Method and device for optimizing proportion of multi-element thermal fluid components of thickened oil with different viscosities

Abstract

The invention discloses a component proportion optimization method for multi-element thermal fluid of thickened oil with different viscosities, which comprises the following steps of: based on oil well injection parameters of a mine field, obtaining the volume ratio of N2 to CO2 in the injected multi-element thermal fluid; according to the volume ratio of N2 to CO2 in the injected multi-element thermal fluid, multiple groups of multi-element thermal fluids with different proportions of N2 to CO2 are determined; according to the multiple groups of multi-element thermal fluids with different proportions of N2 and CO2, the oil change rate and the economic index of the oil well under different multi-element thermal fluid injection parameters are obtained; and determining the component proportion of the multi-element thermal fluid according to the oil change rate and the economic index of the oil well under different multi-element thermal fluid injection parameters. Experiments are further designed through oil well multi-element thermal fluid huff and puff injection parameters on an oil field site, the proportion of all components of the multi-element thermal fluid is optimized, the overall experiment range can be narrowed, and an optimization result with higher precision is obtained while fewer experiments are designed.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy oil multi-component thermal fluids, and in particular to a method and device for optimizing the component ratio of heavy oil multi-component thermal fluids with different viscosities. Background Art

[0002] Non-condensable gas-assisted steam is recognized as a promising thermal composite technology for heavy oil recovery. Multi-component thermal fluid technology involves injecting a specific ratio of two non-condensable gases, N2 and CO2, simultaneously with steam injection. This technology leverages the synergistic effects of steam, nitrogen, and CO2, including thermal and dissolution viscosity reduction, reduced heat loss, expanded heating range, and gas pressurization and energy enhancement, to enhance the recovery rate of heavy oil reservoirs.

[0003] Currently, some oilfields have severe reservoir geology heterogeneity and a wide range of crude oil viscosities. During multi-component thermal fluid (MTF) development, heavy oils of varying viscosities exhibit distinct production characteristics. Furthermore, the ratio of the MTF components can influence development effectiveness. Therefore, optimizing the MTF composition for heavy oils of varying viscosities is necessary to further enhance MTF performance and optimize throughput strategies.

[0004] Currently, some scholars have proposed optimizing the ratio of components of multi-component thermal fluids by using reservoir numerical simulation technology to determine the relationship between the cumulative oil production during a certain optimization cycle and the volume ratio of N2 to CO2 in the multi-component thermal fluid. Other scholars have proposed fixing the amount of water vapor in the multi-component thermal fluid and conducting indoor multi-component thermal fluid throughput experiments with different molar ratios of N2 and CO2 injected. This yields a curve showing the relationship between the cycle recovery rate and the throughput cycle for different molar ratios of N2 and CO2. This allows the N2 to CO2 molar ratio with the best cycle recovery rate after several throughput cycles to be selected as the optimal result, ultimately leading to the optimized multi-component thermal fluid component ratio.

[0005] However, these methods have not been combined with the actual situation of the oil field, resulting in unreasonable design of the ratios of the three different components of water vapor, carbon dioxide, and nitrogen when injecting multi-component thermal fluids. The following problems exist: For example, the design of the ratios of the components of the multi-component thermal fluid does not conform to the actual situation of the oil field. Under the influence of limiting factors such as economy or on-site technology, it is difficult or even impossible to achieve in actual operation. Summary of the Invention

[0006] The present invention aims to provide a method and device for optimizing the ratio of components of multi-component thermal fluids of heavy oils with different viscosities, so as to solve the above-mentioned technical problems.

[0007] To achieve the above object, the present invention provides a method for optimizing the ratio of components of multi-component thermal fluids of heavy oil with different viscosities, the method comprising:

[0008] Based on the well injection parameters at the mine, the volume ratio of N2 to CO2 in the injected multi-component thermal fluid is obtained;

[0009] According to the volume ratio of N2 to CO2 in the injected multi-component thermal fluid, multiple groups of multi-component thermal fluids with different ratios of N2 and CO2 are determined;

[0010] Based on multiple groups of multi-component thermal fluids with different ratios of N2 and CO2, the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters are obtained;

[0011] The component ratio of the multi-component thermal fluid is determined according to the oil exchange rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters.

