Reservoir Eng 7: Geophysics for reservoir characterization
Objectives
The oil and gas reservoir characterisation is part of the global process of Reservoir Management. This consists on the application of all industrial technologies and field practice to efficiently develop the hydrocarbons and maximise the return on investment.
Seismic is one important technique that participates to a better reservoir knowledge.
While wells are discrete locations in an oil and gas field, seismic is the only technique that gives a continuous picture of the reservoir characteristic.
The reservoir is complex and invisible. Seismic project dedicated to the reservoir should be well planned and executed as reservoir characterisation needs the use of different seismic techniques. These techniques start with structural interpretation going through stratigraphy interpretation, then acoustic and elastic inversion, amplitude versus offset (AVO) study, attribute study and more advanced techniques such as un-supervised and supervised classification of the reservoir data and artificial neural network (ANN).
Understanding the long-term behaviour of the reservoir, 4-D seismic should be applied.
The present course is an overview of all these techniques that allows petroleum engineers to understand how the seismic data can help them in their day by day work. Each seismic study is presented according to the specific reservoir parameters that is be able to define and clarify. Participants will also familiarise themselves with the terminology of these techniques to be able to have constructive discussions with the other members of the exploration and production team.
Different types of interpretation are presented starting from prospect generation going through facies and stratigraphy interpretation and finally more advanced techniques are discussed with emphasis on reservoir parameters determination. Each new concept is followed by some exercises. About half the time will be dedicated to practical and manual exercises. This gives attendees the possibility to manipulate many different seismic lines to understand the added value of seismic techniques in their future activities.
Content
Day 1
Introduction to reservoir characterisation
The reservoir characterisation within the reservoir management process.
Different components of hydrocarbon reservoir.
Why we need better reservoir knowledge?
The reservoir as seen in seismic data.
Tools for reservoir characterisation.
Fundamentals laws in seismic reflection technique
Propagation of seismic waves in stratified medium. Equations of waves in a shot point.
The concept of seismic acquisition
Exercises
Shot point analysis.
The concept of Common Mid-Point (CMP)
The concept of fold of coverage.
Day 2
02.1 From Shotpoint to seismic line
General expression of a seismic trace
From shotpoint domain to CMP domain.
Recovery of the reflectivity
Noise reduction
Deconvolution
NMO correction and Stacking
Migration
02.2 Exercises
02.3 Reservoir in seismic structural interpretation
Calibration of seismic data with well data
Principle of structural interpretation
Selection of marker and polarity
Posting and contouring
Fault in extensional regime
Fault in compressional regime
Posting and contouring
Mapping
Reservoir parameters .
Day 3
03.1 Exercises
Interpretation of seismic lines
Contouring
Parameters of the reservoir
03.1 Reservoir in stratigraphy interpretation
Principles of stratigraphy interpretation
Shoreline migration
Sequence boundary
Sequence stratigraphy
Boundary relationships
Internal configurations
Progradation
Reservoir facies and parameters
Day 4
04.1 Exercises
Internal fill and configurations
Progradation
Facies and other reservoir parameters
04.2 4-D Technique
What is 4-D seismic and when is needed
Preparing 4-D project
4-D attributes
04.3 AVO and reservoir classification
Principles of AVO (Amplitude Versus Offset)
Reflection coefficients and offsets
AVO attributes
Reservoir classification
Exercises