مطالعه اثرات تغييرات فشار متوالي بر خواص پتروفيزيکي سنگ مخازن کربناته
محورهای موضوعی :علی مرادزاده 1 * , یاسر سلیمی دلشاد 2 , عزت اله کاظم زاده 3 , عباس مجدی 4
1 - دانشگاه تهران
2 - دانشگاه تهران
3 - پژوهشگاه صنعت نفت
4 - دانشگاه تهران
کلید واژه: سنگ مخزن کربناته طبقه بندي آرچي بارگذاري سيکليک تخلخل, تراوايي تصاوير سي‌تي اسکن.,
چکیده مقاله :
امروزه صنعت نفت بسيار متكي به تعيين دقيق خصوصيات سنگ مخزن است كه اين مهم مي تواند سبب كاهش هزينه ها و ريسك برنامه ريزي توليد شود. سنگ مخزن همواره با افت فشار منفذي ناشي از توليد متراكم ميشود که اين امر سبب افزايش تنش مؤثر، فشردگي مخزن و تغييرات در خواص مخزني ميگردد. از آنجاييکه اين تغييرات فشار مي تواند بر خواص پتروفيزيکي اثرگذار باشد، در اين مطالعه، چندين نمونه سنگ مخزن کربناته با بافت و نوع تخلخل متفاوت براساس تصاوير سي‌تي اسکن و طبقه بندي آرچي تحت بارهاي متوالي و کوتاه مدت، از 600 تا 6000 پوند بر اينچ مربع قرارگرفته اند و خصوصيات پتروفيزيکي و تراکمي آنها شامل حجم فضاي منفذي، نفوذپذيري و تراکم‌پذيري توسط دستگاه CMS-300 مورد مطالعه قرار گرفته است. همچنين بررسي ساختاري و ناهمگني نمونه مغزه ها توسط تصاوير سي‌تي اسکن مورد آناليز قرار گرفته اند. در واقع به کمک اين پژوهش شناسايي اندازه اثر پسماند بر روي نمونه سنگ مخزن در اثر افزايش و کاهش فشار، طي اعمال بار سيکليک مقدور خواهد بود. نتايج حاصل نشان دادند که در اثر بارگذاري تغييرات حجم فضاي منفذي و نفوذپذيري روند کاهشي از خود نشان مي دهند، بطوريکه کاهش نفوذپذيري چندين برابر کاهش حجم منفذي است. همچنين اين کاهش حجم فضاي منفذي در نمونه هاي داراي تخلخل حفره اي با شدت کمتري است که اثر همگني و نوع تخلخل بر ميزان پديده پسماند را نشان مي دهد. همچنين نتايج به‌دست آمده از چگونگي رفتار سنگ مخزن تحت تنش-هاي مختلف در اين مطالعه، مي تواند الگوي مناسب براي مطالعات مربوط به تزريق گاز به منظور ازدياد برداشت و همچنين متناسب با اهداف مرتبط ديگر نظير ذخيره‌سازي گاز طبيعي را فراهم آورد.
Today, oil industry significantly relies on the precise determination of rock reservoir properties, which reduces the costs and risks of production planning. The reservoir rock always is compacted by pressure drop of the reservoir, which rises effective stress, reservoir compaction and alterations of reservoir properties. As these pressure variations can considerably affect petrophysical properties, in this study, several carbonate reservoir rock samples with different fabric and porosity type (according to CT scan and Archie classification analysis) subjected to cyclic and short-term loading from 600 to 6000 psi. Their petrophysical and compressive properties including pore volume, permeability and compressibility were measured using CMS-300 apparatus. Moreover, structural analysis and heterogeneity of core samples were analyzed by CT scan images. By performing this study, it will be possible to identify the value of the hysteresis effect on the reservoir rock samples as a result of increasing and decreasing of the pressure during cyclic loading. The obtained results show that, pore volume and permeability are both decreased due to loading, whereas reduction of the permeability is several times than the pore volume ones. Moreover, this reduction of pore volume is less severe in vuggy porous samples that shows the effect of heterogeneity and porosity type on hysteresis. Also, the results obtained from the behavior of the reservoir rock under various pressure conditions can provide a suitable design for gas injection studies to enhance oil recovery and also natural gas storage.
