Skip to Main Content
Book Chapter

Well Logs

January 01, 1982


The hydrocarbon potential of an area is often judged by the existing production and reserve estimates of the area. For a new exploration program, all available geophysical, geologic, and engineering data must be interpreted. The results of the new wells must be integrated for subsequent development operations. Such exploration studies normally include an understanding of the regional geology, geologic and/or geophysical maps, show maps, cores, tests, mud logs, and wire line logs.

Cores and wire line logs are among the most important data to a formation evaluationist, whether he is a geologist or an engineer. Petrophysicists integrate these data to derive indirectly many basic reservoir parameters, such as porosity and fluid saturation, and to determine volumetrically the reservoir oil in place. There are many current logging techniques which can be combined for this purpose.

A well log is a graphical presentation of a physico-chemical characteristic of the geologic formations measured in a borehole as a function of depth. The logs determine lithologic characteristics of the sedimentary rocks and pinpoint hydrocarbon-bearing strata. Before the invention of well logs, such geologic variables were ascertained by (1) inspection and analysis of drill cuttings and cores and (2) formation tests. Many of these operations are being used less today because the necessary subsurface information can be obtained from well logs at lower costs and with sufficient resolution.

The first well log was designed and recorded in 1927 by the Schlumberger brothers in Pechelbronn, Alsace, France (Allaud and Martin, 1976).

This chapter presents

You do not currently have access to this article.

Figures & Tables


Concepts and Techniques in Oil and Gas Exploration

Kamal C. Jain
Kamal C. Jain
Venex Corporation Houston, TX
Search for other works by this author on:
Rui J. P. deFigueiredo
Rui J. P. deFigueiredo
Rice University Houston, TX
Search for other works by this author on:
Society of Exploration Geophysicists
ISBN electronic:
Publication date:
January 01, 1982




Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal