Oil spill pollution risk assessment method based on multiple environmental factors

Abstract

The invention discloses an oil spill pollution risk assessment method based on multiple environmental factors, and belongs to the field of marine oil spill pollution disastrous risk assessment. The method comprises the following steps: a, on the basis of oil spill accident cause analysis, determining core environment factors which influence oil spill, including sea condition severity, oil platform influence, channel density and ship activity intensity, and constructing a multi-factor collaborative oil spill pollution risk assessment model; b, respectively calculating to obtain a sea condition severity index, an oil platform influence index, a route busy density index and a ship activity intensity index of the evaluated sea area; c, calculating the weight of each environment factor based on an entropy weight method; and d, calculating to obtain a comprehensive risk index, and completing oil spill pollution risk assessment. According to the method, accurate assessment and efficient management and control of the marine oil spill occurrence risk can be realized, prevention and control resources can be reasonably utilized, and technical support is provided for assessment of marine ecological protection and sustainable development of marine economy in a sea area.

Description

Technical Field

[0001] This invention relates to the field of marine oil spill pollution hazard risk assessment, and more specifically to a method for assessing the risk of oil spill pollution based on multiple environmental factors. Background Technology

[0002] In some sea areas, marine economic activity is highly active, with many important ports nearby, numerous offshore oil exploration platforms, and key shipping routes. However, this intense economic activity also exposes these areas to a persistent threat of oil spills.

[0003] Accurate assessment of oil spill pollution hazards is a crucial prerequisite for accident prevention and loss reduction. Existing research on oil spill pollution hazard assessment has significant limitations: on the one hand, most studies focus only on single or a few influencing factors, such as oil platform distribution or waterway density, failing to fully reveal the nonlinear impact mechanism of multiple environmental factors synergistically affecting oil spill pollution; on the other hand, pollution assessment results lack clear zoning standards, leading to insufficiently targeted prevention and control measures and difficulty in achieving precise resource allocation. For example, some studies identify high-risk areas using probabilistic models, but fail to quantify the correlation between risk levels and dynamic environmental factors, limiting the practical guidance of the assessment results. Summary of the Invention

[0004] To address the aforementioned technical challenges, this invention proposes a method for assessing the risk of oil spill pollution based on multiple environmental factors. This method integrates multiple environmental factors to construct an assessment model, optimizes model parameters to improve assessment accuracy, classifies risk zones, and achieves precise assessment and efficient management of oil spill risks.

[0005] The technical solution adopted in this invention is: A method for assessing the risk of oil spill pollution based on multiple environmental factors, comprising the following steps: a. Construct an oil spill pollution hazard assessment model; Based on the analysis of the causes of oil spill accidents, the core environmental factors affecting oil spill occurrence are identified, including sea condition severity, oil platform impact, channel density, and vessel activity intensity. A multi-factor collaborative oil spill pollution hazard assessment model is constructed, as shown in the following expression: ; OSI is the Overall Risk Index, with a value ranging from [0,1]. A higher value indicates a higher risk of oil spill. ocean The sea state severity index, I platform For the impact index of oil platforms, I lane I is the air traffic density index. vessel, where w1, w2, w3, and w4 are the weights of each environmental factor; and S is the environmental sensitivity index. b. Calculate the indices of each environmental factor; The sea condition severity index, oil platform impact index, shipping route density index, and vessel activity intensity index for the assessment area were calculated and obtained respectively. c. Calculate the weights of each environmental factor; Based on the entropy weight method, the influence weight is determined by the information dispersion of each environmental factor indicator data, and the weight of each environmental factor is calculated. d. Calculate the risk of oil spill pollution; The sea condition severity index, oil platform impact index, shipping route density index, and vessel activity intensity index of the assessment area obtained in step b, as well as the weights of each environmental factor obtained in step c, are substituted into step a to calculate the comprehensive risk index, thus completing the oil spill pollution risk assessment.

[0006] The beneficial technical effects of the present invention are as follows: This invention integrates environmental factors such as sea conditions, oil platforms, waterways, and ships to construct a comprehensive risk assessment model for oil spill pollution, optimizes model parameters to improve assessment accuracy, and further classifies risk zones to achieve accurate assessment and efficient management of oil spill risks in the assessed sea area.

