edge of the fire line has not passed through this area, and thus the production level of this area is insufficient.

[0049] In some embodiments, Figure 3 As shown, after S40, the following S50 to S80 are also included.

[0050] S50: Based on the fire drive implementation mining plan, the following parameters are adjusted to form an extended mining plan: the depth of the injection well in the physical model cavity, the setting position of the production well on the physical model surface, and the depth of the production well in the physical model cavity.

[0051] Normally, once the shell of a physical model is formed, its structure cannot be changed. The effect of parameter change can be achieved by establishing multiple physical models with different shell structures. Alternatively, an interface for changing parameters can be reserved in advance on the shell of the physical model to facilitate flexible parameter changes. For example, a spare production well can be reserved in advance, which can be plugged when not in use and opened when needed.

[0052] S60: simulating the implementation process of each extended mining plan using a physical model, monitoring the temperature in the physical model cavity in real time through a temperature measuring well during the implementation of the extended mining plan, and monitoring the liquid production and gas concentration of each production well.

[0053] S70: Evaluate the mining effect of the extended mining scheme based on the temperature monitoring data in the physical model cavity, the liquid production and output gas concentration monitoring data of each production well.

[0054] S80: Based on the evaluation results, the plan with the highest recovery rate is selected as the final mining plan.

[0055] In some embodiments, the physical model is further provided with a first pressure gauge and a second pressure gauge, wherein the first pressure gauge collects the injection pressure of the injection well, and the second pressure gauge collects the internal pressure of the recovery ends of each production well when they are connected.

[0056] The fire drive production scheme needs to produce as much remaining oil as possible in the reservoir. The non-uniform expansion of the fire cavity often leads to a smaller fire cavity sweep coefficient and a lower crude oil recovery rate. Effective control measures can improve the non-uniform expansion behavior of the fire cavity, expand the volume sweep coefficient of the fire cavity, and improve the recovery level of the fire drive technology. Traditional fire drive control measures use manual adjustment. During the manual adjustment process, the fire drive control is delayed, the control is not accurate, the control efficiency is low, the operation is complicated, time-consuming and labor-intensive, and improper operation can easily cause human injuries. The fire drive production scheme simulated by the physical model in this scheme is not only safe, but also can achieve automated high-precision control.

[0057] like Figure 4 As shown, the fire drive production plan includes: after reaching the control timing, closing each production well, and cyclically executing the following S1 and S2.

[0058] S1: When the production pressure difference reaches the upper limit pressure, open the production well corresponding to the low permeability area and keep the opening at the maximum; open the production well corresponding to the high permeability area and keep the opening at the minimum; the production pressure difference is the difference between the pressures collected by the first pressure gauge and the second pressure gauge.

[0059] During the fire drive experiment, high temperature combustion changes the properties of crude oil, reduces viscosity, and makes it easier for crude oil to flow. Generally speaking, the resistance of crude oil in the high permeability area is smaller than that in the low permeability area, which makes it easy to form an advantageous channel for fire drive.

[0060] The hyperpermeability zone and the hypopermeability zone are relative. The hyperpermeability zone is the zone with the highest permeability among all the permeability zones, and the hypopermeability zone is the zone with the lowest permeability among all the permeability zones.

[0061] The upper limit pressure may be the maximum pressure that the physical structure of the physical model can withstand during operation, or may be a relatively large pressure value determined based on experience that can improve the recovery rate. For example, the upper limit pressure may be 1200 kPa.

[0062] S2: When the production pressure difference drops to the target pressure range, shut down each production well.

[0063] The intermittent control method described in S1 and S2 above utilizes the disturbance of flow field and thermal field to reduce or slow down the advancement speed of the front edge of the fire line in the dominant channel (high permeability area), and increase the advancement speed and affected range of the front edge of the fire line in the low permeability area. The above intermittent control method can reduce the fluid flow rate in the high permeability area, slow down the combustion reaction rate, avoid the destruction of the formation rock structure due to excessive temperature in the high permeability area, reduce the advancement speed of the front edge of the fire line in the high permeability area, weaken the degree of flow field and thermal field disturbance in the high permeability area, increase the combustion reaction rate in the low permeability area, increase the degree of flow field and thermal field disturbance in the low permeability area and the advancement speed of the fire line in the low permeability area, which helps to improve the overall effective utilization rate of heat, reduce the occurrence of gas channeling, improve the uniform diffusion of heat inside the reservoir, weaken the uneven distribution of pressure inside the reservoir, and improve the displacement efficiency.

