Optimization Algorithms with Structure Constraints for Multi-Parameter Seismic Inversion

الموضوعات

علوم تطبيقية وتكنولوجية

الملخص

Multi-parameter inversion is often encountered in geophysical imaging due to the various rock physical proprieties, such as density, magnetism and up to 21 elastic moduli for anisotropic rocks. The main challenge of the multi-parameter inversion is the non-uniqueness of its solution. Optimization algorithms are utilized to minimize the appropriate objective functions. However, some higher-order algorithms are computationally expensive, and many new first-order optimization algorithms have been developed for machine learning. In this thesis, we have examined four first-order optimization algorithms for 2D seismic anisotropic tomography in an attempt to find a reliable alternative to the common conjugate gradient algo rithm. The results show that Nesternov Accelerated Gradient (NAG) is a reliable first-order algorithm since it has achieved a low loss that is comparable to the conjugate gradient and a smooth, stable convergency. To further improve the objective function of the inversion, L0-quasinorm and L1-norm have been inves tigated against L2-norm. It was found that L0 and L1 norms help increase the accuracy of the inversion, however, at the expense of its stability. Lastly, geolog ical structure constraints such as the zero cross-gradient are useful to mitigate the problem of undefined structural boundaries from inverting different types of data. Therefore, we propose to implement the zero-cross gradient method for multi-parameter inversion. Our rational is that by enforcing structural similarity in multi-parameter inversion we are reducing the number of acceptable models and ensuring a more accurate, consistent interpretation of the subsurface. Date of Award Dec 2021 Original language American English

روابط وملفات

التعريف والنوع

رقم الوثيقة

f54c6855-b51b-4911-a096-bf96dd74b7e8

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل ماجيستير

نوع الملف

pdf text

أسماء الملفات

2282821_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Bassam Farwana","title_ar":"اعداد","title_en":"Preparation"},{"name_ar":"Bing Zhou","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"Jorge Zubelli","title_ar":"اشراف","title_en":"Supervision"}]

اللغة

English

المصدر والدورية

اسم المصدر

Optimization Algorithms with Structure Constraints for Multi-Parameter Seismic Inversion

المحتوى والصفحات

عدد الصفحات

0

كلمات الباحثين

Inversion, gradient descent, geophysical constraints, anisotropy,seismic tomography.

إشراف وإعداد

الإشراف

Bing Zhou, Jorge Zubelli

الإعداد

Bassam Farwana

الاقتباسات الببليوغرافية