بررسی آزمایشگاهی اثر شرایط تنش‌های اعمال‌شده بر روی نحوه شکست دیواره چاه‌های نفت

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، مهندسی استخراج معدن، دانشگاه بین­المللی امام خمینی قزوین (ره)

2 دانشیار گروه مهندسی معدن، دانشگاه بین­المللی امام خمینی قزوین (ره)

چکیده

حفر چاه در صنایع مختلف مانند نفت، گاز و معدن همواره با مشکل ناپایداری مواجه بوده و نیاز به‌ صرف هزینه­های زیاد دارد. با کنترل تغییر شکل و شکست در دیواره­ی چاه می­توان به حداقل ممکن ناپایداری رسید. در این مقاله، برای بررسی تغییرشکل و نحوه­ی شکست در دیواره­ی چاه­های نفت، مطالعات آزمایشگاهی به وسیله سلول هوک اصلاح ­شده بر روی نمونه­های استوانه­ای توخالی جدار ضخیم ماسه­سنگ، مارن و آهک­رسی انجام شده است. شرایط تنش اعمال ­شده از مهمترین عوامل در تغییر شکل و نحوه­ی شکست در دیواره چاه است. بنابراین شرایط تنش در دو حالت: در حالت اول تنش محوری ثابت و تنش جانبی متغیر و در حالت دوم تنش جانبی ثابت و تنش محوری متغیر، اعمال شد. نتایج آزمایش­­های انجام شده نشان داد که نحوه­ی شکست و تغییر شکل به شدت وابسته به‌ اندازه و جهت تنش­های اعمال­ شده در دیواره­ی چاه است. نحوه­ی شکست برای نمونه­های ماسه­سنگ و آهک­رسی در دیواره چاه طی شرایط تنش محوری ثابت و تنش جانبی متغیر به­صورت پوسته‌پوسته شدن به سمت داخل گمانه است. در حالت تنش جانبی ثابت و تنش محوری متغیر، نحوه­ی شکست در نمونه­های آهک­رسی و مارن با توزیع تصادفی در سه نقطه از روی دیواره­ی چاه که با یکدیگر زاویه 120 درجه می‌سازند، اتفاق می­افتد.

کلیدواژه‌ها

عنوان مقاله [English]

Experimental investigation of effect of applied stresses condition on shape of failure in wall of oil wells

نویسندگان [English]

  • Sonya Aghaei 1
  • Mahdi Hosseini 2
1 MSc Student, Department of Mining Engineering, Imam Khomeini International University, Ghazvin, Iran
2 Assistant Professor, Department of Mining Engineering, Imam Khomeini International University, Ghazvin, Iran,
چکیده [English]

The wells drilling in various industries such as oil, gas and mining have always been faced with the instability problem and the solving this need to spend a lot of money. The instability of wall of wellbore can be minimized by controlling deformation and failure. In this paper, experimental investigation has been carried out in two different stress conditions on thick-walled hollow cylindrical samples of sandstone, argillaceous limestone and marl using modified Hoek’s cell to predict the deformation and shape of failure in the wall of wellbore.
In the first series of tests, axial stress is constant and confining stress is changing and the second series of tests condition is vice versa. Experimental results indicated that, the deformation and shape of failure strongly depends upon the magnitude and direction of the imposed stress in the wall of well. Also result illustrated that, under constant axial stress condition, the wall of well, for both sandstone and argillaceous limestone specimens, broke out toward inside the wall of wellbore. Under the constant confining stress condition for argillaceous limestone as well as marl specimens, the failure occurred with random distribution in three points, which meet at 120 degrees

کلیدواژه‌ها [English]

  • Well instabilit
  • Hoek’s cell
  • deformation
  • Failure shape
  • Thick-walled hollow cylinder specimens