[0012] Optionally, the oil well injection parameters include: natural gas injection volume, water injection volume, and air injection volume.

[0013] Optionally, based on the well injection parameters at the mine, the volume ratio of N2 to CO2 injected into the multi-component thermal fluid is obtained, including:

[0014] Based on the well injection parameters at the mine, the actual injection rates of CO2, N2, and H2O during the multi-component thermal fluid huff-and-puff phase were obtained;

[0015] According to the actual injection amounts of CO2, N2, and H2O during the multi-component thermal fluid intake and discharge phase, the volume ratio of N2 to CO2 injected into the multi-component thermal fluid is obtained.

[0016] Optionally, according to the volume ratio of N2 to CO2 injected into the multi-component thermal fluid, multiple groups of multi-component thermal fluids with different ratios of N2 and CO2 are determined, including:

[0017] Determine the volume ratio of N2 and CO2 based on the volume ratio of N2 to CO2 injected into the multi-component thermal fluid;

[0018] According to the volume ratio range of N2 and CO2, multiple groups of multi-component thermal fluids with different proportions of N2 and CO2 are designed.

[0019] Optionally, based on multiple sets of multi-component thermal fluids with different ratios of N2 and CO2, the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters are obtained, including:

[0020] Obtaining reservoir geological models;

[0021] Inputting multiple sets of multicomponent thermal fluids with different ratios of N2 and CO2 into the reservoir geological model to obtain the cumulative oil production and cumulative water production of the oil well under different multicomponent thermal fluid injection parameters;

[0022] According to the cumulative oil production and the cumulative water production, a relationship diagram between the cumulative oil production and the CO2 ratio is obtained;

[0023] Based on the relationship diagram between cumulative oil production and CO2 proportion, the oil change rate and economic indicators are obtained.

[0024] Optionally, obtain a reservoir geological model, including:

[0025] Obtain basic parameters of oil wells;

[0026] Build a grid model;

[0027] The basic parameters of the oil well are input into the grid model to obtain the reservoir geological model.

[0028] Optionally, the basic parameters of the oil well include: oil saturation, permeability, crude oil viscosity, reservoir temperature and pressure.

[0029] Optionally, the proportion of the multi-component thermal fluid components is determined based on the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters, including:

[0030] According to the oil change rate and economic indicators of the oil well under different multi-element thermal fluid injection parameters, the relationship curves between different CO2 proportions and the oil change rate and economic indicator A were established;

[0031] The proportion of multi-component thermal fluid components is determined based on the relationship curves between different CO2 proportions, oil change rate and economic index A.

[0032] The present invention also provides a device for optimizing the ratio of components of multi-component thermal fluids of heavy oils with different viscosities, the device comprising:

[0033] A volume ratio obtaining unit is used to obtain the volume ratio of N2 to CO2 injected into the multi-component thermal fluid based on the oil well injection parameters of the mine;

[0034] A multi-group ratio determination unit is used to determine a plurality of groups of multi-component thermal fluids with different ratios of N2 and CO2 according to the volume ratio of N2 to CO2 injected into the multi-component thermal fluid;

[0035] An index obtaining unit is used to obtain the oil change rate and economic index of the oil well under different multi-component thermal fluid injection parameters based on multiple groups of multi-component thermal fluids with different ratios of N2 and CO2;

[0036] The component ratio determination unit is used to determine the component ratio of the multi-component thermal fluid according to the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters.

[0037] Optionally, the oil well injection parameters include: natural gas injection volume, water injection volume, and air injection volume.

[0038] Technical effects and advantages of the present invention:

[0039] 1. Further design experiments based on the huff-and-puff injection parameters of multi-component thermal fluids at oil wells in the oil field and optimize the proportions of each component of the multi-component thermal fluid. This can narrow the overall experimental scope and obtain more accurate optimization results while designing fewer experiments.

[0040] 2. Taking into account the on-site processes and actual operating conditions of the oilfield mine, the optimized results of the multi-component thermal fluid component ratio are more in line with the actual oilfield conditions, more feasible, and can be more effectively applied to the oilfield site. The multi-component thermal fluid component ratio is optimized in combination with economic conditions, making the optimization results more economical and reliable;

[0041] 3. A method for optimizing the ratio of multi-component thermal fluids for crude oils with different viscosities is considered, which can optimize the ratio of multi-component thermal fluids according to the different crude oil viscosities in the oil layer.

