1. MAXIMIZING THE EFFECTIVENESS
OF TIME-LAPSE (4D) SEISMIC :
NIGER DELTA AS A CASE STUDY
AKPOGUMA V. MUDIAGA
DECEMBER,2014

2.  INTRODUCTION
 WHAT IS TIME-LAPSE SEISMIC?
 STEPS IN ACHIEVING TIME-LAPSE SEISMIC DATA
 EFFECTIVENESS OF TIME-LAPSE SEISMIC
 CASE STUDIES IN NIGER DELTA
 MAXIMIZING TIME-LAPSE IN NIGER DELTA
 CONCLUSION
OUTLINE

3. INTRODUCTION
 What if your company is offered a tool that can tell you if a field is:
 Performing according to plan
 Help you locate undrained hydrocarbons,
 Optimize infill-well and
 Help ensure maximum recovery of Crude.
 Would you purchase that tool?
 The cost is less than that of drilling a single well.
 If you might guess, the tool is 4D (time-lapse) seismic Technology

4.  The 4th Dimension is just time. The time is calendar
time and not geological time.
 In short, while 3D is a snapshot, 4D is a movie.
WHAT IS TIME-LAPSE SEISMIC ?

5. 4D, or time-lapse seismic, is a series of repeated seismic
surveys used to aid the description and understanding of a
reservoir as it changes over time. Changes in the reservoir
properties such as fluid saturation and pressure, result in
changes in the elastic properties can be detected under
favorable circumstances by the seismic data.
WHAT IS TIME-LAPSE SEISMIC?
The 2D/3D is called the Baseline survey while the 4D seismic is the
Monitor Survey

6. Amplitude
Early time Later time after
production
Difference
-
Example of a Time-Lapse Survey
WHAT IS TIME-LAPSE SEISMIC ?
After Ubeku 2005

7. Feasibility study
Acquisition
Processing
Inversion & Interpretation
STEPS IN ACHIEVING TIME-LAPSE SEISMIC DATA

8. Feasibility study
Feasibility study answers questions like:
 Will 4D work in my reservoir?
 What is the expected benefit of 4D survey?
 When should I carry out my 4D?
Rock physics modelling, geological modelling and reservoir
simulation modelling are all done at this stage

9. Acquisition
Processing
Key factors in processing
Mute application.
Pre-stack de-convolution
parameters.
Pre-stack, multi-channel noise
attenuation (amplitude).
Imaging Velocities – NMO and/or
migration velocities.
After Ubeku 2005

10. Inversion and Interpretation
For 3D seismic data, we tie seismic to well-log synthetics. For
4D data, however, we tie our interpretation not only to the well
logs but also to the dynamic reservoir information, such as
production and injection, flow simulation, and repeat logs.
The interpretation is focused on the production &
development stages of a field and is concerned with changes
in the reservoir, usually the fluid content and movement
within the structures.

11. EFFECTIVENESS
Carbon Capture Sequestration and Environmental Monitoring
Update Reservoir Models
Locate New Wells & Tap Undrained Hydrocarbon.
Monitor Enhanced Oil Recovery Projects
Increase Hydrocarbon Production & Reserves

12. EFFECTIVENESS
GeoExpro 2009

13. EFFECTIVENESS
Ubeku 2005

14. CASE STUDY OF 4D IN NIGER DELTA

15. Bonga Field
OML 118 (from OPL 212)
120km offshore 1000m
water depth
After Johnston 2010

16. The Bonga field was discovered in 1995 and the Bonga-1 discovery well was the first well
drilled
First seismic acquisition was by streamer in 1993.
The baseline survey was acquired in 2000 by also a 3D seismic streamer survey
First oil production started in November 2005 and Bonga has an average production of
20,000 barrels/day.
Oil production is from 4 main stacked turbidite reservoir (690, 702, 710/740 and 803)
using pressure maintenance via water injection through producer and injector well pairs.
Bonga Field

17. Bonga Field
 After 2 years of production, the first 4D (streamer survey) was
acquired successfully in 2008 and this was Nigeria first 4D survey in
deep waters.
 The Repeat seismic survey was planned to understand reservoir
sweep through time (after 2 years of production) and enable better
well placements such that the Bonga Field life-cycle production will
be maximized.
 The 4D results of this survey added significant value to the
development of the asset by improving the understanding of the
reservoir connectivity and swept efficiency between injector and
producer wells, making the project a clear technical and business
success.

