Microsoft Word - cet-01.docx CHEMICAL ENGINEERING TRANSACTIONS VOL. 46, 2015 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Peiyu Ren, Yancang Li, Huiping Song Copyright © 2015, AIDIC Servizi S.r.l., ISBN 978-88-95608-37-2; ISSN 2283-9216 An Oilfield Ecological Risk Assessment System Integrating OERAM and GIS Yingchang Xiu*a, Wenbao Liua, Bing Liua, Haixia Lib a College of Geomatics, Shandong University of Science and Technology, Qingdao, Shandong, China b College of economics and management, Shandong University of Science and Technology. Qingdao, Shandong, China xiuyingchang@163.com The oilfield ecological risk assessment model (OERAM) analyzes the effects of the oil pollutants on ecological system. In this paper, according to oilfield characteristics and ecological risk assessment receptor expose effect assessment, a modified oilfield ecological risk assessment model structure is established which referencing the relationship between ecological receptor exposure ways and ecological effect. Comparing the current ecological risk assessment methods, the joint probability evaluation is selected to establish oilfield ecological risk assessment model. Finally, the oil ecological risk assessment system based on geographic information system and geo-database technology is developed integrating the modified oilfield ecological risk assessment model. This system realizes spatial information analysis, ecological risk assessment and results visualization functions. Through the application in Shengli Oilfield, the comprehensive assessment result of oilfield risk could provide decision-making basis for the oilfield environment management. 1. Introduction Chen and Liu (2014) reported ecological risk assessment (ERA) is a major part of the environmental risk assessment which assesses the potential harmfulness of one or more risk factors to the ecological results. With the development of oil exploitation in recent ten years, oilfield ecological risk assessment has become a focus problem in the field. Oilfield risk refers to the pollution and harm of crude oil and various oil products in the stage of oil exploration, refining, storage and use. Sidortsov (2014) found it may cause damages to the local environment and even affect the development of the ecological environment. According to assess the risk level of oilfield, Posthuma et al. (2008) suggested the ERA can provide the oil risk management solutions, in order to reduce the harm of oil exploitation risk to the environment and reduce the cost of oil field development. The oilfield risk assessment model (ORAM) experienced from environmental impact assessment to ecological environmental risk assessment which was confirmed (Tian and Gang(2014)). At first, the ORAM evaluates the possible impact on the social environment during oil development process. Later, it evaluates the hazards of oilfield development to the whole social environment and ecological system. Especially in recent years, the oilfield risk assessment has aroused widespread concern with the rapid development of risk assessment on natural disasters and man-made disasters. Chengzao et al.(2014) found in China, the oil industry has become one important basic industries which support the sustained and rapid development of the national economy. However, Li et al. (2014) reported the study on risk assessment of oil mining area is still weak. What's worse, the ecological environment of the regions where mining area distributed is fragile and the oil exploitation may damage the local biodiversity. These brought great difficulties to the traditional ecological risk study which was confirmed by Xu et al. (2004). In this study, according to previous studies of Carignan and Villard (2002), Liao et al.(2013), La and Martinico (2013), Wang et al.(2012) etc., the oilfield ecological risk assessment system for oilfield ecological environment protection is designed integrating the modified oilfield environmental risk assessment model (OERAM) and geographic information system (GIS) technology to analyse and simulate the oilfield ecological risk. DOI: 10.3303/CET1546123 Please cite this article as: Xiu Y.C., Liu W.B., Liu B., Li H.X., 2015, An oilfield ecological risk assessment system integrating oeram and gis, Chemical Engineering Transactions, 46, 733-738 DOI:10.3303/CET1546123 733 Figure 1: Modified oilfield ecological risk assessment model 2. Modified oilfield ecological risk assessment model General studies suggest that ecological risk assessment include hazard assessment, exposure assessment, receptor analysis and risk characterization. The oilfield ecological risk assessment was similar to it. According to the ecological risk assessment framework proposed by Hunsaker et al.(1990), Suter II et al.(2003) and Hayes and Landis(2004),we established a framework to assess the regional ecological risk. The key components include: (1) selection of endpoints; (2) description of reference environment; (3) development of source terms; (4) exposure or habitat modification assessment; (5) effects assessment (Figure 1). In this study, pollution receptor selection was introduced to the framework. In this framework, before the risk assessment of oil, a detailed survey of oil mining area, containing the economic, social and environmental, is necessary. Then identify the pollution factors that may produce harmful effects on the ecological environment, this contains oilfield risk identification and oilfield risk description. Next, the receptor which will became the bearer of the harmful effects from pollution factors need to be identified, and it must follow the two principles: (1) it may reflect the overall oil pollution in the region; (2) it’s simple calculation and facilitate understanding. Exposure assessment function analysis the transfer and change process when oilfield pollution seeps into soil and water. The environmental pollutants concentration (PEC) was used as a monitoring index. It can be obtained by detecting or through forecasting model. Considering the space distribution difference between risk source and receptor, the effects of pollutants can’t be superimposed. So it makes the exposure analysis complicate and difficult which was confirmed by Oughton et al.(2013). The relationship between risk source and risk receptor can be expressed as the following Eq(1). dttCF t t  1 2 )( (1) in which, F represents the amount of total exposure from t1 to t2, C(t) represents the concentration of toxic substances at a certain moment, t1and t2 represent the start and end time. In addition, the hazard analysis is closely linked with exposure analysis. Through it, the probability damage of risk sources to risk receptor could be calculated. Before analysing the hazard, the mechanism of pollution source on risk receptor needs to be clear. Combining related assessment technologies, the hazard could be assessed and predicted. At last, summarizing the previous content, we could assess the risk and the probability of occurrence. In the risk assessment, the influence of toxicity is not independent, but a comprehensive result of several compounds. The comprehensive impact assessment of pollutants is necessary. In order to realize the comprehensive evaluation, each kind of pollutants was given a weight. The weight formula is Eq (2).    k i iji iji ij px px w 1 )( (2) in which, xi represents the average exposure concentration of pollutants i; pij represent hazard concentration of pollutants i to biological receptors j; k represent the number of pollutants. According to the weight, we could obtain the comprehensive risk assessment result P of oilfield pollutants in the whole region. See Eq (3).   k n ijij FwP 1 )( (3) Finally, we ranked the risk level based on the study of Moraes and Molander(2004) (Table 1). 734 Table 1: The level of oil pollution risk Level P Warning type Description 1 P<0.1 No alert Pollutants had no effect on receptor 2 0.1