unit size/lateral directions

I've noticed on all the maps I've seen pertaining to the horizontal wells drilled that the laterals all go nortwest or southeast. some go over a mile in those directions. Would like to learn why? Is it because of how the shale formation is laying? Also. does this mean that the unit size ,whether 640 acres,or 1280 acres, will be a long rectangle,as opposed to a square unit? Would royalties only go to the landowners within that unit?  Could your land be only a few thousand feet directly east of the well & not be part of it?

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Permalink Reply by owner on January 23, 2012 at 7:18am

I am not a geologist, but my guess would be that this direction intersects the natural clevage joints in the shale seam.  All seams have natural clevage joints and by intersecting this joints at a 90 degree angle would maximize the release of gas.  This would also aide with having a seam for the fracing fluid to sepearte.  

Permalink Reply by mike on January 23, 2012 at 10:36am

How I understand it is how it was explained to me is take a phone book and go through the front to back and you went through all of the pages unlike just going through one or two pages, think of the shale as pages in a book.

Permalink Reply by gary smith on January 23, 2012 at 11:03am

mark, i believe shale has layers all through it. the drillers may want to stay away from faults as they may allow the fracturing energy to dissapate away from the shale seam in the segment they are fracturing. i've worked alot of deep sewer jobs where we had to blast solid rock for our trenches. the dynamite in the holes was always set to go off a miiisecond after the shot in front of it so the rock had somewhere to move to . i would think the frackers would want a consistent material to frack from one end of segment to the other. maybe.

Permalink Reply by Brian Powers on January 24, 2012 at 11:23am

Mark -

 

Your comment is spot on. When the horizontal wellbore intersects the fracture plane orientation, good things can happen. Also bad things such as lost circulation, stuck pipe, etc. It takes a good understanding of the regional rock stresses to properly align the laterals with the natural fracture planes. When I worked in the Middle East, we developed a rich gas/condensate field by targeting the laterals to intersect the fractures within the carbonate (limestone) reservoir. We used sophisticated (and expensive) imaging tools which would show the fractures, their width and azimuth, and the number per foot or over a longer interval. We also took pressure measurements on pipe that roughly correlated to the rock permeability and liquid yield of the gas. As this project evolved, we gradually switched to low head and then underbalanced drilling, and we actually sold gas to the pipeline while drilling the target laterals! The completions were simple, "barefoot" as we called them, just an open hole with production tubing within the casing or liner, and no stimulation required, an engineer and petroleum geologist's dream!!

Permalink Reply by bo boboski on January 23, 2012 at 3:04pm

Odnr Div. of geological survey.   Ohio geological survey interactive maps. click on emergency oil & gas well locators.  You can type in the county, zoom in on the wells, the laterals are shown,but only after you zoom in. there are 5   horizontal weels in guernsey county,one in noble,one in belmont, 12 or so in carroll co. click on the identy feature & see the info from the drilling co.  very interesting,but it will take some time to learn how to use the features.

Permalink Reply by caualie on January 23, 2012 at 5:42pm

  So how do they propose to drill 4 or 6 laterals from a single 5 acre or so pad & have all the laterals run in a N.W-S.E orientation ? Assuming a lateral is a rectangular 1000' x 5000+'. The bores would need to be 1,000' apart wouldn't they ? The pads I've seen look to be basicly square.

Permalink Reply by monty deruyter on January 23, 2012 at 5:58pm

Caualie, The way it was explained to me is that the center bore goes strait out and the rest go out at an angle first and then turn parallel to the center one. Just what I've been told.

Permalink Reply by craig on January 23, 2012 at 8:36pm

Think of 2 three pronged pitchforks one pointing NNW and the other SSE.  Six wells on a pad. We have a few pads that are setup for 10 wells on one pad.  

    

Permalink Reply by farmgas on January 23, 2012 at 9:37pm

 

Are additional vertical wells drilled to drain the area between the kick-off point and where the well bore enters the MS layer?  It would seem this area wouldn`t drain gas otherwise.

Permalink Reply by craig on January 23, 2012 at 9:40pm

This is explained in other topics here in detail. In our area each lateral has its own vertical bore. Essentially each leg is a separate well.

Permalink Reply by farmgas on January 23, 2012 at 10:02pm

 

I understand each well from surface to the end of the well bore is one well.  Each lateral has a vertical well to the kick-off point and then is curved to a horizontal bore into the MS layer.  My question is focused on the area for approx. 1,200 feet or so between the kick-off point and the horizontal well bore that won`t be included in the fracking step, and thus won`t be included in receiving gas.   Will this area be included somehow for gas production, too?   Maybe just a vertrical well drilled into this area alone to drain this gas...

Permalink Reply by Finnbear on January 23, 2012 at 9:59pm

caualie,

Take a look at this file. In particular, look at the first slide on page 5. It should shed some light on the subject.

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