Formation evaluation and reservoir properties estimation of hydrocarbon zone in ' Azoh' field onshore Niger Delta
Date
2023-09
Authors
Journal Title
Journal ISSN
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Publisher
Federal University of Technology, Owerri.
Abstract
Formation evaluation of three wells in the ‗Azoh‘ field, Northern Delta Depobelt, was carried out in
this study in order to identify potential prospective pay zones, their potential hydrocarbon fluid
content and reservoir quality. An integrated methodology involving the use of well logs, mud logs and
core data (sidewall core descriptions and core photos) was adopted to delineate three reservoir sand
units, designated D2000, E3100 and F1000 reservoir sands respectively. Reservoir properties
including water saturation, effective porosity and net reservoir thickness were computed and used to
estimate the volume of in-place hydrocarbons within these reservoirs. In addition, the depositional
environments were characterized using gamma ray log shape. Results of the petrophysical analysis
revealed that these reservoirs are high quality sands, with estimated average effective porosity values
of 20% for D2000 sand, 30% for E3100 sand and 25% for F1000 sand, respectively, which are within
the range for commercial accommodation of hydrocarbon. Generally, the petrophysical characteristics
of the reservoirs are good especially at the areas of interest (hydrocarbon zones). This can be
attributed to their depositional environment which ranges from distributary mouth bars to shoreface
deposits. The volume of shale values for some of the reservoirs are within the limits that could not
affect the water saturation, while the water saturation in some zones is appreciably low (1%- 21%),
indicating that hydrocarbon production from these reservoirs are likely to be water free. D2000 sand
and F1000 sand tested oil in the three wells, while E3100 sand tested gas in the wells. Each of the
reservoir sand have an average estimated permeability value of 16.92mD for D2000 sand, 47.80mD
for E3100 sand and 28.05mD for F1000 sand respectively, indicating that the reservoirs have good
interconnected pores. Estimates of hydrocarbon volumes showed that D2000 and F1000 sands both
have 2.9 and 2.4 billion barrels of recoverable oil respectively, while E3100 have 3.1 trillion cubic
feet of recoverable gas. These results on the whole suggest that the reservoir sand units of ‗Azoh‘
Field contain significant accumulations of hydrocarbon.
Description
Master of Science ( M.Sc ) in Petroleum/Sedimentary Geology.
Keywords
Hydrocarbon, Permeability, Petrophysics, Water saturation, Well log.
Citation
Ozah, E. (2023).Formation evaluation and reservoir properties estimation of hydrocarbon zone in ' Azoh' field onshore Niger Delta . { Unpublished masters thesis }, Federal University of Technology, Owerri.