TIME LAPSE AMBIENT NOISE TOMOGRAPHY TO MODEL THE S-WAVE VELOCITY (VS) STRUCTURE IN THE “NR” OIL AND GAS FIELD (PERIOD M7 AND M8 AFTER FLUID INJECTION)

• Main Author: Erry Nurfauziah, Siti
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86954
• Institution: Institut Teknologi Bandung

Fluid injection is one of the methods to increase the oil productivity of a reservoir. Fluid injection activities in NR Field cause changes in subsurface conditions in the field. This final project applies the Time Lapse Ambient Noise Tomography (TL-ANT) method to see the changes in subsurface conditions in NR Field. TL-ANT was conducted at two different periods after the fluid injection activity. The subsurface conditions were observed in week 7 and week 8 after fluid injection, 7-day and 6-day periods respectively. Observations of subsurface conditions are the result of direct tomographic inversion based on cross-correlation of ambient seismic noise data. The ambient seismic noise data used is the result of continuous recording by 37 seismometers in the field. Daily waveform data that has been recorded is then crosscorrelated for each pair of stations, and then stacked for each period of 7 days and 6 days. The stacking results were used for Green's Function determination. The dispersion curves obtained for each station pair are input for tomographic inversion and describe the pattern of S-wave velocity (VS). The results can be interpreted as a pattern of changes in the subsurface structure in NR Field at different periods. Based on the velocity change results, well connectivity can be estimated. Injection well W12 is interpreted as possibly connected to production wells W01 and W03, while injection well W13 is possibly connected to production wells W04, W05, W08 and W11.