The Oil and Gas industries, especially in the exploration stage rely so much on subsurface earth condition information. Geophysical methods are tools that help deliver much information to obtain good decisions in the oil and gas projects. All of it comes with some challenges in various aspect.
DC MACHINE-Motoring and generation, Armature circuit equation
Geophysical Challenge in Oil and Gas Project
1. Geophysical Challenge in Oil &
Gas Exploration
Gilang Wiranda
Pertamina Upstream Research and Technology Innovation
2. What is Geophysics ?
Geophysics is the application of physics to study the Earth,
oceans, atmosphere and near-Earth space. It is a broad
subject that encompasses many of the major sciences –
physics, astronomy, planetary science, geology,
environmental science, oceanography, and meteorology.
- British Geophysical Association
What is Geophysics ?
Geophysics deals with a wide array of geologic
phenomena, including the temperature distribution
of the Earth’s interior; the source, configuration, and
variations of the geomagnetic field; and the
large-scale features of the terrestrial crust, such as
rifts, continental sutures, and mid-oceanic ridges.
- Britannica
3. OIL & GASGEOPHYSICS
Seismic
methods
Petrophysics
Gravity &
EM Survey
Reservoir
Modeling
Production
EOR
Downstream
Operation
Economical
Assessment
Exploration
Rock physics
Groundwater
Earthquake
mechanism
Remote sensing
Environmental
Artificial Lift
5. Method Measured Rock Property
SEISMICS Travel time & amplitude Elastic moduli (density &
velocity)
GRAVITY Variation in gravitational
field
Density
MAGNETICS Variation in magnetic field Magnetic susceptibility
ELECTRICAL /
ELECTROMAGNETICS
Specific resistivity Electrical conductivity
RADAR Travel time Dielectric constant
NUCLEAR Variation in natural
radioactivity
Nuclear decay
Geophysicist utilizes every
physical properties that
could be measured
numerically.
6. Geological Survey
● Rock sampling
● Surface Geological
Mapping
Initial
Geophysics
● Gravity
measurement
(aeiral or
surface)
● Magnetic and
Electric Data
Exploration Well
● Well Data logging
● Petrophysics
Interpretation
● Integration with
Seismic Data
● Seismic Interpretation
Reflection Seismic
● 2D Seismic Survey
● 3D Seismic Survey
● Land or Marine Acquisition
● Data Processing
● Seismic Gather and Stack
OIL AND GAS EXPLORATION PHASES
7. First Geophysical Logging
Conrad & Marcel Schlumberger, 1927
Conrad developed the method of using electrical measurement to map underground rock formation through a well borehole. The demonstration was held on
Pechelborn, France,1927.
8. Gravity Measurement
From the geological viewpoint, all
subsurface rocks are part of the earth’s
mass. They cause an attraction on a
test-mass, spring-mounted in a
gravimeter, the instrument that
measures gravity.
With Gravity method inversion, a
prediction of subsurface structure could
be done. Its useful for identifying
hydrocarbon basins to limit the area for
following seismic survey
Gravity measurement could be done on
surface by portable gravimeter, a plane
mounted, or even Satellites!
Nowaday global gravity data have been
obtained and helpful to be used for local
measurement correction.
You’ll Fall in Faster
acceleration in certain place
on earth
9. Electromagnetic Measurement
Hydrocarbon bearing structures often have a distinctive resistivity due to
the oil and gas electrical and magnetic characteristic. Magnetotelluric
method measures subsurface electrical conductivity from measurements
of natural geomagnetic and geoelectric field variation at the Earth's
surface.
The Energy source of MT are:
1. Natural Earth Magnetic
Field variations
2. Solar Wind
3. worldwide thunderstorm
4. Manmade EM source in
CS-AMT method
10. Seismic Method Land Seismic
Marine Seismic
Two
Phenomenon
in a Seismic
Wave
Propagation
11. Seismic Method
Principle of Wave observed in data recording
WHAT WE WANT:
Wave Reflection from the original
source ( dynamite, vibroseis, air gun)
WHAT WE DONT WANT
Wave energy from
1. Nearby Vehicle
2. Human activities
3. Natural Earthquake
4. Vibration from wind hitting trees and roots
5. Ground roll from the dynamite explosion
The unwanted wave energies are so called NOISE
13. Interpretation
+ =
Migrated Seismic Data
Well Log Data Well Tied Seismic Section
for Interpretation
Seismic Interpretation gives a good understanding of the subsurface condition by the petrophysical attributes
applied on the rock layers provided by a good well tie operation.
14. Reservoir Monitoring
Three-dimensional (3D)
seismic data acquired at
different times over the same
area to assess changes in a
producing hydrocarbon
reservoir with time. Changes
may be observed in fluid
location and saturation,
pressure and temperature. 4D
seismic data is one of several
forms of time-lapse seismic
data. Such data can be
acquired on the surface or in a
borehole.
Using Seismic Method
Example of 4D seismic technology: time-lapse seismic images of the Sleipner CO2 plume.
(top) seismic profile along a line and (bottom) plan view of seismic amplitude in the field
(Chadwick et al., 2010).
Reservoir CO2 Storage example
15. Challenges
Oil and Gas Business Situation
Source:
*Oil Production and Consumption 2000-2005: BP Statistical
Review of World Energy 2011
*Oil Production and Consumption 2006-2017: SKK Migas,
Ministry of Energy and Mineral Resources (MoEMR), Fitch
Connect - Business Monitor International
*Oil Production and Consumption 2018 : DGOG, BP Statistical
Review of World Energy 2019
Declining oil price = Less Profit
There is an urgency for the discovery of new oil reserve in
Indonesia because of the increasing demand of fuel led to
dependency on oil import. Exploration is a must.
18. ● As Conventional Oil Depleted, the Unconventional Reserves needs to be focuses
more.
● Unconventional reserves often needs an extra work in the Exploration
Anticlinal Trap Fault Trap Salt Dome Trap
Deep Sea Exploration
MOVING TO THE UNCONVENTIONAL
23. Global Pandemic
- Increased Operational Costs
- Health Protocol (PPE, Quarantine, Medical Staff)
- Costs of Mobilization (Crew plane tickets, accomodation, etc.)
SEISMIC SURVEY
24. Advanced Exploration Methods
- Improved Instrumentation Technology
- Booming of Computation Technology
- Matured communication infrastructure
Passive Seismic Method
Reconstructing Old Seismic Data
Full Waveform Inversion
Maximizing
information
obtained from the
data
