Method and system for calculating reservoir-level carbon dioxide burying amount

Abstract

The invention discloses an oil reservoir grade carbon dioxide burying stock calculation method and system, and relates to the technical field of oil and gas field development, and the method comprises the steps: carrying out a core waterflooding-CO2 flooding pore scale fluid characterization experiment based on a micro-nano core CT online scanning technology, and calculating CO2 burying efficiency ES; measuring a core oil-gas phase permeability curve and oil displacement efficiency ED, and judging whether a semi-logarithmic relation curve of kro / krg and Sg in the CO2 displacement stage meets a binomial change relation or not; obtaining target oil reservoir static parameters and production dynamic indexes, describing a gas-oil ratio and cumulative oil production change relation in a gas seeing stage, establishing a CO2 flooding characteristic curve, and performing data point fitting, oil reservoir recovery rate ER prediction and oil reservoir swept volume V calculation through a binomial expression; and calculating the reservoir-level CO2 burying amount VS according to the reservoir swept volume V and the CO2 burying efficiency ES. According to the method disclosed by the invention, the required data are few in types and high in availability, and the CO2 burying amount can be accurately calculated simply, conveniently and quickly only by the basic physical properties of crude oil and rock and the production dynamic data of an oil well.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and in particular to a method and system for calculating reservoir-level carbon dioxide storage. Background Art

[0002] As global warming and other climate change issues become increasingly serious, reducing greenhouse gas emissions has gradually attracted attention at home and abroad. Carbon dioxide flooding and storage technology (CCUS) is an important technology to ensure national oil security. This technology injects carbon dioxide (CO2) into the target reservoir, displacing crude oil to increase recovery while storing CO2 in the natural closed geological body of the reservoir, reducing CO2 emissions, and thus taking into account both economic and social benefits.

[0003] Before CO2 injection into the target reservoir in CCUS projects, reliable evaluation of CO2 storage capacity is helpful to understand the geological storage potential of CCUS, which is of great significance for the implementation of CCUS. At present, scholars at home and abroad have proposed a variety of CO2 storage calculation methods, such as indoor experimental method, theoretical formula method, numerical simulation method, etc. However, the methods have not yet formed a systematic understanding, and the application methods are relatively single.

[0004] Patent document CN103927913A discloses "a deep formation environment carbon dioxide geological storage simulation experimental system", which specifically discloses a carbon dioxide geological storage simulation experimental system composed of an acoustic probe, a temperature-pressure-flow-stress coupling core device and related supporting components. However, the system can only measure macroscopic physical parameters such as core porosity, permeability, and water saturation, and only stays at the calculation of core-scale storage capacity, making it difficult to achieve a quantitative description of reservoir-level CO2 storage capacity.

[0005] Ding Shuaiwei et al. proposed a theoretical formula method for calculating the CO2 storage capacity of oil reservoirs in the calculation method of CO2 geological storage potential of oil reservoirs. However, the calculation process is relatively complicated, with many input parameters, high requirements on data accuracy, and less consideration of reservoir characteristics, resulting in low accuracy of calculation results.

[0006] In addition, numerical simulation calculation methods often require fine geological modeling and numerical simulation, and require a large amount of accurate reservoir geology, fluid properties, phase permeability relationship and other data. The simulation is time-consuming and labor-intensive, and the workload is large. Therefore, in low-permeability and ultra-low-permeability continental sedimentary reservoirs with extremely strong heterogeneity, it is important to establish a more complete storage calculation method and clarify the storage size of reservoir-level CO2, which is of great significance for the next step of injection and production optimization and the preparation of the full-process CCUS plan. Summary of the invention

[0007] The present invention aims to provide a method and system for calculating the storage capacity of CO2 at the reservoir level. Specifically, a method for calculating the storage capacity of CO2 that combines indoor experiments with reservoir engineering is proposed. On the basis of obtaining various physical parameters of the core of the target block, the storage efficiency is determined by core CT (Computed Tomography) scanning, and the CO2 swept volume at the reservoir scale is calculated based on production dynamic data and CO2 flooding characteristic curves, thereby calculating the storage capacity of CO2 at the reservoir level. It can provide technical support for the reliable evaluation of the geological storage potential of CCUS, and has good applicability in continental sedimentary reservoirs with strong heterogeneity and high complexity.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] The present invention provides a method for calculating reservoir-level carbon dioxide storage, the method comprising the following steps:

[0010] Step S101: Based on the micro-nano core CT online scanning technology, a pore-scale fluid characterization experiment of core water flooding-CO2 flooding is carried out to determine the distribution ratio of different fluids at the pore scale and calculate the CO2 storage efficiency E S ;

[0011] Step S102: Determine the core oil-gas phase permeability curve and oil displacement efficiency E D , determine the CO2 flooding stage k ro / k rg With S g Check whether the semi-logarithmic relationship curve satisfies the binomial change relationship; if so, proceed to the next step; if not, adjust the experimental conditions and retest;

[0012] Step S103: Obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, fit the data points through the binomial equation, and calculate the reservoir recovery factor E. R Prediction and calculation of reservoir swept volume V;

[0013] Step S104: Based on the reservoir swept volume V and CO2 storage efficiency E S Calculate the CO2 storage volume V at the reservoir level S .

[0014] Furthermore, the method further comprises the following steps:

[0015] Step S100, selection, pretreatment and basic physical property measurement of target reservoir layer cores; wherein, at least 20 target reservoir layer cores are selected, and the core size is 25 mm in diameter and 120 mm in length; the basic physical properties of the cores are measured, including length, diameter, mass, porosity and gas permeability; the pretreatment of the reservoir layer cores includes: after the basic physical property measurement of the cores, at least 3 cores are selected according to the permeability distribution and cut into two sections with a diameter of 25 mm and a length of 100 mm and a diameter of 25 mm and a length of 20 mm.

