Foam oil thermal recovery steam injection parameter determination method, control device and storage medium

Abstract

The embodiment of the invention provides a determination method for foam oil thermal recovery steam injection parameters, a control device and a storage medium, and belongs to the technical field of oilfield development. The determination method comprises the following steps: determining thermal recovery steam injection influence parameters based on experimental simulation; determining the grey correlation degree between each thermal recovery steam injection influence parameter and the thermal recovery steam injection effect through a grey correlation model; key thermal recovery steam injection influence parameters are screened out; and establishing a corresponding foam oil reservoir numerical model, and performing numerical simulation on the foam oil reservoir numerical model by adjusting the values of the key thermal recovery steam injection influence parameters to obtain an optimal combined value of the key thermal recovery steam injection influence parameters. According to the method, experimental simulation is combined with the mathematical grey correlation theory, key thermal recovery steam injection influence parameters influencing the thermal recovery steam injection effect are comprehensively determined, the combined value of the key thermal recovery steam injection influence parameters is determined through numerical simulation, the purposes of optimizing the steam injection parameters and improving the foam oil reservoir production degree are achieved, and therefore the recovery efficiency of foam oil is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development, and in particular to a method for determining steam injection parameters for foam oil thermal recovery, a control device and a storage medium. Background Art

[0002] Foamy oil refers to the process of natural energy extraction of heavy oil or super-heavy oil reservoirs. As the reservoir pressure decreases, the dissolved gas in the crude oil does not instantly break away to form free gas, but is highly dispersed in the oil flow in the form of extremely complex microbubbles, forming "oil-in-gas" foam dispersed in the oil phase. Different from the development method of conventional heavy oil and condensate oil, foamy oil reservoirs mostly adopt the depletion development method. During the development process, they have the characteristics of high oil production, low gas production and slow pressure reduction. Researchers generally believe that the reason for this phenomenon is due to the existence of foamy oil. Foamy oil is different from conventional two-phase flow. It requires a liquid phase to make it continuous to flow, and it contains dispersed bubbles. Although there is still controversy about the mechanism of foamy oil to enhance recovery, this conclusion is widely used in field and indoor experimental studies.

[0003] At present, the research on foamy oil is still immature. Some studies attribute foamy oil flow to a fluid property of very small bubbles that occupy a large volume fraction in heavy oil. When researchers tried to verify this high dispersion fluidity in the laboratory, they found that the appearance of newly nucleated bubbles actually reduced the fluidity, and dispersed gas flow is possible under the conditions of dissolved gas drive. This is why dissolved gas drive in foamy oil reservoirs has an unusual effect. Other studies have proposed that the stability of dispersed microbubbles is related to asphaltene adsorbed on the oil-gas interface, which can protect bubbles from agglomeration. In microscopic model experiments, researchers observed that asphaltene can reduce the aggregation of bubbles. Some researchers have observed and analyzed the nucleation, growth, splitting, coalescence, and migration characteristics of bubbles in foamy oil through microscopic model experiments; then, based on the study of the special flow characteristics of bubbles in foamy oil, a porous media network model was established. The model takes into account the effects of surface tension, viscosity, capillary force, and wettability on the growth of bubbles in foamy oil. Other researchers have observed and analyzed the nucleation, growth, splitting, coalescence, and migration characteristics of bubbles in foam oil from the perspective of microscopic media through microscopic model experiments. It was found that the splitting of bubbles in foam oil has a special splitting mode due to the presence of asphaltene; at the same time, it was also found that the migration of bubbles in foam oil is not only affected by the distribution of rocks, but also by the adsorption of asphaltene in crude oil on the rock surface. The researchers established a mathematical model for the nucleation and growth of bubbles in foam oil and heavy oil. Based on this model, it is believed that the change process of bubbles in heavy oil is mainly affected by two forces: hydrodynamic force and diffusion force. The researchers conducted a performance evaluation study on foam oil in the Orinoco reservoir, using a high-temperature and high-pressure foam oil sampler independently developed to prepare foam oil, analyzed the effects of viscosity, temperature, salinity, dissolved gas-oil ratio, etc. on the stability of foam oil, and measured the rheology of foam oil by rheometer and core flow device. The experimental results show that as the viscosity of degassed crude oil increases, the half-life of foam oil becomes longer and the stability becomes better; the higher the temperature, the worse the stability; the higher the dissolved gas-oil ratio, the stronger the stability of foam oil; the mineralization does not have a significant effect on stability; foam oil has shear-thinning properties and slight thixotropy; in porous media, as the injection pressure increases, the viscosity of foam oil first decreases and then increases, and under the same pressure gradient, the fluidity of foam oil is significantly higher than that of degassed crude oil. This study has improved researchers' understanding of foam oil performance and is conducive to further improving foam oil performance research.