[0042] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Flowchart of the optimization method for the ratio of components of multi-component thermal fluids for heavy oils with different viscosities;

[0044] Figure 2 The curves of CO2 proportion and N2 proportion in the multi-component thermal fluid injected into the target reservoir / target well in a specific embodiment are shown;

[0045] Figure 3 is a geological model of a target oil reservoir in a specific embodiment;

[0046] Figure 4 The cumulative oil production and component ratio curves of the multi-component thermal fluids with different component ratios in a specific embodiment;

[0047] Figure 5 The relationship curve between the throughput rate of a certain viscosity heavy oil multi-element thermal fluid and the proportion of CO2 in the multi-element thermal fluid is shown in a specific embodiment;

[0048] Figure 6 : is a relationship curve between the throughput economic index A of a certain viscosity heavy oil multi-component thermal fluid and the proportion of CO2 in the multi-component thermal fluid in a specific embodiment. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings provided by the present invention. Moreover, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for understanding and reading by those familiar with this technology, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0051] In order to solve the deficiencies of the existing technology, the present invention discloses a method for optimizing the ratio of multi-component thermal fluid components based on the actual situation of the oil field, taking into account the feasibility of the oil field process technology and economic conditions, which can achieve a higher precision optimization of the ratio of multi-component thermal fluid components under different viscosity heavy oils, and provide a basis for further improving the throughput effect of multi-component thermal fluids and optimizing the throughput plan, so as to realize the efficiency of multi-component thermal fluid throughput at the oil field site, thereby being more effectively applied to the oil field site. Figure 1 A detailed introduction to the optimization method of the component ratio of multi-component thermal fluids for heavy oils with different viscosities:

[0052] A method for optimizing the ratio of components of multi-component thermal fluids for heavy oils with different viscosities, the method comprising:

[0053] 1. Based on the oil well injection parameters of the mine, the volume ratio of N2 to CO2 in the injected multi-component thermal fluid is obtained.

[0054] Specifically, it is to obtain the basic geological parameters of the oil reservoir, such as oil saturation, permeability, crude oil viscosity, reservoir temperature and pressure, and the injection parameters of the oil well, such as the amount of injected natural gas, water, and air;

[0055] Based on the actual production of oil fields and mines, relevant programs were written using MATLAB software. The oil well injection parameters were entered into the program to obtain the actual injection amounts of nitrogen, carbon dioxide and water vapor in the target oil reservoir during the multi-component thermal fluid huff and puff stage, thereby obtaining the volume ratio of N2 to CO2 in the multi-component thermal fluid injected during the multi-component thermal fluid huff and puff cycle of the oil well.

[0056] 2. According to the volume ratio of N2 to CO2 in the injected multi-component thermal fluid, determine multiple groups of multi-component thermal fluids with different ratios of N2 and CO2;

[0057] Specifically: Repeat step 1 to obtain multiple volume ratios of N2 and CO2, and then determine the ratio range of CO2 and N2. Within this range, artificially change the ratio of CO2 and N2 and design experimental plans with different ratios of CO2 and N2.

[0058] 3. Based on multiple groups of multi-component thermal fluids with different ratios of N2 and CO2, the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters are obtained.

[0059] Specifically, in the STARS module of the CMG software, a grid model was established and the basic reservoir geological parameters obtained in step 1 were input to ultimately obtain a reservoir geological model. The injection parameters of several designed experimental schemes were input into the model and run separately to obtain the cumulative oil and water production of the wells under different multi-component thermal fluid injection parameters. Based on the cumulative oil and water production, a relationship diagram between cumulative oil production and CO2 content was obtained. Based on this relationship diagram between cumulative oil production and CO2 content, the oil exchange rate and the economic indicator A (oil production * oil price - air injection volume * air cost per cubic meter - natural gas injection volume * natural gas cost per cubic meter - water injection volume * water injection cost per cubic meter) were obtained.

[0060] 4. Determine the proportion of multi-component thermal fluid components based on the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters.

[0061] Specifically: Based on the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters, the relationship curve between different CO2 proportions and oil change rate and economic indicator A is established; based on the relationship curve between different CO2 proportions and oil change rate and economic indicator A, the proportion of multi-component thermal fluid components is determined.

