#TITLE_ALTERNATIVE#

• Main Author: RIZALDI (NIM 12404024), OKI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/14375
• Institution: Institut Teknologi Bandung

Seismic waves energy decrement and selected frequency absorption by rock material known as intrinsic attenuation affected by physical properties of rocks (porosity, grain size, density, fluid saturation, fluid viscousity, pressure, etc.). From well informations at ORiza* field show the existence of gas saturation wich causing intrinsic attenuation in seismic waves, by using vertical seismic profiling data well OR_1* and OR_A2* from ORiza* field the intrinsic attenuation can be quantified as seismic quality factor (Q) using spectral ratio method. Quantification of intrinsic attenuation applied to P-waves using primery downgoing P-waves and to S-waves using SV-waves from converted wave of primary downgoing P-waves when passing trough medium boundary, far offset VSP acquisition design and seismic wave propagation modelling make estimation of P-SV conversion point easier.<p>Heterogenity of physical properties and thickness from rocks layer causing cumulative attenuation did not always increase with depth, Q estimation from large depth interval give Q more stable than Q from small depth interval because we get Q average from that depth interval. As the result at OR_1 * well (Qp + 20) for depth interval 715.59m - 1382.50m, at OR_A2* well (Qp + 20) for depth interval 98.46m - 1186.92m and (Qs + 13) for depth interval 1109.49m - 1408.72m.