1963 Paper (E)

PRINCIPLES OF LOG INTERPRETATION BY USE OF MULTIPLE CURVES

By

C. Richard Glanville, Member SPWLA Jersey Production Research Company

ABSTRACT

Accurate measurement of reliable detection of formation and borehole parameters commonly requires two or more logging curves. These curves must have different responses to given physical properties, or they must have different "fields of investigation."

Multiple-curve interpretation is accomplished by many methods. Only four distinctly-different methods based on sound physical principles have generally application. They are: (1) Superimposed Curves Method, (2) Data Plot Method, (3) Quantitative Field of Investigation Method, and (4) Direct Calculation Method. The first two methods detect materials within the borehole or formations. The other two methods provide quantitative information, such as porosity and fluid saturation.

Continuous profile curves of interpretation parameters, such as Rxo/Rt and Fr/Fs, may become important exploration tools when logs are extensively recorded on magnetic tape.