[0004] Over the past decade, researchers have conducted extensive research and exploration on foam oil flow. Existing research content mainly focuses on the oil-gas permeability laws of foam oil under reservoir conditions, the oil-increasing laws of foam oil depletion development, etc. Other aspects need to be studied to expand the oil-increasing effect of foam oil. Summary of the invention

[0005] The purpose of the embodiment of the present invention is to provide a method for determining steam injection parameters for foam oil thermal recovery, which can optimize the value of steam injection parameters for foam oil thermal recovery and expand the oil-increasing effect of foam oil.

[0006] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a method for determining steam injection parameters for thermal recovery of foam oil, and the method for determining steam injection parameters for thermal recovery of foam oil comprises: performing experimental simulation based on the seepage mechanism of foam oil reservoir and the reservoir production process to determine the thermal recovery steam injection influencing parameters that affect the foam oil generation and growth process; determining the grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect through a preset grey correlation model of the foam oil thermal recovery steam injection influencing parameters; screening out key thermal recovery steam injection influencing parameters based on the determined grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect; and establishing a corresponding foam oil reservoir numerical model through historical production data of foam oil reservoirs in a preset area, and numerically simulating the foam oil reservoir numerical model by adjusting the values ​​of the key thermal recovery steam injection influencing parameters to obtain the optimal combination value of the key thermal recovery steam injection influencing parameters.

[0007] Optionally, the experimental simulation based on the seepage mechanism of the foam oil reservoir and the reservoir production process includes: establishing a rock model of the foam oil reservoir with porous structure; and performing the experimental simulation based on the rock model.

[0008] Optionally, the thermal recovery steam injection influencing parameters that affect the foam oil generation and growth process are determined by one or more of the following influencing factors: the influencing factor of asphaltene on bubble nucleation in foam oil reservoirs; the influencing factor of the supersaturation driving force of bubble formation on nucleation; the influencing factor of the change in production pressure depletion rate on nucleation; the influencing factor of viscosity and capillary pressure in porous media on the bubble growth process; the influencing factor of bubble growth rate; the influencing factor of diffusion in fluid mechanics on bubble growth; and the influencing factor of spatial relative position on bubble growth.

[0009] Optionally, the thermal recovery steam injection influencing parameters include one or more of the following: formation pressure, injection temperature, steam injection intensity, steam injection rate, liquid production volume, pressure reduction rate, dissolved gas-oil ratio, crude oil viscosity, steam injection timing and well soaking time.

[0010] Optionally, the grey correlation model of the preset foam oil thermal recovery steam injection influencing parameters is used to determine the grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, including: for each thermal recovery steam injection influencing parameter, selecting n groups of thermal recovery steam injection influencing parameter values ​​and corresponding thermal recovery steam injection effect values, and calculating the correlation coefficient through the grey correlation model; and calculating the grey correlation through the correlation coefficient.

[0011] Optionally, the key thermal recovery steam injection influencing parameters are screened out based on the determined grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, including: sensitivity sorting of the thermal recovery steam injection influencing parameters based on the size of the grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect; and screening out the key thermal recovery steam injection influencing parameters based on the sensitivity sorting.

[0012] Optionally, the method of adjusting the value of the key thermal recovery steam injection influencing parameter to numerically simulate the foam oil reservoir numerical model to obtain the optimal combination value of the key thermal recovery steam injection influencing parameter includes: based on the sensitivity ranking of the key thermal recovery steam injection influencing parameters, adjusting the value of the key thermal recovery steam injection influencing parameter with the greatest sensitivity, performing numerical simulation on the foam oil reservoir numerical model to obtain the optimal value of the key thermal recovery steam injection influencing parameter; for the remaining key thermal recovery steam injection influencing parameters, fixing the obtained optimal value, adjusting the value of the key thermal recovery steam injection influencing parameter with the current greatest sensitivity, performing numerical simulation on the foam oil reservoir numerical model to obtain the optimal value of the key thermal recovery gas injection influencing parameter, and repeating the process to obtain the optimal combination value of the key thermal recovery gas injection influencing parameters.

[0013] Optionally, when the numerical model of the foam oil reservoir is numerically simulated by adjusting the value of the key thermal recovery steam injection influencing parameter, the method for determining the foam oil thermal recovery steam injection parameters also includes: performing gas injection pressure maintenance simulation in the cold recovery area of ​​the preset area, stabilizing the dissolved gas-oil ratio, extending the foam oil utilization time, and using steam throughput to simulate steam injection development within the range of substantial degassing and thickening of the foam oil.

[0014] An embodiment of the present invention also provides a control device for determining steam injection parameters for foam oil thermal recovery, the control device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the above-mentioned method for determining steam injection parameters for foam oil thermal recovery.

[0015] An embodiment of the present invention further provides a machine-readable storage medium, on which instructions are stored, and the instructions enable a machine to execute the above-mentioned method for determining steam injection parameters for foam oil thermal recovery.

