Marcellus Well Site Spacing

[troutbert]

Is there anyone here who know what is the typical spacing of well sites now? And is it about the same across the Marcellus zone, or does it vary a lot?

And I've read about a trend to "downspacing", i.e. much closer spacing, being used in shale formations in other states. And I read that this is being experimented with in Susquehanna County.

Anybody have info on the current spacing? And what spacing they may be going to, if in fact they will be going to tighter spacing?

 

[pcray1231]

No, no current info. I do know the spacing is a lot closer for the old shallow wells. There's one of those every 500 yards or so in some areas of western PA. I can see 5 of them, on the same hillside, from my dad's back porch.

Last I knew they were typically being spaced around 2 miles apart. But that coulda changed. I too would be interested to know if it has.

 

[troutbert]

I also heard the 2 mile figure used too, early on. But it seems like the spacing may be "evolving."

Here's an excerpt from what I read:

"Cabot mentioned that it sees at least 3,000 future drilling locations on its “couple of hundred thousand acres” in Susquehanna County. The location count includes staggered wells, at least on a portion of the acreage, with laterals landed in the Lower Marcellus and the Upper Marcellus and separated by 500 feet (a pilot well pair drilled by Cabot in 2012 has so far shown positive results).

Cabot will also test down-space opportunities in the lower Marcellus."

3,000 wells on a “couple of hundred thousand acres” is pretty tight spacing.

Suppose we estimate that a couple hundred thousand = 300,000 acres.

That comes out to one well for every 100 acres.

 

[pcray1231]

They coulda gotten tighter. Perhaps, more likely, 2 miles was the "ideal". They were to drill like 12 wells on a single pad, going out in a star pattern, a mile in each direction. But, if say, one direction is cut off by someone who refused a lease, well there's no wells going in that direction at all. Even if the other side of his property isn't very far away, to get gas from it, you gotta come in from the other direction...

Also, a star pattern obviously means the holes are spreading out as you get away from the pad. Perhaps, to up output from the farther away regions, you overlap that area, like the teeth of a gear.

Or, rock types and such could force a reduction in that "optimum" 1 mile in each direction.

Or maybe it's just more cost effective to make shorter wells and space em tighter.

I dunno, I'm guessing here. But would be interested in whatever solid info comes out of this thread.

 

[troutbert]

Here's another tidbit, from a report by Rex Energy. Note the reference to an 80 acre well spacing.
-----------------------------------------------------------
03/30/2010

Rex Energy - Marcellus Shale Reserves

“To try and illustrate the future reserve potential from our current 68,700 Marcellus Shale acres. To start we have assumed that only 75% of our net acreage will be drilled on 80-acre well spacing, which is the spacing we are currently using.
---------------------------------------------------------------------

 

[pcray1231]

I find it possible that you are seeing the difference between horizontal and vertical wells. Many in the Marcellus play are indeed using vertical wells, especially in the western side of the state, where the formation is apparantly thicker.

They have 1 well per site, so the pad is "disturbed" for far less time before they finish the well. They also use far less water, pressure, etc., and that often results in smaller pads as well. But well spacing is much tighter.

For shallow wells, 10-20 acre spacing was/is not uncommon. For deep vertical wells, 40-80 acre spacing is among the norm.

Horizontal well spacings are much larger, and more variable, I think. For the ideal scenario, with 8-12 wells/pad, I think that's where the 2 mile figure came from. But perhaps it's less if they have less wells/pad. If, in practice, the figure is far less than originally thought, that's something I'd like to know. IMO, even if they do use less water and pressures and so forth, the biggest impact is the pads, and denser spacing certainly increases the impact.

