Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 7 4 2021 11 01 Comparison of environmental risks of drilling operations of cluster and single ring models 305 319 1132 10.22104/aet.2022.5265.1425 EN Soheil Zamanzadeh Department of Environment, Management Faculty, Islamic Azad University, West Tehran Branch, Tehran, Iran Sanaz Khoramipour Department of Environmental Science and Engineering, West Tehran Branch, Islamic Azad University, Tehran, Iran Fatemeh Razavian Department of Environmental Science and Engineering, West Tehran Branch, Islamic Azad University, Tehran, Iran Journal Article 2021 10 20 The purpose of this study is to compare the environmental risks arising from two models of drilling operations of single-ring and clustered wells in the land area, and finally, to select the most appropriate drilling operations to reduce environmental risks. For this purpose, after identifying the most important drilling activities of oil and gas wells and collecting the opinions of the statistical community, the risks arising from the activities in this field for both drilling models were identified and evaluated using the failure modes and effects analysis (FMEA) method. Then, the best option was selected using the hierarchical analysis process technique, which is useful in prioritizing and selecting the best option. The location of drilling risks in the high and medium risk matrix was determined using the FMEA method for both models with 1<RPN<30. And using the analytic hierarchy process (AHP) technique in the range of zero and one and between the single ring and cluster prioritized the techniques, and the best drilling technique for oil and gas wells, namely cluster drilling, was selected. https://aet.irost.ir/article_1132_9a4df2833c0b8e934331a9e4aa9da3da.pdf