Reservoir Characterization Using Curved Pseudo Elastic Impedance (CPEI) and Pseudo Elastic Impedance for Lithology (PEIL) in 'x' Area of North Carnarvon Basin, Australia

Abstract

Hydrocarbon identification requires accurate information regarding the presence of subsurface reservoirs. One commonly used approach is to characterize the reservoir using various methods to describe the distribution of reservoir lithology and fluids, namely seismic inversion. However, seismic data interpretation involves a high of uncertainty due to variations in subsurface characteristic. This study utilizing Curved Pseudo Elastic Impedance (CPEI) and Pseudo Elastic Impedance for Lithology (PEIL) based on trigonometry approach to observe the distribution of lithology and fluid reservoir in the Barrow Group of North Carnarvon Basin, Australia. The data used in this study include well log data from three wells (Well 1, Well 2, and Well 5) and 3D partial angle stack seismic data, which gathered data used to perform simultaneous inversion for generate CPEI and PEIL attributes. The crossplot of the CPEI attribute is low at 4.30-4.90 g/cc*km/s indicates hydrocarbon presence and also the PEIL attribute is low to moderate at 9.0-11.0 g/cc*km/s show the lithology with a good porosity (>15%). Based on the attribute volume and slicing results of CPEI and PEIL in ANS-AAR, the low CPEI value around well 1 and 5 represent hydrocarbon bearing zones and the low PEIL values correspond to reservoir lithology with high porosity. Well 2 area produces high CPEI and PEIL indicating heavier fluid content (water) and more stiff rock such as low porosity. The other area with white polygon in slice map shows the distribution of reservoir which is hydrocarbon bearing zones with high porosity. This confirmed, reservoir characterization by the presence of hydrocarbon indication and high porosity has trend distribution from northeast-southwest (NE-SW). Based on this study, rock physics attributes such as CPEI and PEIL are effective in reservoir characterization.