تحلیل حساسیت و تعیین مهم‌ترین پارامترهای مؤثر بر پایداری چاه نفت بر اساس مدل‌سازی عددی در نرم‌افزار Phase2 | |
| روش های تحلیلی و عددی در مهندسی معدن | |
| مقاله 7، دوره 14، شماره 38، فروردین 1403، صفحه 89-98 اصل مقاله (1.18 M) | |
| نوع مقاله: مقاله پژوهشی | |
| شناسه دیجیتال (DOI): 10.22034/anm.2022.2859 | |
| نویسندگان | |
| ماهان امیرخانی؛ ابوالفضل عبدالهی پور* | |
| دانشکده مهندسی معدن، دانشکدگان فنی، دانشگاه تهران، تهران، ایران | |
| چکیده | |
| ناپایداری چاه در صنعت نفت مسئله مهمی بوده و عموماً به دلیل عوامل مکانیکی، شیمیایی و گرمایی هرساله باعث ایجاد هزینه‌های قابل‌توجهی می‌گردد. این موضوع دلیل اصلی گسیختگی چاه‌ها بوده و نشان‌دهنده مشکلی جدی در صنعت حفاری است. با افزایش عمق حفاری، پایداری چاه در سازندهای عمیق دارای شکستگی طبیعی بیشتر و بیشتر موردتوجه قرارگرفته است. هدف از انجام این تحقیق بررسی میزان تأثیر هر پارامتر بر پایداری چاه نفت و مشخص کردن مهم‌ترین آن‌ها و مرتب نمودن آن‌ها بر اساس اهمیت در پایداری چاه نفت است. در این مطالعه با استفاده از تحلیل حساسیت به بررسی میزان تأثیر هفت پارامتر بر پایداری چاه پرداخته‌شده است. حداکثر جابه‌جایی ایجادشده در دیواره چاه به‌عنوان معیار پایداری در نظر گرفته‌شده است. درنهایت این پارامترها به ترتیب از بیشترین تأثیرگذاری تا کمترین تأثیرگذاری مرتب شده‌اند. تحلیل حساسیت به‌وسیله مدل‌سازی عددی انجام خواهد شد. در مدل مربوطه برای مجموعه‌ای از پارامترهای مهم که انتخاب شده‌اند مقادیری پایه‌ای مشخص‌شده، با تغییر دادن مقدار یک پارامتر در محدوده تغییرات خود و ثابت نگه‌داشتن سایر پارامترها و تحلیل آن در نرم‌افزار Phase2 میزان تأثیرگذاری پارامتر مزبور بر پایداری چاه نفت بررسی‌شده یا به عبارتی، حساسیت آن پارامتر بررسی خواهد شد. سپس این فرآیند برای سایر پارامترها نیز انجام‌شده و درواقع حساسیت سایر پارامترها بررسی شد. درنهایت مشخص شد پارامترهای موردبررسی به ترتیب از حساسیت زیاد به کم عبارت‌اند از: فشار منفذی، فشار گل حفاری، نسبت تنش‌های افقی جانبی، زاویه اصطکاک داخلی، ضریب چسبندگی، مدول یانگ و نسبت پوآسون. | |
| کلیدواژه‌ها | |
| تحلیل حساسیت؛ پایداری چاه نفت؛ مدل‌سازی عددی؛ Phase2 | |
| عنوان مقاله [English] | |
| Sensitivity Analysis and determination of the most important affecting parameters in the stability of oil wellbores based on numerical modeling in Phase2 | |
| نویسندگان [English] | |
| Mahan Amirkhani؛ Abolfazl Abdollahipour | |
| Dept. of Mining Engineering, Technical College, University of Tehran, Tehran, Iran | |
| چکیده [English] | |
| Summary In this research, the importance of the parameters affecting the oil wellbore stability has been investigated. This study has been performed by the finite element method and modeling in the Phase 2 software. “Maximum total displacement” is considered as the representative of wellbore stability. The impact of each parameter on the wellbore stability was investigated by changing the values of the parameters. Finally, pore pressure and drilling mud pressure were recognized as the most important parameters affecting the wellbore stability. Introduction Excavation of oil wells causes stress concentration in the wellbores’ wall by removing the in-situ material from the well. Wellbore wall failures force very high non-productive costs on the oil industry. As a result, performing a suitable stability analysis for the oil well is necessary, for which the parameters affecting the stability of the oil well should be identified. Some many factors and parameters affect the rock mass stability but the role of all these parameters is not the same. One has to identify the order of importance of all the parameters. Some parameters are called controllable parameters like pore pressure their values can be increased or decreased by the driller but others like pore pressure, friction angle, and cohesion coefficient are called uncontrollable parameters and the driller cannot increase or decrease their values, but the accuracy in the measurement of them is important that controllable parameters can be adjusted based on them. Therefore, because their measurement and adjustment have a direct relationship with the stability of the wellbore and achieving