July 19, 2010
Listening to the news this morning as I drove to work, I heard that BP is saying that the seep discovered near the blownout well might be a natural seep .
A BP spokesman said the seepage was detected by its engineers but it was unclear whether the source was the blown-out well, adding that seepage was a natural phenomenon in the Gulf.
Indeed, a breaking news headline across the web reads:
“BP spokesman says seepage nearly 2 miles from its ruptured Macondo well in the Gulf of Mexico is natural and is unrelated to the oil leak.”
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.
Because BP would like to minimize leak estimates to minimize the damages it has to pay under the Clean Water Act, BP would undoubtedly try to pretend that the nearby natural seeps always had the same volume. In other words, the owner of the oil drilling prospect where the spill is occuring – BP – may be the only party to have mapped out the nearby seeps ….
So don’t be surprised if – when formerly tiny seeps become gushers – BP tries to pretend that they were always that large.
Indeed – given BP’s track record of prevarication – don’t be shocked if BP pretends that brand new gushers are ancient, natural seeps.
Indeed, as 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.
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.
In addition, there are logs of where BP’s underwater submersibles (ROVs) have traveled since they arrived at the scene. Tracking the logs would show whether any ROVs had visited the current seep before today. If so – and my hunch is that they have – then the corresponding footage would show how big those seeps were previously.
Indeed, enterprising citizen journalists who have recorded and stored the footage from BP’s underwater cams could compare the compass readings from the current feeds showing seepage to previous similar compass readings, and find the footage themselves.
This article was posted: Monday, July 19, 2010 at 2:51 pm