[0016] Furthermore, in step S101, based on the micro-nano core CT online scanning technology, a pore-scale fluid characterization experiment of core water flooding-CO2 flooding is carried out to determine the distribution ratio of different fluids at the pore scale and calculate the CO2 storage efficiency E S , specifically including the following steps:

[0017] Step S101.1, setting the pressure and temperature of the micro-nano CT scanning device to the target reservoir pressure and temperature;

[0018] Step S101.2, drilling a small portion from the core samples at three typical permeability points, respectively, grinding them into a size suitable for the CT special core holder, and installing them into three special core holders;

[0019] Step S101.3, connecting three specially made core holders to the displacement equipment and the displacement system, applying a set confining pressure, and obtaining pore space structure distribution information;

[0020] Step S101.4, remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, set the displacement parameters, complete the oil-water displacement process, turn the CT scanning table under pressure, establish a scanning program, carry out CT scanning, and establish a fluid distribution state diagram under the initial oil saturation state;

[0021] Step S101.5, using water to displace oil until the outlet end stops producing oil, completing the water-to-oil process, switching the CT scanning table under pressure, scanning and imaging again, and establishing a distribution state diagram of each phase of fluid in the core pore space under the residual oil saturation state;

[0022] Step S101.6, using CO2 to displace until no more oil and water are produced at the outlet end, completing the CO2 flooding process, closing all valves, entering the burial process, maintaining the confining pressure, and transferring each core holder to the CT scanning table under pressure, performing scanning imaging again, and establishing a distribution state diagram of each phase fluid in the pore space of each core at the end of the burial;

[0023] Step S101.7: Obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and calculate the percentage of CO2 in the total pore space of the three cores to obtain the storage efficiency E.S .

[0024] Furthermore, in step S103, the static parameters and production dynamic indicators of the target reservoir are obtained, the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage is described, and the CO2 flooding characteristic curve is established. The data points are fitted by binomial, and the reservoir recovery factor E is calculated. R The prediction and calculation of reservoir swept volume V specifically include the following steps:

[0025] Step S103.1, collect and collate static parameters and production dynamic indicators of the target oil reservoir; the static parameters include: oil reservoir reserves, daily liquid / oil production, water content, cumulative oil production and gas-oil ratio;

[0026] Step S103.2: According to the cumulative oil production N p and gas-oil ratio GOR, lgGOR~N p For the semi-logarithmic curve graph, binomial fitting is adopted to obtain the binomial fitting formula;

[0027] Step S103.3: Determine the limit gas-oil ratio GOR m , substituted into the binomial fitting formula, the corresponding cumulative oil production under the limit gas-oil ratio condition is calculated as the recoverable reserves of CO2 flooding, and then the reservoir recovery factor E is calculated. R ;

[0028] Step S103.4: According to the oil reservoir recovery factor E R and oil recovery efficiency E D Calculate the reservoir sweep efficiency E v , and then calculate the reservoir swept volume V.

[0029] Furthermore, in step S103.2, the binomial fitting formula is expressed as:

[0030]

[0031] in,

[0032]

[0033]

[0034]

[0035] Where GOR is gas-oil ratio, unit: m 3 / m 3 ; N p Indicates the cumulative oil production, unit 10 4 t;S wc Indicates bound water saturation, unit: %; γ o Represents the relative density of formation oil; γ gIndicates the relative density of formation gas; μ o Indicates formation oil viscosity, unit: mPa·s; μ g Indicates formation gas viscosity, unit: mPa·s; B o Indicates the oil volume coefficient; B g represents gas volume coefficient; N represents geological reserves, 10 4 t; a, b, c, d, e, A, B, C are all calculation coefficients.

[0036] Furthermore, in step S103.3, the calculation formula for the recoverable reserves of CO2 flooding is:

[0037]

[0038] Where N pm Indicates CO2 flooding recoverable reserves, unit 10 4 t;GOR m Indicates the limit gas-oil ratio, unit: m 3 / m 3 ; A, B, C are all calculation coefficients.

[0039] Furthermore, in step S103.4, the calculation formula of the reservoir swept volume V is:

[0040] V=E V ×Ahφ;

[0041] in,

[0042]

[0043] In the formula, E R Represents oil reservoir recovery rate, unit %; E D Indicates oil recovery efficiency, unit: %; E v represents the reservoir sweep efficiency, in %; V represents the reservoir sweep volume, in m 3 ; A represents the oil-bearing area, unit km 2 ; h is the reservoir depth, unit is m; φ is the porosity, unit is %.

[0044] Furthermore, the reservoir-level CO2 storage capacity V S The calculation formula is:

[0045] V S =V·E S ;

[0046] Where V S Indicates the calculated oil reservoir storage volume, unit: m 3 ; V represents the reservoir swept volume, unit: m 3 ; E SIt indicates the oil reservoir storage efficiency, in %.

[0047] The present invention also provides a reservoir-level carbon dioxide storage volume calculation system, the system comprising: a first calculation unit, a judgment unit, a second calculation unit and a third calculation unit; wherein,

[0048] The first calculation unit is used to carry out pore-scale fluid characterization experiments of core water flooding and CO2 flooding based on micro-nano core CT online scanning technology, determine the distribution ratio of different fluids at the pore scale, and calculate the CO2 storage efficiency E S ;

[0049] Judgment unit, used to determine the core oil-gas phase permeability curve and oil recovery efficiency E D , determine the CO2 flooding stage k ro / k rg With S g Check whether the semi-logarithmic relationship curve satisfies the binomial change relationship; if so, proceed to the next step; if not, adjust the experimental conditions and retest;

[0050] The second calculation unit is used to obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, and perform data point fitting and reservoir recovery factor E through binomial. R Prediction and calculation of reservoir swept volume V;

[0051] The third calculation unit is used to calculate the oil reservoir swept volume V and CO2 storage efficiency E S Calculate the CO2 storage volume V at the reservoir level S .

[0052] Furthermore, the system further comprises: a selection unit;

[0053] The selection unit is used for the selection, pretreatment and basic physical property determination of the cores of the target reservoir layer; wherein, at least 20 cores of the target reservoir layer are selected, and the core size is 25mm in diameter and 120mm in length; the basic physical properties of the cores are measured, including: length, diameter, mass, porosity and gas permeability; the pretreatment of the cores of the reservoir layer includes: after the basic physical property measurement of the cores, at least 3 cores are selected according to the permeability distribution and cut into two sections with a diameter of 25mm and a length of 100mm and a diameter of 25mm and a length of 20mm.