[0064] In some embodiments, Figure 5 As shown, between S1 and S2, there is also S3: if the advancement progress of the front edge of the fire line in the high permeability area exceeds that of the low permeability area, the opening and frequency of the production wells corresponding to the low permeability area are increased, and the opening and frequency of the production wells corresponding to the high permeability area are reduced.

[0065] After ignition in the physical model cavity, the fire front will advance forward with the circulation of air. However, due to the difference in permeability, the air flow rate in the high permeability area and the low permeability area is different, and the fire front advances at different speeds in the heavy oil reservoir. If the advancement of the fire front is not intervened, the fire front may approach the vicinity of the production well corresponding to the high permeability area early, resulting in the premature end of the fire drive experiment process (fire or gas channeling). In this case, there may be a lot of oil and gas left in the low permeability area that has not been exploited, resulting in a low overall recovery rate of the heavy oil reservoir.

[0066] When the openings of the production wells corresponding to the high-permeability area and the low-permeability area are the same, the air diffuses better in the high-permeability area, forming a superior channel for air circulation, so that the front edge of the fire line in the high-permeability area advances faster.

[0067] By increasing the opening and frequency of the production wells corresponding to the low permeability area, the diffusion effect of air in the low permeability area can be enhanced. However, during the fire drive experiment, the advancement path of the front edge of the fire line is not only affected by the air diffusion effect in the low permeability area, but also by the air diffusion effect in the high permeability area. For example, if the air diffusion effect in the dominant channel (i.e., the high permeability area) is better, then although the air diffusion effect in the non-dominant channel (i.e., the low permeability area) is improved, it is impossible to increase the fire line advancement speed in the low permeability area and reduce the fire line advancement speed in the high permeability area, that is, it is impossible to achieve the expected fire line traction effect. This scheme gradually increases the opening and frequency of the low permeability production wells while gradually reducing the opening and frequency of the high permeability production wells, which can achieve the above-mentioned expected fire line traction effect, thereby improving the fire drive efficiency in the low permeability area and the production rate of the high permeability production wells.

[0068] The opening refers to the opening of the valve in the production well. The valve adopts a proportional solenoid valve whose opening can be controlled by an input signal. Each proportional solenoid valve is controlled by the same controller. The controller controls the opening of the proportional solenoid valves in each production well synchronously according to the temperature monitoring data in the physical model cavity. The controller can also control the opening of the proportional solenoid valves in each production well in combination with the production pressure difference, the liquid production of each production well, and the concentration of the produced gas. The controller includes a PWM electronic controller and a computer. Figure 6 As shown, each proportional solenoid valve corresponds to a PWM electronic controller, the valve opening of the proportional solenoid valve is driven by the PWM electronic controller to adjust, and control instructions are sent to each PWM electronic controller through the computer.

[0069] The advancement progress of the front edge of the fire line can be the ratio of the advancement distance to the overall length in the injection-production connection direction. Each temperature measuring well can be set at an equal distance, and thermocouples are set at different heights in each temperature measuring well to form multiple temperature measuring layers with different distances from the production plane. In this case, each thermocouple can be numbered, and the corresponding relationship between the number and position of the thermocouple can be determined in advance. The position of the front edge of the fire line can be judged according to the collected value of the thermocouple, and then the advancement distance of the front edge of the fire line can be determined.

[0070] When the fire line front position is determined to reach a position near any production well through the collected values ​​of each thermocouple, the fire line pulling control process can be ended, and nitrogen can be injected into the physical model to extinguish the fire in the cavity.

[0071] In some embodiments, when the rate of change of the cumulative liquid production rate of each production well decreases to a preset liquid production rate (for example, the preset liquid production rate may be 0, or a smaller value close to 0), and / or when the oxygen concentration (rising rate) in the produced gas concentration reaches a preset threshold value, it is determined that the timing for regulation has been reached.

[0072] In some embodiments, during the experiment, the switch status of the production wells in each area is automatically controlled according to the advancement status of the fire line during the fire drive process in the following way: if the advancement progress of the front edge of the fire line in the first area exceeds that of the second area, the opening and frequency of the production wells corresponding to the first area are increased, and the opening and frequency of the production wells corresponding to the second area are reduced.

