Method for analyzing characteristic values of overpressure in combustible gas explosions at offshore oil and gas production facilities

Abstract

This invention relates to a method, apparatus, medium, and equipment for analyzing the overpressure characteristic values ​​of combustible gas explosions in marine oil and gas production facilities. The analysis method includes the following steps: geometrically modeling the marine oil and gas production facility; calculating the congestion degree of the process area of ​​the marine oil and gas production facility; calculating the volume of the combustible gas cloud under different filling ratios in the process area of ​​the marine oil and gas production facility; performing transient CFD simulations of combustible gas explosions with varying gas cloud positions and ignition positions to obtain the overpressure value of the protected target changing over time; determining the maximum overpressure value of the protected target under combustible gas explosion conditions; expanding the sample and performing statistical analysis and characteristic value calculations to obtain probability density curves and characteristic values; and determining the explosion-proof level of the protected target according to protection requirements.

Description

Technical Field

[0001] This invention relates to an analytical method for the overpressure characteristic values ​​of combustible gas explosions in marine oil and gas production facilities, belonging to the field of marine oil safety production technology. Background Technology

[0002] With the development of my country's offshore oil and gas industry, offshore oil and gas production facilities are becoming increasingly complex and large-scale, with ever-expanding processing capacity and more concentrated equipment. Combustible gas leaks and explosions pose a significant risk that offshore oil and gas production facilities must address, seriously threatening the safety of these facilities and personnel. Assessing the severity of combustible gas explosions and subsequently strengthening the protective design of key targets is crucial for improving the safety level of offshore oil and gas production facilities. Therefore, during the planning and design phase of large-scale offshore oil and gas production facilities, it is necessary to design the blast resistance level of key protected targets within the facility, i.e., determining the minimum blast resistance strength of key protected targets (such as blast walls).

[0003] The current main approach is to simulate the consequences of accidents under the most severe or credible operating conditions to determine the explosion resistance requirements of the protected target. However, this approach has certain shortcomings: 1. It does not reflect the impact of different ignition locations and cloud locations on the explosion consequences; 2. It cannot reveal the overall pattern of overpressure induced by the explosion, i.e., it cannot reflect the statistical patterns of explosion overpressure across the entire offshore oil and gas production facility, thus failing to inform design decisions; 3. The results obtained by this method are often overly conservative, leading to wasted investment and operating costs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for analyzing the overpressure characteristics of combustible gas explosions in marine oil and gas production facilities.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for analyzing the overpressure characteristics of combustible gas explosions in marine oil and gas production facilities includes the following steps:

[0007] Geometric modeling based on offshore oil and gas production facilities;

[0008] Calculate the congestion level of the process area of ​​offshore oil and gas production facilities;

[0009] Based on geometric modeling and congestion, the volume of combustible gas clouds under different filling ratios in the process area of ​​offshore oil and gas production facilities is calculated.

[0010] Based on the volume of combustible gas clouds with different filling ratios, transient CFD simulations of combustible gas explosions with varying gas cloud positions and ignition locations were performed to obtain the overpressure value of the protected target as a function of time.

[0011] Based on the curve of overpressure value of the protected target changing over time, the maximum overpressure value of the protected target under the condition of combustible gas explosion is determined.

[0012] Based on the maximum overpressure value of the protected target under combustible gas explosion conditions, the sample was expanded, and statistical analysis and eigenvalue calculation were performed to obtain the probability density curve and eigenvalues.

[0013] Based on probability density curves and eigenvalues, the explosion-proof level of the protected target is determined according to protection requirements.

[0014] The aforementioned analysis method, preferably, involves geometric modeling based on offshore oil and gas production facilities, and the specific process is as follows:

[0015] Based on the overall layout plan and equipment list of the offshore oil and gas production facility, a full-size geometric model of the offshore oil and gas production facility is established.

