Trends Extracted From 800 Gulf Coast Blowouts During 1960-1996

Abstract

Abstract The cost of blowouts and the loss of lives incurred from blowouts warrant the study of past occurrences in order to reduce the possibilities of future blowouts. Even though we continuously learn more about how to handle an unstable well, it seems that the problems of detection, handling kicks and loosing control do not change much with time in the real world - out on the rig. The small changes and improvements that do occur are first of all seen thorough statistical data. A new data base resently compiled will soon contain extensive data on more than 800 blowouts from the Gulf Coast area and adjoining states during the period 1960 through 1996. At the moment the compiling work has not been completed. However, at the 1998 IADC/SPE Drilling Conference an updated version of this paper will be available. Five agencies contributed blowout report information. The State Oil and Gas Boards/Conservation Office of Alabama, Mississippi and Louisiana, The Railroad Commission of Texas and the Mineral Management Service (MMS) of the Dept. of Interior. At the moment the Texas blowouts make up approximately 50% of the blowouts in the data base but range below the average blowout frequency of 0.15 blowouts pr. 100 well-ft. drilled. The three major operations in progress when blowouts occurred were exploratory drilling, workover and development drilling. Most frequently blowouts occurred during the activity of actual drilling, tripping out and circulating/killing. The analysis indicated also that the major causes were related to swabbing, drilling into a high pressure zone or formation break down while the secondary barrier after a kick has occurred which most often failed were either failure to close BOP, failure to stab string valve or BOP failed after closure. P. 539