[0073] The above-mentioned “first region” and “second region” are only used to indicate two different permeation regions, and do not refer to any particular region.

[0074] In some embodiments, each production well has multiple opening levels; the opening of the production well is periodically adjusted according to actual production conditions.

[0075] During the experiment, the opening of the production well is adjusted in the following way: if the progress of the hotline in the high permeability area is greater than the preset progress, and the current opening of the production well in the high permeability area is the first opening level, and it is currently necessary to reduce the opening of the production well, then in the next cycle the opening of the production well will be reduced to the next opening level. When it is necessary to reduce the opening of the production well again, the production well will be further adjusted to the next opening level or a fully closed state until there is no need to reduce the opening of the production well.

[0076] For example, the production well can be set with multiple gears such as fully closed, 1 / 8, 1 / 4, 1 / 2, 3 / 4, and fully open, and the opening can be adjusted periodically according to the actual production situation. For example, if the fire line in the high permeability area advances too fast, the current opening of the production well in the high permeability area is 1 / 4, and the opening of the production well needs to be reduced, then the opening of the production well can be adjusted to 1 / 5 in the next cycle. When the opening of the production well needs to be reduced again, the production well will be adjusted to a full 1 / 8 or fully closed state until the opening of the production well needs to be reduced, so that the front edge of the fire line can be balanced and stably advanced in the high permeability area and low permeability area of ​​the target reservoir.

[0077] The present specification provides an automated control and exploitation experimental device for a heavy oil reservoir, comprising a physical model for simulating a heavy oil reservoir, an injection and production subsystem, a monitoring subsystem and a control subsystem.

[0078] The physical model of the heavy oil reservoir is a simulated model that is proportionally reduced from the actual well network distribution. The shell of the physical model forms a cavity with injection wells, production wells, and temperature measurement wells. The interior of the cavity of the physical model is filled with heterogeneous oil sands based on the reservoir physical property parameters of the heavy oil reservoir and is sealed to simulate the heterogeneous reservoir.

[0079] The injection and production subsystem is used to inject gas from the injection well into the cavity of the physical model, and collect and measure the produced gas and produced liquid of each production well. The injection and production subsystem measures and separates the produced liquid at the production end of each production well separately.

[0080] The monitoring subsystem is used to monitor the gas pressure, temperature and gas concentration during the simulation of the production plan of the heavy oil reservoir.

[0081] The control subsystem includes a valve body and a controller arranged in each production well. The controller observes the production conditions of production wells in different permeability areas in real time according to the metering results of the injection and production subsystem, determines the production degree of different permeability areas, sends control instructions to the valve body according to the liquid production rate of each production well to adjust the progress of the fire line expansion, and sends control instructions to the valve body to realize the above-mentioned automatic control and exploitation experimental method of heavy oil reservoirs.

[0082] Figure 7 The schematic diagram of the structure of an automated control and exploitation experimental device for a heavy oil reservoir is shown in FIG. 1, which represents a high-pressure nitrogen bottle, 2, which represents a high-pressure air bottle, 3, which represents a ball valve, 4, which represents a gas flow meter, 5, which represents a physical model for simulating a heavy oil reservoir, 6, which represents a pressure regulating tank, 7, which represents a first pressure gauge, 8, which represents a computer or a controller, 9, which represents a thermocouple, 10, which represents a proportional solenoid valve, 11, which represents a horizontal production well, 12, which represents a second pressure gauge, 13, which represents a back pressure regulating valve, 14, which represents a gas-liquid separator, 15, which represents a gas analyzer, and 16, which represents a flue gas processor.

[0083] The high-pressure nitrogen cylinder 1 and the high-pressure air cylinder 2 are connected to the gas flowmeter 4 through the ball valve 3. The gas flow enters the physical model 5 for simulating the heavy oil reservoir through the pressure regulating tank 6. The first pressure gauge 7 is used to measure the injection pressure of the injection well of the physical model 5. The second pressure gauge 12 is used to measure the internal pressure of each production well in the connected state. 132 thermocouples 9 are arranged inside the cavity of the physical model 5 and inserted into the temperature measuring well for temperature detection. The proportional solenoid valve 10 is connected to the horizontal production well 11. The computer or controller 8 is used to send a control instruction to the proportional solenoid valve 10 to control the opening of the horizontal production well. The back pressure regulating valve 13 is used to maintain the pressure stability of the pipeline and the model. The gas-liquid separator 14 separates the output gas and the output liquid, and the liquid cylinder is used for metering after separation. One end of the gas analyzer 15 is connected to the gas-liquid separator, and the other end is connected to the flue gas processor 16. The gas analyzer 15 detects the separated flue gas, and the flue gas processor 16 collects and processes the flue gas discharged by the gas analyzer 15.

