Thursday, September 23, 2010
Oil-industry expert Bob Cavnar says that the Macondo well is dead.
True, there may still be some bubbles leaking:
However, that might just be naturally-occurring methane being released from the seafloor.
For example, this video made by University of Mississippi researchers in the Gulf in 2006 - years before the BP blowout - shows methane bubbles rising naturally from the seafloor (when contained by a test tube, they turn into snowflake-like methane hydrate crystals).
Indeed, as oil disaster expert Dr. Robert Bea pointed out in May:
About a month before the blowout, a "kick" of gas pressure hit the well hard enough that the platform was shut down. "Something under high pressure was being encountered," says Bea—apparently both hydrates and gas on different occasions.
Sealing the well wouldn't necessarily close off all of the normal avenues for methane bubbles to escape from the seafloor in a high-methane region. Therefore, I'm not sure that the small bubbles seen after the relief well was completed mean much.
But What About the Nearby Seeps?
A more interesting question concerns the seeps.
As Dr. Bea explained to me last month:
WB: Is it possible that this fractured, subsea salt geology will make it difficult to permanently kill the oil leak using relief wells?
Bea: Yes, it could. The Santa Barbara channel seeps are still leaking, decades after the oil well was supposedly capped. This well could keep leaking for years.
Scripps mapped out seafloor seeps in the area of the well prior to the blowout. Some of the natural seeps penetrate 10,000 to 15,000 feet beneath the seafloor. The oil will follow lines of weakness in the geology. The leak can travel several horizontal miles from the location of the leak.
[In other words, the geology beneath the seafloor is so fractured, with soft and unstable salt formations, that we may never be able to fully kill the well even with relief wells. Instead, the loss of containment of the oil reservoir caused by the drilling accident could cause oil to leak out through seeps for years to come. See this and this for further background].
As I wrote in June:
The deep sea subs have found other leaks a couple of miles from BP's gushing blowout preventer and riser.
For example, the Houston Chronicle noted on June 21st:A report from the National Oceanic and Atmospheric Administration on Monday noted research vessels found natural gas seeping from the sea floor several miles away from the well.
The Chronicle goes on to explain:Those appear to be pre-existing seeps that occur naturally, a NOAA spokeswoman said, and unrelated to the spill.
But the Washington Post made a very important point yesterday:
Bruce Bullock, director of the Maguire Energy Institute at Southern Methodist University, said additional leaks are a possible source of deep-sea plumes of oil detected by research vessels. But this part of the gulf is pocked with natural seeps, he noted. Conceivably the drilling of the well, and/or the subsequent blowout, could have affected the seeps, he said.
"Once you started disturbing the underground geology, you may have made one of those seeps even worse," he said.
Remember that geologists have said that if the well casing is substantially breached, the oil and methane gas will find a way through fractures in the surrounding geology and make it into the ocean. For example, the Houston Chronicle notes:If the well casing burst it could send oil and gas streaming through the strata to appear elsewhere on the sea floor ....
Obviously, if there are natural oil or gas seeps nearby, there are already pre-existing channels up to the seafloor ... so that may very well be the path of least resistance for the subterranean oil to flow up to the seafloor.
Therefore, if there were a substantial breach in the well bore, nearby natural oil and gas seeps could very well increase in volume.
So don't be surprised if - when formerly tiny seeps become gushers - BP tries to pretend that they were always that large.
As I noted in July:
The Times-Picayune reported yesterday:
Scientists have discovered four gas "seeps" at or near BP's blown-out Macondo well since Saturday ...
Berkeley engineering professor Bob Bea has very little confidence in what’s been said publicly about the seeps.
He’s troubled that we’re just now hearing about seeps three kilometers away, because a survey of the seabed conducted before BP drilled its well didn’t indicate anything like that.
“There was nothing that indicated the presence of such a seep,” Bea said. “I wonder why we’re just now finding that out?”BP has yet to release other ROV video that Bea’s study group requested more than a month ago about what may have been shots of nearby seeps.
(Bea explained to me last month: "In May, ... Senator Boxer subpoenaed information from BP regarding footage of the seafloor taken before the blowout by BP's remotely operated vehicles (ROVs). We still have not received a response 12 weeks later.")