[0062] In order to better understand the present solution, examples are provided below.

[0063] A method for optimizing the ratio of multi-component thermal fluid components for heavy oils with different viscosities, comprising the following steps:

[0064] (1) Obtaining oilfield geological parameters and oil well parameters

[0065] Obtain basic reservoir geological parameters such as oil saturation, permeability, crude oil viscosity, reservoir temperature and pressure, as well as oil well injection parameters such as injected natural gas volume, water volume, and air volume.

[0066] (2) Convert the injection parameters of the mine into the actual injection amount of CO2, N2, and H2O

[0067] Based on the actual production of oil fields and mines, relevant programs were written using MATLAB software. The oil well injection parameters, such as natural gas injection rate, water injection rate, and air injection rate, were entered into the program to obtain the actual injection rates of nitrogen, carbon dioxide, and water vapor in the target oil reservoir during the multi-component thermal fluid huff and puff stage. The volume ratio of N2 to CO2 and the volume proportion of H2O in the multi-component thermal fluid injected during the multi-component thermal fluid huff and puff cycle of the oil well were thus obtained.

[0068] (3) Design experiments on multicomponent thermal fluids with different component ratios

[0069] Since the volume fraction of H2O obtained in step 2 fluctuates around 0.0025, the volume fraction of H2O is fixed at 0.0025, i.e. 80m 3 / d. And according to the volume ratio of N2 to CO2 obtained in step 2, the volume ratio range of N2 and CO2 in each multi-element thermal fluid huff-and-puff cycle of the target well is obtained, such as Figure 2 As shown, eight groups of experimental schemes with CO2 proportions of 0.075, 0.077, 0.079, 0.081, 0.083, 0.085, 0.087, and 0.089 were finally determined, that is, eight groups of multi-component thermal fluid component injection ratios of the oil well were optimized.

[0070] (4) Establish a reservoir geological model and numerically simulate the oil change rate under different test schemes

[0071] In the STARS module of CMG software, a grid model (50×31×43) was established, and the basic geological parameters of the reservoir were input to obtain the reservoir geological model. The permeability field is as follows: Figure 3 As shown. A vertical well with a throughput is defined at the center (26, 17), with perforation layers 15 to 28, a total of 8 cycles of throughput (5 cycles of steam throughput + 3 cycles of multi-component thermal fluid throughput), 20 days of steam / gas injection, 10 days of well blocking, and 60 days of oil production. The optimized sets of multi-component thermal fluid ratio data are input into the model respectively, and the model is run separately to obtain the cumulative oil production and cumulative water production of the oil well under the input of several sets of different multi-component thermal fluid injection parameters, and the relationship diagram between cumulative oil production and CO2 ratio is obtained, as shown below. Figure 4 , and calculate the corresponding oil change rate and economic index A.

[0072] (5) Optimize the proportion of components to ensure economic benefits

[0073] Establish the relationship curves between different CO2 proportions, oil change rate and economic index A, as shown below: Figure 5 、 Figure 6As shown in the figure, the proportion of multi-component thermal fluid components under this viscosity is optimized from the perspective of economic benefits. It can be seen from the figure that the higher the CO2 proportion, the greater the oil change rate and economic indicators. The final determined CO2 proportion is 0.087, that is, H2O:CO2:N2=0.0025:0.087:0.9105.

[0074] The present invention also provides a device for optimizing the component ratios of multi-component thermal fluids for heavy oils of different viscosities, the device comprising: a volume ratio obtaining unit for obtaining the volume ratio of N2 to CO2 in the injected multi-component thermal fluid based on the injection parameters of the oil wells in the mine; a multi-group ratio determining unit for determining multiple groups of multi-component thermal fluids with different ratios of N2 and CO2 based on the volume ratios of N2 to CO2 in the injected multi-component thermal fluids; an index obtaining unit for obtaining the oil change rate and economic index of the oil well under different multi-component thermal fluid injection parameters based on the multiple groups of multi-component thermal fluids with different ratios of N2 and CO2; and a component ratio determining unit for determining the component ratios of the multi-component thermal fluid based on the oil change rate and economic index of the oil well under different multi-component thermal fluid injection parameters.

