Pemodelan Anomali Gravitasi Menggunakan Grablox untuk Identifikasi Injeksi Fluida pada Reservoir

Abstract
The 4D microgravity method is a development of the gravity method with the time as the fourth dimension. This research was conducted to find a better way of interpreting the 4D gravity anomaly due to fluid injection around the reservoir. Researchers used GRABLOX for the interpretation of 4D anomalies around the reservoir. The results of the inversion of field data using GRABLOX provide the value of the injection fluid infiltration volume, which shows the distribution of the injection fluid movement on the reservoir. Another physical parameter that can be generated from GRABLOX with a modified value is the reduction in oil and gas saturation due to fluid injection. The inversion results using GRABLOX in the field data indicate a change in reservoir rock density up to 0.28 gr/cc associated with a reduction in gas and oil saturation. The reduction in gas saturation due to the injection fluid has the smallest value of 0% and the largest is up to 66%. The reduction in oil saturation only contributes to a density change of 20% of the reduction in gas saturation. The results of the GRABLOX trial on synthetic data and field data show that both can provide an identification of the movement of the injection fluid in the reservoir, as well as provide other physical parameters, ie. the reduction in oil saturation due to fluid injection.