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3D SEISMIC INTERPRETATION AND PETROPHYSICS (SEISMIC STRATIG

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Shorouk Elkobrsi

on 27 June 2015

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Transcript of 3D SEISMIC INTERPRETATION AND PETROPHYSICS (SEISMIC STRATIG

2. Overview & Workflow
3D SEISMIC INTERPRETATION AND PETROPHYSICS
Agenda:
1. Geologic Background

2.4 Seismic well ties

1. Geologic Background.
2. Overview & workflow.
3. Seismic interpretation.
4. Well log interpretation.
5. References.
6. Acknowledgments.
Original 3D seismic has Area 90.51 (sq km) there are two wells in the study area Penobscot L-30, drilled in 1976 by Petro-Can Shell, and Penobscot B-41, drilled in 1977 by Shell Petro-Can.
Data Set
Outline of original 3D seismic survey (left). zooms into constrained around well control (right) "OpendTect5"

Seismic section SEGY Inline 1300 using Petrel Software "Low resolution"

Seismic section CBVS Inline 1300 using OpendTect Software "high resolution"

Seismic section SEGY Inline 1300 using Petrel Software "high resolution"

Synthetic seismogram

wavelet can be estimated from the seismic data

A reflecting boundary to appear as a trough in the seismic trace if Z2>Z1 and A reflecting boundary to appear as a peak in the seismic trace if Z2<Z1 as show in Figure (3)

left (a) minimum and (b) Zero-phase wavelets at an acoustic impedance boundary with a positive reflection coefficient but Right is synthetic seismogram polarity check shot.

Figure shows Synthetic seismogram in well L-30 using Check shot, Sonic Delta-T, Corrected sonic "to calculate sonic velocity", Bulk Density, from it’s the Acoustic impedance and Reflection coefficients can calculate then synthetic

Figure shows Synthetic seismogram in well B-41 using Check shot, Sonic Delta-T, Corrected sonic "to calculate sonic velocity", Bulk Density, from it’s the Acoustic impedance and Reflection coefficients can calculate then synthetic

Synthetic seismogram

Seismic to well tie in well B-41 at Inline 1178
Seismic to well tie in well

Seismic to well tie in well L-30 at Inline 1178

To convert the well from depth to time for but the well on seismic, is with check shot or sonic log
3. Seismic interpretation
3.1 Horizon interpretations

The next step after seismic to well tie and getting the formation tops, starting to interpret (picking) Tops of formations in the whole seismic volume.


We already made the interpretation for 7 horizons as shown by the seismic section below. From top to base:

3.4 Velocity model

3.5 Depth map

3.6 Attributes to appear major fault

"Variance"
Attributes to appear oil sand channel.

3.7 Stratigraphy Interpretation

SPECTRAL DECOMPOSITION

1. Before sand channel
- Within sand channel
- Within source rock
ISO FREQUENCY

1. Before sand channel
- Within sand channel
- Within source rock



3.8 Time slice
before
channel sand reservoir

3.9 Time slice
within
channel sand reservoir

3.10 Time slice
within
channel sand reservoir

3.11 Time slice
at source rock
4.Well log Interpretation


4.3 Generate other logs and interpretation

4.3.1 P-wave sonic log

The P-wave sonic log measures the transit time (Δt in µs/ft) of an acoustic waveform between a transmitter and a receiver

4.3.2 Shale Volume

Shale is usually more radioactive than sand or carbonate. Volume of shale can be calculated from the gamma ray log and can indicate the presence or absence of clay.

Vsh= (GR- GRmin)/ (GRmax- GRmin) (2)
6. Acknowledgments
We wish to express our sincere
thanks to
Mohammed Abdel-Hay
engineer at Rashid Petroleum Company for their valuable help and dynamic guidance.
Special thanks to
Dr. Ali Bakr

(Regional work flow, Shell Egypt, Exploration department)
for his valuable guidance.
We are highly indebted to
Prof. Dr. Mohamed Gobashy

(Head of Geophysics Department, Cairo university),
Prof. Dr. Sharaf El Dien Mahmoud
(professor, Geophysics Department, Cairo university).
and
Dr. Zain Diab
(Geophysics department staff, Cairo university) for his keen interest and comments to improve this work.
We thank our friends who helped us, especially
Mahmoud Hossam.

BY:
MUHAMMED ESSAYED
SALEM SALAH
ESLAM NAGAH
MUHAMMD AHMED MORSI

UNDER SUPERVISION OF:

DR:MUHAMMED HASSAN

3D SEISMIC INTERPRETATION AND PETROPHYSICS
The porosity of a zone can be estimated either from a single "porosity log" (sonic, density, neutron, or magnetic resonance log) or a combination of porosity logs, in order to correct for variable lithology effects in complex reservoirs.

