Using Well Logs Data in Logfacies Determination By Applying the Cluster Analysis technique for Khasib Formation, Amara Oil Field, South Eastern Iraq

Abstract

Reservoir facies determination is the most important job in oil industry which dominantly
relies on the major properties of rocks. Fundamental properties of rocks are usually understood
by their detailed description in the field (lithofacies analysis) and laboratory (petrofacies
analysis). The facies (lithofacies and petrofacies) determination in most subsurface studies is
impractical, due to lack of cores and cuttings. In such situations, where the wire line logs are
the only data available, the logfacies or electrofacies are determined instead. In this study, the
available logs (gamma ray, density,Neutron, and sonic logs) for four wells (Am-1, Am-4, Am-
5, and Am-6) were used to predicate logfacies of Khasib Formation in Amara oil field. Using
Cluster Analysis in this study practiced the logfacies determination in each unit of khasib
Formation in Amara oil Field using Interactive Petrophysics software. The types of input data
into Interactive Petrophysics software to determine logfacies are available logs which are used
to create 15 clusters and determine five groups of logfacies. In this paper, the vertical
variations of logfacies for Khasib Formation are carried out based on five groups of logfacies.
These groups of logfacies are classified based on responses of well logs after divided Khasib
Formation into three units :( upper, middle and lower Khasib). In order to estimate the ratio of
existence of logfacies, the histogram of logfacies was built for each unit of Khasib Formation
in studied wells.