[0007] Specifically, this invention overcomes the limitations of traditional single-factor assessments by constructing a comprehensive risk assessment model for oil spill pollution in marine areas and using the model results to assist in risk level classification. This allows for a more accurate reflection of the risk of oil spills. Based on a comprehensive analysis of various environmental factor indices and ecological sensitivity, and by calculating the weights of each factor using the entropy weight method, the invention transforms pollution risk assessment from qualitative description to quantitative classification, providing a clear basis for differentiated management. The assessment results and corresponding countermeasures can provide scientific decision-making support for maritime and environmental protection departments in the assessed marine area, helping to reduce the incidence of oil spill accidents and minimize ecological and economic losses. This is of great significance for the protection and sustainable development of the marine ecosystem in the assessed marine area. Attached Figure Description

[0008] Figure 1 A schematic diagram illustrating the framework of the multi-factor synergistic oil spill pollution hazard assessment model constructed by the method of this invention; Figure 2 The distribution of the sea condition severity index in a certain sea area was assessed in August of that year. Figure 3 The distribution of the impact index of offshore oil platforms in a certain sea area was assessed in August of a certain year. Figure 4 To assess the distribution of shipping route busyness density index in a certain year's August; Figure 5To assess the distribution of the intensity index of ship activity in a certain sea area in August of a certain year; Figure 6 To assess the distribution of marine environmental sensitivity indices; Figure 7 The purpose was to assess the distribution of oil spill pollution risks in a certain sea area in August of a certain year. Detailed Implementation

[0009] Most existing studies on oil spill pollution hazard assessment focus only on single or a few influencing factors, failing to fully reveal the nonlinear impact of the synergistic effects of multiple environmental factors on oil spill occurrence and the assessment mechanism of pollution hazard based on the environmental sensitivity of the affected area. Furthermore, the pollution hazard assessment results lack clear grading standards, leading to insufficient targeting of prevention and control measures and hindering precise resource allocation. In view of this situation, this invention proposes an oil spill pollution hazard assessment method based on multiple environmental factors. This method integrates environmental factors such as sea state, offshore oil and gas platforms, waterways, and vessels to construct an assessment model, optimizes model parameters to improve assessment accuracy, and classifies risk zoning levels, thereby achieving accurate assessment and efficient management of oil spill pollution hazards in the assessed sea area.

[0010] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0011] A method for assessing the risk of oil spill pollution based on multiple environmental factors includes the following steps: a. Construct an oil spill pollution hazard assessment model; Based on the causal analysis of oil spill accidents, the core environmental factors influencing oil spill occurrence are identified, including sea condition severity, the impact of oil platforms, channel density, and vessel activity intensity. Assuming a relatively timely response after an oil spill, regional differences in response capabilities can be ignored, and risk transmission is primarily modulated by spatial attributes. A multi-factor synergistic comprehensive oil spill pollution hazard assessment model is constructed, expressed as follows: ; OSI is the Overall Risk Index, with a value ranging from [0,1]. A higher value indicates a higher risk of oil spill pollution. ocean The sea state severity index, I platform For the impact index of oil platforms, I lane I is the air traffic density index. vessel The index represents the intensity of ship activity; w1, w2, w3, and w4 are the weights of each factor, determined based on the entropy weight method. S is the environmental sensitivity index, determined based on the environmental sensitivity index published by the U.S. National Oceanic and Atmospheric Administration (NOAA). Taking the Bohai Sea as an example, the environmental sensitivity indices of various regions in the Bohai Sea are shown in Table 1.

