Publications

2D seismic data in the South Ardjuna Basin were used to map Upper Cibulakan hydrocarbon reservoirs with large or similar acoustic impedance relative to the encasing shale. Normalization, residual mistie corrections, and alternative display techniques were applied to increase the visibility of subtle amplitude features in post-stack data. These corrected data were interpreted over known hydrocarbon accumulations to calibrate the techniques. The greatest success was realized for high impedance calcareous sandstone or carbonate reservoirs having significant impedance contrasts between the reservoirs and encasing shale. These reservoirs exhibited decreases in relative amplitude or ",dim spots", associated with hydrocarbons. Similar techniques were applied to data prior to drilling wells in the KWKKN area. Overall, the results were encouraging and demonstrate that these post-stack techniques can be used for predicting hydrocarbon occurrence in some of the Ardjuna reservoirs. These post-stack amplitude techniques are difficult to apply successfully when mapping reservoirs having acoustic impedance similar to interbedded shales. The signal to noise ratio is small and the reflectivity of such reservoirs are usually ",swamped", by interference from overlying and underlying larger amplitude reflections. Initial work with pre-stack gathers in the KK/KKN Field show that pre-stack techniques can be applied successfully to these reservoirs. Pre-stack amplitude interpretation techniques including near/far stacks and AB cross plotting will become important tools for future prospecting in ONWJ.