[0016] The aforementioned analysis method, preferably, calculates the congestion degree of the process area of ​​offshore oil and gas production facilities, and the specific process is as follows:

[0017] Based on the overall layout plan of offshore oil and gas production facilities and the geometric dimensions of mechanical equipment in the equipment list, the congestion level of the process area of ​​offshore oil and gas production facilities is estimated:

[0018] First, calculate the total volume of the entire process area. Then, calculate the volume of the equipment within the process area. Finally, calculate the congestion level, which is the proportion of the equipment volume within the process area to the total volume of the space.

[0019] The analysis method, preferably, calculates the volume of combustible gas clouds in the process area of ​​marine oil and gas production facilities under different filling ratios based on geometric modeling and congestion degree, wherein the filling ratios include at least 5%, 10%, 20%, 40%, 60%, and 75%.

[0020] The preferred method of analysis involves performing transient CFD simulations of combustible gas explosions with varying gas cloud positions and ignition positions based on the volume of combustible gas clouds at different filling ratios. This yields the curve of the overpressure value of the protected target changing over time. During this process, gas clouds are evenly distributed at the ignition positions, and the number of positions where the gas clouds change is at least five. The position of the gas clouds depends on their volume, and the cumulative total must cover the entire process area.

[0021] The analytical method, preferably, determines the maximum overpressure value of the protected target under combustible gas explosion conditions based on the overpressure value change curve of the protected target over time. The explosion conditions refer to the determined gas volume filling ratio, the determined position of the isochemical equivalent gas cloud, and the determined ignition position.

[0022] The aforementioned analysis method, preferably, involves expanding the sample based on the maximum overpressure value of the protected target under combustible gas explosion conditions, and performing statistical analysis and eigenvalue calculation to obtain the probability density curve and eigenvalues. The specific process is as follows:

[0023] The sample expansion method for different explosion overpressures under the same filling ratio linearly expands the values ​​from the explosion simulation value to the larger and smaller values ​​respectively, and finally forms 9 sample points. First, sample expansion and eigenvalue estimation are performed under the same filling ratio, and then the overall eigenvalue estimation is performed.

[0024] Based on the above analysis method, a second aspect of the present invention provides an analysis apparatus, comprising:

[0025] The first processing unit is used to perform geometric modeling based on offshore oil and gas production facilities;

[0026] The second processing unit is used to calculate the congestion level of the process area of ​​offshore oil and gas production facilities.

[0027] The third processing unit is used to calculate the volume of combustible gas clouds under different filling ratios in the process area of ​​marine oil and gas production facilities based on geometric modeling and congestion.

[0028] The fourth processing unit is used to perform transient simulations of combustible gas explosions with varying gas cloud positions and ignition positions based on the volume of combustible gas clouds with different filling ratios, and to obtain the curve of overpressure value of the protected target changing over time.

[0029] The fifth processing unit is used to determine the maximum overpressure value of the protected target under combustible gas explosion conditions based on the overpressure value of the protected target changing over time.

[0030] The sixth processing unit is used to expand the sample based on the maximum overpressure value of the protected target under the combustible gas explosion condition, and to perform statistical analysis and eigenvalue calculation to obtain the probability density curve and eigenvalue.

[0031] The seventh processing unit is used to determine the explosion-proof level of the protected target based on the probability density curve and eigenvalues, according to the protection requirements.

[0032] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described analysis method.

[0033] A fourth aspect of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described analysis method.

[0034] The present invention has the following advantages due to the adoption of the above technical solutions:

[0035] 1. The analytical method of the present invention is based on the volume of combustible gas clouds under different filling ratios, and performs transient simulation of combustible gas explosion with varying gas cloud positions and ignition positions. The gas clouds are evenly distributed at the ignition positions, and there are at least 5 positions where the gas clouds change. The position of the gas clouds depends on the volume of the clouds, and the cumulative total needs to cover the entire process area. This method can reflect the influence of different ignition positions and cloud positions on the explosion consequences.