[0012] Table 1

[0013] b. Calculation of various environmental factor indices; Before calculating each environmental factor index, the assessment sea area was divided into 2,548,643 grid cells with a resolution of 10″×10″. Then, within the assessment period, the environmental factor indices were calculated for each grid cell. Finally, based on the calculation results of all grid cells, a spatial distribution map of each environmental factor index covering the entire assessment sea area was constructed. The specific calculation method for the environmental factor indices is as follows: (1) Sea condition severity index; Sea state is a key natural factor influencing oil spill occurrence. Severe sea state reduces ship navigation stability and increases the load on oil platform equipment, thereby increasing the risk of oil spills. Taking into account the effects of significant wave height, storm surge, current velocity, wind speed, visibility, and winter icing, the sea state severity index (I) of the grid cells within the assessed time period is determined. ocean The formula for calculating ) is: ; Among them, H w U represents the average significant wave height (m) of the grid cells during the assessment period, and Δh represents the average storm surge height (m) of the grid cells during the assessment period. c W represents the average flow velocity (m / s) of the grid cells during the evaluation period. w H represents the average wind speed (m / s) of the grid cells during the assessment period, and Vi represents the average sea surface visibility of the grid cells during the assessment period. wmax Δh max U cmax W wmax Vi max These represent the maximum values ​​(units consistent with the corresponding parameters) of significant wave height, storm surge height, current velocity, wind speed, and visibility in the grid cells covering the entire sea area during the assessment period; F ice The icing impact coefficient is set to 1 for areas with sea ice and 0 for areas without sea ice during the assessment period.

[0014] (2) Impact index of offshore oil platforms; Offshore oil platforms, or offshore oil and gas platforms, are potential sources of oil spill risk. Their impact on the surrounding area decreases with distance and is affected by their own service life, design life, and probability of facility failure. The Offshore Oil Platform Impact Index (IPI) is a key indicator of oil spill risk. platform The formula for calculating ) is: ; Where N represents the total number of offshore oil platforms in the study area, based on statistics from the monitoring ledger of oil platforms in the assessment area; d k A is the straight-line distance (km) from the grid cell to the k-th platform;k P represents the platform's aging and overdue coefficient. k The overall failure probability of the platform facilities, where A k Based on platform service life (Y) f ) and design life (Y s The calculation is as follows: ; P k The calculation references the OREDA dataset for reliability of land and marine equipment, selecting three categories of critical facilities. Based on the dataset, the basic failure probabilities of oil pipelines, oil storage tanks, and valves / joints at different service years are denoted as T. pipe T tank T valve The overall failure probability of the platform facilities was calculated comprehensively: ; (3) Airline congestion density index;

[0015] Channel density reflects the level of ship traffic; higher density indicates a higher risk of collisions and oil spills. The Bohai Sea is divided into 10″×10″ grid cells, and the calculation formula is as follows: ; Where, N l The number of waterway passages within the time period evaluated for the grid cell, based on Marine Traffic ® Website channel density data statistics; N lmax N lmin These are the maximum and minimum values ​​of the number of grid channels in the entire assessment sea area during the assessment period (i.e., the maximum and minimum values ​​are selected from all grid cells in the assessment sea area).

[0016] (4) Ship activity intensity index; The intensity of ship activity comprehensively reflects both ship tonnage and voyage density, and the calculation formula is as follows: ; Among them, T t N represents the total tonnage of ships within the time period assessed by the grid cell. v The number of vessel voyages within the time period assessed for each grid cell is based on navigation reports from the maritime authorities in the assessed sea area; T tmax N vmax These are the maximum values ​​of total tonnage and number of voyages for the entire assessment sea area (all grid units) during the assessment period, respectively; similarly, the maximum value is selected from all grid units.

[0017] c. Calculation of the weighting of environmental factors; The weights of environmental factors are calculated using the entropy weight method, which determines the weights based on the information dispersion of the indicator data itself: the greater the difference between indicators in the sample (the smaller the information entropy), the more significant their contribution to oil spill risk assessment, and the higher their weights; conversely, the smaller the difference between indicators (the larger the information entropy), the lower their weights, which can adapt to the dynamic characteristics of the marine environment.

[0018] Within the assessed sea area, using the time dimension, step b calculates four indicator data points at different times within the assessed time period (i.e., daily sea condition severity, oil platform impact, channel traffic density, and vessel activity intensity), obtaining a total of n samples, forming an indicator matrix X = [x ij ] n×4 , used for weight calculation in the entropy weight method, where i = 1, 2, … n are sample numbers, and j = 1, 2, 3, 4 correspond to 4 indicators.

[0019] Further transforming the indicators, we calculate the probability contribution p of the i-th sample under the j-th indicator. ij This reflects the relative proportion of the sample's indicator value in the entire sample: ; Based on this, the information entropy e of the j-th indicator is calculated. j To measure the dispersion of indicator data: ; Further, by calculating the difference d of the j-th indicator j And normalize to obtain the weight w j :

[0020] .

