Learning Objectives
After completing this course “Quick-look Interpretation“, you will be able to:
- Define “quick-look” well log interpretation.
- Summarize the overlays that can be used to facilitate quick-look well log interpretations.
- Summarize the crossplots that can be used to facilitate quick-look well log interpretations.
- Describe how algorithms and histograms are used in quick-look well log interpretation.
Introduction to Quick-Look Interpretation
Quick-look well log analysis comprises a number of techniques for interpreting logging while drilling (LWD) and wireline well log data speedily, to determine the formation’s lithology, porosity, shale content and fluid saturation. These methods are widely used by log analysts and others working with subsurface data, often for real-time petrophysical evaluations, to facilitate well operational decisions at the wellsite or at the operating oil company’s offices with transmitted data. The appeal of quick-look analysis lies in its simplicity and practicality, while still generating acceptable and fit-for-purpose results.
Quick-look well log analyses can be divided into four main categories:
- Overlays
- Crossplots
- Histograms
- Algorithms
Overlays can eliminate one unknown petrophysical parameter by using a ratio, while revealing another parameter of interest, such as the water saturation.
Crossplots are indispensable for computer-processed interpretations, and also offer a quick and convenient method of determining petrophysical parameters such as porosity, shale volume, or formation water resistivity, Rw.
Algorithms offer a quick and simple means of calculating parameters such as formation temperature and water saturation. They are widely incorporated into computer, tablet and calculator log analysis routines.
Histograms can be used to determine data minima and maxima, rescale old and poorly calibrated logs, and check the validity of computed results.