the desired result, their level of accuracy should be proportional to their importance. More cost for more important parameters is reasonable and leads to better results. Methodology and approaches Nowadays, several numerical methods are available for the stability analysis of oil wells. Among them, the most commonly used are the finite element method (FEM), boundary element method (BEM), and discrete element method (DEM) and hybrid methods. In this research finite element models were made by Phase2 software and then a dimensionless sensitivity analysis was performed using the results of FEM models. In this research effect of seven parameters (including Young’s modulus, cohesion coefficient, internal friction angle, drilling mud pressure, Poisson ratio, pore pressure, and horizontal lateral stresses ratio) on the stability of wellbore is studied. In the dimensionless sensitivity analysis given a system whose character, , is governed mainly by factors of and is a function of and Then a function is defined based on the relation between and where and finally determines a factor called “sensitivity factor”. The sensitivity factor indicated the relation of relative variation in (Maximum total displacement in this study) to the relative error of (the seven parameters mentioned above in this study). The sensitivity factor of each parameter shows the importance of that parameter. To analyze the sensitivity of each parameter, the parameter varies within its variation range but the other parameters remain constant, and other models of the studied parameter are made. The models are solved and the maximum total displacement of the wellbore wall is considered as a parameter representing the wellbore stability. Then the relation between the studied parameter and maximum total displacement (wellbore stability) is expressed by a function. Then the sensitivity factor of the studied parameter is determined. Then the process will be repeated for the other parameters. Then the effect of each parameter on the stability of the wellbore was investigated by analyzing the diagrams and the parameters were arranged from highest to lowest by comparing the sensitivity factors. In this research, a plan view of a wellbore was investigated. The wellbore is vertical and has a circular section with a diameter of 10 cm. Firstly, an initial pore pressure of 21 MPa is given to the basic model and its loading conditions are as shown in Fig. 1 and the basic values of parameters and the variety range of them are shown in the Table 1. Results and conclusions The final result of this research is rating the parameters' stability based on their importance of in the wellbore stability. This importance was expressed by the sensitivity factor. Then the parameters were rated based on their sensitivity factors as summarized in Table 2. Sensitivity factors from highest to lowest are as follows: pore pressure, drilling mud pressure, horizontal lateral stress ratio, internal friction angle, cohesion coefficient, Young’s modulus, and Poisson’s ratio. The results show that the pore pressure is the most important parameter affecting the wellbore stability and its sensitivity factor is 7.25. This means that a variation of 15% in , leads to a relative variation in Maximum total displacement of . The sensitivity of two parameters, pore pressure and drilling mud pressure, is significantly higher than the other parameters, and on average, it is about 4.5 times more important than other parameters. | |
| کلیدواژه‌ها [English] | |
| Sensitivity Analysis, Oil Wellbore Stability, Numerical Modeling, Phase 2 | |
|
سایر فایل های مرتبط با مقاله
|
|
| مراجع | |
|
[1] R. M. Holt, I. Larsen, E. Fjær, and J. F. Stenebråten, “Comparing mechanical and ultrasonic behaviour of a brittle and a ductile shale: Relevance to prediction of borehole stability and verification of shale barriers,” J. Pet. Sci. Eng., vol. 187, no. November 2019, p. 106746, 2020, doi: 10.1016/j.petrol.2019.106746.