[0021] d. Classify and assess the hazard level of oil spill pollution in the sea area; Based on steps a, b, and c, the distribution of the Overall Occupational Risk Index (OSI) in the assessed sea area is calculated and divided into 6 levels according to size, as shown in Table 2 below.

[0022] Table 2

[0023] This level can provide a precise and differentiated basis for assessing marine ecological and environmental protection, marine oil spill emergency management, and the deployment of prevention and control materials. It is conducive to the rational use of prevention and control resources and provides technical support for the protection of the Bohai Sea's marine ecology and the sustainable development of the marine economy.

[0024] The invention will be further explained below with reference to specific application examples.

[0025] 1. Research data; To verify the practicality of the method of the present invention in complex real-world scenarios, this invention is based on the background field and survey data of the North China Sea Forecasting and Disaster Reduction Center of the Ministry of Natural Resources in a certain year in the Bohai Sea, and explores the performance of the present invention in actual situations.

[0026] 2. Model input; Sea state data: Data products from the Copernicus Marine Environment Monitoring Service (CMEMS) and the European Centre for Medium-Range Weather Forecasts (ECMWF) integrated forecasting system include significant wave height, storm surge, current velocity, wind speed, visibility, and sea ice distribution.

[0027] Offshore oil and gas platform data: sourced from CNOOC (China) Limited Beijing Research Center, including the platform's latitude and longitude coordinates, years of operation, and design life.

[0028] Waterway and Vessel Data: Waterway Density Based on Marine Traffic ® The website uses AIS vessel tracking data to calculate the annual number of vessels passing through the waterway and the total tonnage of vessels in each grid.

[0029] 3. Calculation of environmental factor indicators and their impact weights; Using the results from step 2, environmental factor indices are calculated through step b of the above method. Taking August of that year as an example, the calculated sea state severity index, offshore oil and gas platform impact index, waterway density impact index, and ship activity intensity index are as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown. Through step c, the calculated values ​​of sea state severity index, offshore oil and gas platform impact index, waterway density index impact index, and ship activity intensity index w1, w2, w3, and w4 are 0.2701, 0.2982, 0.2368, and 0.1950, respectively.

[0030] 4. Classification of the risk level of oil spill pollution in the Bohai Sea; Based on the results of step 3, the distribution of environmentally sensitive areas in the Bohai Sea ( Figure 6 Based on the environmental sensitivity coefficients of the Bohai functional zones in Table 1, the risk of oil spill pollution in the Bohai Sea is classified into six levels through step d in the above method, as shown in Table 1. Figure 7 The map showing the risk distribution of oil spill pollution in the Bohai Sea is shown.

[0031] For any parts not mentioned above, existing technologies can be adopted or referenced.

[0032] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for assessing the risk of oil spill pollution based on multiple environmental factors, characterized in that... Includes the following steps: a. Construct an oil spill pollution hazard assessment model; Based on the analysis of the causes of oil spill accidents, the core environmental factors affecting oil spill occurrence are identified, including sea condition severity, oil platform impact, channel density, and vessel activity intensity. A multi-factor collaborative oil spill pollution hazard assessment model is constructed, as shown in the following expression: ； OSI is the Overall Risk Index, with a value ranging from [0,1]. A higher value indicates a higher risk of oil spill. ocean The sea state severity index, I platform For the impact index of oil platforms, I lane I is the air traffic density index. vessel , where w1, w2, w3, and w4 are the weights of each environmental factor; and S is the environmental sensitivity index. b. Calculate the indices of each environmental factor; The sea condition severity index, oil platform impact index, shipping route density index, and vessel activity intensity index for the assessment area were calculated and obtained respectively. c. Calculate the weights of each environmental factor; Based on the entropy weight method, the influence weight is determined by the information dispersion of each environmental factor indicator data, and the weight of each environmental factor is calculated. d. Calculate the risk of oil spill pollution; The sea condition severity index, oil platform impact index, shipping route density index, and vessel activity intensity index of the assessment area obtained in step b, as well as the weights of each environmental factor obtained in step c, are substituted into step a to calculate the comprehensive risk index, thus completing the oil spill pollution risk assessment.

2. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 1, characterized in that, In step a: the environmental sensitivity index is determined based on the environmental sensitivity index published by the U.S. National Oceanic and Atmospheric Administration.

3. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 1, characterized in that, In step b: the assessment sea area is divided into multiple grid cells according to a set resolution. Then, during the assessment period, each environmental factor index is calculated for each grid cell. Finally, based on the calculation results of all grid cells, a spatial distribution result of each environmental factor index covering the entire assessment sea area is constructed.

4. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 3, characterized in that, The formula for calculating the sea state severity index of grid cells within the assessment period is as follows: ； Among them, H w The mean significant wave height of the grid cells during the evaluation period is given in meters (m); Δh is the mean storm surge height of the grid cells during the evaluation period, in meters (m); U c To evaluate the average flow velocity of the grid cells over a time period, m / s; W w The average wind speed (m / s) of the grid cells during the evaluation period; Vi is the average sea surface visibility of the grid cells during the evaluation period; H is the average wind speed of the grid cells during the evaluation period. wmax Δh max U cmax W wmax Vi max These represent the maximum values ​​of significant wave height, storm surge height, current velocity, wind speed, and sea surface visibility within the grid cells covering the entire assessed sea area during the assessed time period; F ice The icing impact coefficient is set to 1 for areas with sea ice and 0 for areas without sea ice during the assessment period.

5. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 3, characterized in that, The formula for calculating the impact index of offshore oil platforms is: ； Where N represents the total number of offshore oil platforms within the assessed sea area; d k A is the straight-line distance from the grid cell to the k-th offshore oil platform, in km; k P represents the aging and overdue coefficient of offshore oil platforms. k The overall failure probability of offshore oil platform facilities, where A k Based on the platform's service life Y f and design life Y s The calculation is as follows: ； Overall failure probability of offshore oil platform facilities: ； Among them, T pipe The probability of foundation failure for the oil pipeline; T tank The basic failure probability of the oil storage tank; T valve This represents the basic failure probability of the valve / connector.

6. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 3, characterized in that, The formula for calculating the air traffic congestion density index is: ； Where, N l N represents the number of channel passages for a grid cell during the evaluation period. lmax N lmin These represent the maximum and minimum number of waterway passages in the grid cells of the entire sea area being assessed during the assessed time period.

7. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 3, characterized in that, The formula for calculating the ship activity intensity index is: ； Among them, T t N represents the total tonnage of ships within the grid cell during the evaluation period. v The number of ship voyages per grid cell within the evaluation period; T tmax N vmax These represent the maximum total tonnage and number of voyages of vessels within the grid units of the entire sea area being assessed during the assessed time period.

8. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 7, characterized in that, In step c: Using the time dimension, four indicators are calculated at different times within the evaluation period of the grid cells, namely the daily sea condition severity index, oil platform impact index, shipping route density index, and vessel activity intensity index, obtained from step b. A total of n samples are obtained, forming the indicator matrix X = [x ij ] n×4 , used for weight calculation of entropy weight method, where i = 1, 2, … n is the sample number, j = 1, 2, 3, 4 correspond to four indicators: sea state severity index, oil platform impact index, shipping route busy density index, and ship activity intensity index, respectively. The indicators are transformed, and the probability contribution p of the i-th sample under the j-th indicator is calculated. ij This reflects the relative proportion of the sample's indicator value in the entire sample: ； Based on this, the information entropy e of the j-th indicator is calculated. j To measure the dispersion of indicator data: ； Then, by calculating the degree of difference d of the j-th indicator... j And normalize to obtain the weight w j : ； 。 9. The method for assessing the risk of oil spill pollution based on multiple environmental factors according to claim 1, characterized in that, Step d also includes classifying the risk level of oil spills in the sea area based on the calculated comprehensive risk index (OSI) value. When the OSI value ranges from [0, 0.2), the risk level is Level I, indicating a low risk. When the OSI value ranges from [0.2, 0.35), the risk level is Level II, indicating a low risk. When the OSI value ranges from [0.35, 0.5), the risk level is Level III, indicating a medium risk. When the OSI value ranges from [0.5, 0.7), the risk level is Level IV, indicating a relatively high risk. When the OSI value ranges from [0.7, 0.8), the risk level is Level V, indicating a high risk. When the OSI value ranges from [0.8, 1.0), the risk level is Level VI, indicating an extremely high risk. Then, by marking different colors, a map showing the distribution of oil spill pollution risks in the assessed sea area is created.

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