by copious.abundance » Fri 21 Oct 2011, 01:15:07
I actually thought the article was pretty good. Points like the one below are really good because you don't usually see them mentioned on places like this or TOD:
$this->bbcode_second_pass_quote('', 'I')n fact continuous resources are often the source rock for many traditional fields. If not for continuous resources traditional traps would not have any hydrocarbons in them. A few percent of the oil and gas contained in continuous resource leaked out over long periods of time (millions of years) and accumulated in traps.
One other thing to note is that the oil in continuous resources (at least, shale source rocks, but definitely not continuous resources like the tar sands) tend to be of higher quality than conventional traps, because during the process of migrating to a trap oil tends to pick up lots of impurities. This isn't always the case, but it's often the case.
It might also be interesting to more fully describe the types of development the two kinds of resources will have.
A conventional trap like the
East Texas oil field were developed with 30K wells. The field covers 140K acres (about 219 square miles). If that same field were developed today with more modern know-how the number of wells would certainly be less, but would still be a lot. Maybe 15-20K wells.
A continuous source rock like
the Bakken covers about 200,000 square miles. According to
this, the Bakken and related formations in the same area will be developed with anywhere from 20K to 40K or more wells over the next 30 years.
So, about the same number of wells have been/will be drilled in the two formations. They both contain about 5 billion barrels of recoverable oil, maybe more. The differences boil down to:
1A) A continuous resource needs more miles of pipe and other infrastructure to be developed, because it's spread out over a larger area.
1B) On the other hand, there is very little exploration risk in developing a continuous resource. Delineating a relatively small trap can be a hit-and-miss process, especially in the early stages, so a lot of dry wells get drilled. In a continuous resource, on the other hand, as long as you know the depth of the rock (which most everyone does by the time they start drilling the first wells, because most of these areas already have a history of conventional development), you are practically guaranteed to hit oil. There will be good spots and not-so-good spots, but at least they've all got at least *some* oil and/or gas.
2A) The oil in a conventional resource might be good quality, but it also might be poor quality.
2B) The oil in a continuous (source rock) resource is almost guaranteed to be high quality.
3A) The oil in a conventional resource flows without having to stimulate the rock.
3B) The oil in a continuous (source rock) resource needs fracture stimulation to free the trapped oil.
4A) Being spread over a smaller area, development of a conventional resource entails less mineral leasing.
4B) Being spread over a large area, development of a continuous resource entails lots of mineral leasing.
So, in a continuous resource you're gaining a lack of exploration risk and (more likely) low refining costs in exchange for higher development costs (land, infrastructure and fracturing).