[0075] Since the content protected by this device is similar to that protected by the above method, we will not introduce it in detail here. Please refer to the discussion section of the above method for details.

[0076] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for optimizing the ratio of components of multi-component thermal fluids for heavy oils of different viscosities, characterized in that: The method comprises: Based on the well injection parameters at the mine, the volume ratio of N2 to CO2 in the injected multi-component thermal fluid is obtained; According to the volume ratio of N2 to CO2 in the injected multi-component thermal fluid, multiple groups of multi-component thermal fluids with different ratios of N2 and CO2 are determined; Based on multiple groups of multi-component thermal fluids with different ratios of N2 and CO2, the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters are obtained; The component ratio of the multi-component thermal fluid is determined according to the oil exchange rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters.

2. The method according to claim 1, characterized in that The oil well injection parameters include: natural gas injection volume, water injection volume, and air injection volume.

3. The method according to claim 1, characterized in that Based on the well injection parameters at the mine, the volume ratio of N2 to CO2 in the injected multi-component thermal fluid is obtained, including: Based on the well injection parameters at the mine, the actual injection rates of CO2, N2, and H2O during the multi-component thermal fluid huff-and-puff phase were obtained; According to the actual injection amounts of CO2, N2, and H2O during the multi-component thermal fluid intake and discharge phase, the volume ratio of N2 to CO2 injected into the multi-component thermal fluid is obtained.

4. The method according to claim 1, wherein According to the volume ratio of N2 to CO2 injected into the multi-component thermal fluid, multiple groups of multi-component thermal fluids with different ratios of N2 and CO2 are determined, including: Determine the volume ratio of N2 and CO2 based on the volume ratio of N2 to CO2 injected into the multi-component thermal fluid; According to the volume ratio range of N2 and CO2, multiple groups of multi-component thermal fluids with different proportions of N2 and CO2 are designed.

5. The method according to claim 1, wherein Based on multiple sets of multi-component thermal fluids with different ratios of N2 and CO2, the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters are obtained, including: Obtaining reservoir geological models; Inputting multiple sets of multicomponent thermal fluids with different ratios of N2 and CO2 into the reservoir geological model to obtain the cumulative oil production and cumulative water production of the oil well under different multicomponent thermal fluid injection parameters; According to the cumulative oil production and the cumulative water production, a relationship diagram between the cumulative oil production and the CO2 ratio is obtained; Based on the relationship diagram between cumulative oil production and CO2 proportion, the oil change rate and economic indicators are obtained.

6. The method according to claim 5, characterized in that Obtain reservoir geological model, including: Obtain basic parameters of oil wells; Build a grid model; The basic parameters of the oil well are input into the grid model to obtain the reservoir geological model.

7. The method according to claim 6, characterized in that The basic parameters of the oil well include: oil saturation, permeability, crude oil viscosity, reservoir temperature and pressure.

8. The method according to claim 1, characterized in that Determine the proportion of multi-component thermal fluid components based on the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters, including: According to the oil change rate and economic indicators of the oil well under different multi-element thermal fluid injection parameters, the relationship curves between different CO2 proportions and the oil change rate and economic indicator A were established; The proportion of multi-component thermal fluid components is determined based on the relationship curves between different CO2 proportions, oil change rate and economic index A.

9. A device for optimizing the ratio of components of multi-component thermal fluids for heavy oils of different viscosities, characterized in that: The device comprises: A volume ratio obtaining unit is used to obtain the volume ratio of N2 to CO2 injected into the multi-component thermal fluid based on the oil well injection parameters of the mine; A multi-group ratio determination unit is used to determine a plurality of groups of multi-component thermal fluids with different ratios of N2 and CO2 according to the volume ratio of N2 to CO2 injected into the multi-component thermal fluid; An index obtaining unit is used to obtain the oil change rate and economic index of the oil well under different multi-component thermal fluid injection parameters based on multiple groups of multi-component thermal fluids with different ratios of N2 and CO2; The component ratio determination unit is used to determine the component ratio of the multi-component thermal fluid according to the oil change rate and economic indicators of the oil well under different multi-component thermal fluid injection parameters.

10. The device according to claim 9, characterized in that The oil well injection parameters include: natural gas injection volume, water injection volume, and air injection volume.

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