[0016] Through the above technical solution, the embodiment of the present invention combines experimental simulation with mathematical grey correlation theory to comprehensively determine the key thermal recovery steam injection influencing parameters that affect the thermal recovery steam injection effect, and through numerical simulation, determine the combined value of the key thermal recovery steam injection influencing parameters, so as to achieve the purpose of optimizing the steam injection parameters and improving the utilization degree of the foam oil reservoir, thereby improving the recovery rate of the foam oil and expanding the foam oil increase effect. It can also prevent the situation where the oil recovery rate is too low and the output is reduced due to degassing at different stages, increased crude oil viscosity, and poor stability of foam oil.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0019] Figure 1 It is a flow chart of a method for determining steam injection parameters for foam oil thermal recovery provided by an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the process of bubble nucleation on the rock surface;

[0021] Figure 3 This is a schematic diagram of the process of bubbles coalescing in pores;

[0022] Figure 4 This is a schematic diagram of the deformation process of an example bubble during its migration in the roar channel;

[0023] Figure 5 is a schematic diagram of an example foam oil reservoir numerical model;

[0024] Figure 6 It is a schematic diagram of the production and water cut fitting results of the example well group;

[0025] Figure 7 It is a bar chart of the incremental increase in oil production during the example period;

[0026] Figure 8 This is a comparison diagram of the optimal selection of different steam injection speeds;

[0027] Fig. 9 This is a comparison chart of the development effects of different fluid production volumes in a single well;

[0028] Fig.10 is a schematic diagram of the relationship between viscosity and temperature of an example heavy oil; and

[0029] Fig.11 The diagram below is an example of the relationship between the gasoline dissolving ratio and the crude oil viscosity and pressure. DETAILED DESCRIPTION

[0030] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0031] Figure 1 This is a flow chart of a method for determining steam injection parameters for foam oil thermal recovery provided by an embodiment of the present invention. Please refer to Figure 1 The method for determining steam injection parameters for foam oil thermal recovery may include the following steps:

[0032] Step S110: Performing experimental simulation based on the seepage mechanism of the foam oil reservoir and the reservoir production process to determine the thermal recovery steam injection influencing parameters that affect the foam oil generation and growth process.

[0033] The embodiment of the present invention conducts experimental simulation based on the seepage mechanism of foam oil reservoir and the reservoir exploitation process. The experimental simulation preferably uses the formation conditions after compounding to ensure the authenticity of the experimental simulation reservoir state. The experiment can clearly observe the changes of foam oil under the influence of pressure, temperature, etc., and produce nucleation, growth, aggregation, splitting and other processes, as well as different flow states. At the same time, the formation of foam oil phenomenon and the mechanism of its action can be observed from a microscopic perspective.

[0034] Preferably, the experimental simulation based on the seepage mechanism of the foam oil reservoir and the reservoir production process includes: establishing a rock model of the foam oil reservoir with porous structure; and performing the experimental simulation based on the rock model.

[0035] In order to observe the microscopic phenomena and seepage mechanism of foamy oil and study the reasons why the foamy oil phenomenon occurs in porous oil, the embodiment of the present invention uses a high-temperature, high-pressure micro-medium experimental device to perform experimental simulation. In the experiment, a rock model with porous oil development is first established. Through the microscopic cast thin section, the pore distribution in the reservoir can be truly observed, which can better simulate the flow of reservoir fluid in the pores. Therefore, the microscopic model experiment can well study the microscopic seepage mechanism of porous media. At the same time, by comparing the bubble flow characteristics of foamy oil and conventional heavy oil, the mechanism of the appearance and action of the foamy oil phenomenon is analyzed from the perspective of microscopic media. Taking the nucleation of bubbles, the aggregation of bubbles and the deformation of bubbles as examples, experimental simulation is carried out.

[0036] 1) Bubble nucleation: When the pressure of the rock model is reduced to the bubble point pressure of low foam oil, the dissolved gas in the foam oil will be slowly released from the crude oil. The process of bubble nucleation is the process in which a large number of gas molecules gather in the crude oil in the rock pores. During this process, bubbles gradually appear in the pores from a single oil phase, and the gas molecules grow into bubbles with gas phase characteristics. The state of gas molecules gathering before the appearance of bubbles can be called "bubble nuclei", such as Figure 2 shown.

[0037] 2) Bubble coalescence: Bubble coalescence is another important mechanism that affects the size and distribution of bubbles in porous media. The coalesced bubbles are generally larger in size because the diameter of the bubbles increases with the coalescence effect. The smaller the resistance between the liquid films caused by the oil / gas interfacial tension around the bubbles, the easier it is for the bubbles to coalesce. Figure 3 shown.

[0038] 3) Bubble deformation: When large bubbles pass through the pore throat, they will be stretched and deformed by the extrusion. After passing through, due to the change of interfacial tension elastic energy, the bubbles will return to their original approximate elliptical shape. In this process, the bubbles will produce the Jamin effect, increase the gas phase flow resistance, thereby reducing the gas phase mobility and the production gas-oil ratio, which can effectively improve the foam oil recovery rate. Figure 4 shown.

