SEISMIC TESTING

DOES ANYONE KNOW HOW FAR IS FRACKED WHEN THEY DRILL DOWN 30 FEET AND SET OFF THE CHARGE I HAVE SPRING WATER AND WORRIED ABOUT IT.THE GUY TOLD ME THEY HAVE TO STAY AWAY FROM BUILDINGS AND SPRINGS 400 FEET AND I WAS CURIOUS HOW MUCH DAMAGE IS DONE UNDERNEATH WHEN THEY SET IT OFF ? THANK YOU

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Permalink Reply by Jack Straw on September 24, 2012 at 2:19pm

RE: "DOES ANYONE KNOW HOW FAR IS FRACKED WHEN THEY DRILL DOWN 30 FEET AND SET OFF THE CHARGE"

Inches, or at most a foot or two, assuming that the bottom of the hole is in solid rock. If the hole bottoms in soil, subsoil, fractured rock - then it will simply temporarily compress.

The idea is to get as much of the energy from the charge to travel down through the earth as a sound wave.

Any energy that would go into fracturing rock would be an unwanted lose of energy.

The explosive used is a high velocity charge; it expends its energy in as short a time duration as possible.

The reasons for this lie in Fourier Theory; the shorter the time duration something is in the Time Domain, the longer it is (greater bandwidth) in the Frequency Domain.

The greater the bandwidth in the Frequency Domain, the greater the resolution that can be obtained.

For a particular survey/area, testing is done to determine the optimum depth of shot holes and size of charge to obtain the best data. For a variety of reasons, the smallest charge that accomplishes the data quality goals is the size of charge one would wish to use. It is usually better to use a number of smaller charges in multiple shot holes than to use a larger charge in a single shot hole.

Many years of science and empirical experience goes into the choice of parameters such that the shots can achieve as much as possible without negative effects.

RE: "THE GUY TOLD ME THEY HAVE TO STAY AWAY FROM BUILDINGS AND SPRINGS 400 FEET AND I WAS CURIOUS HOW MUCH DAMAGE IS DONE UNDERNEATH WHEN THEY SET IT OFF ?"

By staying 400 feet distant, they are being overly cautious, as one would want them to be.

They look at the worst possible occurrance and multiply it by ten, that way everyone (including their insurer) will be happy; the cows will give milk, the chickens will continue to lay eggs, and the shrimp (in their ponds) will grow and prosper.

 

All IMHO,

               JS

 

 

 

 

 

 

 

Permalink Reply by bruce c on September 27, 2012 at 1:21pm

Had a visit yesterday from a guy from Front Runner Seismic/Vector Seismic Processing, he is working to get 1100 Landowners signed up in NW Mahoning & SW Trumbull for testing April-Oct. 2013, he left a 1 Page "Permit to Conduct Geophysical Operations" Form, at $5/Acre for 18 months, I think this sounds like low$$ & a long time frame. Has anyone gotten a better offer?? I asked him who they are doing the work for, he mentioned BP, Chesapeake & Eric Petroleum. I told him the 1 page form was very vague  and gave him the 7 Page form from the ALOV website, he had gotten it from others. He told me the company was reviewing it and he would get back to me.

Permalink Reply by SJL on December 7, 2012 at 6:40am

Bruce,

Did Vector ever sign the ALOV lease for you?

Permalink Reply by bruce c on December 9, 2012 at 1:25pm

Not the entire ALOV agreement, But they did give some additional Landowner protection

Permalink Reply by SJL on December 9, 2012 at 1:32pm

Thanks, Bruce.  A land specialist told me that Vector refuses to sign any of the ALOV leases.

Permalink Reply by DIGGER on September 25, 2012 at 2:04am

THANK YOU That was awesome info. !!

Permalink Reply by Brian Powers on September 26, 2012 at 2:58am

Digger -

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.

