My understanding is that the surest way to permanently stop the flow of oil into the Gulf is to drill a relief well, which will intersect with the oil well deep underground, allowing it to be pumped full of concrete, which should plug it permanently.
I also remember hearing that this is a pretty common method for stopping gushers.
So, given that it apparently takes at least a few months to drill a relief well, during which time oil has been gushing into the ocean, why aren’t relief wells put in place before a disaster like the BP spill happens? Presumably, that would allow the flow to be stopped in a few days or weeks, instead of months.
Are there technical issues that would make this impractical, or is it just a matter of cost?
I assume that drilling a relief well is neither easy nor inexpensive. So, before the Gulf oil spill, would most oil companies simply have assumed that an accident of this magnitude was so unlikely that it wouldn’t be worth the cost of drilling at least one relief well for every oil well, rather than just drilling them as needed?
In the wake of the Gulf spill, has that cost/benefit calculus changed?
Just cost. The oil company would either need to have a single drilling platform drill two holes, or somehow get a second rig to drill the relief well while the first drills the primary well. Either way it’ll cost roughly twice as much as drilling a single well.
Of course, if the oil companies really had to bear the true cost of disasters like this on a regular basis, the cost of a second drilling platform might not be so much. Or it might turn out that deep water drilling isn’t worth the costs and risks.
Maybe they could drill it to, say, 95% completion, so it comes very close to the main well, but doesn’t actually intersect. That way, if the relief well was needed, they’d be able to have it ready in a relatively short amount of time.
But if it really is prohibitively expensive, I suppose the point is moot.
I’m pretty sure I’d heard on the evening news (probably MSNBC) at some point during this disaster that Canada (and other countries?) requires a relief well to be drilled at the same time as the initial well, to help head off problems like this. I can’t find the reference at the moment. At any rate, my guess would be that cost and “because we’re not required to” would be factors.
Cost would have to be the reason not to drill it, especially if a cheaper safety solution is already in place - namely, the blowout preventer - on the primary well. This assumes that the BOP is maintained in good working order, which unfortunately was not the case in the current GOM mess. Not maintaining the BOP would be analogous to not performing proper maintenance/construction on a relief well - IOW, if maintenace was lax on the BOP, there’s no reason to expect that BP would have maintained a pre-drilled relief well in good working order, either.
It would cost way too much to drill relief on every deep well. The safest well is a straight hole down with proper blowout protection on top. BP violated the recommendations of it’s own people.
I had in interest in a deep well in Oklahoma in 1980. Technology has improved yet the process is the same. The well blew out on top spewing 100MMCF gas/day until it clogged itself up. They drilled a second hole and a rigger dropped a large tool down the hole and ruined the hole at about 5,900 ft. on a 12,000 ft. hole. So they decided to intersect the hole below the damage by angle drilling like the BP relief well. Making that connection two miles down is no piece of cake, then and now. Let’s hope BP succeeds because mine did not and another clean well was drilled after all the original principals went bankrupt. Three wells are now safely producing on the section.
that’s not what your cite said. Canadian law requires that companies demonstrate they can drill a relief well if needed within the drilling season (before the water freezes). It doesn’t say that they actually drill the relief well concurrent to the primary well.
When I was a teenager attending summer school, a gasoline pipeline operating at 1500 psi was under the street next to the school. No one knew it was there until one morning when the school was closed because the pipeline had ruptured a couple of blocks away, spilled a whole bunch of gasoline, and started a fire that killed a couple of people and burned down several houses. Neighborhood residents were shocked and appalled to learn that gasoline was being piped right under their houses at such high pressures. After fixing the damage, the pipeline operator resumed operating at a much more modest pressure - but a few years later, quietly bumped the pressure back up to 1500 psi.
Given the level of (bad) publicity maybe BP won’t be able to get away with re-opening this well after it’s shut down, but don’t count on it; a well is an awful big investment to walk away from. They may shut it down for a few years, but once people stop paying attention, it wouldn’t surprise me to see them open it up again.
A relief well needs to intersect the main bore just above where the oil starts. It is tough to know in advance how deep that will be. So you could drill two bore roughly in parallel, and whichever one hits oil first becomes the main bore. Note that a blowout could happen in either bore though, so while you might have improved your ability to deal with a blowout, you have also doubled the odds that you will HAVE a blowout in the first place.
Also, this was the first test well of an entire field - the well was always going to be sealed off while other wells are drilled to determine the extent of the field. Once that process is complete, the location of actual production wells will be determined and opened up or drilled. In this case, however, due to the blowout it will never be used as a production well - there is no way of knowing how stable the well is.
The same reason car companies don’t provide you with an extra engine just in case yours stops working. They COULD do it… but it’s a bit of a resource waster when they could put that engine in another car and sell it, and it’s such a rare occurence. Probably the same thing with drilling holes for no purpose, they’d rather spend the money on something that brings a profit.
It wouldn’t matter if they were supposed to drill a relief well in advance; BP was supposed to do many things that would have prevented this disaster that they just didn’t do, and weren’t forced to do. Adding another regulation to ignore wouldn’t have made much difference, in my opinion.