[0054] Furthermore, the first calculation unit includes: a setting module, an installation module, a first acquisition module, a first establishment module, a second establishment module, a third establishment module and a first calculation module; wherein,

[0055] A setting module, used to set the pressure and temperature of the micro-nano CT scanning device to the target reservoir pressure and temperature;

[0056] Installation module, used to drill a small part from the core sample of three typical permeability points, grind it into the size of the rock sample suitable for CT special core holder, and install it into three special core holders;

[0057] The first acquisition module is used to connect three special core holders to the displacement equipment and the displacement system, add a set confining pressure, and obtain the pore space structure distribution information;

[0058] The first establishment module is used to remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, set the displacement parameters, complete the oil-water displacement process, transfer the CT scanning table under pressure, establish the scanning program, carry out the CT scanning work, and establish the fluid distribution state diagram under the initial oil saturation state;

[0059] The second establishment module is used to use water to drive until no more oil is produced at the outlet end, complete the water drive process, transfer the CT scanning table under pressure, perform scanning imaging again, and establish a distribution state diagram of each phase of fluid in the core pore space under the state of residual oil saturation;

[0060] The third module is used to use CO2 to drive until there is no more oil and water at the outlet, complete the CO2 flooding process, close all valves, enter the burial process, maintain the confining pressure, and transfer each core holder to the CT scanning table under pressure, perform scanning imaging again, and establish the distribution state diagram of each phase fluid in the pore space of each core at the end of the burial state;

[0061] The first calculation module is used to obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and calculate the percentage of CO2 in the total pore space of the three cores, which is the storage efficiency E. S .

[0062] Furthermore, the third calculation unit includes: a second acquisition module, a third acquisition module, a second calculation module and a third calculation module; wherein,

[0063] The second acquisition module is used to collect and collate the static parameters and production dynamic indicators of the target oil reservoir; the static parameters include: oil reservoir reserves, daily liquid / oil production, water content, cumulative oil production and gas-oil ratio;

[0064] The third acquisition module is used to obtain the total oil production N p and gas-oil ratio GOR, lgGOR~N p For the semi-logarithmic curve graph, binomial fitting is adopted to obtain the binomial fitting formula;

[0065] The second calculation module is used to determine the limit gas-oil ratio GOR m, substituted into the binomial fitting formula, the corresponding cumulative oil production under the limit gas-oil ratio condition is calculated as the recoverable reserves of CO2 flooding, and then the reservoir recovery factor E is calculated. R ;

[0066] The third calculation module is used to calculate the oil recovery factor E according to the oil reservoir recovery factor E. R and oil recovery efficiency E D Calculate the reservoir sweep efficiency E v , and then calculate the reservoir swept volume V.

[0067] Technical effects and advantages of the present invention:

[0068] (1) The present invention is the first to combine indoor physical simulation experiments with reservoir engineering calculations, using the results of indoor real core physical simulation experiments directly for reservoir-level CO2 storage calculations.

[0069] (2) The method of the present invention can clearly determine the amount of carbon dioxide stored in the target reservoir under different mechanisms, determine the carbon dioxide storage efficiency through displacement experiments and core CT scanning, and combine with reservoir engineering calculations to achieve accurate calculation of the carbon dioxide storage in the target reservoir.

[0070] (3) The present invention can restore the reservoir environment by precisely controlling the experimental conditions, objectively simulate the migration law of CO2 in the formation through core experiments, fully reflect the physical properties and storage characteristics of the reservoir, and enhance the accuracy of subsequent reservoir engineering calculation results; at the same time, it overcomes the difficulty that a single physical simulation experiment cannot realize the calculation of reservoir-level CO2 storage.

[0071] (4) Compared with complex numerical simulation prediction methods, the method of the present invention requires less data types and is more accessible. It only requires basic physical properties of crude oil and rock and production dynamic data of oil wells to achieve simple and rapid calculation of CO2 storage capacity, thus providing a guarantee for improving the effect of CCUS experiments.

[0072] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing 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

[0073] Figure 1 This is a flow chart of a method for calculating reservoir-level carbon dioxide storage capacity according to an embodiment of the present invention;

[0074] Figure 2 A box plot of the target reservoir permeability distribution according to an embodiment of the present invention;

[0075] Figure 3A physical simulation experimental device for the carbon dioxide recovery and storage technology (CCUS) of an embodiment of the present invention;

[0076] Figure 4 This is the core CT scanning result of the CO2 storage end state in the embodiment of the present invention;

[0077] Figure 5 The core oil-gas phase permeability curve test result of the embodiment of the present invention;

[0078] Figure 6 The core lg (k ro / k rg ) and S g The changing relationship curve diagram;

[0079] Figure 7 The target reservoir lgGOR and N p The changing relationship curve diagram;

[0080] Figure 8 Schematic diagram of a reservoir-level carbon dioxide storage volume calculation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0082] In order to solve the deficiencies of the prior art, the present invention discloses a method for calculating the storage capacity of oil reservoir-level carbon dioxide. Figure 1 FIG. 1 is a flow chart of a method for calculating reservoir-level carbon dioxide storage capacity according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0083] Step S100: core selection, pretreatment and basic physical property determination.

[0084] In order to make the calculation results more reflective of the physical properties of the real reservoir, at least 20 cores of the target reservoir layer were selected, and the basic physical properties of the cores (length, diameter, quality, porosity, gas permeability) were measured. A box plot of the permeability distribution was made, and three typical permeability points, the upper and lower quartiles and the median, were taken as the cores for the reservoir experiment. The drilled core size is 25mm in diameter and 120mm in length. After testing the basic physical properties, it was cut into two sections, 25mm in diameter, 100mm in length and 25mm in diameter, 20mm in length. The shorter section was used for the core CT scanning experiment, and the longer section was used for the phase permeability curve test. The target core sample was placed in a constant temperature box for the next experiment.

[0085] The selection of cores at three typical permeability points, the upper and lower quartiles and the median, in the target reservoir layer is based on the permeability distribution characteristics of the reservoir. The selection of representative cores in the experiment can represent the overall permeability of the target reservoir and avoid the influence of possible extreme permeability values ​​on the experimental results, thus more accurately reflecting the physical properties of the target reservoir.

[0086] Step S101: Based on the micro-nano core CT online scanning technology, a pore-scale fluid characterization experiment of core water flooding-CO2 flooding is carried out to determine the distribution ratio of different fluids at the pore scale and calculate the CO2 storage efficiency E S .

[0087] Step S101.1: Use the improved MicroX micro-nano CT scanning equipment to carry out core CT scanning experiments, and set the pressure and temperature to the target reservoir pressure and temperature.

[0088] Step S101.2, take core samples of three typical permeability points, drill a small part from each core sample, grind it into a size suitable for the CT special core holder, and install the rock samples into three special core holders respectively. The core holder needs to be made of characteristic non-metallic materials, which can be penetrated by X-rays and can withstand a certain pressure.

[0089] Step S101.3, connect three specially made core holders to the displacement equipment and connect them to the displacement system. Apply confining pressure, seal them with a plug, and perform pressurized dry sample scanning to obtain pore space structure distribution information.

[0090] Step S101.4, remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, and displace at a displacement rate of 0.1-0.3 mL / min for 4-6 hours, and the confining pressure of the displacement device is 2.5-4 MPa to saturate the rock pores with formation water. At the set displacement rate, the on-site crude oil dissolved with the developer is driven by oil to the outlet without water, so that the rock pores establish the initial oil content and bound water saturation. After the saturation displacement process is completed, close the outlet valve, the inlet valve and the confining pressure valve, and use the matching plug to completely seal them so that the core is always under confining pressure. Turn the CT scanning table under pressure, establish a scanning program, carry out CT scanning, and establish the fluid distribution under the initial saturated oil state.

[0091] Step S101.5, use water to displace oil until the outlet end stops producing oil and the water-to-oil process is completed, and the CT scanning table is turned under pressure to perform scanning imaging again to establish a distribution state diagram of each phase of fluid in the core pore space under the residual oil saturation state.

[0092] Step S101.6, use CO2 to displace until there is no more oil and water output at the outlet, complete the CO2 flooding process, close the outlet valve, inlet valve and confining pressure valve, enter the burial process, and maintain the confining pressure state for a certain period of time. Transfer each core holder to the CT scanning table under pressure, scan and image again, and establish the distribution state diagram of each phase fluid in the pore space of each core at the end of the burial state.

[0093] Step S101.7: Obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and further obtain the percentage of CO2 in the total pore space of the three cores, which is the storage efficiency E. S .

[0094] Step S102, determine the core oil-gas phase permeability curve and oil recovery efficiency. After the experimental core is saturated with water and oil, it is placed in a core holder. According to the industry standard SYT6339-1998 "Non-steady-state method for determination of oil and gas relative permeability", the oil-gas phase permeability curve under the target reservoir pressure is determined, and the oil recovery efficiency of each core is recorded. The average value of the oil recovery efficiency of the three cores is calculated as the final oil recovery efficiency E D .

[0095] See CO2 flooding stage k ro / k rg With S g The semi-logarithmic relationship curve is used to determine whether the binomial change relationship is satisfied. This condition is based on the previous experimental results and is the main feature of the core-level CO2 displacement experiment. It is also the basis for the next step to derive the relationship between the reservoir swept volume and the gas-oil ratio and cumulative oil production. If it is satisfied, continue to the next step; if not, it does not meet the prerequisite for reservoir swept volume prediction, and the experimental conditions are adjusted and retested.

[0096] Step S103: Obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, and perform data point fitting and reservoir recovery factor E through binomial. R Prediction and calculation of reservoir swept volume V.

[0097] Step S103.1, collect and organize dynamic and static production data such as target reservoir reserves, daily liquid / oil production, water content, cumulative oil production, gas-oil ratio, etc. If there is no gas-oil ratio data for the target block, the CO2 content data of the produced gas can be collected, and the gas-oil ratio can be inverted and calculated based on the phase fitting method; select the stable production stage where there are no major adjustment measures for the gas wells for index prediction.

[0098] Step S103.2, lgGOR~N p The semi-logarithmic curve was plotted and fitted using the binomial to obtain the binomial fitting formula;

[0099] Step S103.3, determine the limit gas-oil ratio, substitute it into the above fitting formula, calculate the corresponding cumulative oil production under the limit gas-oil ratio condition, which is the recoverable reserves of CO2 flooding, and the ratio of recoverable reserves to geological reserves is the reservoir recovery factor E R .

[0100] Step S103.4: Calculate the reservoir swept volume. Calculate the reservoir recovery factor E R and oil recovery efficiency E D The ratio of the two is the reservoir sweep efficiency, and the reservoir sweep efficiency E V The product of the volume of pores is the reservoir swept volume V, which can be calculated as follows:

[0101] V=E V ×Ahφ; (1)

[0102] Among them, the reservoir sweep efficiency E V The calculation formula is as follows:

[0103]

[0104] In formula (1)-(2), E R Represents oil reservoir recovery rate, unit %; E D Indicates oil recovery efficiency, unit: %; E v represents the reservoir sweep efficiency, in %; V represents the reservoir sweep volume, in m 3 ; A represents the oil-bearing area, unit km 2 ; h is the reservoir depth, unit is m; φ is the porosity, unit is %.

[0105] Step S104: Based on the calculated reservoir swept volume V and the CO2 storage efficiency E measured by the core CT experiment,S The product is the reservoir-level CO2 storage capacity V S Size, reservoir-level CO2 storage capacity V S The size is calculated as follows:

[0106] V S =V·E S ; (3)

[0107] In formula (3), V S Indicates the calculated oil reservoir storage volume, unit: m 3 ; V represents the reservoir swept volume, unit: m 3 ; E S It indicates the oil reservoir storage efficiency, in %.

[0108] From the phase permeability curve of the gas phase, k ro / k rg -S g The derivation process of the CO2 flooding production dynamic curve predicted by the change relationship is as follows:

[0109] Assuming that the formation temperature is constant, oil and gas are produced simultaneously after gas is generated, and capillary force and gravity are ignored, the oil-gas relative permeability ratio and gas saturation satisfy the following relationship based on the core relative permeability experimental data:

[0110]

[0111] Under the condition of stable seepage of CO2 flooding, the oil and gas two-phase flow and the instantaneous production of oil and water exist:

[0112]

[0113] For the CO2 flooding process, it is known that the cumulative oil production and gas saturation have the following relationship:

[0114]

[0115] At the same time, the production gas-oil ratio is defined as:

[0116]

[0117] The above four formulas can be combined to obtain:

[0118]

[0119] in,

[0120]

[0121]

[0122]

[0123] When the gas-oil ratio reaches the limit gas-oil ratio, the cumulative oil production is the recoverable reserves of CO2 flooding, then:

[0124]

[0125] In formulas (4)-(12), k ro Represents oil relative permeability; k rg Represents gas relative permeability; S g Indicates gas saturation, unit: %; S wc Indicates bound water saturation, unit %; Q o Indicates the oil output at the output end, unit: m 3 / d;Q g Indicates the gas output at the output end, unit: m 3 / d;γ o Represents the relative density of formation oil; γ g Indicates the relative density of formation gas; μ o Indicates formation oil viscosity, unit: mPa·s; μ g Indicates formation gas viscosity, unit: mPa·s; B o Indicates the oil volume coefficient; B g Indicates gas volume coefficient; N p Indicates the cumulative oil production, unit 10 4 t; N represents geological reserves, unit 10 4 t;N pm Indicates CO2 flooding recoverable reserves, unit 10 4 t; GOR means gas-oil ratio, unit is m 3 / m 3 ;GOR m Indicates the limit gas-oil ratio, unit: m 3 / m 3 ; a, b, c, d, e, A, B, C are all calculation coefficients.