Way back in the early rotary drilling days (" when the men were made of iron and the derricks were made of wood") and long before hydraulic fracturing was invented, a common way to stimulate a vertical well prior to first production was with liquid nitroglycerin. early in my career, I remember reading well files from Panhandle Oilfield wells (Texas Panhandle) drilled in the 1920's and '30's where the wells would be stimulated by dropping X number of quarts of nitro downhole and setting it off, then by dropping large round river rock downhole to minimize fill (it would not be PC of me to repeat  the term used to describe the round hard rock used)

I agree with the other responders of this query that the shot hole  energy would be dissipated rapidly; and it is well worth remembering that a propped hydraulic fracture has two pressure components: the initiation pressure and the extension pressure that allows the proppant laden gelled fluid to fill and hold open the fracture after the fluid leaks off. Unless the rock at the base of the shot hole was of the right type and rubbleized upon detonation, I could not envision any shothole generated frac being capable of flow, therefore, I would not be concerned about your spring, though you may feel the charge through  your boots if you were close enough to the shothole, and you may get some dust or mud on you or your truck too.

 

Brian

Permalink Reply by Brian Powers on September 26, 2012 at 5:06am

Utica -

I found a paper: http://www.public.iastate.edu/~beresnev/Beresnev/lebedev_beresnev_d...

 

that describes a method to mathmatically correct for signal distortions in soft soils. The paper is heavy lifting with lots of math; it may well might be a good sleep aid for you.

 

I would speak to the seismic company rep or the operator rep and pose these questions to them; I'm not sure if dual frequency geophones are available to help filter noise or if there are other methods to improve signal resolution or reduce soft soil signal attenuation. Computer processing power has grown exponentially in the decades since I last studied geophysics.

 

I do remember from my offshore days that explosives are no longer used for marine seismic surveys- compressed air pulses or implosion pulses are used instead.

 

Your concerns about surface damages are also valid. The seismic survey forms but one of the early links in the chain of hydrocarbon extraction; there are significant earth and soil disturbances when the well pad/lease roads are built, when the rig and frac equipment is moved on/off location, when hauling pipe, cement, fuel and other bulk supplies in, etc.

 

Brian    

Permalink Reply by mark ayers on September 26, 2012 at 6:02am

In the early 80's I worked for CGG (now CGG Veritas) and we shot a line from Prudoe Bay to the Canadian boarder on the ice of the Arctic Ocean.

Sercel vibrators at work for CGGVeritas in Alaska.

We also spent a lot of time off road and in fields when we where in California and Oregon. 

Permalink Reply by Kathleen on September 26, 2012 at 6:25am
To even think of using those trucks in fields besides compressing the soil is crazy :0). This process would be so weather depended it would never get done around here. Yup it was dry this year but any other year those big heavy trucks would need to be towed constantly. I get a laugh just thinking of seeing a line of them and their support system all stuck in a field.
Permalink Reply by Billy Park Whyde on September 27, 2012 at 8:03am

I might be wrong but with the amount of surface area upon the flotation tires the vehicles use I would doubt if soil compaction would be any greater than say in comparison a 125 HP tractor with loaded singles.  With them being run on even sand they getr done. 

Permalink Reply by Kathleen on September 27, 2012 at 8:15am
My post reads funny. I meant when they do the vibrations by dropping the heavy plate. That surely would flatten the ground IMO. I do still think those trucks would get stuck before a tractor but than again I decided that just by the vibration trucks I've seen here. There like a big heavy box that stay in one spot a while or move like a sloth and in a wet field I can't image they wouldnt have problems.
they didn't use the trucks in the above picture here. I wonder if sand behaves different? I grew up on sand (new jersey) and we didn't seem to get stuck as much as here when its wet or see awful ruts like I do here. Could just be I do different stuff now and jersey taxes are super high which reflect in there roads all being paved (most of them, I just never seen a dirt road in jersey anywhere in 26 years :0) ). Rather have a rut than those taxes again.

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