Analysis of fold -related fractures development and determination of in -si-tu stresses in the sarvak formation in one of thd west oil filds

Document Type : Original Article

Authors

1 Sarvak Azar Engineering & Development Co.

2 Ph.D. in Tectonic Geology, Faculty of Science, University of Birjand, Sarvak Azar Engineering and Development Co.

3 Department of Geology, Faculty of Science, University of Birjand

Abstract

Abstract
Analysis of seismic sections perpendicular to the fold axis and draw the circles surrounding on this profiles indicate the more bending in forelimb due to the more uplift in sedimentary units in effect the compression performance and thrust faults that caused fractures development and density in the southwest limb. Increasing loss of drilling mud in the forelimb anticline wells is associated with development of tensile and longitudinal fracturs related to increase in shortening and anticline uplift, thrust faults propagation and create the duplex structures in near there wells. The maximum and minimum in-situ stresses directions in well No. 2 located in the medial part of anticline are respectively N50 and N140 which are dependent on the Zagros neogene folding. Tensile-indused fractures or maximum in-situ stress direction was inclined in the eastern part of anticline and showing N30E direction. Borehole Breakout or minimum in-situ stress direction is perpendicular to tensile frauture and has N120 orientation. In the southwest part of this anticline, UGC Map is showing that contours of similar thicknesses are inclined and respect to the adjacent anticline was sinistrally displaced. Very high drilling mud losses in well NO.4 located in fold southeast plange is due to the location of this well in minimum distance to strike slip fault trace between two anticlines and due to concentrated stresses resulting from dual intraction the northeast fault lineament releated from folding and operation the sinstral fault after the zagros neogene folding.
 

Keywords

References

 
مهدور، م.ر.،  فارسی‌مدان، م.، و کمالی، ز.، 1394. بررسی عملکرد شکستگی‌ها و تعیین تنش برجا در سازند مخزنی آسماری میدان نفتی مارون (بر اساس تفسیر نتایج نمودارهای تصویرگر)، مجله زمینساخت، شماره 2، ص 35-14.
یوسفی، مهدی.، موسوی، سید مرتضی.، خطیب، محمد مهدی و یزدانی، محمد.، 1397. تحلیل برهم کنش روند‌‌های گسلی بر توسعه شکستگی‌های مخزن آسماری در تاقدیس رگ سفید با استفاده از نمودار‌های تصویرگر. فصلنامه علوم زمین، سازمان زمین شناسی و اکتشاف معدنی کشور، شماره 110، ص 128-119.
 
 
Berberain, M., 1995. Master blind thrust fault hidden under the Zagros folds: Active basement tectonics and surface morphotectonics. Tectonophys 241, 143-224.
Brudy, M., Zoback, M.D., 1993. Compressive and tensile failure of bore-holes arbitrarily inclined to principal stress axis: application to the KTB boreholes.34th US Symposium on Rock Mechanics Germany.
Intera Petroleum Technologies Company, Ltd, 1992. Marun Field study 9, 554-5621.
Jaeger, J.C., Cook, N.G.W., 1979. Fundamentals of rock mechanics. Chapman & Hall, New York.
Nelson, E.J., 2005. Transverse drilling-induced tensile fractures in the West Tuna area, Gipps land Basin, Australia. implications for the in situ stress regime 42, 361-371.
Peska, P., Zoback, M.D., 1995. Compressive and tensile failure of inclined borehole and determination of in situ stress and rock strength. Journal Geophysics Research 100 (B7), 12791–12811.
Plumb, R.A., Cox, J.W., 1987. Stress directions in eastern North America determined to 4.5 km from borehole elongation measurements. Journal Geophysics Research 90, 5513–5522.
Sherkati, S., Letouzey, j., Frizon de Lamotte., 2006. Central Zagros fold-thrust belt (Iran): New insights from seismic data, field observation, and sandbox modeling. Tectonics 25, 1-27.
Tingay, M,. Reinecker, J., Müller, B., 2008. Borehole breakout and drilling-induced fracture analysis from image logs. World Stress Map Project. Guidelines: Image Logs.
Journal of Tectonics
Volume 2, Issue 6
August 2018
Pages 55-68

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