[0039] In the process of foamy oil dissolved gas drive, under different dispersion states of foamy oil, during the generation and growth of bubbles, one type is that the bubbles are surrounded by the oil phase and grow by their own expansion (pressure reduction) or by the supplement of gas in the oil phase (mass transfer diffusion); the other type is that the bubbles grow by adsorption on the surface of particles such as rocks, colloids, and asphaltene.

[0040] Based on the above experimental simulation, it can be seen that there are many factors that affect bubble growth, such as viscosity and capillary force, bubble mass and momentum, heat and mass transfer, interfacial tension, diffusivity and initial bubble radius, crude oil viscosity and asphaltene, and spatial position. In addition, the composition and amount of dissolved gas in crude oil, temperature, and pressure exhaustion rate also have a certain influence on the bubble growth process.

[0041] Among them, the growth of bubbles in porous media depends on bubble nucleation, diffusion, capillary force and viscosity, etc. During the flow of foamy oil in the reservoir, the viscosity controls the expansion of bubbles, and the bubble expansion must overcome the large viscous resistance. In porous media, the growth of bubbles is neither uniform nor spherical. The capillary pressure at the pore throat is the driving force for the formation of the meniscus interface of the bubble. When the capillary pressure at the pore throat is large enough, the bubble expands and breaks through the pore throat. Therefore, the growth of bubbles can be divided into two steps: pressurization and pore filling. The pressurization process occurs when the gas pressure in the bubble increases to exceed the capillary pressure, and then the bubble interface expands to the new pore, which is the pore filling process.

[0042] Among them, viscosity, interfacial tension, diffusivity and initial bubble radius are important parameters that determine bubble growth. The forces that control bubble growth include hydrodynamic forces and diffusion forces. Hydrodynamic forces include inertial forces, pressure and viscosity. The above forces simulate the growth of a single bubble (including hydrodynamic terms and diffusion terms) in a limited area under reservoir conditions (for example, low pressure depletion rate) in the model. According to the model, viscosity (hydrodynamic force) has little effect on bubble growth, while the diffusion equation can describe the behavior of foamy oil. In addition, the difference in diffusion coefficients is due to the fact that the growth rate of bubbles in heavy oil is lower than that in light oil, not due to viscosity.

[0043] Among them, during the pressure depletion process, the growth rate of bubbles varies with the spatial position of the rock model: in the primary pore area, the bubble growth rate is slightly faster than that in other secondary pore areas; and at the edge of the roar channel, there may also be a phenomenon of rapid bubble generation (bubble nucleation), but at this time, the bubbles grow slowly. The above phenomenon shows that the bubble growth rate is not only related to the composition of the oil and gas system and the pressure depletion rate, but also to the location of the bubble point (nucleation point) and the roughness of the porous medium surface at that location.

[0044] Preferably, the thermal recovery steam injection influencing parameters that affect the foam oil generation and growth process are determined by one or more of the following influencing factors: the influencing factor of asphaltene on bubble nucleation in foam oil reservoirs; the influencing factor of the supersaturation driving force of bubble formation on nucleation; the influencing factor of the change in the production pressure depletion rate on nucleation; the influencing factor of the viscosity and capillary pressure in the porous medium on the bubble growth process; the influencing factor of the bubble growth rate; the influencing factor of the diffusion effect in fluid mechanics on bubble growth; and the influencing factor of the spatial relative position on bubble growth.

[0045] The thermal recovery steam injection influencing parameters preferably in the embodiment of the present invention include one or more of the following: formation pressure, injection temperature, steam injection intensity, steam injection rate, liquid production volume, pressure reduction rate, solution gas-oil ratio, crude oil viscosity, steam injection timing and well soaking time.

[0046] Step S120: Determine the grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect by using the preset grey correlation model of the foam oil thermal recovery steam injection influencing parameters.

[0047] Preferably, step S120 may include: for each thermal recovery gas injection influencing parameter, selecting n groups of thermal recovery steam injection influencing parameter values ​​and corresponding thermal recovery steam injection effect values, and calculating the correlation coefficient through the grey correlation model; and calculating the grey correlation degree through the correlation coefficient.

[0048] Among them, the thermal recovery steam injection effect is a parameter that reflects the thermal recovery steam injection results and evaluates the sensitivity of influencing factors.

[0049] Take an example to illustrate that n groups of thermal recovery steam injection influencing parameters X are selected i The values ​​of (i refers to different thermal recovery steam injection parameters) and the corresponding thermal recovery steam injection effect Y are used as sample sequences:

[0050] Y={Y(k)|k=1,2,...,n}

[0051] X i ={X i (k)|k=1,2,...,n} (1)

[0052] Among them, y(k) represents the value of each thermal recovery steam injection effect, x i (k) represents each value of the i-th thermal recovery steam injection influencing parameter.

