FLUID PATTERN CHANGE MONITORING USING TIME-LAPSE AMBIENT NOISE TOMOGRAPHY (TL-ANT) METHOD AT

• Main Author: Putri Sharfina, Nadira
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86568
• Institution: Institut Teknologi Bandung

Fluid injection activities are carried out as an effort to increase the rate of oil and gas production in the "RR" Field. Fluid injection activities need to be monitored for changes in fluid migration patterns and connectivity between injection wells and production wells. Monitoring changes in fluid migration can be done by applying geophysical methods, one of which is the Time-lapse Ambient Noise Tomography (TL-ANT) method. The TL-ANT method utilizes seismic noise signals recorded at 37 seismic stations installed in the study area continuously over a certain period of time. The TL-ANT method is based on new signals obtained from cross-correlation between two seismic stations. The stages carried out are the identification of the Green Function for each pair of stations and the calculation of the group velocity value for each period taken from the dispersion curve. The next step is the inversion of the group velocity to obtain a 3D Vs tomography image. The data used are passive seismic measurement data for 7 days in the 5th and 6th weeks after injection. In this final project, tomography images are displayed in two types of tomography map cross-sections, namely horizontal cross-sections at a depth of 100-400 meters and vertical cross-sections in east-west and north-south orientations around the injection wells. Based on these results, the low Vs anomaly profile is consistently seen around the injection wells which is interpreted as an indication of the distribution of fluids resulting from fluid injection activities. In addition, there is connectivity between the W06 injection well and the W01, W03, and W08 production wells and between the W07 injection well and the W04 and W10 production wells. While the high anomaly indicates the geological structure