CPG Technology & Digital Tools 3 — Questions and Answers
Question 1: Which software technique is used to extract reservoir properties such as porosity and lithology from seismic amplitude data by comparing them to well log responses?
- Seismic stratigraphy
- Seismic inversion (Correct answer)
- Spectral decomposition
- AVO crossplot analysis
Correct answer: Seismic inversion
Seismic inversion transforms reflection amplitude data into acoustic or elastic impedance volumes that can be directly related to petrophysical properties from well logs.
Question 2: What is the main advantage of using 4D (time-lapse) seismic surveys in reservoir management?
- Improved imaging of deep basement reflectors
- Monitoring fluid movement and pressure changes during production (Correct answer)
- Higher vertical resolution than conventional 3D surveys
- Reducing acquisition cost compared to single 3D surveys
Correct answer: Monitoring fluid movement and pressure changes during production
4D seismic compares repeated 3D surveys acquired at different times to detect changes in fluid saturation and pressure as hydrocarbons are produced.
Question 3: In digital rock physics, what does micro-CT scanning allow geologists to do?
- Measure in-situ reservoir pressure remotely
- Image pore structure in 3D without destroying the core sample (Correct answer)
- Determine hydrocarbon composition by spectroscopy
- Generate synthetic seismic gathers from rock properties
Correct answer: Image pore structure in 3D without destroying the core sample
Micro-CT (computed tomography) scanning creates three-dimensional images of pore networks and grain contacts in rock samples at micron-scale resolution.
Question 4: Which cloud-based collaboration technology has become increasingly important for sharing large seismic datasets between geoscience teams in different locations?
- SFTP file transfer protocol
- OSDU (Open Subsurface Data Universe) platform (Correct answer)
- Relational SQL databases
- Email attachment workflows
Correct answer: OSDU (Open Subsurface Data Universe) platform
The OSDU platform is an industry-standard cloud data ecosystem that enables standardized storage, sharing, and access to subsurface data across organizations.
Question 5: What is the purpose of applying a 'Normal Moveout (NMO) correction' during seismic data processing?
- Remove multiples generated by water-bottom reflections
- Correct for the travel-time difference of reflections at varying offsets (Correct answer)
- Convert seismic data from depth to time domain
- Filter high-frequency noise from individual traces
Correct answer: Correct for the travel-time difference of reflections at varying offsets
NMO correction flattens reflection hyperbolas on common midpoint (CMP) gathers by correcting for the increased travel time at greater source-receiver offsets.
Question 6: Which machine learning approach is most commonly applied in seismic interpretation for automatic fault detection?
- Reinforcement learning with reward signals
- Convolutional Neural Networks (CNNs) trained on labeled seismic volumes (Correct answer)
- Linear regression on amplitude extractions
- K-means clustering of well log data
Correct answer: Convolutional Neural Networks (CNNs) trained on labeled seismic volumes
CNNs excel at recognizing spatial patterns and textures in 3D seismic volumes, making them effective for automated detection of fault geometries.
Question 7: In formation evaluation, what does 'nuclear magnetic resonance (NMR) logging' provide that conventional porosity logs cannot?
- Total organic carbon content of source rocks
- Pore size distribution and bound vs. free fluid volumes (Correct answer)
- In-situ stress orientation from borehole breakouts
- Mineralogical composition of the formation
Correct answer: Pore size distribution and bound vs. free fluid volumes
NMR logging measures the relaxation of hydrogen nuclei to differentiate pore sizes and distinguish capillary-bound, clay-bound, and free-fluid porosity components.
CPG Technology & Digital Tools 3
Which software technique is used to extract reservoir properties such as porosity and lithology from seismic amplitude data by comparing them to well log responses?