Abstract:
The Indus Basin offshore is a rift and passive margin basin of Pakistan and
north-western India. Murray Ridge is in the west, Karachi offshore on the northern
and eastern side whereas Carlsberg Ridge closes the southern margin of the Indus
Fan. Using the well data from PakCan-01 and Indus Marine-1B along with published
information, seven, age - wise horizons from Cretaceous to Pliocene are marked.
Northeast – southwest trending fault pattern has been established in the Indus Fan,
whereas, northwest – southeast trend of the faults have been observed along the
Murray Ridge. To understand the geometry and geological history of the basin, time,
depth and isopach maps have been produced for the respective horizons. Tertiary
platform lies in the eastern part of the basin which has been developed over the
Mesozoic sedimentary sequence. Central part of the basin has enriched sedimentation
associated with the rifting and represents the phase of post-rifting. This particular area
of the basin has extension fault blocks, normal faults, listric faults and associated
rollover anticlines as the major structures that contain petroleum play prospects.
Murray Ridge lies in the western part of the basin which is believed to be going under
transform motion along with the Arabian plate. Rifting associated with breakup of
India from Madagascar / Seychelles began during Late Cretaceous. On the basis of
seismic data, episodic tectono-sequences have been established and correlation has
been made. The area is characterized by pre- rift sequences, pre-collision/drift and
collisional sequences. Normal faulting in the Miocene is attributed to the sinking and
stretching of the basin which is controlled by the listric faulting. Miocene and Plio-
Pliestocene times are characterized by large-scale channel levee complexes covering
the proximal part of the Indus Fan. The attributes analysis including RMS Amplitude,
Instantaneous Frequency and Sweetness have been applied and tested on the selected
set of seismic data and their effectiveness has been substantiated. Fault patterns were
revealed more clearly by the application of variance attribute. Most of the reflection
geometries were observed on the RMS amplitude. Attribute analysis and tectono
sequence stratigraphy provided a base for the hydrocarbon potential of the area.
