How Seismic Testing Works

Seitel Data, Ltd has been contracted by the oil and gas industry to perform a seismographic survey in Crawford, Mercer and Venango Counties in order to map the region’s geology.  While the testing is not slated to occur until March 2013, Seitel is hoping to obtain our written intention of whether to allow the testing or not before the end of 2012.  At this time, the Advisory Group recommends that the seismic testing be allowed only if Seitel agrees to stipulations about where they can and cannot drill test holes as well as the reservation of the right to make a final decision in early 2013 after the issue can be vetted campus-wide.  While any decision to allow or disallow the seismic testing is entirely separate from decisions regarding leasing or drilling, there are still many considerations the campus community must weigh.  To learn more about how seismic testing works, Seitel invites you to join Wally the Wavelet on a guided seismic technology tour.

Seitel showed us a map that plots the proposed placement of geophones and the drill/charge holes to conduct the seismographic survey.  Geophones are basically a data box connected to six wires with a small “plug” at each wire end with 4″ probes which are pressed into the earth.  The six wires/probes form a 4-6′ square.  A receiver line is a line of geophones (about 220′ apart) running basically east to west.  Parallel receiver lines are about 300′ apart.  Drill/charge holes are laid out in parallel diagonal lines.  Ideally Seitel would want to place 35 drill/charge holes in the Bousson area, but they’d be willing to do it with as few as 10-15, even though this is not ideal for their testing.  Each hole is a 3″ diameter and 30′ deep hole.  It’s drilled by a 5×8′ drilling rig on rubber tracks which weighs about 5000#.  We were adamant that we could not and will not allow any new pathways to be created for these vehicles if we were to consider allowing this testing.  Since getting a 5×8′ vehicle through most of Bousson would be impossible without cutting, we could stipulate where we’d permit a drill/charge hole and where they’d have to skip, particularly if we felt they couldn’t access it without impact.  For example, we could tell them they could only drill along existing trails and drives.  We could even have our faculty, staff and students walk with them and select locations for the drill/charge holes.  Once the holes are drilled, they put a 3# charge in the bottom and backfill the hole with gravel.  Once all the geophones are placed and the holes are drilled and charged, they will set them off in swaths.  The charge is directional and blasts downwards, creating a vibration/soundwave into the geology below.  The geophones receive the bounced back soundwaves and this data can be used for mapping purposes and to understand what oil/gas resources are present or absent. Seitel stated that in a few weeks we would not be able to tell where the blast holes had been except for a potential small depression due to settling.

Notes from meeting with Seitel:

10.16.12 Seitel Data

12.01.12 seitel project postponed