Analysis of surface and wellbore hydraulics provides key to efficient blowout control

Assessment of blowout rate and composition is a key issue for decisions concerning blowout control method, design of kill operations, determination of direct (e.g., environmental) and indirect (loss of reserves) damage, etc. Usually, loss of control over the outflow of the well implies that the blowout rate cannot be established with conventional means. Experience shows that, because of the large reservoir decompression, production well performance cannot be extrapolated reliably to blowout conditions. Hence, surface (simple) observations, such as wellhead/drillpipe pressure and temperature, effluent shape and size and noise field, results of previous kill attempts, and pressure response of nearby wells have to be interpreted in terms of the blowout rate. This paper presents two examples of blowouts for which the combination of such data led to a consistent and accurate picture of blowout well performance; it also describes how such estimates contributed to decisions concerning the kill strategy, leading to success in a relatively short time.