[2] M. K. Medetbekova, M. R. Hajiabadi, A. Brovelli, H. F. Christensen, and H. M. Nick, “An integrated rock-mechanics tests and numerical modelling of chalk rocks: An improved integrated workflow for borehole safety,” J. Pet. Sci. Eng., vol. 208, no. PA, p. 109365, 2022, doi: 10.1016/j.petrol.2021.109365.
[3] M. Aslannezhad, A. Kalantariasl, and A. Keshavarz, “Borehole stability in shale formations: Effects of Thermal˗Mechanical˗Chemical parameters on well design,” J. Nat. Gas Sci. Eng., vol. 88, no. February, p. 103852, 2021, doi: 10.1016/j.jngse.2021.103852.
[4] L. Ding, Z. Wang, Y. Wang, and B. Liu, “Thermo-poro-elastic analysis: The effects of anisotropic thermal and hydraulic conductivity on borehole stability in bedding formations,” J. Pet. Sci. Eng., vol. 190, no. February, p. 107051, 2020, doi: 10.1016/j.petrol.2020.107051.
[5] A. Khaksar, M. Aghayari, and B. Sabir, “Stability analysis and trajectory optimization of vertical and deviated boreholes using the extended-Mogi-Coulomb criterion and poly-axial test data,” Upstream Oil Gas Technol., vol. 7, no. April, p. 100052, 2021, doi: 10.1016/j.upstre.2021.100052.
[6] Y. Hao, “Borehole Stability in Mudstone Shale and Coal Seams in the Daniudi Gas Field,” Chem. Technol. Fuels Oils, vol. 52, no. 2, pp. 185–193, 2016, doi: 10.1007/s10553-016-0689-y.
[7] Y. Jin et al., “Analysis of the vertical borehole stability in anisotropic rock formations,” J. Pet. Explor. Prod. Technol., vol. 2, no. 4, pp. 197–207, 2012, doi: 10.1007/s13202-012-0033-y.
[8] L. Ding, Z. Wang, B. Liu, and J. Lv, “Assessing borehole stability in bedding-parallel strata: Validity of three models,” J. Pet. Sci. Eng., vol. 173, no. October 2018, pp. 690–704, 2019, doi: 10.1016/j.petrol.2018.10.065.
[9] A. Abdollahipour, M. Fatehi Marji, A. Yarahmadi Bafghi, and J. Gholamnejad, “Simulating the propagation of hydraulic fractures from a circular wellbore using the Displacement Discontinuity Method,” Int. J. Rock Mech. Min. Sci., vol. 80, pp. 281–291, 2015, doi: 10.1016/j.ijrmms.2015.10.004.
[10] A. Abdollahipour, M. Fatehi Marji, A. Yarahmadi Bafghi, and J. Gholamnejad, “DEM simulation of confining pressure effects on crack opening displacement in hydraulic fracturing,” Int. J. Min. Sci. Technol., vol. 26, no. 4, pp. 557–561, 2016, doi: 10.1016/j.ijmst.2016.05.004.
[11] M. Lak, M. Fatehi Marji, A. Yarahmadi Bafghi, and A. Abdollahipour, “A coupled finite difference-boundary element method for modeling the propagation of explosion-induced radial cracks around a wellbore,” J. Nat. Gas Sci. Eng., vol. 64, no. January, pp. 41–51, 2019, doi: 10.1016/j.jngse.2019.01.019.
[12] H. Yousefian, H. Soltanian, M. F. Marji, A. Abdollahipour, and Y. Pourmazaheri, “Numerical simulation of a wellbore stability in an Iranian oilfield utilizing core data,” J. Pet. Sci. Eng., vol. 168, no. February, pp. 577–592, 2018, doi: 10.1016/j.petrol.2018.04.051.
