1 research outputs found
Seismo-Structural Interpretation and Petrophysical Evaluation of Ugwu-Field, Coastal Swamp Depositional Belt of the Niger Delta Basin
Structural interpretation of 3-D seismic data and well log have been
applied to unravel hydrocarbon entrapment pattern and petrophysical
parameters of X-field within the coastal swamp region of the Niger
Delta.. Four reservoir intervals (A, B, C and D) delineated as (W-026,
032, 042 and 048) using gamma ray and resistivity log response.
Structural interpretation for inline 5158 revealed four horizons (A, B,
C and D) and eight (8) faults labelled (F1, F2, F12, F13, F21, F22,
F23, and F24) were mapped. It was observed that the hanging wall block
due to reverse drag or rollover anticline slided over fault F12 and
created fault F2, thereby creating subsidence where sediments can be
deposited. Therefore, faults F2 and F12 created rollover structures
which cuts across the entire four reservoirs and invaluably responsible
for trapping of hydrocarbon in the field. RMS map developed for
horizons \u2018A\u2019 and \u2018B\u2019 revealed high amplitude
anomalies, while variance attribute for both horizons showed relatively
uniform lithology observed from east to west across the study area.
While from north-east to south west, variance was observed to increase
relatively which indicates different lithology. These trend exposes
dipping of the channel fill at both flanks by creating extensive
faulting. Results of petrophysical evaluation for reservoirs
\u2018A\u2019 and \u2018B\u2019 across the four wells were
analyzed. For reservoir \u2018A\u2019, porosity values of 32.8%,
24.8%, 25.9% and 27.1% were obtained for wells W-048, 042, 026 and 032
respectively with an average of 27.65%, while for reservoir
\u2018B\u2019 porosity values of 26.83%, 26.93%, 25.59% and 27.99%
for wells W-048, 042, 026 and 032 were obtained respectively with an
average of 26.84%. This porosity values were rated very good to
excellent for reservoir \u2018A\u2019 and very good for reservoir
\u2018B\u2019, while Permeability values of the order (K > 1000mD)
were obtained for both reservoirs across the four wells and is rated
excellent. Hydrocarbon saturation (Shc) across the four wells averages
at 68.57% for reservoir \u2018A\u2019 and 68.67% for reservoir
\u2018B\u2019 which is high. Log motifs using gamma ray log for
well-026 was integrated with seismic facies to infer on depositional
environment of the reservoirs horizons showed a combination of serrated
funnel/blocky shape log response and coarsening upward cycles. For
reservoirs \u2018A\u2019, \u2018B\u2019 and \u2018C\u2019 the log
shape pattern indicates deposition in a fluvial / tidal, channel
environment while for reservoir \u2018D\u2019 the pattern indicates
deposition in deltaic front environment. Isochore maps computed for
horizons \u2018A\u2019 and \u2018B\u2019, shows that horizon
\u2018A\u2019 is relatively thick and this pattern suggests increased
tectonic activities during deposition of reservoir \u2018A\u2019 and
is an indication that reservoir \u2018A\u2019 is a synrift deposit