[0053] Preferably, in order to determine the impact of different units of the thermal recovery steam injection parameters (values) on the results, each value of the sample sequence is dimensionally processed, and the processing methods include averaging, maximization, minimization, initialization, etc. Taking averaging as an example, each value of the sample sequence is dimensionally processed by the following formula:

[0054]

[0055]

[0056] The difference sequence Δ is obtained by the following formula: i :

[0057] Δ i =|y(k)-x i (k)| (3)

[0058] The two-level minimum difference of each steam injection and production influencing parameter is obtained by the following formula:

[0059] min i min k |()- i ()| (4)

[0060] The two-level maximum difference of each steam injection and production influencing parameter is obtained by the following formula:

[0061] max i max k |()- i ()| (5)

[0062] The correlation coefficient is calculated through the following grey correlation model:

[0063]

[0064] Furthermore, the grey correlation coefficient is used to calculate the grey correlation coefficient r i Among them, the grey relational degree r i For example, the correlation coefficient ξ i The arithmetic mean of (k) is as follows:

[0065]

[0066] Based on the production test data of a foam oil reservoir in a preset area, the sample sequence is designed by using the depressurization rate, dissolved gas-oil ratio, crude oil viscosity, and gas injection intensity thermal recovery steam injection influencing parameters, using 4×3 orthogonal data. Among them, the depressurization rate is taken as 0.05, 0.1, and 0.5 (MPa / min), and the dissolved gas-oil ratio is taken as 10, 15, and 20 (m 3 / m 3 ), the crude oil viscosity is, for example, 20, 6300, 20000 (mPa.s), the gas injection intensity is 100, 200, 300 (m 3 / m). 24 groups of sample sequences are obtained. Since the units of the (values) of the thermal recovery steam injection parameters and the values ​​of the thermal recovery steam injection effects are different, each value of the sample sequence can be dimensionally processed by formula (2); the correlation coefficient of each thermal recovery steam injection parameter and the corresponding thermal recovery steam injection effect is calculated by formula (6); and the corresponding grey correlation is calculated by formula (7). The grey correlations of depressurization rate, dissolved gas-oil ratio, crude oil viscosity, and gas injection intensity are calculated to be 0.163, 0.164, 0.170, and 0.181, respectively.

[0067] Step S130: based on the determined grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, the key thermal recovery steam injection influencing parameters are screened out.

[0068] Preferably, step S130 may include: based on the magnitude of the grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, performing sensitivity sorting on the thermal recovery steam injection influencing parameters; and based on the sensitivity sorting, screening out the key thermal recovery steam injection influencing parameters.

[0069] The grey correlation between the thermal recovery steam injection influencing parameters and the thermal recovery steam injection effect can reflect the mutual relationship and closeness between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect. The greater the grey correlation (or correlation coefficient) between the two, the greater the correlation between the thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect. Therefore, after calculating the grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, the sensitivity is sorted according to the grey correlation (or correlation coefficient), and the key thermal recovery steam injection influencing parameters can be selected according to the sensitivity sorting. Continuing with the above example, the sensitivity sorting is: gas injection intensity> crude oil viscosity> dissolved gas-oil ratio> depressurization rate. For example, based on the sensitivity sorting, the thermal recovery steam injection influencing parameters with a grey correlation greater than a preset threshold are selected as key thermal recovery steam injection influencing parameters. For example, gas injection intensity, crude oil viscosity, and dissolved gas-oil ratio are key thermal recovery steam injection influencing parameters that affect the foam oil thermal recovery effect. The key thermal recovery steam injection influencing parameters obtained are directly related to the steam injection recovery mechanism of foam oil: the injection intensity directly determines the amount of steam injected, affecting the dissolution and viscosity reduction, expansion of gas cavity and replenishment of formation energy in the foam oil thermal recovery stage; the dissolved gas-oil ratio directly affects the dissolved gas drive effect of the foam oil reservoir; the crude oil viscosity directly affects the flow state of the foam oil in the formation. Therefore, the embodiment of the present invention screened out the key thermal recovery gas injection influencing parameters based on the sensitivity ranking and was verified.

[0070] Step S140: Establish a corresponding foam oil reservoir numerical model based on historical production data of a foam oil reservoir in a preset area, perform numerical simulation on the foam oil reservoir numerical model by adjusting the values ​​of the key thermal recovery steam injection influencing parameters, and obtain the optimal combination value of the key thermal recovery steam injection influencing parameters.

[0071] The embodiment of the present invention establishes a corresponding numerical model of the foam oil reservoir through the historical production data of the foam oil reservoir in the preset area, that is, the numerical model of the foam oil reservoir is fitted with the historical data. In the numerical simulation process of the foam oil reservoir, the dissolved gas can be represented as gas and liquid. When the temperature of the reservoir increases and the pressure decreases, the liquid phase will transform into the gas phase, and the gas phase will easily flow to the production well to be produced. The production well shows an increase in the production gas-oil ratio and serious degassing of the formation crude oil. At this time, the viscosity of the formation crude oil increases; after the steam is injected, the temperature of the crude oil increases and the viscosity decreases, and the oil well production increases again, thereby achieving the effect of simulating the cold production and thermal production processes of foam oil. For the numerical model of the foam oil in the preset area, such as Figure 5 As shown in the figure, the foam oil reservoir numerical model is used to generate historical matching, and the historical matching calculation is performed for the selected well group model to determine the reservoir, relative permeability parameters, crude oil properties, etc. Due to the large difference in crude oil viscosity among the sandstone groups in this area, the vertical crude oil viscosity of the foam oil reservoir numerical model is different in different layers. For example, the production history is from 1956 to 1999. By 1999, all the production wells were shut in, and the overall fitting is good. Figure 6 It shows that the fitting error of the historical fitting cumulative oil production and water production is less than <1%. In the figure, the horizontal axis is time (year), the left vertical axis is the cumulative oil production, and the right vertical axis is the monthly average oil production and comprehensive water content.

