[QUOTE=New Orleans Lady;47282]http://www.consumerenergyreport.com/blogs/rsquared/
[B]A Closer Look at The Commission Report on the Deepwater Horizon Disaster [I]“[BP Wells Team Leader] John Guide explained after the incident that losing returns ‘was the No. 1 risk.’ He and the other BP engineers worried that if their cementing procedure placed too much pressure on the geologic formation below, it might trigger another lost-returns event similar to the one on April 9.” [/I]unstable. Furthermore, BP also limited the volume of cement pumped down the well and chose a less-than-optimal rate of cement flow. While protecting the formation from damage, these compromises increased the risk of a blowout.
[B]To get a blowout you need to remove the hydrostatic pressure overbalance in the well. At no time while cementing was there a threat of a blowout. Instead, there was the real possibility of losses to the weak formation. The cement failure merely means that the barriers are not in place, which should have become apparent at the Negative test and while displacing the well. Then, remedial action would take place to secure the well and either form a new barrier or plug the well and abandon same.
There are countless wells which have been in the same scenario of cement barrier failure. They don’t blow![/B]
[I]Despite the compromises evident in the cement procedure and an earlier decision to use a riskier long string well design, BP decided to dismiss a team of Schlumberger technicians who were on standby at the rig to perform cement evaluation tests if required. Skipping the test saved BP both time—leasing the Deepwater Horizon reportedly cost as much as $1 million per day—and Schlumberger’s $128,000 fee.[/I]
[B]Yes, it saved BP time and money. They should have performed the CBL and Temperature Log. But this information would only verify the presence of cement on the Annulus side. It doesn’t verify the shoe-track has a cement barrier. And so, the Negative test and SW displacement were the only things to verify this barrier was in place.[/B]
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Optimal rates of flow sometimes induce the fracturing of weak formations because of the excessive Annular Pressure losses, the additional pressure acting on the weak formation with high or optimal flow-rates. It is common practice to start pumping at reduced rates and then build the rate in stages as the cement exits the Casing Shoe during the cement Job. But, if you decide to increase to optimal and formation breakdown occurs then you’ll have to answer for it later, especially if the vessel is threatened by losses to the weak formation, and an underground blowout occurs.
I know of many cement job failures, some associated with Reservoir Casing strings. They were solved. And the rigs concerned recognised the failure. TO, recently had a rig in the North Sea which passed the Negative Test, and then failed while the displacement to SW was ongoing. But, the crews were observing volumes and pressure throughout the displacement, as is required, and they noticed the volume and pressure anomalies.
No Blowout occurred, even though they had the same circumstances as the Macondo.
Either, we understand the value of Volume and pressure control or we just send BP to jail and learn nothing about how to avoid further incidents. I’ll bet you there aren’t any rigs out there right now ignoring volume control!