Velocity and Structural Modeling of Mesozoic Chiltan Limestone and Goru Formation for Hydrocarbon Evaluation in the Bitrisim Area, Lower Indus Basin, Pakistan

摘要

The present study focuses on building a workflow for structural interpretation and velocity modeling and implementing to Jurassic-Cretaceous succession(Chiltan Limestone and Massive sand of the Lower Goru Formation).2D-Migrated seismic sections of the area are used as data set and in order to confirm the presence of hydrocarbons in the study area,P and S-wave seismic velocities are estimated from single-component seismic data.Some specific issues in the use of seismic data for modeling and hydrocarbon evaluation need to deal with including distinguishing the reservoir and cap rocks,and the effects of faults,folds and presence of hydrocarbons on these rocks.This study has carried out the structural interpretation and modeling of the seismic data for the identification of traps.The results demonstrate existence of appropriate structural traps in the form of horst and grabens in the area.2D and 3D velocity modeling of the horizons indicates the presence of high velocity zones in the eastern half of the study while relatively low velocity zones are encountered in the western half of the area.Two wells were drilled in the study area(i.e.Fateh-01 and Ichhri-01)and both are dry.Immature hydrocarbons migration is considered as a failure reason for Fateh-01 and Ichhri-01 well.