مجله ژئوفیزیک ایران

مجله ژئوفیزیک ایران

اندازه گیری تانسور کامل گرادیان میدان مغناطیسی با استفاده از حسگرهای ممز، مطالعه موردی بر روی معدن سنگ آهن جعفرخان

نوع مقاله : مقاله پژوهشی‌

نویسندگان
هاشم شاهسونی 1
سنور عبداللهی 2
1 دانشیار، گروه مهندسی معدن، دانشگاه کردستان، کردستان، ایران
2 دانش‌آموخته، کارشناسی ارشد مهندسی اکتشاف مواد معدنی، دانشگاه کردستان، کردستان، ایران
10.30499/ijg.2023.381276.1484
چکیده
یکی از شیوه‌های برداشت مغناطیس‌سنجی، برداشت به‌شیوه تانسور کامل گرادیان مغناطیسی است. به‌منظور به‌دست آوردن تانسور کامل گرادیان مغناطیسی زمین حداقل به چهار حسگر نیاز است. تاکنون، به‌شیوه معمول، از چهار مغناطیس‌سنج اسکوئیدی به‌منظور بدست آوردن تانسور کامل گرادیان مغناطیسی استفاده شده است. اما این حسگرها هزینه زیادی داشته و دامنه عملکرد دمایی کمی دارند. اخیراً حسگرهایی با تکنولوژی سیستم‌های میکرو الکتریکی مکانیکی یا ممز توسعه داده شده‌اند که بسیار کوچک، کم وزن و کم مصرف می-باشند. در این تحقیق از این نوع حسگرها به‌جای حسگرهای اسکوییدی استفاده شده است. هر چند این حسگرها قدرت تفکیکی به اندازه مغناطیس سنج‌های اسکوییدی ندارند و نمی‌توان از آن‌ها بر روی بی‌هنجاری‌های کوچک که تغییراتی کمتر از 160 نانوتسلا بر روی میدان مغناطیسی زمین ایجاد کرده‌اند استفاده کرد، اما این حسگرها قادرند بزرگای میدان مغناطیسی را در سه جهت عمود بر هم اندازه‌گیری کنند و دارای حساسیت قابل قبولی می‌باشند. در این مطالعه چهار حسگر از این نوع با آرایشی متقاطع راه‌اندازی شده‌اند. سپس برداشت‌هایی بر روی یک ذخیره سنگ‌آهن در نزدیکی روستای جعفرخان شهرستان سقز در استان کردستان انجام شده است. به منظور اعتبار سنجی درایه-های ماتریس تانسور کامل گرادیان مغناطیسی با مشتقات سویی حاصل از یک حسگر با یکدیگر مقایسه شده‌اند. این مقایسه نشان می‌دهد روش تانسور کامل گرادیان برای درایه‌های Gxx، Gyx، Gzx، Gzy و Gzz نسبت به مشتق های سویی متناظرشان به ترتیب به اندازه صفر، 79/4، 80/10، 83/83، 46/8 افزایش نسبت سیگنال به نوفه داشته است. این موضوع نشان دهنده توانایی حسگرهای ممز در برداشت به شیوه تانسور کامل گرادیان مغناطیسی است.
کلیدواژه‌ها
حسگر
سیستم‌های میکروساختار مکانیکی (ممز)
جعفرخان
تانسور کامل گرادیان مغناطیسی
مشتق سویی

موضوعات

عنوان مقاله English

Full magnetic tensor gradient survey with MEMS sensor, a case study on the Jafarkhan iron ore deposit

نویسندگان English

Hashem Shahsavani 1
Sonoor Abdollahi 2
1 Assistant Professor, Department of Mining, Faculty of Engineering, University of Kurdistan, Sanandaj, Iran
2 M.Sc. Student, Mining Department, Faculty of Engineering, University of Kurdistan, , Sanandaj, Iran
چکیده English

Magnetometry is one of the geophysical methods that has wide applications. In traditional magnetometry, one sensor so-called magnetometer is used for measurements. In order to obtain the gradient in a specific direction, mathematical derivation can be used. Alternatively, A more accurate method of obtaining the gradient is using two sensors simultaneously measuring the magnetic field. In this case, the gradient is obtained in the direction where the two sensors are placed relative to each other. To obtain the Full Magnetic Tensor Gradient (FMTG) of the Earth’s magnetic field, although direction derivatives can be used, the more accurate method is to use four sensors that measure the Earth’s magnetic field simultaneously. In this way, the FMTG matrix can be obtained. So far, Superconducting Quantum Interference Device (SQID) sensors have been used the most in obtaining the FMTG. But these sensors are very expensive and have accurate performance in a small range of temperatures. By developing the Micro Electro Mechanical System (MEMS) sensor with its variety of applications, geophysicists are also becoming interested in using such sensors. In this study, one of the precise MEMS magnetometers has been selected. Although the MEMS sensors have low sensitivity compared to SQUID magnetometers, due to their availability, being cheap, and lightness, they are a suitable option for FMTG measurements.