[0126] Example:

[0127] A tight oil reservoir is buried at a depth of 2750m, with an oil layer thickness of 13m, a porosity of 8.2%, a formation water type of CaCl2, a formation water salinity of 35.42g / L, a formation temperature of 85℃, an original formation pressure of 19.74MPa, a current formation pressure of 17.21MPa, and a formation crude oil density of 0.84g / cm 3 , crude oil viscosity is 0.73mPa·s, dissolved gas-oil ratio is 85m 3 / t, crude oil volume coefficient is 1.27, produced gas volume coefficient is 0.008, CO2 density under reservoir conditions is 0.53g / cm 3 The oil reservoir has an area of ​​1.96 km 2, the geological reserves used are 62.36×10 4 t, and has switched from water flooding to CO2 flooding since 2014.

[0128] Figure 1 FIG. 1 is a flow chart of a method for calculating the storage capacity of carbon dioxide at the reservoir level according to an embodiment of the present invention. The storage capacity of CO2 at the reservoir is calculated by the method established by the present invention. The overall process is as follows: Figure 1 As shown, the method comprises the following steps:

[0129] Step S100: core selection, pretreatment and basic physical property determination.

[0130] Select at least 20 cores from the target reservoir interval, measure the basic physical properties of the cores (length, diameter, quality, porosity and gas permeability), and make a box plot of permeability distribution. Figure 2 is a box diagram of the target reservoir permeability distribution in an embodiment of the present invention, such as Figure 2 As shown, the three typical permeability points of the upper and lower quartiles and the median are 0.69, 0.34 and 0.47mD respectively, and the cores of these three typical permeability points are taken as the cores for the reservoir experiment. The drilled core size is 25mm in diameter and 120mm in length. After testing the basic physical properties, it is cut into two sections with a diameter of 25mm and a length of 100mm and a diameter of 25mm and a length of 20mm. The shorter section is used for the core CT scanning experiment, and the longer section is used for the phase permeability curve test.

[0131] Step S101: Based on the micro-nano core CT online scanning technology, a pore-scale fluid characterization experiment of core water flooding-CO2 flooding is carried out to measure the distribution ratio of different fluids at the pore scale and determine the CO2 storage efficiency E S .

[0132] Step S101.1, using the improved MicroX micro-nano CT scanning equipment, carry out core CT scanning experiments, determine the pressure to be the target reservoir pressure of 17.21 MPa, and set the temperature to be the target reservoir temperature of 85°C.

[0133] Figure 3 The physical simulation experimental device of the carbon dioxide recovery and storage technology (CCUS) of the embodiment of the present invention is as follows: Figure 3 As shown, 1 is a distilled water container, 2 is a constant speed constant pressure displacement pump, 3 is a valve, 4 is a formation water intermediate container, 5 is a formation crude oil intermediate container, 6 is an inlet pressure gauge, 7 is a CO2 gas storage tank, 8 is a CO2 buffer gas tank, 9 is a gas booster pump, 10 is a parallel core clamp, 11 is a confining pressure device, 12 is a core CT scanning and collection system, and 13 is an electronic computer.

[0134] Step S101.2, take core samples of three typical permeability points with a length of 20 mm, drill a small part from each core sample, grind it into a size suitable for the CT special core holder (a cylinder with a length of 6 mm and a diameter of 5 mm), and install the rock samples into three special core holders respectively. The core holder needs to be made of characteristic non-metallic materials that can be penetrated by X-rays and can withstand a certain pressure.

[0135] Step S101.3, connect three specially made core holders to the displacement equipment and connect them to the displacement system. Add confining pressure to 3 MPa, seal them with a plug, and perform pressurized dry sample scanning to obtain pore space structure distribution information.

[0136] Step S101.4, remove the clamp from the micro-CT scanning device, reconnect it to the displacement experimental device, and displace at a displacement rate of 0.1mL / min for 5h. The confining pressure of the displacement device is 3MPa, so that the rock pores are saturated with formation water. At a displacement rate of 0.1mL / min, the on-site crude oil dissolved with developer is driven by oil to the outlet without water, so that the rock pores establish initial oil and bound water saturation. After the saturation displacement process is completed, close the outlet valve, inlet valve and confining pressure valve, and use the matching plug to completely seal them so that the core is always kept under confining pressure (3MPa). Turn the CT scanning table under pressure, establish a scanning program, carry out CT scanning, and establish the fluid distribution under the initial saturated oil state.

[0137] Step S101.5, use water to displace oil until the outlet end stops producing oil and the water-to-oil process is completed, and the CT scanning table is turned under pressure to perform scanning imaging again to establish a distribution state diagram of each phase of fluid in the core pore space under the residual oil saturation state.

[0138] Step S101.6, use CO2 to displace until there is no more oil and water output at the outlet, complete the CO2 flooding process, close the outlet valve, inlet valve and confining pressure valve, enter the burial process, and maintain the confining pressure state for 24 hours. Each core holder is transferred to the CT scanning table under pressure, and scanning and imaging are performed again to establish the distribution state diagram of each phase fluid in the pore space of each core at the end of the burial state. Figure 4 This is the core CT scanning result of the CO2 storage end state of the embodiment of the present invention, such as Figure 4 As shown, a multiphase fluid distribution image is displayed, in which the yellow part is the CO2-filled space, the red part is the residual oil, and the blue part is the bound water.

[0139] Step S101.7, according to the density difference, the percentage of CO2, oil and water in the pore space of each core is obtained. The calculation results are shown in Table 1. The percentage of CO2 in the total pore space of the three cores is further obtained, that is, the storage efficiency E S It is 54.6%.