[0084] Figure 7 The high-pressure nitrogen cylinder 1, high-pressure air cylinder 2, ball valve 3, pressure-stabilizing tank 6, gas-liquid separator 14, gas analyzer 15, and flue gas processor 16 are components of the injection and production subsystem; the gas flow meter 4, injection end pressure gauge 7, thermocouple 9, and production end pressure gauge 12 are components of the monitoring subsystem; the proportional solenoid valve 10, back pressure regulating valve 13, and computer 8 are components of the control subsystem.

[0085] like Figure 6As shown, in the automated control method for heavy oil reservoirs, the controller includes a PWM electronic controller, the horizontal production well is connected to the proportional solenoid valve, the proportional solenoid valve is connected to the PWM electronic controller, and the PWM electronic controller receives control instructions sent by a computer to control the opening of the proportional solenoid valve and adjust the flow rate of the proportional solenoid valve of the horizontal well.

[0086] like Figure 8 As shown in the figure, the proportional solenoid valve can be composed of a proportional amplifier, a proportional solenoid, and a hydraulic control valve. The proportional solenoid valve receives the PWM command signal, performs power amplification through the proportional amplifier, and outputs current proportionally to the proportional solenoid of the proportional solenoid valve. The proportional solenoid outputs force and moves the position of the valve core proportionally, controls the flow rate of the fluid proportionally, and thus controls the flow rate of the output fluid.

[0087] The gas analyzer 15 may include multiple gas monitoring modules such as O2, CO, CO2, CH4, H2, etc. The flue gas separated by the gas-liquid separator 14 enters the gas analyzer 15. The gas analyzer 15 monitors the concentration data of the gas produced during the fire drive process in real time to assist in judging the fire drive combustion state. Specifically, when the oxygen component is 0, it indicates that it is in the high-temperature combustion stage, and the fire drive combustion state is the best, and the fire line is steadily advancing forward.

[0088] The flue gas processor 16 collects the tail gas flowing through the gas analyzer 15, and removes harmful substances from the tail gas by adsorption. After the tail gas is treated and meets the standards, it is discharged into the atmosphere, thereby reducing pollution and protecting the environment.

[0089] The specific experiment of verifying the heavy oil reservoir exploitation method provided in this specification through the above-mentioned heavy oil reservoir exploitation experimental device may include the following nine steps.

[0090] Step 1: Experimental sample preparation

[0091] Quartz sand, heavy oil and kaolin are added according to the designed proportions, and the heating function of the mixer is turned on. Considering the high viscosity of the oil sample, the stirring time must be at least 4 hours to ensure that the oil sand is stirred evenly.

[0092] Step 2: Oil sand filling and sealing inspection

[0093] The evenly stirred oil sand is spread into the physical model 5, and then compacted evenly with a plunger. After the oil sand is filled, a layer of thermal insulation cement is applied on the top of the oil sand to prevent gas channeling from occurring on the top. Finally, the physical model 5 is covered, and the inlet and outlet pipelines are connected for a sealing inspection.

[0094] Step 3: Set up the thermocouple for temperature measurement

[0095] Three thermocouples at different heights were inserted into each temperature measuring well, forming five temperature measuring layers at different heights to detect the temperature changes inside the model.

[0096] Step 4: Preheat

[0097] Open the high-pressure nitrogen bottle 1, and the nitrogen flows into the gas flowmeter 4 and then into the physical model 5 through the pressure regulating tank 6. Open the back pressure valve 13 to adjust the model pressure. When the back pressure of the physical model 5 remains stable, turn on the preheating program to start preheating. During preheating, set the temperature of the igniter to 200℃~350℃ and the gas injection rate to 1.5L / min. When the oil sand near the igniter rises to about 300℃, the preheating of the physical model 5 is completed. During preheating, the external heating jacket of the physical model needs to be turned on to compensate for the heat loss of the model in real time.

