Минералогия глин, рентгенодифракционный метод, рентгенофлуоресцентный метод, количественный минералогический анализ, горизонт Шуридже. <...> Quantitative analysis OF THE clay minerals IN THE shurijeh reservoir FORMATION using COMBINED X-ray analytical techniQues golnaz jozanikohan, Fereydoun sahabi, gholam hossain norouzi, hossein memarian and Behzad moshiri The Shurijeh reservoir Formation of Neocomian age is represented by a sandstone sequence, occasionally interbedded with shale, in the Gonbadli gas field, Kopet-Dagh Basin, North-eastern Iran. <...> In this study X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques were used to characterize the Shuirjeh clay minerals in 76 core samples, collected from two deep Gonbadli wells. <...> The results of XRF analysis showed high percentages of silicon and moderate to low percentages of aluminum, sulfur, calcium, potassium, sodium, magnesium, and iron in both wells. <...> The XRD analysis indicated that the above elements were concentrated in the form of quartz, anhydrite, dolomite, calcite, plagioclase, K-feldspar, hematite and clay minerals. <...> Further XRD exami© golnaz jozanikohan, Fereydoun sahabia, gholam hossain norouzia, hossein memariana, Behzad moshiri, 2016 e-mail: gjkohan@ut.ac.ir 1332 Doi: 10.15372/gig20160705 nation of the clay fraction, revealed that illite, chlorite, and kaolinite were the major types of clay minerals. <...> Unlike, glauconite, smectite and a mixed layer clays of both the illite-smectite and chlorite-smectite types were observed only in very few samples. <...> The percentages of individual clay minerals were determined using external standard calibration curves, and successfully validated by a system of simultaneous linear equations acquired from detailed elemental information based on the XRF analysis. <...> The amount of error reached ±5% for the main mineral constituent and ±15% for minor minerals. <...> A local regression relationship was also derived, based on the XRF elemental information, which can be used to estimate the clay contents of other Shurijeh drilled wells with data of pulsed-neutron spectroscopy tools. <...> According to the proposed quantitative approach, the amount of illite varied considerably reaching up to 18.3%. <...> In contrast, the amount of kaolinite and chlorite were generally small, i.e. less than 8.4%. <...> An increase in illite with increasing burial depth and temperature was an obvious indication of deep burial diagenesis in this Formation. <...> Keywords: clay mineralogy, Shurijeh <...>