Case History Analyses of Shallow Gas Blowouts

Abstract

ABSTRACT Blowouts have different characteristics for each situation that require a case-by-case analysis to develop the most appropriate control techniques. Shallow gas blowouts, which are the most common type of blowout, follow the same rule requiring a diagnosis for each case. However, experiences gained from working on shallow gas blowouts during recent years and a study of other shallow events have shown important similarities in causes and probable results. If applied properly, these similarities can be used to avoid shallow gas blowouts or develop appropriate response plans. Specifically, our work has shown that many shallow gas blowouts have some relationship to the cementing operations. Also, the paper discusses the details of several case histories (without specific references to the operator or the locale). Since most shallow gas kicks result in a blowout, an additional objective of the paper is to present emergency response procedures for personnel and rig safety. Information is provided which includes drilling procedures, equipment selection guidelines, response of various types of rigs in shallow gas blowouts and a discussion on nser/riserless drilling.