Abstract:
The study area (Sawan Field), located in Lower Indus Basin, Pakistan, is chosen
to perform attribute analysis and check their effectiveness on given seismic data. Before
performing attribute analysis, both manual and digital interpretation was done for the
study area. Nine horizons namely, Pirkoh Formation, Sui Upper Limestone Formation,
Sui Main Limestone Formation, Upper Goru Formation, Lower Goru Formation, C Sand,
Sember Formation and Chiltan Limestone Formation were marked. Time and depth
contour maps were generated. Negative flower structures have been interpreted which are
conforming to transtensional tectonic regime in the study area. The “C” Sand Interval of
the Lower Goru Formation is acting as a reservoir, Sember Shale acts as a source and
upper Goru acts as a seal in the study area. Closure was found around Sawan-01 after
generation of time and depth contour map at “C” Sand level which proves that Sawan-01
was an historical producing well. Structural (faults) and Stratigraphic
(reflection geometries) were studied by applying variance attribute on the seismic data.
However for study purpose much useful information was gathered from selected
attributes. The Sweetness attribute revealed hydrocarbon potential at “C” sand level.
Variance attribute helped in recognizing and marking the faults which were difficult to be
seen on the seismic section. RMS amplitude has proven to be of great importance in
detecting major lithological changes. Instantaneous frequency attribute has proved useful
in indicating lateral changes in lithology as well as fracture zone detection at few
locations in the study area.