[0072] Preferably, the method of adjusting the value of the key thermal recovery steam injection influencing parameter to numerically simulate the foam oil reservoir numerical model to obtain the optimal combination value of the key thermal recovery steam injection influencing parameter includes: based on the sensitivity ranking of the key thermal recovery steam injection influencing parameters, adjusting the value of the key thermal recovery steam injection influencing parameter with the greatest sensitivity, performing numerical simulation on the foam oil reservoir numerical model to obtain the optimal value of the key thermal recovery steam injection influencing parameter; for the remaining key thermal recovery steam injection influencing parameters, fixing the obtained optimal value, adjusting the value of the key thermal recovery steam injection influencing parameter with the current greatest sensitivity, performing numerical simulation on the foam oil reservoir numerical model to obtain the optimal value of the key thermal recovery gas injection influencing parameter, and repeating the process to obtain the optimal combination value of the key thermal recovery gas injection influencing parameters.

[0073] To illustrate with an example, through the above sensitivity ranking: the sensitivity ranking is: gas injection intensity > crude oil viscosity > dissolved gas-oil ratio > depressurization rate, the key thermal recovery steam injection influencing parameters are screened out, such as: steam injection intensity, crude oil viscosity, dissolved gas-oil ratio. 1) The key thermal recovery steam injection influencing parameter with the greatest current sensitivity is the steam injection intensity, so first determine the optimal value of the steam injection intensity. For example, simulation calculation conditions: Based on historical matching, a single cycle comparison of a 20m thick oil layer is selected. Figure 7 As shown in the figure, with the increase of injection intensity, the cyclic oil production of the oil well shows an upward trend. When the steam injection intensity reaches 80-90t / m, the incremental rate of oil production begins to slow down. At this time, the oil-gas ratio of 0.84 is relatively high. The recommended initial injection pressure is 80-90t / m, and the injection intensity is large. The injection intensity can be appropriately reduced to 70-80t / m. 2) After determining the optimal value of the steam injection intensity, the key thermal recovery steam injection influencing parameter with the greatest sensitivity is the crude oil viscosity, and the crude oil viscosity is affected by the steam injection rate. The different steam injection rates affect the development effect. The optimal value of the gas injection rate is determined. For example, the simulation calculation conditions: based on historical fitting, a 20m thick oil layer is selected, the steam injection intensity is 90t / m, and the single-cycle development effect is simulated and compared. As shown in the figure Figure 8As shown, the simulation results show that the oil production reaches the maximum value in a 200t / d cycle. High-speed injection is not recommended in the initial stage. The recommended steam injection rate is 180-200t / d. The bottom hole dryness is calculated by the heat loss of the wellbore at this time, which is 0.36-0.386. 3) The dissolved gas-oil ratio is affected by the amount of liquid produced, and the amount of liquid produced affects the final effect of thermal recovery and development, and determines the optimal value of the liquid production. For example, the simulation calculation conditions: single-cycle comparison of 20m thick oil layer, strength 90t / m, speed 200t / d, well shut-in for 3 days, and compare the development effects of oil wells with different liquid production (range 20-70m 3 / d). Fig. 9 As shown in the figure, the calculation results show that when the maximum liquid production volume is greater than 30m 3 / d, the difference in the development effect of foam oil and heavy oil area is not obvious, and it is recommended that the liquid production volume should not exceed 30m 3 / d. In the figure, the horizontal axis is time (year), the vertical axis on the left is cumulative oil production, and the vertical axis on the right is monthly average oil production.

[0074] Based on the above numerical simulation, the influence of key thermal recovery steam injection parameters on the foam oil thermal recovery effect is determined. The results show that as the liquid production volume increases, the production effect gradually decreases. For example, the optimal liquid production volume in the example is 30m 3 / d; With the increase of soaking time, the periodic oil production shows a trend of increasing first and then decreasing. This is because the increase of soaking time will increase the diffusion of steam and cause temperature cooling. Therefore, there is an optimal soaking time, which is 3d in this example; With the increase of steam injection intensity, the production effect increases first and then decreases. The optimal steam injection intensity in the example is, for example, 70-80t / m. Through numerical simulation, the optimal combination value of the key thermal recovery gas injection influencing parameters is obtained, for example: the liquid production is 30m 3 / d, steam injection intensity 70~80t / m, well soaking time 3d, steam injection rate 180~200t / d.

