Cutoff S w and Production Data
0.4
0.3
Porosity (p.u.)
0.3
Porosity (p.u.)
0.4
Cross plots of porosity and water
saturation from well I, Macuspana
Basin. A lower Pliocene sand has
produced 1.15 Bcf of gas and
condensate. An upper Miocene
interval (square) has produced 516
bopd and 870 Mcfgd. The straight
line indicates final cutoff water
saturation used for all wells in the
Macuspana Basin.
0.2
0.2
Gas & oil
0.1
Cross plots of computed porosity
and water saturation from well H
(the Veracruz Basin), a Pliocene
sand produced at 11 MMcfgd. Cutoff
water saturation line was drawn
between gas and water sands.
Gas
Water zone
Water flow
0
0
0.2
0.4
0.6
0.8
0.1
Adj. perf.
Gas perf.
0
1
Water saturation (fraction)
Water zone
0
0.2
0.4
0.6
1
0.8
QAd837c
Water saturation (fraction)
QAd836c
Geopressure
0
0
500
1000
TVD (m)
TVD (m)
1000
2000
Top
geopressure
1500
2000
M-U Pliocene
2500
L Pliocene
3000
U Miocene, U
3000
U Miocene, L
3500
4000
40
100
200
Lower Pliocene
l
u
G
f
M
30
40
50
60
70
TVD depth and sonic transit time slowdown due to
geopressure. Dt offset will be higher in zones having higher
pressure differences. In general, higher pressure zones are
found in the deeper intervals.
Top of geopressure zone from Macuspana Basin well J. TVD depth and
shale sonic time were plotted with average sonic trend lines (heavy line).
i
x
e
20
Dt slowdown (us/f)
Dt_shale (us/f)
of
10
0
Upper Miocene
co
Gu
lf
of
Me
c
i
x
N
High geopressure
Low geopressure
Normal pressure
0
10 km
o
From pressure test
N
High geopressure
Low geopressure
Normal pressure
0
10 km
QAd711(a)c
From
wireline
logs
Normal pressure
(53 intervals)
High pressure
(43 intervals)
Normal
pressure
(56 intervals)
49 intervals
(52%)
7 intervals
(7%)
Geopressure
(40 intervals)
4 intervals
(4%)
36 intervals
(37%)
Comparison of geopressure intervals in the Macuspana Basin.
High pressure based on pressure tests against wireline logbased geopressure zone.
Distribution of geopressure based on wireline observation. Left map is for the lower Pliocene interval from the
Macuspana Basin. High-pressure area is located in western part of the basin. Right map is for the upper Miocene
interval and shows geopressured area covers main part of the basin.
CONCLUSIONS
An integrated petrophysical analysis for a basin analysis and play characterization study.
ACKNOWLEDGMENTS
The authors are grateful to PEMEX for permission for publication.
Coordination between PEMEX and the BEG was facilitated by Luis SánchezBarreda, Javier Meneses-Rocha, Jorge Enrique Lugo, and Eric Potter.
Editing was by Susann Doenges, and John T. Ames prepared the illustrations
under the direction of Joel L. Lardon, Graphics Manager. Petrophysical
software used in our study was kindly provided by Paradigm Geophysical.
Petrophysical studies included lithological determination, construction of petrophysical models,
and well-by-well petrophysical assessments.
This lithology distribution (sand, shale, conglomerate, igneous rocks, and limestone) was used
for the stratigraphic analysis and for tying with seismic data.
Capillary pressure, photomicrographs and mineralogy reveal unique porosity and saturation
relationships for each lithology.
The complex distribution of the geopressure zones was observed by slow acoustic velocity
and low shale resistivity.
Pressure data from test results and geopressure zone prediction matched reasonably well.
QAd1029(c)c