[0140] Table 1 Core CT scanning experiment storage efficiency test results

[0141] Core Permeability / mD <![CDATA[CO2 pore proportion / %]]> Core 1 0.34 41.3 Core 2 0.47 54.9 Core 3 0.69 68.2 Calculated Value 0.50 54.6

[0142] Step S102, determining the core relative permeability curve and oil displacement efficiency. After the experimental core is saturated with water and oil, it is placed in a core holder, and the oil-gas relative permeability curve under the target reservoir pressure is determined according to the industry standard SYT6339-1998 "Non-steady-state method for determining oil-gas relative permeability", and the oil displacement efficiency of each core is recorded. Figure 5 The core oil-gas phase permeability curve test results of the embodiment of the present invention are as follows: Figure 5 As shown in the figure, the average oil recovery efficiency of the three cores is calculated to be the final oil recovery efficiency E D It is 68.5%.

[0143] Furthermore, ro / k rg With S g The semi-logarithmic relationship curve, Figure 6 The core lg (k ro / k rg ) and S g The change relationship curve diagram, such as Figure 6 As shown in the figure, the measured curve is fitted by binomial relationship, and the fitting correlation coefficient reaches 0.9921, so it is judged to be in line with the binomial change relationship. Production dynamic fitting and swept volume calculation are performed based on the binomial relationship.

[0144] Step S103, obtaining the production dynamic index of the target oil reservoir, describing the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage by binomial, and applying the CO2 flooding characteristic curve method to perform data point fitting, recovery factor prediction and reservoir swept volume calculation.

[0145] Step S103.1, collect and organize dynamic and static production data such as target reservoir reserves, daily liquid / oil production, water content, cumulative oil production, gas-oil ratio, etc., and select a stable production stage.

[0146] Step S103.2, lgGOR~N p Semi-logarithmic curve plotting, Figure 7 The target reservoir lgGOR and N p The change relationship curve diagram, such as Figure 7 As shown, binomial fitting is used to obtain the binomial fitting formula: lgGOR = 0.0068N p 2 -0.0238N p +1.8691;

[0147] Step S103.3: Select the limit gas-oil ratio as 5000m 3 / m 3 , calculate the underground output fluid volume ratio corresponding to the limit underground gas-water content, and substitute it into the above fitting formula lgGOR=0.0068N p 2 -0.0238N p +1.8691, the corresponding cumulative oil production, i.e., CO2 flooding recoverable reserves, is 18.28×10 4 t, the ratio of recoverable reserves to geological reserves is the recovery factor

[0148] Step S103.4: Calculate the reservoir swept volume. Calculate the recovery factor E R and oil recovery efficiency E D Reservoir sweep efficiency The product of reservoir sweep efficiency and pore volume is the reservoir sweep volume, that is, V = E V ×Ahφ×10 6 =42.8%×1.96×11×8.2%×10 6 =76.16×10 4 m 3 .

[0149] Step S104: The product of the calculated reservoir swept volume and the burial efficiency measured by the core CT experiment is the reservoir burial volume V. S =ρ CO2 V.E S =0.53×76.16×54.6%×10 4 =22.04×10 4 t.

[0150] Table 2 compares the calculation results of several different methods. It can be seen that the method given by the present invention is similar to the numerical simulation method, and the result of the theoretical formula calculation method is slightly higher, indicating that the overall calculation result of this method is reliable. At the same time, this method eliminates the complex input and modeling process of the numerical simulation method. Based on the results of indoor real core experiments, it can objectively simulate the migration law of CO2 formations and truly reflect the physical properties and storage characteristics of the reservoir. The experimental process has strong operability, controllability and accuracy. The core experiment results can be directly used for the calculation of reservoir-level CO2 storage, and effectively evaluate the storage potential and migration law of CO2 in the reservoir.

[0151] Table 2 Comparison of different methods for calculating CO2 storage in oil reservoirs

[0152] method This method Numerical simulation method Theoretical formula calculation method <![CDATA[Burial amount calculation result / 10 4 t]]> 22.04 21.65 24.57

[0153] The present invention also discloses a reservoir-level carbon dioxide storage calculation system. Figure 8 FIG. 1 is a schematic diagram of a reservoir-level carbon dioxide storage calculation system according to an embodiment of the present invention. Figure 8 As shown, the system includes: a selection unit, a first calculation unit, a judgment unit, a second calculation unit and a third calculation unit; wherein the selection unit is used for the selection, preprocessing and basic physical property determination of the target reservoir layer core; wherein at least 20 target reservoir layer cores are selected, and the core size is 25 mm in diameter and 120 mm in length; the basic physical properties of the cores are measured, including length, diameter, mass, porosity and gas permeability; the preprocessing of the reservoir layer cores includes: after the basic physical property measurement of the cores, at least 3 cores are selected according to the permeability distribution and cut into two sections with a diameter of 25 mm and a length of 100 mm and a diameter of 25 mm and a length of 20 mm; the first calculation unit is used to carry out the pore-scale fluid characterization experiment of the core water flooding-CO2 flooding based on the micro-nano core CT online scanning technology, determine the distribution proportion of different fluids at the pore scale, and calculate the CO2 storage efficiency E S ; Judgment unit, used to determine the core oil-gas phase permeability curve and oil recovery efficiency E D , determine the CO2 flooding stage k ro / k rg With S g The semi-logarithmic relationship curve of the target reservoir satisfies the binomial change relationship; if it does, proceed to the next step; if not, adjust the experimental conditions and retest; the second calculation unit is used to obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, and perform data point fitting and reservoir recovery factor E through binomial. R Prediction and calculation of reservoir swept volume V; The third calculation unit is used to calculate the reservoir swept volume V and CO2 storage efficiency E S Calculate the CO2 storage volume V at the reservoir level S .

