ANALYSIS OF SURFACE AND WELLBORE HYDRAULICS PROVIDES KEY TO EFFICIENTBLOWOUT CONTROL

Assessment of blowout rate and composition is a key issue for decision s concerning blowout control method, design of kill operations, determ ination of direct (e.g., environmental) and indirect (loss of reserves ) damage, etc. Usually, loss of control over the outflow of the well i mplies that the blowout rate cannot be established with conventional m eans. Experience shows that, because of the large reservoir decompress ion, production well performance cannot be extrapolated reliably to bl owout conditions. Hence, surface (simple) observations, such as wellhe ad/drillpipe pressure and temperature, effluent shape and size and noi se 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 per formance; it also describes how such estimates contributed to decision s concerning the kill strategy, leading to success in a relatively sho rt time.