Coring handbook / Руководство по работе с керном

Coring is the removal of sample formation material from a wellbore. To the extent possible, core samples are taken in an undamaged, physically unaltered state. The formation material may be solid rock, friable rock, conglomerates, unconsolidated sands, coal, shales, gumbos, or clays. Coring can be conducted by various methods with a variety of tools. But in the oilfield, coring is generally accomplished by two methods:

• Full Hole Coring: Core material ranging in diameter from 1¾" to 5¼" is recovered inside of a core barrel in vertical, deviated, horizontal, or sidetracked wells. Depending upon the coring system employed, the core can be recovered in preserved or unpreserved states, and can be used for a wide range of analytical applications. Baker Hughes INTEQ offers a complete range of full-hole coring services.

• Sidewall Coring: Cylindrical plug-shaped samples, generally 1" in diameter, are recovered from the walls of the wellbore by percussion or rotary coring techniques. This sampling takes place in the first few inches of the wellbore wall in regions that generally are invaded by drilling fluid filtrates. The resulting samples are unpreserved and frequently are damaged by the recovery procedure. Sidewall core plugs are of limited use from an analytical standpoint. Baker Hughes INTEQ does not offer sidewall coring services. <...>