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Permalink Reply by Jack Straw on September 27, 2012 at 8:41am

The old Thumpers were Weight Drop, a large rectangular weight dropped from about 10 feet from a draw works at the back of a truck. These Thumpers worked on the pricipal of simple gravity. The last of these were phased out in the mid-1970's, as Vibroseis had already superceded the Thumpers.

Vibroseis works by hydraulically jacking up a portion of the weight of the truck onto a heavy rectangular plate. Then, the plate is (via hydraulics) vibrated  through a sweep of frequencies (typically 8-80 hz.).

The large rectangular pad on a typical Vibroseis truck exerts around 32 tons of force as it pounds the ground (in a merciless fashion).

It will definitly leave its mark in un-compacted soil.

It will definitely compact soft soil, giving gophers more than a simple headache.

While working in the desserts of the Middle East, I could navigate travel cross country (pre-GPS days) by using old seismic survey maps. You could clearly see the pad marks still deeply impressed in the sand and soil from surveys that had been completed 15 years previously. 

 

All IMHO,

                 JS

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Permalink Reply by Jack Straw on September 26, 2012 at 9:32am

RE: "I'm surprised that the regulators even permit the use of explosives for seismic surveys in PA, as vibrator trucks may be able to get usable survey generation energy to the subsurface with a much less obtrusive footprint."

Vibrator Trucks versus Explosives (in shot holes)

Vibrator Trucks travel and operate in groups – typically around four trucks, traveling in-line.

The trucks are large complex electro-hydraulic monsters and require circumstances that allow them substantial continuous surface access.

2D Seismic Surveys operate in an in-line fashion, using Vibrator Trucks along existing highways, roads and lanes make sense.

Today, 2D Seismic Surveys are largely looked upon as reconnaissance in nature.

For detailed exploration and development work 3D Seismic Surveys are preferred; 3D Surveys are laid out in a grid fashion.

In areas where there are vast flat expanses, Vibrator Trucks can travel cross-country; otherwise they are largely restricted to existing roads.

The terrain of PA, OH, WV is not conducive to off road Vibrator Truck use.

Steep topography, streams, wetlands and frequent wooded areas impede access for a parade of large Vibrator Trucks.

For logistical reasons, Explosive Sources (in shot holes) will tend to be the best energy source for many 3D surveys. Where some surface access allows, truck mounted shot hole drilling rigs can be used (essentially the same equipment that could otherwise be drilling water wells).

Elsewhere, portable shot hole drills can be used in difficult terrain, with minimal surface disturbance; they can go virtually anywhere (often assisted by helicopter support).

By now, many have likely seen an ongoing 2D Vibroseis survey (as both they and you have shared the same rural byways). As these initial reconnaissance surveys yield to more detailed 3D surveys, I expect that you will see more shot holes being drilled.

 

ALL IMHO,

                        JS

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Permalink Reply by John Smith on September 26, 2012 at 3:25pm

they are doing seismic testing in portage county right now

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Permalink Reply by wpl on September 28, 2012 at 12:38am

interesting conversation - Veritas just finished survey on family property in Clinton County, PA. It would have been impossible to navigate up to 50% slope with anything except a tracked drill or by flying in drill rigs by helicopter.

They can produce a map showing potential drill sites and listening sites, I assume any other company could also, based on their surveyor's reports of excluded zones for drilling. You should see one when approach you to lease with a general grid of potential sites, then they gave us one marking domestic water sources and other springs, pipelines, dwellings, etc. that were excluded due to sensitive nature of the area and it showed where they were going to locate their stuff. They also preformed both pre and post water tests and shared the information with us regarding wells and springs used as water sources.

 The worst thing to me is that they are all over your land for a several months - surveying, drilling, putting equipment out, picking equipment up, fixing break downs but that is why they pay you. They explained to me they like to have about 20 listening lines down, 10 on each side of blast line, for best results. Then they pick it up and move it one line at a time to maintain that ten line buffer for listening. I only have experience with Veritas but I found them quite accommodating.

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Permalink Reply by Brian Powers on September 28, 2012 at 1:37am

wpl -

This has been an interesting and informative thread for me. In this great and resource bountiful country of ours, it seems that too many folk still suffer from the NIMBY (Not In My Back Yard) syndrome, that is, until the royalty checks start appearing in the post box in the front yard!

 

Brian  

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Permalink Reply by mark ayers on September 28, 2012 at 3:47am

I wish I knew what they where paying back then, but I only worked for them, it would be interesting to find out.

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Permalink Reply by Billy Park Whyde on September 28, 2012 at 4:43am

copy of a email I sent :

dwinn@tgcseismic.com

Hello

  I came accross a situation that you might be able to resolve and feel it's in your interest to do so.  I am a member of Go Marcellus Shale  http://gomarcellusshale.com/ and run the Licking/Muskingum County Group http://gomarcellusshale.com/group/muskingum-licking-county. You may see a pop up that request a donation  just put in O zero and the site is free.

  There at GOMS is a thread about seismic testing that rather attacks (loosley called) thumper trucks. http://gomarcellusshale.com/forum/topics/seismic-testing-2?page=2&a...

  I would think it would be wise to address what you see here. DATA specs such as weight distribution upon the tires PSF imprint and compair it to say the PSF of a farm tractor  with loaded tires. What would be good would be a field video of a farm tractor in say a  soft or marshey area and its imprint or grave, lol, might be as in comparrison to  your vibrosis units. Address the soil compactation  of the contact area as well.  A good example would be say the PSF that a loaded grain gravity wagon would have in a field as compaired to your units as well.

Billy Park Whyde

  Please note but I am not trying to argue here, but rather get data to learn from. As far as payment goes for such testing thats your personal business. Personally I do not believe the trucks would be that bad except possibly in some real bad spring thaws but what isn't? Hopefully they will provide info to us.

 

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