PNGE 450 EXAM 1 Introduction Flashcards
Formation Evaluation
Covers a very wide range of measurement and analytic techniques
Geophysics:
seismic studies
Geology:
stratigraphy, sedimentology, lithology
Petrophysics
core analysis, log analysis
Drilling Eng.:
mud properties, rock properties
Reservoir Eng.
reservoir limits, storage capacity, economic value, EOR considerations
Production Eng.
fluid type, fluid pressure, completion considerations, productivity, injectivity
Formation Evaluation Methods
- Mud Logging
- Coring/Core Analysis
- MWD/LWD
- Formation Testing
- Openhole Logging
- Cased-hole Logging
Well Logging
Measurement of formation properties vs. depth:
- Rock properties
- Fluid properties
Two types of Well Logging
1) Openhole (before casing)
* Conventional (wireline) logging
* LWD/MWD
2) Cased hole
Interpretation:
- Geology
- Petrophysics/reservoir
- Completion/production
Openhole logs can provide either a direct measurement or a good indication of:
- Porosity, both primary and secondary (fractures and vugs)
- Permeability
- Water saturation and hydrocarbon movability
- Hydrocarbon type (oil, gas)
- Lithology
- Formation dip and structure
- Sedimentary environment
- Travel times of elastic waves in a formation
Cased hole logs can provide
- Flow rates
- Fluid type
- Pressure
- Residual oil saturation
- Cement bond log
Pros
- Provides most abundant data from the formation
- Very reliable
- Provides vertical and lateral (map) variations in rock/fluid properties
- Modest cost
Cons
Indirect measurement
* Depth of investigation
* Vertical resolution
* Nuclear hazards