Abstract:
In order to map the subsurface to understand the potential of the hydrocarbons present,
an understanding of the lithology and its
uids is of the utmost importance. Geoscientists
spend a lot of time identifying the lithologies using well logs, but there are instances when
using the conventional methods gives us ambiguous results. Presence of
uids or their
withdrawal can change the signatures that we observe and leads to the ambiguity. In this
study, we use crossplots of di erent petrophysical parameters like Lambda - Mu - Rho,
P impedance and S impedance, Vp, Vs to classify and discriminate among the lithology
and the
uid. This study shows a comparative study of lithology and
uid identi cation
between sandstones and carbonates. Lambda Mu Rho technique, i.e. crossplots of Lambda
Rho and Mu Rho is able to discriminate between gas sand, brine sand, carbonate and
shale in a much better way. It also increases the detectability and sensitivity of
uids and
carbonates over other fundamental methods. In this study we see how the gas sands and
non reservoir sands are separated from the background shales. We also see the behaviour of
carbonates on the crossplots and understand their importance of the mineral constituting
the carbonate formations.
