The Oil Drum | From SEMP to SEMS: Industry’s Response to the Deepwater Horizon / Macondo disaster

The Oil Drum | From SEMP to SEMS: Industry’s Response to the Deepwater Horizon / Macondo disaster

There are TODsters who know about the mechanical side of ops, such as BOP design, then I’ll ever know. Ditto for cement specs and their testing procedures. But I do understand the basic method for preventing a well from blowing out. This may sound stupidly simple to many and they may think I’m leaving something out. I’m not.
Reservoirs, regardless of where they are and at what depth, exist at a certain pressure. The column of fluid in the well bore, whether cased or open hole, has to exert a pressure greater than the reservoir pressure. Basic and undeniable physics: fluid will flow from high pressure to low pressure. It didn’t matter if Halliburton had pumped the best/worst cement on the planet. It didn’t matter if BP had the best/worst cmt testing procedures in the industry. It wouldn’t even matter if BP had pumped no cmt at all. It would not have mattered if BP had the best designed BOP one can imagine or none at all. If BP had left a mud column in the well of sufficient weight to prevent the reservoir from flowing the blowout would not have happened.
Last week I began completing a well I drilled and cased a month ago. Cement was pumped and the drilling rig moved off. I didn’t run a cmt bond log or test neither the cement nor any of the potential annular failures before doing so. There was no need to: I left the mud in the casing that I drilled the reservoir with…the mud weight that prevented the reservoir from blowing out in the first place. I could have left the well with no casing, no cement, no BOP, etc. etc, etc for a 100 years and it would not have blown out.
With the more expensive drilling rig gone I move in a small completion rig. The cement has now had weeks to cure unlike the mere hours the Macondo cmt had. Not only do I run a cmt bond log I test all the cement (in the annulus as well as the bottom cmt plug) to a level exceeding the reservoir pressure. I install a BOP that exceeds the reservoir pressure and actually pressure up on it to make sure it holds that pressure. Then, and only then, do I displace the heavier drilling mud with a lighter weight completion fluid. Then I shoot holes in the casing through the reservoir and since its pressure is now greater than the back pressure exerted by the completion fluid the well begins to flow.
That, boys and girls, is how I’ve completed every well in the last 36 years. Not once have I ever seen an operator temporarily abandon a well without leaving a sufficient mud weight in the hole to prevent a blow out. And that includes offshore wells. I haven’t focused on the offshore for a while, especially Deep Water. I was shocked to discover that the feds allowed this procedure on the Macondo well. I can understand why BP did it. There are no cheap DW completion rigs: they use the same very expensive rig used to drill the well. BP wanted to leave the Macondo well ready to perforate and flow before they moved the rig off location. And that’s exactly what happened…the well flowed. Just a little sooner than they had planned.
Folks can discuss all the things that went wrong in the process: bad cmt, bad testing procedures, management pressure, malfunctioning BOP, drilling hands not monitoring the well properly, etc. But it doesn’t change the fact that had BP left the heavier mud in the hole or had placed packers in the hole isolating the reservoir from the surface before displacing with a lighter fluid the well would not have blown out. Never.
So how do you prevent another Macondo well from blowing out? Just as the doctor said when you told him it hurts when you do this: “Don’t do that”. LOL. There could be a blow out develop during the original drilling phase. That’s a different scenario we can discuss later. But a Macondo type failure need never happen again: just take 15 minutes to rewrite the regs regarding how a well is left temporarily abandoned.
It really is that stupidly simple