Method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology

Abstract

The invention discloses a heavy oil thermal recovery technology carbon utilization efficiency evaluation method comprising the following steps: 1, data collection and pretreatment: collecting data of petroleum coke production, transportation, treatment and utilization links, and carrying out pretreatment and verification; 2, dynamic coupling modeling is conducted, specifically, a multi-physics field simultaneous model is constructed, and a reaction efficiency function is corrected in real time through reservoir numerical simulation; 3, carbon flow analysis: calculating input carbon flow, effective carbon utilization and lost carbon flow according to the carbon flow analysis matrix, and realizing real-time monitoring in combination with a digital twinborn system; 4, index calculation: calculating total carbon utilization efficiency, primary conversion efficiency and secondary cycle efficiency, and introducing carbon negative potential evaluation; 5, dynamic correction, wherein the total carbon utilization efficiency is dynamically corrected according to the petroleum coke quality coefficient, the system integration degree coefficient and the biomass blending combustion coefficient; and 6, evaluation reference comparison: comparing the calculated total carbon utilization efficiency with an evaluation reference value.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon utilization efficiency, and in particular to a method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology. Background Art

[0002] Heavy oil thermal recovery technology is one of the main means of exploiting heavy oil resources at present, including steam stimulation, steam drive, steam-assisted gravity drainage (SAGD) and fire drive. However, these thermal recovery technologies are usually accompanied by high energy consumption and high carbon emissions. Improving the carbon utilization efficiency of heavy oil thermal recovery technology and reducing carbon emissions have become important challenges facing the petrochemical industry. As an important carbon material in the thermal recovery process of heavy oil, the efficient utilization and low-carbon treatment of petroleum coke are of great significance to the sustainable development of the entire industry. Petroleum coke is a by-product in the oil refining process with high carbon content and low calorific value. Its effective utilization and emission reduction treatment are directly related to the overall carbon utilization efficiency of heavy oil thermal recovery technology. By optimizing heavy oil thermal recovery technology, the utilization efficiency of carbon materials such as petroleum coke can be improved, carbon emissions can be reduced, and green and low-carbon development can be achieved.

[0003] In the traditional evaluation of carbon utilization efficiency of heavy oil thermal recovery technology, a relatively rough evaluation method is usually used. These methods often only focus on the total input and output of carbon, ignoring the conversion and utilization efficiency of carbon in different links and forms. Therefore, a method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology is proposed. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology comprises the following steps: Step 1: Data collection and preprocessing: Collect data on petroleum coke production, transportation, processing and utilization, and perform preprocessing and verification based on the characteristics of biomass raw materials; Step 2: Dynamic coupling modeling: construct a multi-physics field joint model and modify the reaction efficiency function in real time through reservoir numerical simulation; Step 3: Carbon flow analysis: Calculate input carbon flow, effective carbon utilization and loss carbon flow based on the carbon flow analysis matrix, and realize real-time monitoring in combination with the digital twin system; Step 4: Indicator calculation: calculate the total carbon utilization efficiency (CUE), primary conversion efficiency, secondary cycle efficiency, and introduce carbon negative potential assessment; Step 5: Dynamic correction: Dynamically correct the total carbon utilization efficiency according to the petroleum coke quality coefficient, system integration coefficient and biomass blending coefficient; Step 6: Comparison of evaluation benchmarks: Compare the calculated total carbon utilization efficiency with the evaluation benchmark value to evaluate the advantages and disadvantages of the technical route.

[0006] The above further includes: Further, in Step 2, the specific steps of the dynamic coupling modeling are as follows: Determine the basic framework of the model: Determine the basic framework of the multi-physics field simultaneous model, including mass conservation, energy conservation, and momentum conservation. For carbon flow analysis, mainly focus on the mass conservation equation, that is, the input, reaction consumption, and output of carbon elements in the system; Establish the carbon flow change rate equation: According to the principle of mass conservation, establish the carbon flow change rate equation, which describes the change rate of carbon elements in the system over time, including the input carbon flow, reaction consumption carbon flow, and diffusion loss carbon flow. The calculation formula is expressed as , where, is the carbon concentration in the system, is time, is the input carbon flow, is the input coefficient, is the change of the input carbon flow over time, is the reaction consumption carbon flow, is the reaction coefficient, is the temperature-pressure correlation reaction efficiency function, is the carbon concentration participating in the reaction, is the diffusion loss carbon flow, is the diffusion coefficient, is the carbon concentration gradient; Determine the reaction efficiency function: The reaction efficiency function is a function of temperature and pressure , and is determined through reservoir numerical simulation. The reaction efficiency function describes the efficiency of carbon elements participating in the reaction under different temperature and pressure conditions. The following reaction efficiency function is obtained through reservoir numerical simulation, and the calculation formula is expressed as , where, is the activation energy, set to 50 kJ / mol, is the gas constant, 8.314 J / (mol·K), is the temperature, in units of K, is the critical pressure, assumed to be 10 MPa, is the system pressure, in units of MPa; Simultaneously solve the carbon flow change rate equation: Substitute the real-time corrected reaction efficiency function into the carbon flow change rate equation, and combine the data of the input carbon flow and the diffusion loss carbon flow to simultaneously solve this equation to obtain the change of the carbon concentration in the system over time.