[0075] Preferably, when the numerical model of the foam oil reservoir is numerically simulated by adjusting the value of the key thermal recovery steam injection influencing parameter, the method for determining the foam oil thermal recovery steam injection parameters also includes: performing gas injection pressure maintenance simulation in the cold recovery area of ​​the preset area, stabilizing the dissolved gas-oil ratio, extending the foam oil utilization time, and using steam throughput to simulate steam injection development within the range of substantial degassing and thickening of the foam oil.

[0076] In order to ensure that the foam oil pressure drops and the foam oil reservoir can be used efficiently and quickly after a large-scale degassing and thickening, so as to achieve efficient development of the thickening area, the following three foam oil production principles are improved, a numerical simulation model is established, and the parameters affecting thermal recovery and steam injection are quantitatively analyzed to achieve the purpose of large-scale utilization of the foam oil thickening area.

[0077] Principle 1: According to the principle of foamy oil formation, when the reservoir pressure is lower than the bubble point pressure, the crude oil is in a supersaturated state. The following formula can be used to determine whether the crude oil can form "bubble nuclei". Based on this principle, a numerical model of foamy oil reservoirs is established.

[0078] like The dissolved gas in the foamy oil will be slowly released from the crude oil, bubbles will gradually appear in the pores from the single oil phase, and "bubble nuclei" will begin to form, and the foamy oil phenomenon will occur.

[0079] like The heavy oil in the reservoir still flows in a single-phase form, and no "bubble nuclei" have been formed, and no foamy oil phenomenon has occurred.

[0080] Among them, Δp is the supersaturation pressure (MPa), p is the reservoir pressure (MPa), and p e is the equilibrium pressure (MPa); Υ is the oil-gas interfacial tension (dyne / cm); r is the pore radius of the porous medium (m); p is the pore radius of the porous medium at the reservoir pressure p (m).

[0081] Principle 2: Viscosity reduction principle of heavy oil by heating. The viscosity of heavy oil is very sensitive to temperature changes. When the temperature rises, the viscosity drops sharply. This is the main mechanism of heavy oil steam injection thermal recovery. Fig.10 shown.

[0082] Principle 3: When the oil layer pressure drops below the saturation pressure, as the pressure decreases, the dissolved gas separates from the crude oil to form bubbles. Under the foamy oil state, the bubbles are highly dispersed in the oil flow in the form of extremely complex microbubbles, forming "oil-in-gas" type foam dispersed in the oil phase. When the bubbles gather together, they are separated and degassed from the oil phase, which will cause the viscosity of the crude oil to increase. Steam injection heating will aggravate this phenomenon. Fig.11 shown.

[0083] Accordingly, the embodiment of the present invention adopts a combination of experimental simulation and mathematical grey correlation theory to comprehensively determine the key thermal recovery steam injection influencing parameters that affect the thermal recovery steam injection effect, and through the numerical simulation method, determine the combination value of the key thermal recovery steam injection influencing parameters, so as to achieve the purpose of optimizing the steam injection parameters and improving the utilization degree of the foam reservoir. It can also prevent the situation where the oil recovery rate is too low and the output is reduced due to degassing at different stages, increased crude oil viscosity, and poor stability of foam oil. Specifically, through the experimental simulation of the seepage mechanism of the foam oil reservoir and the reservoir production process, the generation, growth, aggregation, splitting and other processes of the foam oil in the porous medium reservoir are determined, which more realistically reflects the changes in the fluid and the oil displacement mechanism of the foam oil reservoir under high temperature and high pressure. A grey correlation model of the foam oil thermal recovery steam injection influencing parameters is established, and the grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect is determined through the grey correlation model, and the key thermal recovery steam injection influencing parameters are screened out based on the grey correlation degree. Within the range of significant degassing and thickening of foam oil, the method of reservoir numerical simulation is adopted, and the influence ranking of the determined sensitivity parameters is adjusted by adjusting the values ​​of the key thermal recovery steam injection influencing parameters to perform numerical simulation on the foam oil reservoir numerical model, so as to obtain the optimal combination value of the key thermal recovery steam injection influencing parameters, ensure the development effect of the steam injection operation, and further improve the utilization degree of the reservoir.

[0084] An embodiment of the present invention also provides a control device for determining steam injection parameters for foam oil thermal recovery, the control device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the computer program to implement the above-mentioned method for determining steam injection parameters for foam oil thermal recovery.

[0085] An embodiment of the present invention further provides a machine-readable storage medium, on which instructions are stored, and the instructions enable a machine to execute the above-mentioned method for determining steam injection parameters for foam oil thermal recovery.

