While the official BOEMRE-USCG and National Commission/Chief Counsel investigation reports were quite good and there are countless court documents and ad hoc reviews of the blowout, some important Macondo issues have not been fully addressed. BOE will touch on these issues periodically starting with the decision to terminate the top kill operation on 5/28/2010.
The top kill operation (see diagram above) was intended to overcome and halt the flow of oil by pumping heavy mud into the well bore. The operation was not successful because the pumping rate and mud weight did not generate sufficient pressure. Per an excellent paper by Dr. Mayank Tyagi and colleagues at LSU (Analysis of Well Containment and Control Attempts in the Aftermath of the Deepwater Blowout in MC252):
It is very likely that if the top kill had been designed to deliver more than 109 bpm of 16.4 ppg drilling fluid below the BOP stack for a sustained period, the Macondo blowout could have been stopped between May 26-28, 2010. Given that the well was successfully shut-in with the capping stack in July, and that the subsequent bullhead (static) kill was successful, certainly a higher rate top kill would have been successful at that time.
The American Thinker, citing the New York Times, reports that Energy Secretary Chu stopped the top kill operation over the objections of some BP engineers. While it was reasonable to be concerned about possible casing leaks and the fracturing of subsurface formations, the subsequent (7/15/2010) closure of the capping stack demonstrated that the well had sufficient integrity to support the top kill operation. Questions regarding why a higher rate top kill effort was not attempted and how that decision was made are therefore important and merit discussion. Did the Macondo well flow unnecessarily into the Gulf for an additional 48 days (5/28-7/15)? Did the National Incident Command facilitate or delay source control?
Keep in mind that the NIC almost made a similar mistake in July. Even after the capping stack successfully shut-in the well on 7/15, Incident Commander Thad Allen (USCG) continued to call the closure of the capping stack a temporary test and threatened to require BP to resume flow from the well. Fortunately, informed input from experienced engineers prevailed. The well remained shut-in and the static well-kill operation was successful.
Bud's Offshore Energy (BOE) 