INTEGRATED PETROPHYSICAL AND SEISMIC INTERPRETATION OF OFFSHORE INDUS BASIN, PAKISTAN

Abstract

Seismic data interpretations has been used to identify parasequences, faults, stratigraphic lithologies, stratigraphic features (Channels, truncations and progradational patterns). Time and depth map used to locate the subsurface structures and horizons for petroleum exploration. Parasequences has also been marked by GR log which are confirmed by sonic log. Based on the results, reservoir rock of Miocene age is present in the study area. Shales of Miocene age having high GR readings have the potential for acting as a seal rock. Parasequences have been marked on the basis of GR readings. In IndusMarine 1-A, the lower part of Miocene encountered from 2300m to around 2470m consists of progradation (funnel shape) and aggradation (cylindrical shape) pattern. It is mainly sandstone dominated since the GR values are on the lower side and represents channel fills of Miocene age. Middle Miocene section, from 2300m upwards to around 800m has all three parasequences sets with multiple sequence boundaries. This segment is majorly dominated by shale since GR values are on the higher side (bell shape) with some portions encountering interbedded sandstone and shales. The retrogradational pattern from 1430m to 1500m represents shelf deposits. The symmetrical pattern of GR values encountered from 780m to 570m is of Late Pliocene age and indicates delta fronts. In PakG2-01 and PakCan-01wells Miocene Sands acted as reservoir. Neutron-density and neutron-sonic cross were used for lithology and mineral identification for PakG2-01 well. It was found that log values spotted on calcite and dolomite region, which confirmed the lithology as Carbonates. Many values also spotted sandstone beds.