Investigation into Lithological and Structural Modelling of Gachsaran Formation in Marun Oil Field Using Geostatistic Methods


1 Department of Geology, Shahid Chamran University of Ahvaz

2 M.S.C student of Geology, Shahid Chamran University of Ahvaz

3 N.I.S.O.C


In the present study, the evaporitic Gachsaran Formation in the Marun oil field, using lithological characteristics and their variation, is evaluated. Its structural model was also provided using RMS software to understand the structure and reservoir management. The results indicated that the cap rock consists of anhydrite, marl, salt, bituminous shale and limestone. Among these, anhydrite and marl are main components. On the basis of lithological variation it is revealed that mudstone thickness increases key bed C to key bed F. According to lithological and textural diversity in the cap rock, a lagoonal-sabkha model can be proposed can be proposed for depositional environment. Lithological changes indicate alternative hot-wet to hot-dry climates during depositional time. At The dimensional structural model was constructed by the help of 2D-sciesmogram as well as drilled well information (well pick and well deviation data) of 390 wells. In this area, the presence of zone -6 at shallow depth in north eastern culmination can be ascribed to the northern fault while its deeper position in southern part can be related to southern fault. It seems the lithological characteristics of  Gachsaran Formation were not only attributed to these faults but also converted them into a resistant bar against reservoir oil migration. The present results taken from the model can be important in improving proficiency, decreasing the drilling risk and expenses, drilling time waste and reservoir management as well.


رئیسی، ع.، 1377، مطلعه زمین­شناسی مخزن آسماری جهرم میدان نرگسی، گزرش شماره پ- 6134 گزارش داخلی، شرکت ملی مناطق نفتخیز جنوب).
شایسته، م.، 1381، بررسی علل آلودگی نفت آسماری بوسیله هیدروژن سولفوره در بخشی از میدان مارون، گزارش شماره پ-5207، اداره کل زمین­شناسی گسترشی، شرکت ملی مناطق نفتخیز جنوب، 52 صفحه.
شعبانی، ف.، 1387. مدل­سازی مخزن آسماری میدان نفتی شادگان با استفاده از نرم افزار RMS، پایان نامه­ی کارشناسی ارشد زمین­شناسی نفت، دانشگاه شهید چمران اهواز، 119 صفحه.
قنواتی، ک.، 1383، مطالعه­ی زمین­شناسی مخزن آسماری میدان پارسی (تهیه­ی  مدل سه­بعدی مخزن فوق توسط نرم افزار RMS)، پایان­نامه­ی کارشناسی ارشد مهندسی اکتشاف نفت، دانشگاه تهران.
مطیعی، ه.، 1372، زمین­شناسی ایران، چینه­شناسی زاگرس، سازمان زمین­شناسی کشور، 536 صفحه.
قلی پور، م. ع؛ حقی، ع.،  1369. مطالعه زمین­شناسی میدان نفتی مارون، گزارش شماره پ-4210، اداره کل زمین­شناسی گسترشی، شرکت ملی مناطق نفتخیز جنوب، 55 صفحه.
نظری وانانی، ک.، 1387، مدل­سازی مخزن آسماری میدان نفتی رامین با استفاده از نرم افزار RMS، پایان­نامه­ی کارشناسی ارشد زمین­شناسی نفت، دانشگاه شهید چمران اهواز، 103 صفحه.
Alavi, M., 2004, Regional stratigraphy of the Zagros fold-thrust belt of Iran and proforland evolution, American Journal of Sciences, v.304, p.1-20
Bahroudi, A., and Koyi, H. A., 2004, Tectono-Sedimentary framwork of the Gachsaran Formation in the Zagros foreland basin. Marine and Petroleum Geology.Vol. 21, p. 1295-1310.
Bahroudi, A., and Koyi, H.A., 2004, Tectono-sedimentary framework of the Gachsaran Formation in the Zagros foreland basin, Marine and Petroleum Geology, v. 21, p. 1295-1310
Baker Hughes INTEQ, 1999, Petroleum geology, Baker Hughes INTEQ publisher, Rev, A. 254p.
Caers, J., 2005, Geostatistical reservoir modelling using statistical pattern recognition, Journal of Petroleum Science and Engineering, pp. 188-177.
El-Tabakh. M, Mory. A, Schreiber. B. C, Yasin. R, 2004, Anhydrite cement after dolomitization of shallow marine Silurian carbonate of the Gascoyne platform, Southern Carnarvon basin, Western Australia, Sedimentary Geology, v. 164, p. 75-87.
Ertekin, T,. Abou Kassem, H.J,. King, R.G., 2001, Basic Applied Reservoir Simulation, Society of Petroleum  Engineers Inc, pp. 1-6
Fanchi, J.R., 2001, Principles of Applied Reservoir Simulation, Elsevier(USA), pp.1-175    
Holden, L., Mostad, P., Nielsen, B.F., Gjerde, J., Townsend, C., and Ottesen, S., 2003, Stochastic Structural Modeling, J. Mathematical Geology, Vol.35, No 8, pp. 899-914.
 Kaufmann, O., and Martin, T., 2008, 3D geological modelling from boreholes, cross-sections and geological maps, application over former natural gas storages in coal mines, J. Computers & Geosciences, v. 34, pp. 278–290.
Roxar software solution, 2005, RMS user guide release 7.0.
Schowalter, T.T., 1976, the mechanics are secondary hydrocarbon migration and entrapment Wyoming Geol. Earth science Bull., 9, 1-43.
Slinger, F.C.P., 1949, The Aghajari cap rock Gachsaran Formation Member1, AIOC Report No 751 (Unpubl.).
Stat Oil, 2003, Marun Asmari Full Field Study.
Tearpark, J. D., Bischk. R. E., 1994, Applied subsurface geological mapping, Prentic Hall Inc. 519P.
Tucker, M.E., 1999, Sabkha cycles, stacking and controls, Gachsaran) Formation Mesopotamian basin, Iraq, Neues jahrbuch Geologisch and Plaonatologisch Abhandlung, v. 124, p. 4569
Usiglio, M. J, 1849, Etudes sur la composition de l, exploitation de l, eau de la Mediterranean et sure l, exploitation des sel quy, elle conteint, in J. Warren, (ed.) 1999, Evaporates. Their evolution and economics, Black well Science, 438P.
Valcarce, G.Z., Zapata, T., Ansa, A., and Selva, G., 2006, Three-dimensional structural modeling and its application for development of the El Porto´n field, Argentina, AAPG Bulletin., v.90, no.3, pp. 307–319.
Warren, J. K, 2006, Evaporites: sediment, resources and hydrocarbons. Springer-Verlag, Berlin Heidelberg, 1035P.
Warren, J. K, Kempton. R. H, 1977: Evaporite sedimentology and the origin of evaporate –association Mississippi valley type sulfides in the Cadjebut Mine area, Lenard Shelf, Canning Basin, Western Australia., in Montanez I. P, Gregg J. M, and Shelton. K. L, Basin wide diagenetic patterns: Integrated petrologic, geochemical and hydrologic considerations. SEPM Special Publication 57: 183-205.