On the 18th April, Halliburton commenced the cement job which would lock the casing in place and fill the annulus so that the reservoir was sealed and that no more hydrocarbons would escape (stopping the extraction of oil.) Figure 1.4 shows the process of the cement job which BP eventually failed to do successfully. The cement mix varies depending on the particular conditions underwater as BP had requested a nitrogen foam cement mix which had nitrogen bubbles.They thought that it was just as strong and would lower the density of the mix, placing less pressure onto the pipe. The job initially didn't go smoothly as they had problems setting the float collar but eventually they completed the job. Afterwards, they sent the technicians home without completing cement bond log test. It saved BP a few hours and $25000-$50000 but it would've also shown them the problems with the cement. The cement wasn't set right and the gas penetrated through the shoe track and moved up the annulus as this is shown in Number 1 and 2 of Figure 1.3. The abandonment sequence was rushed in the last 48 hours as the safety margins were reduced and codes were violated.