نوع مقاله : مقاله پژوهشی
موضوعات
عنوان مقاله English
نویسنده English
As the extraction of information about petrophysics and fluid content from near-field versus far-field variations has gained more importance in recent years, understanding the effect of shale anisotropy in near-field versus far-field is essential. The layered structure of clay minerals causes elastic anisotropy. Shales (even conventional shale samples) are often elastically anisotropic due to the alignment of anisotropic clay minerals with the bedding plane. This research aims to address this issue by presenting a method based on rock physics modeling and the use of Thomsen parameters for AVO analysis in VTI environments. In this study, the impact of shale anisotropy on amplitude versus offset (AVO) analysis at the gas sand/shale interface in the Kerman Formation has been examined. This issue is important because accurate AVO analysis can be effective in identifying hydrocarbon areas, but in many previous studies, isotropy in environments has been assumed, which may lead to errors. In this study, the amplitude versus offset analysis in a vertically transverse isotropic (VTI) medium has been examined. For this purpose, Thomsen's anisotropy parameters were calculated. Since the anisotropy of shale affects the results of amplitude versus offset analysis at the gas sand/shale contact in the Kerman Formation, we have evaluated the impact of shale on amplitude versus offset analysis in the Kerman Formation. The results showed that in an anisotropic environment, Class 1 AVO is identifiable, indicating the presence of hydrocarbons, whereas in an isotropic environment, no distinct trend is observed in the AVO class. Additionally, it was observed in synthetic models that the effect of anisotropy is more pronounced at larger angles. The innovation of this study lies in presenting a combined analytical approach based on rock physics modeling and Thomsen parameters for AVO analysis in an anisotropic environment, which goes beyond classical isotropy assumptions and can aid in improving the location of new drilling areas.
کلیدواژهها English