Although these sensors do not have the resolution of SQUID magnetometers and they cannot be used on small anomalies that have caused changes of less than 160 nT on the Earth’s magnetic field, these kinds of sensors are able to measure the magnitude of the magnetic field in three perpendicular directions and have an acceptable sensitivity. In this study, four sensors of this type have been set up in a cross arrangement. In order to solve the problem of the low sensitivity of these sensors compared to SQUID sensors, the distance between the sensors was chosen to be one meter so that the gradient value would be larger enough. Then, a survey has been performed on an iron ore deposit near Jafar Khan village, Saqqz City, Kurdistan province. In order to validate elements of the FMGT matrix, they have been compared with the directional derivatives obtained from a sensor. This comparison shows that the elements Signal-to-noise ratio of elements Gxx, Gyx, Gzx, Gzy, and Gzz have increased around zero, 4.79, 10.80, 83.83, and 8.46, respectively, compared to their corresponding directional derivatives. This issue shows the ability of MEMS sensors to capture the full tensor of the magnetic gradient.

کلیدواژه‌ها English

Sensor
Micro-Electro-Mechanical Systems (MEMS)
Jafar Khan
Full Magnetic Tensor Gradient
Directional Derivative
ملکی، پ.، شاهسونی، ه.، 1396، معرفی سنسور ممز در مگنتومتری: اولین همایش بین‌المللی پژوهش و پیشرفت در علوم زمین.
Chen, J., and Wise, K. D., 1997, A high-resolution silicon monolithic nozzle array for inkjet printing: IEEE Transactions on Electron Devices, 44(9), 1401–1409, https://doi.org/10.1109/16.622594.
Chwala, A., Stolz, R., Zakosarenko, V., et al., 2012, Full tensor SQUID gradiometer for airborne exploration: ASEG Extended Abstracts, 2012(1), 1–4, https://doi.org/10.1071/ASEG2012ab296.
Dentith, M., and Mudge, S., 2013, Geophysics for the Mineral Exploration Geoscientist: Cambridge University Press.
FitzGerald, D., Argast, D., Paterson, R., and Holstein, H., 2010, Progress on interpreting dykes from full tensor magnetic gradiometry: SEG Technical Program Expanded Abstracts, 1162–1166, https://doi.org/10.1190/1.3513050.
Gamey, T. J., Starr, T., Doll, W. E., and Beard, L. P., 2004, Initial design and testing of a full-tensor airborne SQUID magnetometer for detection of unexploded ordnance: 2004 SEG Annual Meeting, https://onepetro.org/SEGAM/proceedings-abstract/SEG04/All-SEG04/SEG-2004-0798/92120.
Ghorbani, M., 2013, The Economic Geology of Iran: Springer Dordrecht.
Gunn, P. J., and Dentith, M. C., 1997, Magnetic responses associated with mineral deposits: Journal of Australian Geology and Geophysics, 17(2), 145–158, https://d28rz98at9flks.cloudfront.net/81499/Jou1997_v17_n2_p145.pdf.
Kearey, P., Brooks, M., and Hill, I., 2002, An Introduction to Geophysical Exploration, 3rd edition: Blackwell Science Ltd.
Kotsiaros, S., and Olsen, N., 2014, End-to-end simulation study of a full magnetic gradiometry mission: Geophysical Journal International, 196(1), 100–110, https://doi.org/10.1093/gji/ggt339.
Liu, H. F., Luo, Z. C., Hu, Z. K., Yang, S. Q., Tu, L. C., Zhou, Z. B., and Kraft, M., 2022, A review of high-performance MEMS sensors for resource exploration and geophysical applications: Petroleum Science, 19(6), 2631–2648, https://doi.org/10.1016/j.petsci.2022.06.005.
Luo, Y., Wu, M. P., Wang, P., Duan, S. L., Liu, H. J., Wang, J. L., and An, Z. F., 2015, Full magnetic gradient tensor from triaxial aeromagnetic gradient measurements: Calculation and application: Applied Geophysics, 12(3), 283–291, https://doi.org/10.1007/s11770-015-0508-y.
Nelson, B., Stolz, R., Schulz, M., Chwala, A., Rothenbach, M., and Meyer, H. G., 2003, The German airborne SQUID tensor magnetic gradiometer: 8th International Congress of the Brazilian Geophysical Society, https://doi.org/10.3997/2214-4609-pdb.168.arq_1104.
Pedersen, L. B., and Rasmussen, T. M., 1990, The gradient tensor of potential field anomalies: Some implications on data collection and data processing of maps: Geophysics, 55(12), 1558–1566, https://doi.org/10.1190/1.1442807.
Petersen, K. E., 1982, Silicon as a mechanical material: Proceedings of the IEEE, 70(5), 420–457, https://doi.org/10.1109/PROC.1982.12331.
Queitsch, M., Schiffler, M., Stolz, R., Rolf, C., Meyer, M., and Kukowski, N., 2019, Investigation of 3D magnetisation of a dolerite intrusion using airborne full tensor magnetic gradiometry (FTMG) data: Geophysical Journal International, 217(3), 1643-1655, https://doi.org/10.1093/gji/ggz104.
Rudd, J., Chubak, G., Larnier, H., et al., 2022, Commercial operation of a SQUID-based airborne magnetic gradiometer: The Leading Edge, 41(7), 486–492, https://doi.org/10.1190/tle41070486.1.
Schmidt, P. W., and Clark, D. A., 2000, Advantages of measuring the magnetic gradient tensor: Preview, 85, 26–30.
Schmidt, P. W., and Clark, D. A., 2006, The magnetic gradient tensor: Its properties and uses in source characterization: The Leading Edge, 25(1), 75–78, https://doi.org/10.1190/1.2164759.
Schmidt, P. W., Clark, D., Leslie, K., Bick, M., Tilbrook, D., and Foley, C., 2004, GETMAG – a SQUID magnetic tensor gradiometer for mineral and oil exploration: Exploration Geophysics, 35(4), 297–305, https://doi.org/10.1071/EG04297.
Schneider, M., Stolz, R., Linzen, S., Schiffler, M., Chwala, A., Schulz, M., Dunkel, S., and Meyer, H. G., 2013, Inversion of geo-magnetic full-tensor gradiometer data: Journal of Applied Geophysics, 92, 57–67,
 
