April 20 Time-line
If you are unclear as to why something happened it is usually helpful to summarize the major events in a time-line. While the preceding event may have no causal effect, it is certain that anything that occurred later definitely didn’t cause earlier events.
All times are in Central Daylight Savings time, the local time for the Deepwater Horizon.
1:00AM – Halliburton finishes its cementing of the well.
8:20AM – the supply ship Damon B. Bankston arrives at the Deepwater Horizon
11:00AM – a Schlumberger team that was to test the cementing is sent back to land without testing.
1:17PM – the process of pumping the heavy mud out of the well to the Bankston begins.
5:00PM – Halliburton informs BP that pressure is building up in the well.
5:17PM – the transfer of the mud stops.
9:00PM – the Bankston is told to expect more mud.
9:45?PM – mud droplets are raining down on the Bankston, and they are told to cast off and stand by.
9:53PM – the Deepwater Horizon is engulfed in flame.
BP spent a lot of money to have a Schlumberger team on stand-by for two days to perform a thorough test of the cementing, and then sent them back to land without doing it.
Just over twelve hours after the cementing was finished, BP started to pump out the heavy mud that was balancing the well pressure.
When the well pressure increased, BP stopped taking mud out, but didn’t pump any back in to balance the pressure. They depended on cement that had been curing for 16 hours.
