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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 21 (1937)

Issue: 5. (May)

First Page: 580

Last Page: 615

Title: Laboratory Orientation of Well Cores by Their Magnetic Polarity

Author(s): Edward D. Lynton (2)


A practical laboratory method of orienting well cores by their magnetic polarity was first developed by the Standard Oil Company of California's research department early in 1928. The procedure is designed to determine the original orientation in the ground of cores obtained in the ordinary rotary system of oil-well drilling, by identifying the north and south sides of a core, after it has been brought to the surface, through residual magnetic polarity in the heavy minerals of the rock. The writer describes the theory and the various steps in developing this idea from the original experimental machine to the commercial one which is self-recording by photographing the deflections of a light beam.

In conjunction with this magnetic core orienter a deviation corrector was developed. Directions of dip obtained from samples cored from crooked holes were worked out as apparent dips and strikes. The instrument, known as a deviation corrector, was designed to correct rapidly the apparent dip to the true dip, whenever the direction and degree of dip of the hole at the depth from which the core came are known. The instrument and mathematical computations are fully described in this paper.

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