[0036] 2. The analytical method of this invention can reveal the overall law of overpressure caused by explosion and reflect the statistical law of explosion overpressure in the entire marine oil and gas production facility. This method can avoid the waste of investment and operating costs. Attached Figure Description

[0037] Figure 1 A calculation process for the overpressure characteristic value of combustible gas explosion in marine oil and gas production facilities, provided in an embodiment of the present invention.

[0038] Figure 2 This embodiment of the invention provides simulated values ​​and sample augmentation values ​​for different maximum overpressures under the same cloud volume;

[0039] Figure 3 The distribution histogram and probability density curve of the overpressure of the protected target caused by the explosion of combustible gas provided in this embodiment of the present invention are shown. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] This invention addresses the shortcomings of current main explosion-proof methods, which simulate accident consequences based on the most severe or credible operating conditions to determine the explosion-proof requirements of the protected target. It proposes an analytical method for the overpressure characteristic values ​​of combustible gas explosions in marine oil and gas production facilities. This method, based on the volume of combustible gas clouds under different filling ratios, performs transient simulations of combustible gas explosions with varying gas cloud positions and ignition points. The gas clouds are evenly distributed at the ignition points, with at least five different gas cloud positions. The position of the gas clouds depends on their volume, and the cumulative total must cover the entire process area. This method can reflect the impact of different ignition and cloud positions on the explosion consequences.

[0042] like Figure 1 As shown, the method for analyzing the overpressure characteristic values ​​of combustible gas explosions in marine oil and gas production facilities provided by this invention includes the following specific steps:

[0043] Step 1: Geometric modeling of offshore oil and gas production facilities:

[0044] Based on the overall layout plan and equipment list of the offshore oil and gas production facility, establish a full-size geometric model of the facility. For larger offshore oil and gas production facilities, only the full-size geometric model of the process area needs to be established.

[0045] Step 2: Calculation of congestion in the process area of ​​offshore oil and gas production facilities:

[0046] Based on the overall layout plan of the offshore oil and gas production facilities and the geometric dimensions of the mechanical equipment in the equipment list, the congestion degree of the process area of ​​the offshore oil and gas production facilities is estimated. First, the spatial volume of the entire process area is calculated: for the lower and middle decks of the offshore platform, the spatial volume of the upper and lower decks containing the process area is the spatial volume of the process area; for the upper deck of the offshore platform, the height of the process area is determined by the highest point of the equipment, and then the volume of the entire process area is calculated. Next, the equipment volume within the process area is calculated: using the geometric dimensions of the equipment in the equipment list, the total volume of the equipment and facilities within the process area is estimated, and then the congestion degree, i.e., the proportion of the equipment volume within the spatial area to the total spatial volume, is calculated.

[0047] Step 3: Calculation of the volume of combustible gas used for filling the process area of ​​offshore oil and gas production facilities:

[0048] Using the geometric dimensions of the process area of ​​the offshore oil and gas production facility, and combining this with the congestion level of the process area calculated in step 2, calculate the volume of combustible gas clouds under different filling ratios. The calculated filling ratios should include at least 5%, 10%, 20%, 40%, 60%, and 75%.

[0049] Step 4: Simulation of a combustible gas explosion with varying gas cloud positions and ignition points:

[0050] Using the stoichiometric cuboid cloud volumes obtained in step 3 at different filling ratios, transient CFD simulations of combustible gas explosions with varying cloud locations and ignition points were conducted in the offshore oil process facility area. The ignition points should be uniformly distributed among the gas clouds, with at least five varying locations; the cloud locations are determined based on the cloud volume, and the cumulative total should cover the entire process area.

[0051] Step 5: Extracting the overpressure value of the protected target:

[0052] Extract the curve of overpressure value versus time obtained in step 4 for the sensitive target protection target, and determine the maximum overpressure value of the sensitive target protection target under a certain combustible gas explosion condition (determined gas volume filling ratio, determined position of equivalent gas cloud and determined ignition position).