 

[bikerfish]

I've noticed the wells being closer together around me. great, now we get even MORE wells. :-x

 

[FarmerDave]

troutbert wrote:
Here's another tidbit, from a report by Rex Energy. Note the reference to an 80 acre well spacing.
-----------------------------------------------------------
03/30/2010

Rex Energy - Marcellus Shale Reserves

“To try and illustrate the future reserve potential from our current 68,700 Marcellus Shale acres. To start we have assumed that only 75% of our net acreage will be drilled on 80-acre well spacing, which is the spacing we are currently using.
---------------------------------------------------------------------

Dwight, I believe 80 acres applies to vertical wells deeper than about 6000 feet ( I don't know the exact number). That is the spacing for vertical wells around me and I know that the new ones are over 6000 feet.

Shallower vertical wells like around where a friend who lives 20 miles north are 40 acres. There the typical wells to same formations are less than a mile deep. Wells to even shallower deposits are probably even smaller spacing.

I've heard 640 acres tossed around for the horizontal sites which is one square mile, but it likely varies depending on how far they go out in any direction. They can go up to a mile as Pat said which would take minimum of 4 sq miles.

 

[FarmerDave]

Apparently there is more to it than that. I just reviewed several drilling permits (online) and saw several well permits of 6800 feet on 40 acres, and then saw a few much shallower ones that said 80 acres.

Type of formation could also enter into this. I'm guessing at this point, but honestly I can't see the horizontal wells covering less than a square mile.

 

[pcray1231]

I also know in WV, at least, they do limit well spacing, I think PA might too. Whether it's strict enough to change this spacing I don't know.

The reason they limited it was competition between companies. A wider spacing may be acceptable to EVENTUALLY retrieve all the gas, and if it were 1 company, that would suit just fine. But when one company would sink a well, another would jump in and sink one nearby. They're both taking from the same pool of gas! It's essentially a race to get it first. And of course, now that first company has an incentive to get it quicker, so perhaps they sink ANOTHER well. On and on it goes.

From the public's perspective, this is just stupid. The idea is to maximize total gas recovery while minimizing impacts. We care little about a competitive race. Hence, well spacing regulations. You can't sink a well if another well is located within X miles, or however it's stated to basically mean "pulling from the same gas reservoir".

If this is what is going on, then we need to look at implementing or strengthening spacing regulations. And yes, I do think this is a proper role of government!

 

[FarmerDave]

What you are talking about fits the older wells where the target "pool" was not the actual shale, but an area of pervious rock holding hydrocarbons and trapped below an impervious layer. Now they are tapping directly into the shale so technically the "pool" covers multiple states. In reality though it only covers the area that they were able to crack, which apparently is still unknown.

Bottom line is that even if a horizontal well is located a mile from my property, they will likely be taking gas from under my property whether I sign a lease or not.

Fortunately, there are no plans for horizontal wells near where I live. Just vertical.

 

[pcray1231]

Yeah, and that's probably Utica, i.e. even deeper than Marcellus, right?

I think the point is, Troutberts spacing number may very well be accurate, and they may very well be Marcellus, but they are probably vertical wells, not horizontal wells.

From what I've seen over 40 or 50 years, if drilling is just in your area, it's better if it is horizontal drilling. If it's in your backyard, vertical is better.

Horizontal pads are larger. They sink more wells from one so it might be a decade before they cap the well and move on. They use more water. Each pad has more traffic, so the roads are bigger/wider. Pressures are greater, so there's more danger of leaks and geyser's, and the impact is greater if one does happen.

But, the spacing is considerably wider. And that offsets everything. I'd much rather have the fewer well sites associated with horizontal drilling than the "total coverage" associated with vertical wells.

 

[pcray1231]

Here's an example of "tight spacing" from NW PA. These are shallow wells and pretty old, on the ANF.

 

[FarmerDave]

pcray1231 wrote:
Yeah, and that's probably Utica, i.e. even deeper than Marcellus, right?

I think the point is, Troutberts spacing number may very well be accurate, and they may very well be Marcellus, but they are probably vertical wells, not horizontal wells.

That was my take on it too, but you may have planted it in my head.

[/quote]

And Utica shale is one of the target plays here. Several others as well, all over 6000' and all under the M-shale. M shale is not as thick here. So far, nothing but vertical wells and there are already plenty of existing shallow wells (Clinton shale),

I probably agree with the rest of your latest too.