[0007] Furthermore, the formula for calculating the input carbon flow is expressed as , where is the carbon content of the i-th carbon source, is the quantity of the i-th carbon source.

[0008] Furthermore, the formula for calculating the effective carbon utilization is expressed as , where is the energy or carbon quantity of the i-th effective carbon utilization method, is the carbon utilization efficiency of the i-th method.

[0009] Furthermore, the formula for calculating the lost carbon flow is expressed as , where is the quantity of the i-th lost carbon flow.

[0010] Furthermore, the specific steps to achieve real-time monitoring by integrating with the digital twin system are as follows: Deploy monitoring equipment: Deploy a distributed optical fiber temperature measurement + LIBS spectroscopy combined device underground and on the ground to achieve synchronous monitoring of carbon flow; Establish a digital twin: Use the monitoring data to establish a digital twin of the three-field coupling of carbon flow - heat flow - oil flow, with the error controlled within < 3%; Real-time monitoring and data analysis: Through the digital twin system, monitor the changes in input carbon flow, effective carbon utilization, and lost carbon flow in real time, conduct real-time analysis of the monitoring data, and promptly detect carbon flow anomalies to provide a basis for system optimization.

[0011] Furthermore, the formula for calculating the total carbon utilization efficiency is expressed as , where is the input carbon flow, is the effective carbon utilization. The formula for calculating the primary conversion efficiency is expressed as . The target value of the primary conversion efficiency is ≥ 95%. Among them, is the gasification carbon conversion rate, is the combustion efficiency. The formula for calculating the secondary circulation efficiency is expressed as . The target value of the secondary circulation efficiency is > 70%. Among them, is the CO 2 capture rate, is the storage utilization rate. By evaluating the carbon negative potential, quantify its actual effect on carbon emission reduction in terms of calculating its contribution rate to carbon emission reduction, calculate its contribution rate to carbon emission reduction, and the biomass co-firing ratio and the contribution rate of biomass directional negative carbon technology are equal to the carbon negative potential.

[0012] Furthermore, the formula for calculating the petroleum coke quality coefficient is expressed as , where is the S content of the petroleum coke, is the ash fusion temperature, is the operating temperature, and the system integration coefficient is . The system integration coefficient is determined according to the system type, taking 1.3 for the gasification - power generation - oil displacement combined heat and power system, 1.2 for the microwave - assisted in - situ catalytic upgrading system, and 0.7 for the single steam generation system. The calculation formula for the biomass co - firing coefficient is expressed as , where is the biomass co - firing ratio, and the calculation formula after dynamically correcting the total carbon utilization efficiency is expressed as .