Thad Allen said today that there are anomalies on the seafloor within 100-200 meters of the blown out well. And oil expert Bob Cavner told MSNBC today:
You know, these seeps that the admiral talked about within 100 meters of the well concern me some… The ones close really concern me.
And there is a possibility, if you look at the well diagram which is complicated and I won’t get into it. There is a path for oil and gas to get out into the sub strata. And I’m concerned about that.
A 20-year petroleum geologist - with 13 years spent in offshore exploration in the Gulf of Mexico - "gasmiinder" noted yesterday:
Mapping of natural methane seeps is required as part of the process of obtaining a drilling permit in the Gulf of Mexico. This is required because the "methane seep communities" are considered environmental "havens" as it were - you have to demonstrate you're not disturbing the critters. [My comment: There are ecosystems which can thrive around small natural seeps. But huge gushers like the BP blow out can kill everything in sight, especially given the large amounts of methane which have spewed from BP's well]. The process does not measure the rate of seepage but you would have some guess based on the areal extent of the communities. This report is filed with the MMS and should be available. I'm surprised and enterprising reporter hasn't requested a copy from the MMS. (Of course enterprising reporter might be an oxymoron in the modern era)
I attended a scientific talk about 20 years ago where the study results estimated about 1 million barrels of oil a year seep into the Gulf from natural seeps. Of course that is spread over a huge area on an entire year.There is no evidence for the existence of high-density chemosynthetic communities within 1,500 ft of the proposed well location.
Gasmiinder responds:The statement regarding the chemosynthetic communities requires a seafloor survey - that's what I'm referring too where there will be a report available having mapped them (the partners will have copies of that report as well).
Here is a copy from the webpage of a company that consults on the interpretation of the hazard surveys. It should give at least a feel for the level of information that is believed to be present in the data (meaning this is what they claim to be able to accomplish with the datasets):
• Assess seafloor conditions and stratigraphy, and geologic processes to evaluate well site locations
• Identify shallow gas and shallow water flow potential [my note: they are referring to shallow layers that could be hazards to drill through)
• Interpret and map geologic constraints, such as faults, gas vents, seafloor depressions and mounds, and any other geologic phenomena that are detectable with seismic data
• Identify potential chemosynthetic communities, archaeological sites, and man-made infrastructure and debris
• Assess mooring spread, anchor locations, and foundation zones
• Produce supporting maps to show water depth, topography, shallow structure, and seafloor and shallow geologic conditions and features in an area that may have an impact on drilling
• Prepare final reports needed for permit application to governmental and insurance bodies
So BP (and its partners in the well, Anadarko and Mitsui) would have maps of all of the nearby seeps which were there before well blew out.
Moreover, Dr. Bea told me last month that there might be other leaks near the Macondo wellhead:
The bottom line is that I believe that the Macondo well has successfully been capped by the relief well.
WB: The chief electronics technician on the Deepwater Horizon said that the Macondo well was originally drilled in another location, but that "going faster caused the bottom of the well to split open, swallowing tools", and that BP abandoned that well. You've spoken to that technician and looked into the incident, and concluded that “they damn near blew up the rig.” [See this and this].
Do you know where that abandoned well location is, and do you know if that well is still leaking?
Bea: The abandoned well is very close to the current well location. BP had to file reports showing the location of the abandoned well and the new well [with the Minerals Management Service], so the location of the abandoned well is known.
We don't know if the abandoned well is leaking.
WB: Matthew Simmons talked about a second leaking well. There are rumors on the Internet that the original well is still leaking. Do you have any information that can either disprove or confirm that allegation?
Bea: There are two uncorroborated reports. One is that there is a leak 400 feet West of the present well's surface location. There is another report that there is a leak several miles to the West.
[Bea does not know whether either report is true at this time, because BP is not sharing information with the government, let alone the public.]
And I have no evidence that there is increased seep activity after the relief well was completed.
But the government and BP must do the following before we can have reassurances that there are no nearby seeps which are now larger because of the April disaster:
(1) Release - at least to Senator Boxer and Bea's study group - maps and video of the seeps within a 5-mile radius which existed before the blow out; and
(2) Release current maps and video of all seeps within a 5-mile radius.