A tradename for a method and system developed for obtaining a number of well logs in highly deviated and bad boreholes. Drill pipe is lowered to a predetermined well depth. The survey cable is then threaded into a side-entry sub and attached to the cable head. which in turn is attached to the subsurface instruments that are to be lowered into the well through the drill pipe. The side-entry sub is attached to the drill pipe.
Once all connections are made, the logging instruments, drill pipe, and sub can be lowered to a predetermined depth by ad ding nmore drill pipe above the sub. After the drill pipe has been lowered to the desired depth, the logging instruments are lowered or pumped out of the drill pipe to perfornm logging operations.
The survey cable is now outside the drill pipe and extending from the side-entry sub to the derrick floor. Mud circulation through the drill pipe can be accomplished at any time during operations.
Once the openhole logging is completed. the subsurface in struments reenter the drill pipe and retrieval can be started. Presently, the Induction Electrolog, compensated neutron log, Compensated Densilog/caliper, BHC Acoustilog, gamma-ray log, and Neutron Lifetime Log can be run on this system. Slant-hole Express is a tradename of Dresser Atlas. See illustration at high-angle borehole logging system.