An Assessment of the Benefits of “Secure Source” Systems for Nuclear Logging-While-Drilling Operations

摘要

This presentation discusses the health, safety andenvironmental risks associated with the deployment of nuclearlogging services while drilling (LWD). During theseoperations, radioactive sources are inserted into logging toolswhich are run in hole as part of the drill string bottom-holeassembly.This paper summarizes the key radiation safety andenvironmental protection aspects of a 'secure source' loggingsystem, designed to deliver the highest possible standard ofprotection to the logging sources during drilling operations.The risks associated with various critical scenarios areassessed and compared. The discussion includes a summary ofthe procedures followed when stuck nuclear logging tools arerequired to be abandoned in hole and the importance ofavoiding loss of the sources at an unknown location in thewell.The conclusions are presented within the context of anongoing debate on the relative merits of 'secure' loggingsources and alternative 'retrievable' systems, involvingsources which may be able to be returned to the surface if thebottom-hole assembly gets stuck in hole.