[0098] Step 5: Transfer air for ignition

[0099] After the preheating is completed, the nitrogen valve is closed and the high-pressure air bottle 2 is opened to inject air for ignition. During this process, the igniter temperature is gradually increased to 600°C and the gas injection rate is gradually increased to 2L / min. At the same time, the production pressure difference is recorded according to the collected values ​​of the first pressure gauge 7 and the second pressure gauge 12, the collected values ​​of each thermocouple in the temperature measuring well 9 are recorded, and the volume fraction change of the produced gas is recorded according to the analysis value of the gas analyzer 16.

[0100] Step 6: Determine when to adjust

[0101] When the rate of change of the cumulative liquid production rate of each production well decreases to 0, it is determined that the target control timing is reached.

[0102] Step 7: Fire drive automation control

[0103] The specific operation of fire drive automation control is as follows:

[0104] After the timing for regulation is reached, regulation is implemented and intermittent measures are taken. It is necessary to maintain the synchronous and stable advancement of the fire line and the oil wall in the low-permeability area and the high-permeability area according to the production pressure difference. The regulation pressure difference range is maintained at 300kPa~900kPa, so that the amplitude and cycle frequency of the pressure change over time of the fire drive regulation are maintained within a reasonable range, thereby forming a stable oil wall migrating toward the production well.

[0105] When the regulation timing is reached, first start to shut down the production wells in the low-permeability, medium-permeability, and high-permeability regions. When the production pressure reaches the upper limit pressure of 1200 kPa in the fire flooding process, open the production well in the low-permeability region (N1), keep it fully open, open the production well in the medium-permeability region (N3) with a 1 / 2 opening, open the production well in the high-permeability region (N2) with a 1 / 4 opening. When the production pressure drops to the P1 value, where 300 kPa < P1 < 900 kPa, shut down the production wells N1, N2, and N3 in the low-permeability, medium-permeability, and high-permeability regions; then when the production pressure difference rises to 1200 kPa again, open the production well in the low-permeability region (N1), keep it fully open, open the production well in the medium-permeability region (N3) with a 1 / 2 opening, open the production well in the high-permeability region (N2) with a 1 / 4 opening. When the production pressure difference drops to P1, shut down the production wells N1, N2, and N3 in the low-permeability, medium-permeability, and high-permeability regions, and then repeat the operation periodically to make the fire front advance steadily towards the low-permeability and high-permeability production wells evenly. During the intermittent regulation process, if the fire front leading edge in the low-permeability region still lags behind the fire front leading edge in the high-permeability region in terms of the advancing progress, or the fire front advancing speed in the high-permeability region is too fast and greater than the fire front advancing speed in the low-permeability region, then it is necessary to adjust the opening and frequency in the high-permeability region, that is, reduce the opening or opening frequency of the production wells in the high-permeability region. At this time, the regulation measures are as follows:

[0106] When the production pressure difference reaches the upper limit pressure of 1200 kPa, open the production well in the low-permeability region (N1), keep it fully open, open the production well in the medium-permeability region (N3) with a 1 / 4 opening, open the production well in the high-permeability region (N2) with a 1 / 8 opening. When the production pressure difference drops to the P1 value, shut down the production wells in the low-permeability, medium-permeability, and high-permeability regions; then when the production pressure difference rises to 1200 kPa again, open the production well in the low-permeability region, open the production well in the medium-permeability region (N3) with a 1 / 4 opening, open the production well in the high-permeability region with a 1 / 8 opening. When the production pressure difference drops to P1, shut down the production wells N1, N2, and N3 in the low-permeability, medium-permeability, and high-permeability regions again, and then repeat the operation periodically. Real-time detect the position of the fire front leading edge. Among them, if the fire front leading edge position in the high-permeability region is still advancing too fast, then shut down the production wells in the high-permeability region and only intermittently regulate the production wells in the low-permeability and medium-permeability regions. The opening and intermittent closing frequency of the production wells in the low-permeability and medium-permeability regions are adjusted as follows:

[0107] When the production pressure difference reaches the upper limit pressure of 1200 kPa, open the production well N1 in the low-permeability region, keep it fully open, the production well N2 in the high-permeability region remains in the normally closed state, and the production well N3 in the medium-permeability region is opened with a 1 / 4 opening. When the production pressure difference drops to the P1 value, shut down N1 and N3; then when the production pressure difference rises to 1200 kPa again, open N1, keep it fully open, N2 remains closed, N3 is opened with a 1 / 4 opening. When the production pressure difference drops to P1, shut down N1 and N3 again; then repeat the above operations until the fire front has advanced stably to near the production wells in the low, medium, and high-permeability regions, and then end the regulation.