[0013] The present invention has the following beneficial effects: In the present invention, while calculating the total carbon utilization efficiency (CUE), the grading index is upgraded, and the primary conversion efficiency, secondary circulation efficiency, and system efficiency - increasing coefficient are added, making the evaluation more detailed and in - depth. Through the multi - physical - field coupling model and the digital twin carbon flow tracking system, real - time monitoring and dynamic correction of the carbon flow are achieved, improving the accuracy and timeliness of the evaluation. The total carbon utilization efficiency is dynamically corrected according to the petroleum coke quality coefficient, system integration coefficient, and biomass co - firing coefficient. Among them, the biomass co - firing coefficient helps to evaluate the impact of biomass co - firing on the carbon utilization efficiency and provides a scientific basis for optimizing the co - firing ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a step diagram of a method for evaluating the carbon utilization efficiency of heavy oil thermal recovery technology proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] Please refer to Figure 1 shown. The present invention is a method for evaluating the carbon utilization efficiency of heavy oil thermal recovery technology, including the following steps: Step 1: Data collection and pre - processing: Collect data on the production, transportation, processing, and utilization of petroleum coke, and perform pre - processing and verification in combination with the characteristics of biomass raw materials; Step 2: Dynamic coupling modeling: Construct a multi - physical - field coupling model and real - time correct the reaction efficiency function through reservoir numerical simulation; Step 3: Carbon flow analysis: Calculate the input carbon flow, effective carbon utilization, and loss carbon flow according to the carbon flow analysis matrix, and achieve real - time monitoring in combination with the digital twin system; Step 4: Index calculation: Calculate the total carbon utilization efficiency (CUE), primary conversion efficiency, and secondary cycle efficiency, and introduce the evaluation of carbon negative potential; Step 5: Dynamic correction: Dynamically correct the total carbon utilization efficiency according to the petroleum coke quality coefficient, system integration coefficient, and biomass co-firing coefficient; Step 6: Comparison with the evaluation benchmark: Compare the calculated total carbon utilization efficiency with the evaluation benchmark value to evaluate the advantages and disadvantages of the technical route.

[0017] In one embodiment, in Step 2, the specific steps of the dynamic coupling modeling are as follows: Determine the basic framework of the model: Determine the basic framework of the multi-physical field coupling model, including mass conservation, energy conservation, and momentum conservation. For carbon flow analysis, mainly focus on the mass conservation equation, that is, the input, reaction consumption, and output of carbon elements in the system; Establish the carbon flow rate change equation: According to the principle of mass conservation, establish the carbon flow rate change equation, which describes the change rate of carbon elements in the system over time, including input carbon flow, reaction consumption carbon flow, and diffusion loss carbon flow. The calculation formula is expressed as , where is the carbon concentration in the system, is time, is the input carbon flow, is the input coefficient, is the change of the input carbon flow over time, is the reaction consumption carbon flow, is the reaction coefficient, is the temperature-pressure correlation reaction efficiency function, is the carbon concentration participating in the reaction, is the diffusion loss carbon flow, is the diffusion coefficient, is the carbon concentration gradient; Determine the reaction efficiency function: The reaction efficiency function is a function of temperature and pressure , and is determined by reservoir numerical simulation. The reaction efficiency function describes the efficiency of carbon elements participating in reactions under different temperature and pressure conditions. The following reaction efficiency function is obtained through reservoir numerical simulation, and the calculation formula is expressed as , where is the activation energy, set to 50 kJ / mol, is the gas constant, 8.314 J / (mol·K), is the temperature, in units of K, is the critical pressure, assumed to be 10 MPa, is the system pressure, in units of MPa; Simultaneously solve the carbon flow rate equation: Substitute the reaction efficiency function corrected in real time into the carbon flow rate equation, and combine the data of the input carbon flow and the diffusive loss carbon flow to simultaneously solve the equation to obtain the change of carbon concentration in the system over time.

[0018] In one embodiment, the calculation formula for the input carbon flow is expressed as , where is the carbon content of the i-th carbon source, is the quantity of the i-th carbon source. Assuming that the fixed carbon content of petroleum coke is 85% and the output is 1000 tons, the input carbon flow of petroleum coke is 85%×1000 = 850 tons of carbon. The consumption of auxiliary fuel carbon (natural gas) is 50000 cubic meters. Assuming its carbon content is 75% (calculated based on methane), the input carbon flow of natural gas is 50000×0.75×12 / 22.4 ≈ 20089.29 tons of carbon (here, cubic meters are converted to moles and then multiplied by the molar mass of carbon). The fixed carbon content of biomass carbon (Cyperus esculentus-based biochar) is 70% and the output is 200 tons, so the input carbon flow of biomass is 70%×200 = 140 tons of carbon. The carbon of process consumables (catalyst consumption) is assumed to be 10 tons with a carbon content of 5%, so the input carbon flow of process consumables is 10×5% = 0.5 tons of carbon. Total input carbon flow: = 850 + 20089.29 + 140 + 0.5 ≈ 21079.79 tons of carbon.