      https://doi.org/10.1016/j.jappgeo.2013.02.007.
Stolz, R., Fritzsch, L., and Meyer, H. G., 1999, LTS SQUID sensor with a new configuration: Superconductor Science and Technology, 12(11), 806–808, https://doi.org/10.1088/0953-2048/12/11/334.
Stolz, R., Zakosarenko, V., Schulz, M., Chwala, A., Fritzsch, L., Meyer, H. G., and Köstlin, E. O., 2006, Magnetic full-tensor SQUID gradiometer system for geophysical applications: The Leading Edge, 25(2), 178–180, https://doi.org/10.1190/1.2172308.
Sui, Y., Li, G., Wang, S., and Lin, J., 2014, Compact fluxgate magnetic full-tensor gradiometer with spherical feedback coil: Review of Scientific Instruments, 85(1), 014701, https://doi.org/10.1063/1.4856675.
Sui, Y., Miao, H., Wang, Y., Luan, H., and Lin, J., 2016, Correction of a towed airborne fluxgate magnetic tensor gradiometer: IEEE Geoscience and Remote Sensing Letters, 13(12), 1837–1841, https://doi.org/10.1109/LGRS.2016.2614538.
Sui, Y., Miao, H., Zhou, Z., Luan, H., Yu, S., and Lin, J., 2015, A case of fluxgate magnetic gradient tensor measurement system on microlight: International workshop and gravity, electrical and magnetic methods and their applications, Chenghu, China, 25–28, https://doi.org/10.1190/GEM2015-007.
Wynn, W., Frahm, C., Carroll, P., Clark, R., Wellhoner, J., and Wynn, M., 1975, Advanced superconducting gradiometer/magnetometer arrays and a novel signal processing technique: IEEE Transactions on Magnetics, 11(2), 701–707, https://doi.org/10.1109/TMAG.1975.1058672.
Xu, L., Zhang, N., Fang, L., Chen, H., Lin, P., and Lin, C., 2021, Simulation analysis of magnetic gradient full-tensor measurement system: Mathematical Problems in Engineering, 1–13, https://doi.org/10.1155/2021/6688364.
Yue, L., Cheng, D., Qiao, Y., and Zhao, J., 2022, Error calibration for full tensor magnetic gradiometer probe based on coordinate transformation method: IEEE Transactions on Instrumentation and Measurement, 71, 1–11, https://doi.org/10.1109/TIM.2022.3193977.
Zhdanov, M. S., Cai, H., and Wilson, G. A., 2011, 3D inversion of full tensor magnetic gradiometry (FTMG) data: SEG Technical Program Expanded Abstracts, 791–795, https://doi.org/10.1190/1.3628195.
Zhdanov, M. S., Cuma, M., Wilson, G. A., and Polomé, L., 2012, 3D magnetization vector inversion for SQUID-based full tensor magnetic gradiometry: SEG Annual Meeting, SEG-2012-0740.
 
مجله ژئوفیزیک ایران
دوره 17، شماره 4
پاییز 1402
صفحه 81-98