[0108] The P1 value can be adjusted according to the actual situation. When the outlet liquid discharge rate is stable, the P1 value can be appropriately reduced, that is, the injection-production pressure difference can be increased. The opening and frequency of the production well can be adjusted in real time according to the fire drive effect until the fire line stably advances forward to the vicinity of the production well, and the regulation is ended.

[0109] Step 8: Turn off the flame

[0110] When the oxygen concentration of the produced gas exceeds the preset concentration value or the combustion front approaches the production well, the air injection is stopped and nitrogen is injected to extinguish the flame and terminate the experiment.

[0111] The automated control and exploitation experimental method and device for heavy oil reservoirs provided in this specification can use the physical model of the heavy oil reservoir to carry out a one-injection-multiple-recovery exploitation scheme experiment, so as to study the dynamic evolution law of the fire cavity in the heterogeneous reservoir; the heterogeneity of the model body can be optimized and adjusted according to the actual formation parameters, and the model can simulate the formation heterogeneity of any parameters; the experimental method can solve the problems of time-consuming and labor-intensive manual control, untimely control and inaccurate control, and achieve the technical effect of accurately determining the combustion state of the production well and accurately controlling the fire drive oil production process; it can detect the dynamic changes of the fire line development in the fire drive process in real time, control and pull the fire line direction in real time, and control and increase the fire cavity swept volume, thereby improving the reservoir utilization degree.

[0112] The experimental method and device for the production of heavy oil reservoirs provided in this specification have a very wide range of applications and excellent versatility. They can not only carry out heavy oil fire drive experiments very effectively, deeply explore the complex physical and chemical changes of heavy oil under fire drive, displacement mechanism and related production characteristics, but also show strong adaptability and reliability in the thin oil air injection drive experiment. In the thin oil air injection drive experiment, the experimental device can accurately simulate the actual geological environment and conditions of the thin oil reservoir, strictly control various parameters of air injection, such as flow, pressure, temperature, etc., so as to carefully observe the interaction process between thin oil and injected air under different conditions. Accurately monitoring and analyzing various data indicators during the experiment, including but not limited to changes in thin oil production, changes in gas components, and displacement efficiency at different stages, can provide a very critical and comprehensive theoretical basis and practical guidance for the application of thin oil air injection drive technology in actual oilfield development, effectively promote the efficient development and utilization of thin oil resources, and greatly expand the application value and depth of the experimental device in the field of oil production technology research.

[0113] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and variations to the present application without departing from the spirit of the present application, and it is intended that the appended claims include these modifications and variations without departing from the spirit of the present application.

Claims

1. An experimental method for automated control and exploitation of heavy oil reservoirs, characterized in that: include: Obtain reservoir physical property parameters and well pattern distribution of heavy oil reservoirs; A physical model of a heavy oil reservoir is designed according to the reservoir physical property parameters and the well pattern distribution, wherein the physical model is a simulated model of the actual well pattern distribution of the heavy oil reservoir in a proportional manner, and the shell of the physical model forms a cavity with injection wells, production wells, and temperature measurement wells; the cavity of the physical model is filled with heterogeneous oil sands according to the reservoir physical property parameters and sealed to simulate a heterogeneous oil reservoir; During the physical model simulation experiment, the temperature in the cavity of the physical model is monitored in real time through the temperature measuring well, and the liquid production and gas concentration of each production well are monitored; According to the temperature monitoring data in the physical model cavity, the liquid production and gas concentration monitoring data of each production well, the fire drive development effect of the target oil reservoir under different gas injection schemes and control measures is evaluated.

2. The method according to claim 1, characterized in that The cavity of the physical model is filled with heterogeneous oil sands in the following manner: Dividing the heavy oil reservoir into a plurality of permeable areas with different permeability differences, and setting a partition inside the cavity of the physical model according to the division result to divide the cavity into a plurality of permeable areas; Determine the oil sand mixing ratio corresponding to each permeable area according to the reservoir physical property parameters of the heavy oil reservoir, mix quartz sand, crude oil and high-alkaline land according to the predetermined oil sand mixing ratio and then fill it into the corresponding permeable area; Adjacent permeable areas correspond to different mixing ratios and compaction degrees to result in different permeabilities.