[0053] Step 6: Statistical analysis and characteristic value estimation of overpressure on protected targets caused by flammable gas explosion:

[0054] Using the maximum overpressure values ​​of explosions at different gas cloud locations and ignition locations under the same filling ratio obtained in step 5, the sample was expanded, and statistical analysis and eigenvalue calculation were performed. The method for expanding the sample of different explosion overpressures under the same filling ratio was to linearly expand from the explosion simulation value to the nearest value, ultimately forming 9 sample points. Figure 2 This section presents the sample point values ​​after sample expansion for different explosion overpressures of combustible gas cloud volumes under the same filling ratio. First, sample expansion and eigenvalue estimation are performed under the same filling ratio. Then, overall eigenvalue estimation is performed. The eigenvalue estimation method assumes that the overpressure values ​​under the same filling ratio follow a BETA distribution, i.e., the sample points follow a BETA distribution. Parameter estimation is performed using the sample points as statistical sampling data to calculate the expected value and probability density curves under the same filling ratio; the expected value is the eigenvalue under the same filling ratio. The estimation of the overall explosion overpressure eigenvalue is similar to the calculation of the eigenvalue under the same filling ratio, assuming that all explosion overpressure values ​​follow a BETA distribution, and then parameter estimation and eigenvalue (expected value) calculation are performed. Figure 3 Histograms and probability density curves of the explosion overpressure values ​​obtained for parameter estimation and eigenvalue (expectation) calculation.

[0055] Step 7: Determine the explosion-proof rating of the target object based on the protection requirements:

[0056] Based on the probability density curve of the overpressure value of the protected target obtained in step 6, and in conjunction with the requirements of the offshore oil and gas production facility construction unit, the explosion protection level of the protected target is determined. For example, if the protection requirement of a certain offshore oil and gas production facility construction unit is that a certain protected target can withstand more than 80% of the explosive overpressure, then the explosive overpressure value corresponding to a cumulative probability of 80% is selected as the minimum design explosion overpressure load according to the probability density curve.

[0057] Based on the above analysis method, a second aspect of the present invention provides an analysis apparatus, comprising:

[0058] The first processing unit is used to perform geometric modeling based on offshore oil and gas production facilities;

[0059] The second processing unit is used to calculate the congestion level of the process area of ​​offshore oil and gas production facilities.

[0060] The third processing unit is used to calculate the volume of combustible gas clouds under different filling ratios in the process area of ​​marine oil and gas production facilities based on geometric modeling and congestion.

[0061] The fourth processing unit is used to perform transient CFD simulation of combustible gas explosion with varying gas cloud positions and ignition positions based on the volume of combustible gas clouds with different filling ratios, and to obtain the curve of overpressure value of the protected target changing over time.

[0062] The fifth processing unit is used to determine the maximum overpressure value of the protected target under combustible gas explosion conditions based on the overpressure value of the protected target changing over time.

[0063] The sixth processing unit is used to expand the sample based on the maximum overpressure value of the protected target under the combustible gas explosion condition, and to perform statistical analysis and eigenvalue calculation to obtain the probability density curve and eigenvalue.

[0064] The seventh processing unit is used to determine the explosion-proof level of the protected target based on the probability density curve and eigenvalues, according to the protection requirements.

[0065] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described analysis method.

[0066] A fourth aspect of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described analysis method.

[0067] This invention is described based on flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to specific embodiments. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowcharts and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0068] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for analyzing the overpressure characteristics of combustible gas explosions in marine oil and gas production facilities, characterized in that, Includes the following steps: Geometric modeling based on offshore oil and gas production facilities; Calculate the congestion level of the process area of ​​offshore oil and gas production facilities; Based on geometric modeling and congestion, the volume of combustible gas clouds under different filling ratios in the process area of ​​offshore oil and gas production facilities is calculated. Based on the volume of combustible gas clouds with different filling ratios, transient simulations of combustible gas explosions with varying gas cloud positions and ignition locations were performed to obtain the overpressure value of the protected target as a function of time. Based on the curve of overpressure value of the protected target changing over time, the maximum overpressure value of the protected target under the condition of combustible gas explosion is determined. Based on the maximum overpressure value of the protected target under combustible gas explosion conditions, the sample was expanded, and statistical analysis and eigenvalue calculation were performed to obtain the probability density curve and eigenvalues. Based on probability density curves and eigenvalues, the explosion-proof level of the protected target is determined according to protection requirements.

