EVALUATION OF DIRECT HYDROCARBON INDICATOR (DHI) AND ANALYSIS OF AMPLITUDE VARIATION WITH OFFSET (AVO) IN LOWER TALANG AKAR FORMATION UNTIL GUMAI FORMATION (LTAF-GUF) IN “IF” FIELD, JABUNG BLOCK, SOUTH SUMATERA BASIN

• Main Author: Ferucha, Istifani
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76135
• Institution: Institut Teknologi Bandung

The "IF" field is located in the Jabung Block, South Sumatra Basin, which is known to dominate gas production in the Lower Talang Akar Formation (LTAF). However, the thin layer on the LTAF is thought to cause a tuning effect. Thus, it is necessary to carry out seismic enhancement so that the continuity of seismic events can be seen more clearly, and it can be seen whether the anomaly seen is a fluid influence or a tuning effect is occurring. In addition, based on the potential in the LTAF, there are indications of an up-site potential in the Upper Talang Akar Formation (UTAF) to the Gumai Formation (GUF). So, it is necessary to screen the Direct Hydrocarbon Indicator (DHI) zone, either in the form of a bright spot or sweet spot using amplitude attributes and complex attributes and to analyze the presence of gas sand, oil sand and water in the reservoir using Amplitude Variation with Offset (AVO) analysis. Based on the results obtained, it shows that there is an increase in frequency which is higher than the frequency on the seismic before enhancement is carried out. So that the reservoir sand can be better resolved. In addition, after the seismic enhancement, it also shows the continuity of the seismic reflector which is more clearly than before the enhancement, and the DHI anomaly can be seen in more contrast, as shown in the sweetness attribute with an increase in amplitude which was originally 0.25 become 0.55 in the target zone at LTAF, 0.23 become 0.42 in the target zone in BRF, and 0.18 become 0.39 in the target zone in GUF. Anomalies suspected of being gas, oil, and water can be distinguished using the AVO attribute, where the product attribute is the most sensitive AVO attribute to show differences between gas, oil, and water fluids. AVO products that have been enhanced also show a more contrasting increase in amplitude compared to AVO products that have not been enhanced, both in the anomalies that exist in the LTAF, BRF, and GUF intervals.