EVALUATION OF LATE MIOCENE HYDROCARBON RESERVOIRS, THROUGH COMPUTER PROCESSED INTERPRETATIONS ON THE WELL LOG DATA OF NIDOCO FIELD, NILE DELTA, EGYPT

Authors

1 AL-Azhar University

2 Belayim Petroleum Company, Cairo, Egypt.

Abstract

The present study deals with a comprehensive interpretation of the available well-log data at the Central part of the Nile Delta (Nidoco Field). The regional geologic setting of the area was discussed before going deeply in the petrophysical interpretation of the study area. The geologic interpretation was started by good geologic correlation, subdividing the studied Late Miocene section into levels and units. These levels and units are correlated among wells, according to their remarkable changes in log responses and similarity.
Tri-porosity (M-N) cross-plots for mineral identifications were used, to detect in general the types of lithology. Lithological identification is achieved through the cross-plots between ρb, Øn and ∆t to detect the exact lithology for each layer. These plots showed that, sandstone and shale represent the main components of the Late Miocene section. Pickett’s plots were constructed to determine the formation water resistivity (Rw), and the water and hydrocarbon saturations (Sw and Shr). Dia-porosity cross-plots were established, to determine the shale volume (Vsh) and effective porosity (Øeff). Shale types cross-plots were used also to detect the shale types in the studied section, which are mainly laminated with a mixture of dispersed shales. Shale minerals cross-plots were used too to indicate that, Montmorillonite is the main shale component in the studied section.
The petrophysical characteristics of the studied wells were represented vertically in the form of litho-saturation cross-plots inferred from the computer processed interpretation (CPI). The lateral variations of the mentioned petrophysical characteristics were represented in the form of iso-parametric maps (shale content, effective porosity and hydrocarbon saturation).
The petrophysical characteristics of studied levels and units reflect the ability of some layers to store and produce hydrocarbon. It is clear that, Level-2, Level-3, Level-3A, Level-3 Lower, Unit-A and Unit-B show better reservoir characterization and higher gas potentialities than these of the remaining studied levels and units. According to these results, it is recommended to drill more exploratory and development wells, to produce more hydrocarbons from the study area, which is thought to preserve high hydrocarbon potentialities.

Main Subjects