SEISMIC PROCESSING & INVERSION IN RAY PARAMETER DOMAIN: GAS CLOUD CASE STUDY & STUDY OF LITHOLOGY SEPARATION

• Main Author: Immanuel Sinaga - NIM: 22315003 , Edycakra
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26849
• Institution: Institut Teknologi Bandung

<p align="justify">Combining the lateral-rich seismic data with vertical-rich well log information, seismic impedance remains a very useful tool in reservoir characterization. Acoustic Impedance is a product of density and P-wave velocity. Elastic Impedance (EI) uses P-wave velocity, S-wave velocity, and density in order to pinpoint a better separation of hydrocarbon within the reservoir. However, Elastic Impedance has an assumption of single angle for both incidence and transmitted angle, which neglects the Snell’s Law. This study offers another insight in form of Ray Impedance (RI). Processed in ray parameter domain, Ray Impedance is defined along constant ray path that contains various angle and velocity for each subsurface layer. To construct the Ray Stack, the seismic data need to be transformed from offset domain to ray parameter domain during the seismic data processing step. For the input data for Ray Impedance inversion, we stack the designated Near-Ray, Mid-Ray, and Far-Ray as a Partial Ray Section. For comparison, we also perform Elastic Impedance inversion to the Near-Angle, Mid-Angle, and Far-Angle which is the counterpart for the representative Ray Stack. The Post-Stack Impedance Inversion is conducted for CDP Stack, Ray Stack and Angle Stack to derive AI, EI, RI respectively. This thesis focus on data with information of gas cloud that makes a poor imaging of seismic data. Stack section in ray parameter domain showcases a better approach for seismic imaging in gas cloud area. There’s also a comparison between impedance log which showcases that RI has a better separation for low vclay. The comparison of these stack sections show that Ray Stack can be considered as an alternative approach to enhance subsurface imaging in gas cloud case. And the comparison between the impedance log crossplot shows that RI has potential to be a better approach for lithology separation.<p align="justify">