PENGARUH SUBSTITUSI FLUIDA PADA MEDIUM SANDSTONE TRANSVERSE ISOTROPIK : SUATU STUDI PEMODELAN NUMERIK DAN EKSPERIMEN

• Main Author: Mohaad Ishaq, Usep
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/5468
• Institution: Institut Teknologi Bandung

<b>Abstract:<p align="justify"> <br /> <br /> Fractured reservoir rock are becoming important study recently, it is due to the high demand of oil and gas. Some of fractured reservoir are basement rock, carbonate as well as vulcanic rock. They have two kinds of porosity, primary and secondary porosity. The primary porosity is caused by matrix and frame, and it is much smaller compared to secondary porosity that caused by fractured zone. <br /> Elastic isotropy is assumed in most cases of seismic analysing, processing and interpretation. Anisotropic especially transverse isotropic behavior of seismic velocity, however, is found to exist in most crustal and subsurface media especially in fractured reservoir rock.<p align="justify"> <br /> <br /> In this theses, some studies are done to investigate the effect of saturation on three types of fracture: isotropic, vertical transverse isotropic and horizontal transverse isotropic rock. They are studied using analytical model through extended Gassmann modeling and seismic core physics laboratory. <br /> The analytical model of fractured zone is derived by extending Gassmann equation for anisotropic model, it is known as Brown-Korringa equation. This equation model the effect of fluid saturation in anisotropic fractured reservoir rock.<p align="justify"> <br /> <br /> The samples of fractured rock are built from fractured sandstone in several conditions, such as: isotropic, vertical transverse isotropic and horizontal transverse isotropic. Then, they are measured in high pressured laboratory with several types scenarios, such as variation of both overburden and pore pressure, several types of saturation: SWIRR (saturated water irreducible), full water saturated and light oil saturated.<p align="justify"> <br /> <br /> The results of numerical modeling show that in traverse isotropic media, both of P and SV wave increase due to the fluid inclusion. The SH wave velocity is unaffected by fluid inclusion. These results are different compared to isotropic Gassmann equation's assumption that S wave velocity is not sensitive to fluid substitution. Experimental studies confirmed this results. In isotropic sample, with variational overburden pressure 500 to 3500 psi and pore pressure 500-3500 psi, P wave velocity increase about 25% to 52% with water inclusions, and 12% to 41% due to light oil inclusions. On vertical traverse isotropic (VTI) media, P wave increase up to 34% due to water saturation, and in horizontal traverse isotropic (HTI) media increase about 13% to 17%. AVO responses due to the fluid inclusion in several types of fractured reservoir rocks are presented also in this thesis.