Improvement and Development of Core Drilling Method in Scientific Drilling

Abstract:

This paper deseribes features,advantages, disadvantages,present development and application status of a few core drilling systems, suitable for scientific slim hole deep drilling, including wireline coring with hydro- hammers, retractable bit systems, retractable bit system-percussive rotary coring, retractable bit system- down hole motors, and intelligent wire-line coring, with future trend presented.