[0019] In one embodiment, the calculation formula for the effective carbon utilization is expressed as , where is the energy or carbon quantity of the i-th effective carbon utilization method, is the carbon utilization efficiency of the i-th method. The effective calorific value carbon for displacing heavy oil: Suppose 10000 tons of crude oil are displaced, and the effective calorific value carbon per ton of crude oil is 0.8 tons of carbon (assumed value), then the effective calorific value carbon for displacing heavy oil is 10000×0.8 = 8000 tons of carbon. The carbon equivalent of electricity output: Suppose the electricity output is 10000 MWh, and the carbon equivalent per MWh of electricity is 0.5 tons of carbon (assumed value), then the carbon equivalent of electricity output is 10000×0.5 = 5000 tons of carbon. The carbon sequestration quantity: Suppose the CO 2 -EOR sequestration rate is 70%, and the carbon quantity available for sequestration in the input carbon flow is 2000 tons (assumed value), then the carbon sequestration quantity is 2000×70% = 1400 tons of carbon. The carbon conversion rate of methanol synthesis: Suppose the carbon conversion rate of CO 2 hydrogenation to methanol is 85%, and the carbon quantity available for methanol synthesis in the input carbon flow is 1000 tons (assumed value), then the carbon utilization quantity of methanol synthesis is 1000×85% = 850 tons of carbon. Total effective carbon utilization: = 8000 + 5000 + 1400 + 850 = 15250 tons of carbon.

[0020] In one embodiment, the formula for calculating the loss carbon flow is expressed as , where is the amount of the i-th type of loss carbon flow. Unconverted residual carbon: Assuming the carbon content in the ash is 5% and the ash output is 100 tons, the unconverted residual carbon is 100 × 5% = 5 tons of carbon. Escaped carbon emissions: Assume that the total escaped carbon emissions such as CH 4 , VOCs, etc. are 10 tons of carbon. Carbon leakage amount of the system: Assume that the carbon leakage amount of the pipeline / equipment is 5 tons of carbon. Total loss carbon flow: = 5 + 10 + 5 = 20 tons of carbon.

[0021] In one embodiment, the specific steps for realizing real-time monitoring by combining with the digital twin system are as follows: Deploy monitoring equipment: Deploy a distributed optical fiber temperature measurement + LIBS spectroscopy combined device underground and on the ground to realize synchronous monitoring of the carbon flow; Establish a digital twin body: Use the monitoring data to establish a digital twin body of the three-field coupling of carbon flow - heat flow - oil flow, with the error controlled within < 3%; Real-time monitoring and data analysis: Through the digital twin system, real-time monitor the changes in the input carbon flow, effective carbon utilization, and loss carbon flow, conduct real-time analysis of the monitoring data, promptly detect carbon flow anomalies, and provide a basis for system optimization.

[0022] In one embodiment, the formula for calculating the total carbon utilization efficiency is expressed as , where is the input carbon flow, is the effective carbon utilization. The formula for calculating the primary conversion efficiency is expressed as . The target value of the primary conversion efficiency: ≥ 95%, where is the gasification carbon conversion rate, is the combustion efficiency. The formula for calculating the secondary cycle efficiency is expressed as . The target value of the secondary cycle efficiency: > 70%, where is the CO 2 capture rate, is the storage utilization rate. By evaluating the carbon negative potential, quantify and calculate its actual effect on carbon emission reduction in terms of the contribution rate to carbon emission reduction, calculate its contribution rate to carbon emission reduction, and the biomass co-firing ratio and the contribution rate of the biomass directional negative carbon technology are equal to the carbon negative potential.

[0023] In one embodiment, the formula for calculating the petroleum coke quality coefficient is expressed as , where is the S content of the petroleum coke, is the ash fusion point, is the operating temperature, and the system integration coefficient is , the system integration coefficient is determined according to the system type, taking 1.3 for the gasification - power generation - oil displacement combined heat and power system, 1.2 for the microwave - assisted in - situ catalytic upgrading system, and 0.7 for the single steam generation system. The calculation formula for the biomass co - firing coefficient is expressed as , where is the biomass co - firing ratio, and the calculation formula after dynamically correcting the total carbon utilization efficiency is expressed as .

[0024] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology, characterized in that: The following steps are involved: Step 1: Data collection and preprocessing: Collect data on petroleum coke production, transportation, processing and utilization, and perform preprocessing and verification based on the characteristics of biomass raw materials; Step 2: Dynamic coupling modeling: construct a multi-physics field joint model and modify the reaction efficiency function in real time through reservoir numerical simulation; Step 3: Carbon flow analysis: Calculate input carbon flow, effective carbon utilization and loss carbon flow based on the carbon flow analysis matrix, and realize real-time monitoring in combination with the digital twin system; Step 4: Indicator calculation: calculate the total carbon utilization efficiency, primary conversion efficiency, secondary cycle efficiency, and introduce carbon negative potential assessment; Step 5: Dynamic correction: Dynamically correct the total carbon utilization efficiency according to the petroleum coke quality coefficient, system integration coefficient and biomass blending coefficient; Step 6: Evaluation benchmark comparison: Compare the calculated total carbon utilization efficiency with the evaluation benchmark value to evaluate the advantages and disadvantages of the technical route.

2. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: In step 2, the specific steps of the dynamic coupling modeling are: Determine the basic framework of the model: Determine the basic framework of the multi-physics field model, including conservation of mass, conservation of energy and conservation of momentum. For carbon flow analysis, focus on the mass conservation equation, that is, the input, reaction consumption and output of carbon elements in the system; Establish the carbon flow rate equation: According to the principle of mass conservation, establish the carbon flow rate equation, which describes the rate of change of carbon elements in the system over time, including input carbon flow, reaction consumption carbon flow and diffusion loss carbon flow. The calculation formula is expressed as ,in, is the carbon concentration in the system, It's time. is the input carbon flow, is the input coefficient, is the variation of input carbon flow over time, is the carbon flow consumed by the reaction, is the reaction coefficient, is the temperature-pressure related reaction efficiency function, is the carbon concentration involved in the reaction, is the diffusion loss carbon flow, is the diffusion coefficient, is the carbon concentration gradient; Determine the reaction efficiency function: Reaction efficiency function It is the temperature and pressure The reaction efficiency function is determined by reservoir numerical simulation. The reaction efficiency function describes the efficiency of carbon participating in the reaction under different temperature and pressure conditions. The following reaction efficiency function is obtained by reservoir numerical simulation. The calculation formula is expressed as ,in, is the activation energy, is the gas constant, is the temperature in K, is the critical pressure, is the system pressure in MPa; Solve the carbon flow rate equation by simultaneous calculation: Substitute the real-time corrected reaction efficiency function into the carbon flow rate equation, combine the input carbon flow and diffusion loss carbon flow data, and solve the equation by simultaneous calculation to obtain the change of carbon concentration in the system over time.

3. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: The input carbon flow calculation formula is expressed as ,in, is the carbon content of the ith carbon source, is the quantity of the ith carbon source.

4. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: The calculation formula for effective carbon utilization is expressed as: ,in, is the energy or carbon content of the ith effective carbon utilization mode, is the carbon utilization efficiency of the ith mode.

5. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: The loss carbon flow calculation formula is expressed as: ,in, is the amount of the i-th lost carbon flow.

6. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: The specific steps of combining the digital twin system to achieve real-time monitoring are: Deploy monitoring equipment: deploy distributed optical fiber temperature measurement + LIBS spectroscopy devices underground and on the ground to achieve synchronous monitoring of carbon flow; Establish digital twin: Use monitoring data to establish a digital twin of carbon flow, heat flow and oil flow; Real-time monitoring and data analysis: Through the digital twin system, the changes in input carbon flow, effective carbon utilization and lost carbon flow can be monitored in real time.

7. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 1, characterized in that: The total carbon utilization efficiency calculation formula is expressed as: ,in, is the input carbon flow, is the effective carbon utilization, and the primary conversion efficiency calculation formula is expressed as ,in, is the gasification carbon conversion rate, is the combustion efficiency, and the secondary cycle efficiency calculation formula is expressed as ,in, is the CO2 capture rate, It is the storage utilization rate. By evaluating the carbon negative potential, its contribution rate to carbon emission reduction is quantified and its actual effect in reducing carbon emissions is calculated. Its contribution rate to carbon emission reduction is calculated. The biomass blending ratio and the contribution rate of biomass targeted negative carbon technology are equal to the carbon negative potential.

8. The method for evaluating carbon utilization efficiency of heavy oil thermal recovery technology according to claim 7, characterized in that: The petroleum coke quality coefficient calculation formula is expressed as: ,in, is the S content of petroleum coke, is the ash melting point, is the operating temperature, the system integration factor is The system integration coefficient is determined according to the system type. The gasification-power generation-oil recovery trigeneration system takes 1.3, the microwave-assisted in-situ catalytic reforming system takes 1.2, and the single steam generation system takes 0.

7. The calculation formula of the biomass blending coefficient is expressed as follows: ,in, is the biomass blending ratio, and the calculation formula for the total carbon utilization efficiency after dynamic correction is expressed as .

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