2. The analytical method according to claim 1, characterized in that, The specific process of geometric modeling based on offshore oil and gas production facilities is as follows: Based on the overall layout plan and equipment list of the offshore oil and gas production facility, a full-size geometric model of the offshore oil and gas production facility is established.

3. The analytical method according to claim 1, characterized in that, The specific process for calculating the congestion level of the process area of ​​offshore oil and gas production facilities is as follows: Based on the overall layout plan of offshore oil and gas production facilities and the geometric dimensions of mechanical equipment in the equipment list, the congestion level of the process area of ​​offshore oil and gas production facilities is estimated: First, calculate the total volume of the entire process area. Then, calculate the volume of the equipment within the process area. Finally, calculate the congestion level, which is the proportion of the equipment volume within the process area to the total volume of the space.

4. The analytical method according to claim 1, characterized in that, Based on geometric modeling and congestion, the volume of combustible gas clouds in the process area of ​​offshore oil and gas production facilities is calculated under different filling ratios, including at least 5%, 10%, 20%, 40%, 60%, and 75%.

5. The analytical method according to claim 1, characterized in that, Based on the volume of combustible gas clouds with different filling ratios, transient CFD simulations of combustible gas explosions with varying gas cloud positions and ignition positions are performed to obtain the overpressure value of the protected target changing over time. During this process, gas clouds are evenly distributed at the ignition positions, and the positions of the gas clouds change at least 5. The position of the gas clouds depends on the volume of the clouds, and the cumulative total needs to cover the entire process area.

6. The analytical method according to claim 1, characterized in that, Based on the overpressure value of the protected target changing over time, the maximum overpressure value of the protected target under the combustible gas explosion condition is determined. The explosion condition refers to the determined gas volume filling ratio, the determined position of the isochemical equivalent gas cloud, and the determined ignition position.

7. The analytical method according to claim 1, characterized in that, Based on the maximum overpressure value of the protected target under combustible gas explosion conditions, the sample was expanded, and statistical analysis and eigenvalue calculation were performed to obtain the probability density curve and eigenvalues. The specific process is as follows: The sample expansion method for different explosion overpressures under the same filling ratio linearly expands the values ​​from the explosion simulation value to the larger and smaller values ​​respectively, and finally forms 9 sample points. First, sample expansion and eigenvalue estimation are performed under the same filling ratio, and then the overall eigenvalue estimation is performed.

8. An analytical device for analyzing the overpressure characteristics of combustible gas explosions in marine oil and gas production facilities, characterized in that, include: The first processing unit is used to perform geometric modeling based on offshore oil and gas production facilities; The second processing unit is used to calculate the congestion level of the process area of ​​offshore oil and gas production facilities. The third processing unit is used to calculate the volume of combustible gas clouds under different filling ratios in the process area of ​​marine oil and gas production facilities based on geometric modeling and congestion. The fourth processing unit is used to perform transient CFD simulation of combustible gas explosion with varying gas cloud positions and ignition positions based on the volume of combustible gas clouds with different filling ratios, and to obtain the curve of overpressure value of the protected target changing over time. The fifth processing unit is used to determine the maximum overpressure value of the protected target under combustible gas explosion conditions based on the overpressure value of the protected target changing over time. The sixth processing unit is used to expand the sample based on the maximum overpressure value of the protected target under the combustible gas explosion condition, and to perform statistical analysis and eigenvalue calculation to obtain the probability density curve and eigenvalue. The seventh processing unit is used to determine the explosion-proof level of the protected target based on the probability density curve and eigenvalues, according to the protection requirements.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the analysis method according to any one of claims 1-7.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the analysis method according to any one of claims 1-7.

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