18. 2000 2008
Bonga Field
International Petroleum Training Conference 2013
Difference

19.  Although, No 4D response was expected in the undershoot
region during the time the first monitor was acquired, this
area contain significant reserves (800mb STOIP) and will be
require good 4D data quality in the near future to be able to
effectively monitor the updip Reservoirs.
 For better monitoring of the updip reservoir, in 2010,
SNEPCo acquired an Ocean Bottom Node (OBN) survey
around the Bonga main FPSO and SPM area to serve as a
Baseline for the future OBN surveys.
Bonga Field

20. Bonga Field
International petroleum training conference 2013

21. Meren field
After Lumley 2000

22.  The Meren field (OML 95 of Niger delta) is operated by Chevron and is
located in shallow water (50 feet deep) in south-east of Lagos ,Nigeria
about 10 miles offshore.
 Meren field was discovered in 1965 and first production began in
1968, and has over 80 producer and injector wells.
 The baseline seismic survey was a 1987 Chevron legacy 3D survey
while the 4D survey was short in 1996.
Meren field

23.  Three areas within the
E303 that may contain
major bypassed oil
reserves were identified
flowpaths of water
through the injector
wells were understood.
This enabled drilling of
new wells.
Meren field
Lumley 2000

24. OFON field Block OML102 offshore
 The Ofon field is
located in Oil Mining
Lease OML 102,
offshore Nigeria in
40 meters water
depth operated by
Total E&P and
NNPC
 Production began in the Ofon field in 1997 and has produced over 200
million barrels of crude oil.
OffshoreEnergyToday.com 2012

25.  The base survey was a 3D marine dataset recorded between 1990 and 1992 by DIGICON with
a dual source and one streamer configuration, a nominal stacking fold of 30, a cable length of
3000m, and an acquisition bin of 6.25m x 25m
 The repeated survey was the 3D OBC 2C seismic recorded in 2004, employing 4 ocean
bottom cables per swath, shot along the cables with maximum offsets of 4000m and nominal
stacking fold 120 for a 12.5m x 25m bin size.
 The two seismic acquisitions were very different in terms of data quality (azimuths, Signal to
Noise ratio, fold coverage, radio navigation and positioning quality).Because of this, special
attention was paid, during the processing.
OFON field Block OML102 offshore

26. OFON field Block OML102 offshore
3D Section:
Minimum Amplitude Full OBC
4D Section : Difference between Minimum
Amplitude “OBC – Streamer”After Castex et al 2007

27. MAXIMIZING 4D SEISMIC IN NIGER DELTA
 Considering the role of 4D seismic in Enhanced oil recovery, 4D
seismic will also have a role in meeting our target.
 From 2.5M bbl/d in 2012 to 4 Mbbl/d in 2020
Maximized EOR will be key for Nigeria
After Al-Khatib 2013

28. MAXIMIZING 4D SEISMIC IN NIGER DELTA
 Implement favorable Government Policies
 Investors ! Focus on Value and not cost
 Use Modern technology for Acquisition, Processing and
Interpretation.
 Target more offshore and onshore fields (both new & mature)
 Its not just Oil and Gas, find new opportunities with 4D

29. CONCLUSION
Considering the Effectiveness of Time-lapse Seismic in few Oil Fields in
Niger Delta, we see that there is a need for its expansion. This is
imperative since we must supply to meet up the high Energy demand for
Oil and Gas.
The Question right now
 Shouldn’t be why 4D Seismic ? but Should be why not 4D Seismic?

30. THANKS !