[0154] Furthermore, the first calculation unit includes: a setting module, an installation module, a first acquisition module, a first establishment module, a second establishment module, a third establishment module and a first calculation module; wherein the setting module is used to set the pressure and temperature of the micro-nano CT scanning device to the target reservoir pressure and temperature; the installation module is used to drill a small part from the core samples of three typical permeability points respectively, grind them into the size of the rock sample suitable for the CT special core holder, and install them into three special core holders; the first acquisition module is used to connect the three special core holders to the displacement device, connect them to the displacement system, add the set confining pressure, and obtain the pore space structure distribution information; the first establishment module is used to remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, set the displacement parameters, complete the oil-water displacement process, transfer the CT scanning table under pressure, and establish the scanning The scanning program is used to carry out CT scanning work and establish a fluid distribution state diagram under the initial oil saturation state; the second establishment module is used to use water to displace until no oil is produced at the outlet, complete the water-to-oil process, transfer to the CT scanning table under pressure, scan and image again, and establish a distribution state diagram of each phase of fluid in the core pore space under the residual oil saturation state; the third establishment module is used to use CO2 to displace until no oil and water are produced at the outlet, complete the CO2-to-oil process, close all valves, enter the burial process, maintain the confining pressure, transfer each core holder to the CT scanning table under pressure, scan and image again, and establish a distribution state diagram of each phase of fluid in the pore space of each core under the end of burial; the first calculation module is used to obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and calculate the percentage of CO2 in the total pore space of the three cores, which is the burial efficiency E. S .

[0155] Furthermore, the third calculation unit includes: a second acquisition module, a third acquisition module, a second calculation module and a third calculation module; wherein the second acquisition module is used to collect and collate static parameters and production dynamic indicators of the target reservoir; the static parameters include: reservoir reserves, daily liquid / oil production, water content, cumulative oil production and gas-oil ratio; the third acquisition module is used to calculate the cumulative oil production N according to the cumulative oil production N. p and gas-oil ratio GOR, lgGOR~N p Semi-logarithmic curve, using binomial fitting to obtain binomial fitting formula; the second calculation module is used to determine the limit gas-oil ratio GOR m , substituted into the binomial fitting formula, the corresponding cumulative oil production under the limit gas-oil ratio condition is calculated as the recoverable reserves of CO2 flooding, and then the reservoir recovery factor E is calculated. R ; The third calculation module is used to calculate the oil reservoir recovery factor E R and oil recovery efficiency E D Calculate the reservoir sweep efficiency E v , and then calculate the reservoir swept volume V.

[0156] 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, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to 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 protection scope of the present invention.

Claims

1. A method for calculating reservoir-level carbon dioxide storage, characterized in that: The method comprises the following steps: Step S101: Based on the micro-nano core CT online scanning technology, a pore-scale fluid characterization experiment of core water flooding-CO2 flooding is carried out to determine the distribution ratio of different fluids at the pore scale and calculate the CO2 storage efficiency E S ; Step S102: Determine the core oil-gas phase permeability curve and oil displacement efficiency E D , determine the CO2 flooding stage k ro / k rg With S g Check whether the semi-logarithmic relationship curve satisfies the binomial change relationship; if so, proceed to the next step; if not, adjust the experimental conditions and retest; Step S103: Obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, fit the data points through the binomial equation, and calculate the reservoir recovery factor E. R Prediction and calculation of reservoir swept volume V; Step S104: Based on the reservoir swept volume V and CO2 storage efficiency E S Calculate the CO2 storage volume V at the reservoir level S .

2. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 1, characterized in that: The method further comprises the steps of: Step S100, selection, pretreatment and basic physical property measurement of target reservoir layer cores; wherein, at least 20 target reservoir layer cores are selected, and the core size is 25 mm in diameter and 120 mm in length; the basic physical properties of the cores are measured, including length, diameter, mass, porosity and gas permeability; the pretreatment of the reservoir layer cores includes: after the basic physical property measurement of the cores, at least 3 cores are selected according to the permeability distribution and cut into two sections with a diameter of 25 mm and a length of 100 mm and a diameter of 25 mm and a length of 20 mm.

3. A method for calculating reservoir-level carbon dioxide storage according to claim 1 or 2, characterized in that: The step S101, based on the micro-nano core CT online scanning technology, carries out the pore-scale fluid characterization experiment of core water flooding-CO2 flooding, determines the distribution ratio of different fluids at the pore scale, and calculates the CO2 storage efficiency E S , specifically including the following steps: Step S101.1, setting the pressure and temperature of the micro-nano CT scanning device to the target reservoir pressure and temperature; Step S101.2, drilling a small portion from the core samples at three typical permeability points, respectively, grinding them into a size suitable for the CT special core holder, and installing them into three special core holders; Step S101.3, connecting three specially made core holders to the displacement equipment and the displacement system, applying a set confining pressure, and obtaining pore space structure distribution information; Step S101.4, remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, set the displacement parameters, complete the oil-water displacement process, turn the CT scanning table under pressure, establish a scanning program, carry out CT scanning, and establish a fluid distribution state diagram under the initial oil saturation state; Step S101.5, using water to displace oil until the outlet end stops producing oil, completing the water-to-oil process, switching the CT scanning table under pressure, scanning and imaging again, and establishing a distribution state diagram of each phase of fluid in the core pore space under the residual oil saturation state; Step S101.6, using CO2 to displace until no more oil and water are produced at the outlet end, completing the CO2 flooding process, closing all valves, entering the burial process, maintaining the confining pressure, and transferring each core holder to the CT scanning table under pressure, performing scanning imaging again, and establishing a distribution state diagram of each phase fluid in the pore space of each core at the end of the burial state; Step S101.7: Obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and calculate the percentage of CO2 in the total pore space of the three cores to obtain the storage efficiency E. S .

4. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 2, characterized in that: Step S103, obtaining the static parameters and production dynamic indicators of the target reservoir, describing the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establishing the CO2 flooding characteristic curve, fitting the data points through the binomial, and the reservoir recovery factor E R The prediction and calculation of reservoir swept volume V specifically include the following steps: Step S103.1, collect and collate static parameters and production dynamic indicators of the target oil reservoir; the static parameters include: oil reservoir reserves, daily liquid / oil production, water content, cumulative oil production and gas-oil ratio; Step S103.2: According to the cumulative oil production N p and gas-oil ratio GOR, lgGOR~N p For the semi-logarithmic curve graph, binomial fitting is adopted to obtain the binomial fitting formula; Step S103.3: Determine the limit gas-oil ratio GOR m , substituted into the binomial fitting formula, the corresponding cumulative oil production under the limit gas-oil ratio condition is calculated as the recoverable reserves of CO2 flooding, and then the reservoir recovery factor E is calculated. R ; Step S103.4: According to the oil reservoir recovery factor E R and oil recovery efficiency E D Calculate the reservoir sweep efficiency E v , and then calculate the reservoir swept volume V.

5. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 4, characterized in that: In step S103.2, the binomial fitting formula is expressed as: in, Where GOR is gas-oil ratio, unit: m 3 / m 3 ; N p Indicates the cumulative oil production, unit 10 4 t;S wc Indicates bound water saturation, unit: %; γ o Represents the relative density of formation oil; γ g Indicates the relative density of formation gas; μ o Indicates formation oil viscosity, unit: mPa·s; μ g Indicates formation gas viscosity, unit: mPa·s; B o Indicates the oil volume coefficient; B g Indicates gas volume coefficient; N indicates geological reserves, unit 10 4 t; a, b, c, d, e, A, B, C are all calculation coefficients.

6. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 4, characterized in that: In step S103.3, the calculation formula for the recoverable reserves of CO2 flooding is: Where N pm Indicates CO2 flooding recoverable reserves, unit 10 4 t;GOR m Indicates the limit gas-oil ratio, unit: m 3 / m 3 ; A, B, C are all calculation coefficients.

7. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 4, characterized in that: In step S103.4, the calculation formula of the reservoir swept volume V is: V=E V ×Ahφ; in, In the formula, E R Represents oil reservoir recovery rate, unit %; E D Indicates oil recovery efficiency, unit: %; E v represents the reservoir sweep efficiency, in %; V represents the reservoir sweep volume, in m 3 ; A represents the oil-bearing area, unit km 2 ; h is the reservoir depth, unit is m; φ is the porosity, unit is %.

8. The method for calculating reservoir-level carbon dioxide storage capacity according to claim 1, characterized in that: The reservoir-level CO2 storage capacity V S The calculation formula is: V S =V·E S ; Where V S Indicates the calculated oil reservoir storage volume, unit: m 3 ; V represents the reservoir swept volume, unit: m 3 ; E S It indicates the oil reservoir storage efficiency, in %.

9. A reservoir-level carbon dioxide storage calculation system, characterized in that: The system comprises: a first calculation unit, a judgment unit, a second calculation unit and a third calculation unit; wherein, The first calculation unit is used to carry out pore-scale fluid characterization experiments of core water flooding and CO2 flooding based on micro-nano core CT online scanning technology, determine the distribution ratio of different fluids at the pore scale, and calculate the CO2 storage efficiency E S ; Judgment unit, used to determine the core oil-gas phase permeability curve and oil recovery efficiency E D , determine the CO2 flooding stage k ro / k rg With S g Check whether the semi-logarithmic relationship curve satisfies the binomial change relationship; if so, proceed to the next step; if not, adjust the experimental conditions and retest; The second calculation unit is used to obtain the static parameters and production dynamic indicators of the target reservoir, describe the relationship between the gas-oil ratio and the cumulative oil production in the gas emergence stage, establish the CO2 flooding characteristic curve, and perform data point fitting and reservoir recovery factor E through binomial. R Prediction and calculation of reservoir swept volume V; The third calculation unit is used to calculate the oil reservoir swept volume V and CO2 storage efficiency E S Calculate the CO2 storage volume V at the reservoir level S .

10. The reservoir-level carbon dioxide storage calculation system according to claim 9, characterized in that: The system further comprises: a selection unit; The selection unit is used for the selection, pretreatment and basic physical property determination of the cores of the target reservoir layer; wherein, at least 20 cores of the target reservoir layer are selected, and the core size is 25mm in diameter and 120mm in length; the basic physical properties of the cores are measured, including: length, diameter, mass, porosity and gas permeability; the pretreatment of the cores of the reservoir layer includes: after the basic physical property measurement of the cores, at least 3 cores are selected according to the permeability distribution and cut into two sections with a diameter of 25mm and a length of 100mm and a diameter of 25mm and a length of 20mm.

11. The reservoir-level carbon dioxide storage calculation system according to claim 9, characterized in that: The first calculation unit includes: a setting module, an installation module, a first acquisition module, a first establishment module, a second establishment module, a third establishment module and a first calculation module; wherein, A setting module, used to set the pressure and temperature of the micro-nano CT scanning device to the target reservoir pressure and temperature; Installation module, used to drill a small part from the core sample of three typical permeability points, grind it into the size of the rock sample suitable for CT special core holder, and install it into three special core holders; The first acquisition module is used to connect three special core holders to the displacement equipment and the displacement system, add a set confining pressure, and obtain the pore space structure distribution information; The first establishment module is used to remove the special core holder from the micro-nano CT scanning device, reconnect it to the displacement experimental device, set the displacement parameters, complete the oil-water displacement process, transfer the CT scanning table under pressure, establish the scanning program, carry out the CT scanning work, and establish the fluid distribution state diagram under the initial oil saturation state; The second establishment module is used to use water to drive until no more oil is produced at the outlet end, complete the water drive process, transfer the CT scanning table under pressure, perform scanning imaging again, and establish a distribution state diagram of each phase of fluid in the core pore space under the state of residual oil saturation; The third module is used to use CO2 to drive until there is no more oil and water at the outlet, complete the CO2 flooding process, close all valves, enter the burial process, maintain the confining pressure, and transfer each core holder to the CT scanning table under pressure, perform scanning imaging again, and establish the distribution state diagram of each phase fluid in the pore space of each core at the end of the burial state; The first calculation module is used to obtain the percentage of CO2, oil, and water in the pore space of each core according to the density difference, and calculate the percentage of CO2 in the total pore space of the three cores, which is the storage efficiency E. S .

12. The reservoir-level carbon dioxide storage calculation system according to claim 9, characterized in that: The third calculation unit includes: a second acquisition module, a third acquisition module, a second calculation module and a third calculation module; wherein, The second acquisition module is used to collect and collate the static parameters and production dynamic indicators of the target oil reservoir; the static parameters include: oil reservoir reserves, daily liquid / oil production, water content, cumulative oil production and gas-oil ratio; The third acquisition module is used to obtain the total oil production N p and gas-oil ratio GOR, lgGOR~N p For the semi-logarithmic curve graph, binomial fitting is adopted to obtain the binomial fitting formula; The second calculation module is used to determine the limit gas-oil ratio GOR m , substituted into the binomial fitting formula, the corresponding cumulative oil production under the limit gas-oil ratio condition is calculated as the recoverable reserves of CO2 flooding, and then the reservoir recovery factor E is calculated. R ; The third calculation module is used to calculate the oil recovery factor E according to the reservoir recovery factor E. R and oil recovery efficiency E D Calculate the reservoir sweep efficiency E v , and then calculate the reservoir swept volume V.

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