[0086] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0087] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0088] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0089] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0090] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0091] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0092] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0093] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0094] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for determining steam injection parameters for foam oil thermal recovery, characterized in that: The method for determining steam injection parameters for foam oil thermal recovery comprises: Based on the seepage mechanism of foam oil reservoirs and the reservoir production process, experimental simulation was carried out to determine the thermal recovery steam injection parameters that affect the foam oil generation and growth process; The grey correlation model of the influencing parameters of thermal recovery steam injection of foam oil is used to determine the grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect; Based on the grey correlation between the determined thermal recovery steam injection influencing parameters and the thermal recovery steam injection effect, the key thermal recovery steam injection influencing parameters are screened out; and By presetting the historical production data of the foam oil reservoir in the preset area, a corresponding foam oil reservoir numerical model is established. By adjusting the values ​​of the key thermal recovery steam injection influencing parameters, the foam oil reservoir numerical model is numerically simulated to obtain the optimal combination value of the key thermal recovery steam injection influencing parameters.

2. The method for determining steam injection parameters for foam oil thermal recovery according to claim 1, characterized in that: The experimental simulation based on the seepage mechanism of foam oil reservoir and the oil reservoir production process includes: Establish rock models of porous structures in foamy oil reservoirs; and Experimental simulations are performed based on the rock model.

3. The method for determining steam injection parameters for foam oil thermal recovery according to claim 1, characterized in that: The thermal recovery steam injection influencing parameters that affect the foam oil generation and growth process are determined through one or more of the following influencing factors: The influencing factors of asphaltene on bubble nucleation in foamy oil reservoirs; The factors affecting the supersaturation driving force of bubble formation on nucleation; Factors affecting nucleation due to changes in production pressure depletion rate; The factors affecting the growth of bubbles in porous media such as viscosity and capillary pressure; Factors affecting the growth rate of bubbles; The influence of diffusion on bubble growth in fluid mechanics; and Factors affecting the relative position in space on bubble growth.

4. The method for determining steam injection parameters for foam oil thermal recovery according to claim 1, characterized in that: The thermal recovery steam injection influencing parameters include one or more of the following: formation pressure, injection temperature, steam injection intensity, steam injection rate, liquid production volume, pressure reduction rate, dissolved gas-oil ratio, crude oil viscosity, steam injection timing and well soaking time.

5. The method for determining steam injection parameters for foam oil thermal recovery according to claim 1, characterized in that: The grey correlation model of the influencing parameters of thermal recovery steam injection of foam oil is preset to determine the grey correlation degree between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, including: For each thermal recovery gas injection influencing parameter, select n groups of thermal recovery steam injection influencing parameter values ​​and corresponding thermal recovery steam injection effect values, and calculate the correlation coefficient through the grey correlation model; and The grey relational degree is calculated by using the relational degree coefficient.

6. The method for determining steam injection parameters for foam oil thermal recovery according to claim 5, characterized in that: The key thermal recovery steam injection influencing parameters are screened out based on the grey correlation between the determined thermal recovery steam injection influencing parameters and the thermal recovery steam injection effect, including: Based on the grey correlation between each thermal recovery steam injection influencing parameter and the thermal recovery steam injection effect, the thermal recovery steam injection influencing parameters are sorted by sensitivity; and Based on the sensitivity ranking, the key thermal recovery gas injection influencing parameters are screened out.

7. The method for determining steam injection parameters for foam oil thermal recovery according to claim 6, characterized in that: The method of adjusting the values ​​of the key thermal recovery steam injection influencing parameters to perform numerical simulation on the foam oil reservoir numerical model to obtain the optimal combination values ​​of the key thermal recovery steam injection influencing parameters includes: Based on the sensitivity ranking of the key thermal recovery steam injection influencing parameters, by adjusting the value of the key thermal recovery steam injection influencing parameter with the greatest sensitivity, the foam oil reservoir numerical model is numerically simulated to obtain the optimal value of the key thermal recovery steam injection influencing parameter; For the remaining key thermal recovery gas injection influencing parameters, the optimal values ​​that have been obtained are fixed, and by adjusting the values ​​of the key thermal recovery gas injection influencing parameters with the greatest current sensitivity, the numerical simulation of the foam oil reservoir numerical model is performed to obtain the optimal values ​​of the key thermal recovery gas injection influencing parameters, and the process is repeated to obtain the optimal combination values ​​of the key thermal recovery gas injection influencing parameters.

8. The method for determining steam injection parameters for foam oil thermal recovery according to claim 1, characterized in that: When the foam oil reservoir numerical model is numerically simulated by adjusting the value of the key thermal recovery steam injection influencing parameter, the method for determining the foam oil thermal recovery steam injection parameter further includes: In the cold production area of ​​the preset area, a gas injection and pressure maintenance simulation is carried out to stabilize the dissolved gas-oil ratio and prolong the foam oil effect time. Within the range of significant degassing and thickening of foamed oil, steam stimulation is used to simulate steam injection development.

9. A control device for determining steam injection parameters for foam oil thermal recovery, characterized in that: The control device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to implement the method for determining steam injection parameters for foam oil thermal recovery according to any one of claims 1-8.

10. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions, which enable the machine to execute the method for determining steam injection parameters for foam oil thermal recovery according to any one of claims 1-8.

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