Risk Assessment of Gas Condensates Export Pipelines by Indexing Method (Case Study: Special Economic Energy Zone of South Pars-Assaluyeh)

Due to the sensitivity and vital and undeniable role of gas energy in the energy basket of the country, especially in economy, evaluation of risk assessment studies on the designing and exploiting of this massive and extensive industry including oil and gas pipelines seems to be very necessary. Generally, risk assessment is process of the determining the risk quantity and quality by analyzing potential risks in the project which will be done by taking into account the sensitivity or vulnerability of the surrounding environment. kent Muhlbauer’s method based on relative scoring of parameters that are involved in risks creation deals with the risk assessment. In order to establishment this system for risk assessment of statistical data collection, due to the failure of Iranian oil and gas pipelines, experts and scholars’ experiences as a field project (South Pars gas condensate export pipeline) were collected. According to the existing conditions and availability of information sources in the Iranian oil and gas industry, finally, these data as safety risk assessment criteria of pipelines were processed in a graph and scoring was conducted based on the relative weighting of risk starter elements in the pipeline. according to the obtained scores and the relative risk of different areas of pipeline by considering km scale of areas, it was identified that 16% of the total pipeline had very high risk level, 34% of the total pipeline had high risk level, 34% of the total pipeline had medium risk level and 16% of the pipeline had low risk level


Introduce the Problem
Oil and gas from the first days of the eruption, always have been the driving force of the society towards progress and development and Iran with more than 30,000 kilometers of oil and gas transmission pipelines, is one of the leading countries in the operation and exploitation of this huge and valuable infrastructure.Oil and gas pipelines have been considered as the main pillars of the transfer process and according to the expansion of these lines in different facility or even residential regions and high potential of vulnerability, pipeline safety is of utmost importance [8].Environmental risk assessment is a potential qualitative and quantitative risk analysis process and by considering sensitivity or vulnerability of its surrounding environment, it is the prediction process of potential risk [12].Iranian Oil Terminals Company, with respect to the development of oil and gas fields and 20-year vision of development of the oil industry and the subsequent development of gas condensates export, since 2003 is located in the South Pars region and now export, totally, 600 thousand gas condensates barrels per day through pipelines and the floating buoy which are produced by South Pars refineries.So traversing a relatively long way from production to export requires a safety management system and detailed assessment at any time and any negligence and error will cause financial losses, losses in lives and damage to the environment [Map1, 2 and Figure 1].Nowadays, safety knowledge as an integral part of human life has always been used in reducing adverse events and incidents, especially in the industrial sector of each country [14].Now in all over the world, the pipeline risk assessment is done by methods such as FMEA / FTA/HAZOP that each has its own advantages but the new appraisal method that is designed by Kent

Method
In this rese and comp company w

Results
In this study, according to the conducted studies, dynamic method has been used in the pipeline division.Since the under study area contained Manifold valves stations and installations for the measurement of gas condensates export pipelines from refineries, during the 11-kilometer of the pipeline, manifold taps, climate change, pipeline circumstances and pipeline route change were used as dividing point.In [Table 3] the third-party damage index variables and points are shown.Finally in [Tables 8, 9] sum and averages index and in [Tables 10, 11] relative risk score and overall risk assessment are shown: In the assessment of incorrect operation index, it was clarified that with regard to the integrity of the pipeline and the impact of parameters of the index for the entire route as well as its construction by reputable and experienced foreign companies (Total & Petronas), same and acceptable scores were obtained.However, since in the past years, the results of analysis showed that human errors are the cause of the events that have occurred in gas condensate export pipelines, the assessment conducted is not satisfactory.Among the main reasons for this are, respectively, level one (low level) procedural facilities safety system, lack of SCADA systems, and 80% operator regulatory system, lack of holding occupational exams related to beneficiary employees, absence of evidence showing drug test after hiring personnel, and lack of optimal worker participation in safety programs designed.
Total results of safety indicators indicate that in the second and third sections, achieved points were not satisfactory and were riskier than other areas.Although the rest of the areas according the maximum safety index score (400) that they can gain in ideal conditions, they did not have acceptable level of scores and they were in the notification area but not paying attention to them can, in not too distant future, cause unwanted events.
So after averaging the safety indicators of the studied range, it was found that the pipelines conditions with regard to the corrosion index and the index of operation and malfunctions are in the worse than the other indices situation that it is necessary to perform precautionary measures related to the aforementioned indicators variables.
The leakage impact factors index results suggest that the leakage impact with respect to the information contained in the gas condensates SDS, NFPA704 standard and DOT 192 classification in the terms of the toxicity and health, environmentally sensitive and economically valuable areas are not in the too acute area and if rating each of the pipelines move toward zero, the severity of the consequences of leakage will be less and the only reason to increase the points of the third, second and fifth areas in compare with other regions will be the crossing of the pipeline from environmentally sensitive and economically valuable areas, and in case of leakage that could have more deleterious effects.The results of the level relative risk index that represents relative risk and total assessment and by dividing the total index with the index of the health risks and environmental impact of the leakage, showed that third section of pipe had very high risk level, the second and fifth section had high risk level, fourth and sixth sections had medium risk level and the first section had low risk level, also relative percentages with regard to the total risk level obtained with respect to the results are as: 16% of the total pipeline had a very high, 34% of the pipeline had a high, 34% of the total pipeline had medium and 16% of the total pipeline had a low risk level.

Discussion
The highest risk of plan related to gas condensate leakage and future consequences (fire, explosion, personal accident, environmental pollution…) therefore, it is necessary that in the early designing stages (feasibility) all the factors should be assessed and evaluated using appropriate methods of risk assessment of the pipeline.Moreover, all requirements and standards of implementation and risk management program of pipeline should be considered from the beginning, and in case of making corrections and modify in the pipeline and its environmental conditions, management of change program must be institutionalized and implemented in the company.
Pipelines threatening factors and variables vary from state to state and appropriate preventive measures specific to each region should be considered Figure Muhlbauer is devoted to pipelines risk

Table 2 .
Pipeline characteristics of case study

Table 3 .
Assessment of third-party damage index variables

Table 4 ]
corrosion index variables and Scores are shown:

Table 4 .
Assessment of corrosion index variable Design Index variables and scores are shown in [Table5]:

Table 5 .
Assessment of corrosion index variable

Table 6 ]
incorrect operations index variables and scores are shown:

Table 6 .
Assessment of corrosion index variable

Table 7 .
Assessment of corrosion index variable