4.3.3 Porosity from the neutron and density
Show porosity in well L-30

Porosity well B-41

Sw in well L-30
Sw in well B-41

4.3.4 Water saturation (Sw)

This is the fraction of the pore volume filled with formation water (Sheriff, 2002) and is generally calculated by Archie’s formula, which is

4.3.5 Permeability log

Permeability in well L-30 and well B-41
respectively

"Morris-Biggs

d = 6.0, e=2
Kw = 62500 for oil ,
Kw = 6500 for gas
but
"Timur"

d = 4.4, e = 2,
Kw = 3400 for oil, and Kw = 340 for gas."
The ability, or measurement of a rock's ability, to transmit fluids, typically measured in Darcies or millidarcies

logging of sand 1 reservoir in well L-30

4.3.6 Output Well interpretations

A petrophysical assessment of the Penobscot L-30 and B-41 was conducted using available log. The Penobscot reservoir sands are wet in Penobscot B-41; however 7 hydrocarbon bearing zones were encountered in Penobscot L-30. Each sand,

15.3.1 Well Penobscot L-30

The Penobscot reservoir sands have 7 hydrocarbon bearing zones were encountered in Penobscot L-30. Each sand, in L-30, was interpreted to have a separate log defined oil-water contact

15.3.1.1 Sand 1

4.3.6.1 Sand 1

(Figures 37) Show logging of sand 2 reservoir in well L-30

4.3.6.2 Sand 2

logging interpretation of sand 2 reservoir in well L-30

logging of sand 3 reservoir in well L-30

logging interpretation of sand 3 reservoir in well L-30

Stratigraphy

Structure
Scotian basin
1.3 STRATIGRAPHY
2.1.1 Survey parameters

2.3 Load 3D Seismic

The seismic data cube is not with SEGY Type but CBVS Type that we need to convert the CBVS to SEGY to available to import in petrel software OpendTect Software can convert the CBVS to SEGY.

4.1 signal processing attribute

After convert the seismic cube the resolution of seismic is poor so we must make signal processing to increase seismic resolution

4.1.1 AGC

Trace AGC (Amplitude Gain Control) scales the instantaneous amplitude value with the normalized RMS amplitude over a specified window

Where max is computed over the entire survey.

3.2 Fault interpretation

3.3 Time Map
logging interpretation of sand 1 reservoir in well L-30

4.3.6.3Sand 3

4.3.6.4 Sand 4

logging of sand 5 reservoir in well L-30

4.3.6.5 Sand 5

logging interpretation of sand 5 reservoir in well L-30

logging of sand 6 in well L-30

logging of sand 7 reservoir in well L-30

logging interpretation of sand 7 reservoir in well L-30

logging of well B-41

4.3.7 Well Penobscot B-41

5. References
OETR (Offshore Energy Technical Research Association) (2011), Play Fairway Analysis Offshore Nova Scotia – An Integrated Project for: Nova Scotia Department of Energy, www.novascotiaoffshore.com 57
Keen, C.E. and Potter, D. P. (1995), The transition from a volcanic to a nonvolcanic rifted margin off eastern Canada, Tectonics, Vol. 14, no. 2, p. 359-371.
Kidston, A.G., Brown, D.E., Smith, B. and Altheim, B., 2005: The Upper Jurassic Abenaki Formation, Offshore Nova Scotia: A Seismic and Geologic Perspective. Canada-Nova Scotia Offshore Petroleum Board, Halifax, Nova Scotia, 168 p.
Jansa, L.F. and Wade, J.A., (1975a) Paleogeography and sedimentation in the Mesozoic and Cenozoic, southeastern Canada; in Canada’s Continental Margins and Offshore Petroleum Exploration, ed. C.J. Yorath, E.R. Parker and D.J. Glass; Canadian Society of Petroleum Geologists, Memoir 4, p. 79-102.
Gradstein, F.M., L.F. Jansa, S. P. Srivastava, M. A. Williamson, G. Bonham-Carter, and B. Stam (1990), Aspects of North Atlantic paleo-oceanography, in Geology of Canada, vol. 2, Geology of the Continental Margin of Eastern Canada, edited by M. J. Keen and G. L. Williams, p. 351-389, Geological Survey of Canada, Ottawa.
Cummings, D.I., Hart, B.S., and Arnott, R.W.C. (2006), Sedimentology and stratigraphy of a thick, areally extensive fluvial-marine transition, Mississauga Formation, offshore Nova Scotia, and its correlation with shelf margin and slope strata, Bulletin of Canadian Petroleum Geology, Vol. 54, no. 2, p. 152-174.
CNSOPB (Canada–Nova Scotia Offshore Petroleum Board) (2000), Technical Summaries of Scotian Shelf Significant and Commercial Discoveries: Halifax, CNSOPB, 212 p.
Castagna, J. P. and Sun, S. (2006), Comparison of spectral decomposition methods: EAGE, First break, Vol. 24, Technology Feature, p. 75-79.
Albertz, M., Beaumont, C., Shimeld, J., Ings, S.J., and Gradmann, S. (2010), An investigation of salt tectonics structural styles in the Scotian Basin, offshore Atlantic Canada: 1. Comparison of observations with geometrically simple numerical models, Tectonics, Vol. 29, no. 4.


Thank You
:)
2.1.2 Available Data

2.1.3 Program Software

Density and neutron logs

Illustrating the presence of hydrocarbons, that the low value of density value and neutron value is identify the presence of hydrocarbons which make crossover, if high separation is due to presence of gas and , if low separation is due to presence of oil.
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