Acoustic Impedance (AI) from post-stack inversion is commonly used to find sweet spots with favorable sedimentary facies during exploration. It is used in this study to explain the facies variation as a result of sea level change. To better understand the production difference in the reservoirs with low AI, the influence of pore structure on AI was analyzed on core samples and explained by a rock physical parameter called frame flexibility factor ?. With similar AI, reservoirs dominated by moldic pores are more restricted in flow and have lower production compared to reservoirs dominated by intercrystalline pores. To distinguish the two pore systems, ‘Poisson Impedance (PI)’ was introduced and extracted from the results of Pre-stack Simultaneous Inversion. 1000 km/s*g/cc was determined to be the boundary of PI for the two pore systems where ? equals 3. The results show that carbonate shoals are widely distributed during early HST and prograding seaward as sea level drops. Pore spaces (low AI) within ooid shoals are limited during transgression while moldic and intercrystalline pores are widely developed during the long term regression. As sea level drops, moldic pores are more developed during early HST (PI <1000 km/s*g./cc) while micro-intercrystalline pores from micritic dolomite dominate during late HST.
Presentation Date: Wednesday, October 19, 2016
Start Time: 1:55:00 PM
Presentation Type: ORAL