 

[bikerfish]

a question to those that might know. I've noticed at least two wells near me that appear to have two well heads in place. would one be for Marcellus and one for Utica? or would the two types be separated by more space?
The one closest to me seemed to take forever to drill, months and months, that's why I wonder if they were targeting both layers of shale.

 

[pcray1231]

It's possible, but I doubt it. If it's a straight vertical well, you just go deeper, no need for multiple wells on a pad to hit different formations. Unless one failed or something (they coulda failed to set the concrete right or something, and if unfixable, just abandoned it and drilled another hole). I'm just guessing there.

But much more likely that you have a horizontal drill site. They may put like 8 wells on that pad before all is said and done. They go down, and then turn horizontal, and go up to a mile parallel ot the ground. Each one going in a different direction. Those sites will be active for much longer. Drill crew, frac crew, drill crew, frac crew, etc. 1 well at a time...

Regarding timing, it does seem to vary a lot. The wells near my family, first comes the landscaping crew. They do their thing, make the pad, pool, erosion controls, etc., and are out in a few days. Then it can sit for MONTHS with no activity. Then the drill crew shows up. Again, a week or so of nonstop, night and day activity, and then they too leave, and it can sit for months. Then the frac crew. Sit for months, and finally the landscaping crew comes back and removes the pool, pulls out most of the equipment, smooths it over, replants vegetation, and leaves only the well head and condensate tank(s). These are vertical wells only. The whole process takes 2-3 years per pad, but probably no more than a months worth of actual activity. Other than that, it just sits there waiting for the next crew.

But a horizontal well pad will be active for much longer due to the multiple wells. There's also more and bigger trucks and equipment in general, and a bigger pad. In exchange for this, you get far fewer pads, wider spacing.

 

[FarmerDave]

I think I agree with Pat, plus I am not nearly as familiar with the horizontal wells as Pat. But I found this interesting.

pcray1231 wrote:
It's possible, but I doubt it. If it's a straight vertical well, you just go deeper, no need for multiple wells on a pad to hit different formations. Unless one failed or something (they coulda failed to set the concrete right or something, and if unfixable, just abandoned it and drilled another hole). I'm just guessing there.

Something similar actually happened at a straight well a mile and a half from my place.

Permit was for 7000 foot straight well. Target formations were "QUEENSTON THRU TREMPEALEAU." Multiple formations as Pat suggested.

First off, ... With these deep straight wells they are targeting existing fractures in the shale that they locate through 3D seismic testing. Why not, it's already cracked. And contrary to what some people say, earthquakes are not an issue.

If they just poked a hole in the shale without some type of fracturing, they would get a small amount of gas under very high pressure for a few seconds and then very little. Fffft! Definitely not cost effective. However, if they poke into an existing large crack from millions of years ago where gas was already collecting, frack it to open it up a little more and then collect gas (and oil and even more valuable condensates), these wells pay for themselves in months. Production does drop off after about a year, but still very profitable for about 10.

Anyway, on that well I mentioned, they got the bit stuck in a fault and couldn't back it out. Chit happens. The plan was to cap that "well" and move the rig 5 feet and drill another hole aiming for the same crack, but that was eventually scrapped in favor of moving up the road 6 miles where other crews had already drilled 3 successful wells.

I know of another permit issued for a well within a 1000 feet or so of that one (no closer to my place though), but they haven't done that one yet, either.

 

[osprey]

Don't just take someones word for it my daughter showed me on Google earth , the pads are super easy to see. And those are old pics in many instances.

 

[melvinp]

in my area approx. 40 acres.The can watch each other work. And I no longer need a night light.But I do need ear plugs.

 

[troutbert]

melvinp wrote:
in my area approx. 40 acres.The can watch each other work. And I no longer need a night light.But I do need ear plugs.

So, they we know they are going to tight spacing on private land.

Now for the next questions.

Are they going to go to tight spacing on state lands? Sproul State Forest?

"The horror, the horror."