3. The method according to claim 1, characterized in that During the fire flooding experiment, at least one of the following operations is intermittently performed during the fire cavity expansion stage: gas injection, hot water injection, and water vapor injection.

4. The method according to claim 1, characterized in that: After evaluating the fire drive development effect of the target oil reservoir under different gas injection schemes and control measures based on the temperature monitoring data in the physical model cavity, the liquid production and gas concentration monitoring data of each production well, the method further includes: On the basis of the fire flooding implementation mining plan, the following parameters are adjusted to form an extended mining plan: the depth of the injection well in the physical model cavity, the setting position of the production well on the physical model surface, and the depth of the production well in the physical model cavity; The implementation process of each extended production plan of the heavy oil reservoir is simulated by a physical model, and during the implementation of the extended production plan, the temperature in the cavity of the physical model is monitored in real time through a temperature measuring well, and the liquid production and gas concentration of each production well are monitored; Evaluate the mining effect of the extended mining scheme based on the temperature monitoring data in the physical model cavity, the liquid production and gas concentration monitoring data of each production well; According to the evaluation results, the plan with the highest recovery rate is selected as the final exploitation plan for the target oil reservoir.

5. The method according to claim 1, characterized in that: The physical model is also provided with a first pressure gauge and a second pressure gauge, wherein the first pressure gauge collects the injection pressure of the injection well, and the second pressure gauge collects the internal pressure of each production well when the recovery end is connected; the fire drive experimental production plan includes: after reaching the control time, closing each production well, and cyclically executing the following S1 and S2: S1: When the production pressure difference reaches the upper limit pressure, the production well corresponding to the low permeability area is opened and the opening is kept at the maximum; the production well corresponding to the high permeability area is opened and the opening is kept at the minimum; the production pressure difference is the difference between the pressures collected by the first pressure gauge and the second pressure gauge; S2: When the production pressure difference drops to the target pressure range, shut down each production well.

6. The method according to claim 5, characterized in that The method further includes: during the experiment, automatically controlling the switch state of production wells in each area according to the advancement state of the fire line during the fire drive process in the following manner: If the advancement progress of the front edge of the fire line in the first area exceeds that of the second area, the opening and frequency of the production wells corresponding to the first area will be increased, and the opening and frequency of the production wells corresponding to the second area will be reduced.

7. The method according to claim 5, characterized in that Each production well has multiple opening gears; the opening of the production well is periodically adjusted according to the actual mining situation; The method also includes: during the experiment, adjusting the opening of the production well in the following manner: if the progress of the hotline advancement in the high permeability area is greater than the preset progress, and the current opening of the production well in the high permeability area is the first opening level, and it is currently necessary to reduce the opening of the production well, then in the next cycle, the opening of the production well is reduced to the next opening level; when it is necessary to reduce the opening of the production well again, the production well is further adjusted to the next opening level or a fully closed state until there is no need to reduce the opening of the production well.

8. The method according to claim 5, characterized in that The method further comprises: When the rate of change of the cumulative liquid production rate of each production well decreases to a preset liquid production rate, and / or when the oxygen concentration in the produced gas concentration reaches a preset threshold, it is determined that the timing for regulation has been reached.

9. An automated control and exploitation experimental device for heavy oil reservoirs, characterized in that: include: A physical model for simulating a heavy oil reservoir; the physical model is a simulated model of the actual well pattern distribution of the heavy oil reservoir in a proportional manner, the shell of the physical model forms a cavity with injection wells, production wells, and temperature measurement wells; the cavity of the physical model is filled with heterogeneous oil sands according to the reservoir physical property parameters of the heavy oil reservoir and sealed to simulate the heterogeneous reservoir; The injection-production subsystem is used to inject gas from the injection well into the cavity of the physical model, and collect and measure the produced gas and produced liquid of each production well; the injection-production subsystem measures and separates the produced liquid at the production end of each production well separately; A monitoring subsystem for monitoring gas pressure, temperature, and gas concentration during simulation of production plans for heavy oil reservoirs; A control subsystem comprises a valve body and a controller arranged in each production well. The controller observes the production conditions of production wells in different permeability areas in real time according to the metering results of the injection-production subsystem, determines the degree of production in different permeability areas, sends control instructions to the valve body according to the liquid production rate of each production well to adjust the progress of the fire line expansion, and sends control instructions to the valve body to realize the automated control and exploitation experimental method of heavy oil reservoirs as described in any one of claims 1 to 8.

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