Stratigraphic interpretation

1. Stratigraphic Interpretation
Prof. ADEL ELMORSY
Presented By: EMAN MOHAMED
OMAR ATEF
MOHAMMED ELSAYED

2. 1. Recognition of Characteristic
Shape.
 Vertical Seismic Section
 Horizontal Seismic Section

3. Vertical Seismic Section
Fig. 4-1. Five adjacent vertical
sections from 3-D survey in the
Williston basin of North Dakota.
(Courtesy Geophysical Service Inc.)

4. Horizontal Seismic Section
Fig. 4-2. Horizontal sections from 1812 and 1828 MS. from
North Dakota, each showing positive amplitudes only. The
approximately circular outline between the black and the gray
indicates the shape of a carbonate buildup. (Courtesy
Geophysical Service Inc.)

5. Fig. 4-(3,4). Horizontal section at 820
MS. from 3-D survey over Mackerel
field in offshore Gippsland basin,
southeastern Australia. Circular
objects are interpreted as sinkholes in
karst topography. (Courtesy Esso
Australia Ltd.)

6. Fig. 4-(5,6,7). Sum of horizontal sections at 812 and 816
MS from same survey as Figure 4-5 showing a branching
channel. (Courtesy Chevron U.S.A. Inc.)

7. Fig. 4-8. Composite display of horizontal sections at 812 and 816 MS
showing western branch of channel and at 820 MS showing eastern
branch. (Courtesy
Chevron U.S.A. Inc.)

8. Fig. 4-9. Composite display of vertical and horizontal sections
from Gulf of Thailand showing spatial continuity of vertical section
event segments. (Courtesy Texas Pacific Oil Company Inc.)

9. Fig. 4-10. Horizontal section at 196 MS. from Gulf of Thailand
showing meandering stream channel. (Courtesy Texas Pacific
Oil Company Inc.)

10. Fig. 4-11. Schematic diagram of delta prograding across the Gulf
of Thailand 3-D survey area between mid- Miocene and
Pleistocene.

11. Fig. 4-12. Horizontal section at 608 MS from
Gulf of Thailand showing delta front channel.
(Courtesy Texas Pacific Oil Company Inc.)

12. Fig. 4-13. Horizontal section at 488 MS
from Gulf of Thailand showing large
offshore sand bar. (Courtesy Texas
Pacific Oil Company Inc.)
Fig. 4-14. Horizontal section at 360
MS from Gulf of Thailand showing
small sand bars. (Courtesy Texas
Pacific Oil Company Inc.)

13. Fig. 4-15. Horizontal section at 304 MS
from Gulf of Thailand showing a
reworked bar and distributary
channels. (Courtesy Texas Pacific Oil
Company Inc.)
Fig. 4-16. Horizontal section at 228
MS from Gulf of Thailand showing
several channels, large and small.
(Courtesy Texas Pacific Oil Company
Inc.)

14. Fig. 4-17. Horizontal section at 100 MS
from Peciko 3-D survey recorded in the
Mahakam delta offshore Kalimantan,
Indonesia. The deltaic features seen
here are about 18,000 years old.
(Courtesy Total Indonesie.)
Fig. 4-18. Satellite photograph of part
of present Mahakam delta for
comparison with Figure 4-17.
(Courtesy Total Indonesie.)

15. Fig. 4-19. Horizontal section at 104 MS from NUBI 3-D survey
recorded in the Mahakam delta offshore Kalimantan, Indonesia. Note
the dendritic patterns of incised canyons. (Courtesy Total
Indonesia.)

16. Fig. 4-20. Shallow horizontal section
from Gulf of Thailand showing
channels, point bars and crevasse
splays. (Courtesy Unocal Thailand
Ltd.)

17. Fig. 4-23. Horizontal section at 936
MS from Mobile area, offshore
Alabama, showing interpretation of
numerous Miocene deltaic fans.
(Courtesy Conoco Inc. and Digicon
Geophysical Corp.)
Fig. 4-24. Horizontal section at 1268
MS from Mobile area, offshore
Alabama, showing one Miocene
deltaic fan. Gas is being produced
from one of the black channels.
(Courtesy Conoco Inc. and Digicon
Geophysical Corp.)

18. Methods of Making Horizon Slices
A horizon slice is by definition a slice along
a bedding plane, but the methods by
which an interpreter may make such a slice
are many and varied (Figure 4-35).

21. Fig. 4-33. Lines 57 from a 3-D survey in
the Gulf of Mexico showing a tracked
horizon above bright events indicating
channel intersections. (Courtesy
Chevron U.S.A. Inc.)

23. Fig. 4-35. Methods of making horizon slices.
The tracking level and the slicing level need
not be the same. Amplitude corrections may
be necessary to compensate for shallower
effects

24. Windowed Amplitude
• The window can be flat, defined by a
start time and an end time only; the
window can be the interval between
two structurally interpreted horizons.
• Types : average absolute amplitude
and root-mean-square (RMS)
amplitude.

27. Horizon Slice Examples
Fig. 4-38. Line 325 from
3-D survey in the Gulf of
Thailand showing
interpreted horizon
through many fault
blocks. (Courtesy Unocal
Thailand Ltd.)

28. Fig. 4-41. Time structure map for a horizon
interpreted from a 3-D survey offshore
Louisiana. (Courtesy Geophysical Service Inc.)
Fig. 4-42. Horizon slice showing spatial
distribution of amplitude over the horizon
mapped in Figure 4-41 and indicating two
channels. (Courtesy GeophysicalService Inc.)

29. Fig. 4-43. Horizon slice from Gulf of Mexico with overlain structural contours showing high
amplitudes caused by gas in several sand bodies. (Courtesy GeoQuest Systems Inc.)

30. Unconformity Horizon Slices
• An unconformity is a break in the rock record produced by
erosion and/or non-deposition.
• Types of unconformity:
I. Nonconformity
II. Angular unconformity
III. Disconformity

32. Fig. 4-50. Vertical section from Lisburne 3-D survey, North Slope of Alaska,
showing Lower Cretaceous unconformity. (Courtesy Standard Alaska
Production Company)

33. Reference
• [Alistair_R._Brown]_Interpretation_of_Three-
Dimens(Bookos.org)

34. Thank you