REY area has been located in Tehran Province and several archaeological ruins of this area indicate that the settlement in this area has been started since several thousand years ago. In this paper, the main investigation items consist of analysis of oil components and groundwater quality inside the wells. By finding the contents of oil in the well, it is possible to find out the pollution source by comparing the oil contents of well with other oil products that are used inside and outside of the oil farm. Investigation items consist of analysis of BTEX (Benzene, Toluene, Ethyl-benzene, Xylene), Gas chromatographic distillation characteristics, Water content, Density, Sulfur content, Lead content, Atmospheric distillation, MTBE(Methyl tertiary butyl ether). Analysis of polluting oil components showed that except MW(Monitoring Well)10 and MW 15 that oil with slightly heavy components was detected in them; with a high possibility the polluting oil is light oil., {"references":["Wang, Z., Fingas, M., Page, D.S., \"Oil spill identification. J.\nChromatogr.\" 1999, A 843, 369e411.","B. Mrayyan, M.N. Batikhi, \"Biodegradation of total organic carbon\"\n(TOC in Jordanian petroleum sludge, J. Hazard. Mater. B120 ,2005, 127-\n134.","Zhou, E., Crawford, R., \"Effects of oxygen, nitrogen, and temperature on\ngasoline biodegradation in soil.\" 1995,Biodegradation 6, 127e140.","Liebeg, E.W., Cutright, T.J., \"The investigation of enhanced\nbioremediation through the addition of macro and micronutrients in a\nPAH contaminated soil.\" 1999, International Biodeterioration and\nBiodegradation 44, 55e64.","Ting, Y.P., Hu, H.L., Tan, H.M., \"Bioremediation of petroleum\nhydrocarbons in soil microcosms.\" 1999,Resource and Environmental\nBiotechnology 2, 197e218.","Vasudevan, N., Rajaram, P., Bioremediation of oil sludgecontaminated\nsoil. Environment International 26, 409e411.","Xie, G., Barcelona, M.J., \"Efficient Quantification of TPH and\nApplications at Two Contaminated Sites.\" 2001,Ground Water\nMonitoring and Remediation, 64-70.","Einhorn, I.N., Sears, S.F., Hickey, J.C., Viellenave, J.H., Moore, G.S.,\n\"Characterization of Petroleum Contaminants in Groundwater and Soils.\"\nIn Hydrocarbon Contaminated Soils, Vol. 2, P.T. Kostecki and E.J.\nCalabrese (Eds). Amherst, Massachusetts, USA, 1992, pp. 89-143.","American Society for Testing and Materials, ASTM D6563 - 05e1\nStandard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates\nAnalysis by Gas Chromatography.\n[10] American Society for Testing and Materials, ASTM D2887-04a Standard\nTest Method for Boiling Range Distribution of Petroleum Fractions by\nGas Chromatography.\n[11] American Society for Testing and Materials, ASTM D1533 - 00(2005)\nStandard Test Method for Water in Insulating Liquids by Coulometric\nKarl Fischer Titration.\n[12] American Society for Testing and Materials, ASTM D4052- 96(2002)e1\nStandard Test Method for Density and Relative Density of Liquids by\nDigital Density Meter.\n[13] American Society for Testing and Materials, ASTM D4294-03-Standard\nTest Method for Sulfur in Petroleum and Petroleum Products by Energy-\nDispersive X-Ray Fluorescence Spectrometry .\n[14] American Society for Testing and Materials, ASTM D3237-02-Standard\nTest Method for Lead In Gasoline By Atomic Absorption Spectroscopy.\n[15] American Society for Testing and Materials, ASTM D86-04b Standard\nTest Method for Distillation of Petroleum Products at Atmospheric\nPressure.\n[16] American Society for Testing and Materials, ASTM D4815- American\nSociety for Testing and Materials Standard, D4815-04 Standard Test\nMethod for Determination of MTBE, ETBE, TAME, DIPE, tertiary-\nAmyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas\nChromatography.\n[17] Cheremisinoff, P.N. \"A guide to underground storage tanks,\nevaluation, site assessment and remediation.\" 1992, Published by\nPrentice- Hall Inc. Englewood Cliffs, New Jersey.\n[18] Dragun, J., and Hellings, C. S., \"Physicochemical and structureal\nrelationships of organic chemicals undergoing soil and clay catalyzed\nfree radical oxidation.\" Soil Science., 1985, 139, 100-111."]}