[13] T. Ma, Y. Zhang, Y. Qiu, Y. Liu, and Z. Li, “Effect of parameter correlation on risk analysis of wellbore instability in deep igneous formations,” J. Pet. Sci. Eng., vol. 208, no. PC, p. 109521, 2022, doi: 10.1016/j.petrol.2021.109521.
[14] F. Zhang, H. Liu, Y. Meng, S. Cui, and H. Ye, “Study on Wellbore Stability and Failure Regions of Shale considering the Anisotropy of Wellbore Seepage,” vol. 2021, 2021.
[15] A. Abdollahipour and R. Rahmannejad, “Sensitivity analysis of influencing parameters in cavern stability,” Int. J. Min. Sci. Technol., vol. 22, no. 5, pp. 707–710, 2012, doi: 10.1016/j.ijmst.2012.08.020.
[16] R. Bhasin and K. Høeg, “Parametric study for a large cavern in jointed rock using a distinct element model (UDEC-BB),” Int. J. Rock Mech. Min. Sci., vol. 35, no. 1, pp. 17–29, 1998, doi: 10.1016/S0148-9062(97)00312-4.
[17] X. HAN, M. chao HE, and B. ZHANG, “Sensitivity analysis for parameters of a monitoring system for steep slopes of open-pit mines,” Min. Sci. Technol., vol. 19, no. 4, pp. 441–445, 2009, doi: 10.1016/S1674-5264(09)60082-X.
[18] P. Starzec and J. Andersson, “Application of two-level factorial design to sensitivity analysis of keyblock statistics from fracture geometry,” Int. J. Rock Mech. Min. Sci., vol. 39, no. 2, pp. 243–255, 2002, doi: 10.1016/S1365-1609(02)00026-6.
[19] H. Patel and S. Salehi, “Structural integrity of liner cement in oil & gas wells: Parametric study, sensitivity analysis, and risk assessment,” Eng. Fail. Anal., vol. 122, Apr. 2021, doi: 10.1016/J.ENGFAILANAL.2020.105203.
[20] A. Abdollahipour, H. Soltanian, Y. Pourmazaheri, E. Kazemzadeh, and M. Fatehi-Marji, “Sensitivity analysis of geomechanical parameters affecting a wellbore stability,” J. Cent. South Univ., vol. 26, no. 3, pp. 768–778, 2019, doi: 10.1007/s11771-019-4046-2.
[21] J. Zhao and W. Zhu, Stability Analysis and Modelling of Underground Excavations in Fractured Rocks. 2003.
[22] M. Heydari, M.R. Aghakhani Emamqeysi, M. Sanei, Finite element analysis of wellbore stability and optimum drilling direction and applying NYZA method for a safe mud weight window, Journal of Analytical and Numerical Methods in Mining Engineering 11 (2022) 67–76.
[23] A. Abdollahipour, A. Kargar, M. Fatehi-Marji, Numerical modeling of the effect of Anderson’s stress regimes on the volume of sand production in oil wellbores, Journal of Analytical and Numerical Methods in Mining Engineering 13 (2023) 31–38.
[24] E. Emami Meybodi, J. Hajibagheri Foroshani, F. Kargaran Bafghi, Numerical modeling for Selection of appropriate tunneling method in S station of Isfahan subway, Journal of Analytical and Numerical Methods in Mining Engineering 11 (2022) 27–40.
[25] W. S. Zhu et al., “A study on sidewall displacement prediction and stability evaluations for large underground power station caverns,” Int. J. Rock Mech. Min. Sci., vol. 47, no. 7, pp. 1055–1062, 2010, doi: 10.1016/j.ijrmms.2010.07.008.
[26] A. Abdollahipour and R. Rahmannejad, “Investigating the effects of lateral stress to vertical stress ratios and caverns shape on the cavern stability and sidewall displacements,” Arab. J. Geosci., vol. 6, no. 12, pp. 4811–4819, 2013, doi: 10.1007/s12517-012-0698-z.
|
|
آمار
تعداد مشاهده مقاله: 625
تعداد دریافت فایل اصل مقاله: 405