مراجع

شرکت ملی مناطق نفت خیز جنوب، 1392. نقشه میادین نفتی حوضه زاگرس (منتشرنشده).
مطیعی، ه، 1370. چینه‌شناسی زاگرس: سازمان زمین‌شناسی و اکتشاف معدنی کشور.
Adams, F. D., 1912. An experimental contribution to the question of the depth of the zone of flow in the earth's crust: Journal of Geology, 20 ( 2): 97-118.
Al-Ajmi, A. M. and Zimmerman, R. W. ,2006. Stability analysis of vertical boreholes using the Mogi–Coulomb failure criterion: International Journal of Rock Mechanics and Mining Sciences, 43(8):1200–1211.
Alsayed, M, 2002. Utilising the Hoek triaxial cell for multiaxial testing of hollow rock cylinders: International Journal of  Rock Mechanics and Mining Science.  39(3): 355–366.
Bandis, S. C., Lindman, J. and Barton, N. ,1987. Three-dimensional stress state and fracturing around cavities in overstressed weak rock: 6th ISRM Congress.
Bell, J. and Bachu, S., 2003. In situ stress magnitude and orientation estimates for Cretaceous coal-bearing strata beneath the plains area of central and southern Alberta: Bulletin of Canadian PetroleumGeology. 51(1): 1-28.
Bridgman, P. , 1918. The failure of cavities in crystals and rocks under pressure: American Journal of Science. 4(4): 243-268.
Brown, E.T. (ed), 1981. “Suggested Methods for Determining Indirect Tensile Strength of  Rock Materials By The Brazil Test”, Rock Characterization, Testing and Monitoring I.S.R.M, Suggested Methods, Pergamon Press, Oxford, PP 120/121.
Brown, E.T.(1981), “Rock characterization, testing and monitoring, ISRM suggested methods” Pergamon Press, Oxford, UK, PP 107-110.
Dresen, G., Stanchits, S., and Rybacki, E. , 2010. Borehole breakout evolution through acoustic emission location analysis: International Journal of Rock Mechanics and Mining Sciences. 47 (3): 426–435.
Elkadi, A., Van Mier, J. , 2004. Scaled hollow-cylinder tests for studying size effect in fracture processes of concrete: 5th International conference on fracture mechanics of concrete and concrete structures.
Ewy, R. & Cook, N. , 1990. Deformation and fracture around cylindrical openings in rock—I. Observations and analysis of deformations: International Journal of Rock Mechanics and Mining Sciences & Geomechanics. 27(5): pp 387–407.
Fjar, E., Holt, R. M., Raaen, A., Risnes, R., and Horsrud, P., 2008. Petroleum related rock mechanics: Elsevier, Radawage 29: 211.
Gay, N. , 1973. Fracture growth around openings in thick-walled cylinders of rock subjected to hydrostatic compression: International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, Elsevie: 10 (3): 209–218.
Haimson, B., 2007. Micromechanisms of borehole instability leading to breakouts in rocks: International Journal of Rock Mechanics and Mining Science. 44(2):157–173.
Hoek, E. and Franklin, J. A. , 1967. A simple triaxial cell for field or laboratory testing of rock: Imperial College of Science and Technology, University of London, Trans. Instn Min. Metall. 77: 22- 26.
Hoskins, E. , 1969. The failure of thick-walled hollow cylinders of isotropic rock: International Journal of Rock Mechanics and Mining Sciences & Geomechanics.  6 (1): 99–116.
ISRM, 1979a. Suggested method for determining water content, porosity,density, absorption and related properties and swelling and slake durability index properties. Int J Rock Mech Min Sci. 66: 141–156.
ISRM, 1979b. Suggested methods for determining the Uniaxial Compressive Strength and Deformability of Rock Materials: Int J Rock Mech Min Sci Geomech Abstr. 99–103.
ISRM, 1978a. Suggested methods for determining the Strength of Rock Materials in Triaxial Compression: Int J Rock Mech Min Sci Geomech Abstr. 15: 47-51.
ISRM, 1978b. Suggested methods for determining tensile strength of rock materials: Int J Rock Mech Min Sci Geomech Abstr. 15:99–103.  10.1016/0148-9062(78)90003-7
Khan,S.A.I., 2006. Wellbore stability during underbalanced drilling: in Masters Abstracts International. 45(03).
King, L. V., 1912. On the limiting strength of rocks under conditions of stress existing in the earth's interior: The Journal of Geology. 20( 2) : 119-138.
Papamichos, E., Liolios, P. and Van Den Hoek, P. , 2004. Breakout stability experiments and analysis:  Gulf Rocks  the 6th North America Rock Mechanics Symposium (NARMS), American Rock Mechanics Association.
Pašić, B, N., 2007. Gaurina Međimurec, and D. Matanović. Wellbore instability: causes and consequences: Rudarsko-geološko-naftni zbornik . 19(1): 87-98.
Perie, P. and Goodman, R. , 1989. Evidence of new failure patterns in a thick-walled cylinder experiment:  Proc. 12th ETCE/ASME Conf. 22: 23-27.
Robertson, E. C. , 1955. Experimental study of the strength of rocks; Geological Society of America Bulletin. 66(10): 1275-1314.
Santarelli, F. & Brown, E. , 1989. Failure of three sedimentary rocks in triaxial and hollow cylinder compression tests: International Journal of Rock Mechanics and Mining Sciences & Geomechanics. 26(5): 401–413.
Suggested Method for Determining Strength of Rock Materials in Triaxial Compression": Revised Version, Int. J. of Rock Mech. Min. Sci. & Geomech Abstr., Vol 20, No.6, Pp. 283-290, May 1983 (I.S.R.M).
Suggested Methods for Determining the Uniaxial Compressive strength and Deformability of  Rock Materials”. Rock Characterization, Testing and Monitoring – ISRM Suggested Methods, E.T. Brown (editor) Pergamon Press, Oxford, 1981, PP 113-116.
Warlick, L., Abass, H., Khan, M., Pardo Techa, C., Tahini, A., Shehri, D., Badairy, H., Shobaili, Y., Finkbeiner, T. & Perumalla, S. , 2009. Evaluation of Wellbore Stability during Drilling and Production of Open Hole Horizontal Wells in a Carbonate Field: In SPE Saudia Arabia Section Technical Symposium. Society of Petroleum Engineers.
Wang, J. Wan, R. Settari, A. and Walters, D., 2005. Prediction of volumetric sand production and wellbore stability analysis of a well at different completion schemes:  in Alaska Rocks 2005.The 40th US Symposium on Rock Mechanics (USRMS) held in Anchorage, Alaska, June 25-29, USRMS 05-842.
Younessi, A. V. Rasouli, and B. Wu. , 2012. The Effect of Stress AnisotropyOn Sanding: An Experimental Study:  in 46th US Rock Mechanics/Geomechanics Symposium.
Zoback, M. D., 2010. Reservoir geomechanics: The Edinburgh building. Cambridge CB2 8RU, UK.
نشریه انجمن زمین شناسی مهندسی ایران
دوره 9، شماره 3 و 4
اسفند 1395
صفحه 75-69

فایل ها

سابقه مقاله

  • تاریخ دریافت: 10 فروردین 1394
  • تاریخ بازنگری: 29 اسفند 1395
  • تاریخ پذیرش: 02 شهریور 1396

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