[1] سعادت، کاظم؛ شريفي گلويك، حميد. "تعيين برخي خواص سنگ شناسي و پتروفيزيکي با استفاده از تکنولوژي سي‌تي اسکن". اولين کنفرانس و نمايشگاه تخصصي نفت، تهران#
[2] KARACAN, C. O., GRADER, A. S., & HALLECK, P. M. (2001, January 1). 4-D Mapping of Porosity and Investigation of Permeability Changes in Deforming Porous Medium. Society of Petroleum Engineers. doi:10.2118/72379-MS#
[3] FJAER, E., HOLT R. M., HORSRUD P., RAAEN A.M., RISNES R., “Petroleum Related Rock Mechanics”, Elsevier, 1992#
[4] DAIM, F., EYMARD, R., HILHORST, D., MAINGUY, M., & MASSON, R. (2002). A preconditioned conjugate gradient-based algorithm for coupling geomechanical-reservoir simulations. Oil & Gas Science and Technology, 57(5), 515-523.#
[5] HALL, H.N., (1953). Compressibility of reservoir rocks. Petroleum Transactions, Alme, 198, 309-311.#
[6] HARARI, Z., SHU-TEH, W., & SALIH, S. (1995). Pore-compressibility study of Arabian carbonate reservoir rocks. SPE Formation Evaluation, 10(04), 207-214.#
[7] LIU, H. H., RUTQVIST, J., & BERRYMAN, J. G. (2009). On the relationship between stress and elastic strain for porous and fractured rock. International Journal of Rock Mechanics and Mining Sciences, 46(2), 289-296.#
[8] TELKU, T. W., ZHOU, Z., Li, X., & ABASS, H. (2016, June 26). Cyclic Permeability and Porosity Hysteresis in Mudrocks – Experimental Study. American Rock Mechanics Association.#
[9] RANDOLPH, P. L., SOEDER, D. J., & CHOWIAH, P. (1984, January 1). Porosity and Permeability of Tight Sands. Society of Petroleum Engineers. doi:10.2118/12836-MS#
[10] TEKLU, T. W., LI, X., ZHOU, Z., & ABASS, H. (2017, October 1). Experimental Investigation on Permeability and Porosity Hysteresis of Tight Formations. Society of Petroleum Engineers. doi:10.2118/180226-PA#
[11] AL-HARTHY, S. S., DENNIS, J. W., JING, X. D., & MARSDEN, J. R. (1998, January 1). Hysteresis, True-Triaxial Stress-Path and Pore Pressure Effects on Permeability. Society of Petroleum Engineers. doi:10.2118/47269-MS#
[12] HUGHES, J. D. (2014). Drilling deeper. Post carbon institute Mechanics. #
[13] ANDERSON, D. M., NOBAKHT, M., MOGHADDAM, S., & MATTER, L. (2010). Analysis of production data from fractured shale gas wells. In SPE unconventional gas conference. Society of Petroleum Engineers.#
[14] EIA. (2016). "Drilling Productivity Report for Key tight oil and shale gas regions". Retrieved from http://www.eia.gov/.#
[15] EKER, I., KURTOGLU, B., & KAZEMI, H. (2014). Multiphase Rate Transient Analysis in Unconventional Reservoirs: Theory and Applications. In SPE/CSUR Unconventional Resources Conference–Canada. Society of Petroleum Engineers. #
[16] TEKLU, T. W., ZHOU, Z., LI, X., & ABASS, H. (2016). Experimental Investigation on Permeability and Porosity Hysteresis in Low-Permeability Formations. In SPE Low Perm Symposium. Society of Petroleum Engineers. #
[17] SKINNER, J. T., TOVAR, F. D., & SCHECHTER, D. S. (2015, November 18). Computed Tomography for Petrophysical Characterization of Highly Heterogeneous Reservoir Rock. Society of Petroleum Engineers. doi:10.2118/177257-MS#
[18] ADEBAYO, A. R., KANDIL, M. E., OKASHA, T. M., & SANNI, M. L. (2017). Measurements of electrical resistivity, NMR pore size and distribution, and x-ray CT-scan for performance evaluation of CO2 injection in carbonate rocks: A pilot study. International Journal of Greenhouse Gas Control, 63, 1-11.#
[19] CIVAN, F. (2018, April 22). Effect of Stress Shock and Pressurization/Depressurization Hysteresis on Petrophysical Properties of Naturally-Fractured Reservoir Formations. Society of Petroleum Engineers. doi:10.2118/190081-MS#
[20] SHEERANG S. Ch., EDWARD M. B., SOMNATH S., MATTEW D. D., QUINN R. P., TIMOTHY E. Z., ALEX C. W., JEFF A. B., DANIEL W. B., SERGIO A. LEONARDI, and RYAN A. K, (2015). Steady-state stress-dependent permeability measurements of tight oil-bearing. ExxonMobil Upstream Research Company, Petrophysics, 56 (2): Page 116–124.#
[21] HUEVKEL, T., & NOVA, R. (1979). Some hysteresis effects of the behaviour of geologic media. International Journal of Solids and Structures, 15(8), 625-642. #
[22] HOLT, R. M., FLORENCE, O., Li, L., & FJAER, E. (2004). Consequences of Depletion-Induced Stress Changes On Reservoir Compection and Recovery. In Gulf Rocks 2004, the 6th North America Rock Mechanics Symposium (NARMS). American Rock Mechanics Association. #
[23] DUSSEAULT, M. B., & SANTARELLI, F. J., 1989. A Conceptual Model for Massive Solids Production in Poorly-Consolidated Sandstones," Rock at Great Depth, Maury & Fourmantraux (Eds.), Balkema, Rotterdam, 789–797.#
[24] ROEHLoehl, P. O., & CHOQUETTE, P. W. (Eds.). (2012). Carbonate petroleum reservoirs. Springer Science & Business media.#
[25] KARACAN, C. O., GRADER, A. S., & HALLECK, P. M. (2001, January 1). 4-D Mapping of Porosity and Investigation of Permeability Changes in Deforming Porous Medium. Society of Petroleum Engineers. doi:10.2118/72379-MS.#