My experience with Marcellus wells in north central PA.....they always drill to either the NNW (NW) or SSE (SE) in every well plat I have reviewed.
It was explained to me....this gets the best results during the fracing process....either with or against the rocks' grain. I don't know if that is true or if this person was pulling my leg....but the direction from the pad is consistent in NC PA.
Almost all shale plays have a predominant direction in which the naturally occurring fissures exist or are deemed to form under elevated (fracturing) pressure.
Operators try to intersect these fissures at a 90 degree angle to maximize the number of induced 'cracks' through which the oil/gas will flow to the wellbore when the 'cracks' are effectively propped open.
180 degree direction is usually due to topside considerations.
Completion technology has improved to an almost unimaginable extent these past 5 years with more precise targeting, real time microseismic monitoring of fractures, degradable diverters- both near wellbore and far field - with which to control the geometry of the SRV (Stimulated Reservoir Volume), and the recent introduction or micro proppants.
This last is especially intriguing as these ultra small particles enter and scour tiny fissures so the bigger 100 mesh can enter and prop.
There are several other things going on, but operators are generally close mouthed as these techniques are considered highly proprietary.
Without going "too far out into the weeds" on this, there is a process called 'zipper frac' wherein alternating stages from adjacent wells are frac'd one after the other.
The elevated induced pressure underground assists in controlling where the new fractures are formed so as to maximize the stimulation.
A lot more to this that is over my head, but no doubt operators will return to the same pad and drill/frac 3 to 5 wells at a time depending on many factors.
The pad is preferentially situated where all future wells can be most optimally drilled.
You should know that virtually ALL the oil/gas states have pre-determined 'Drilling/Leasing Units - almost always one square mile (North Dakota is 2 sq. mile).
This makes it way easier for operators to get permission to drill and divvy up royalties.
You eastern states do not have that and it makes things way more challenging for development.
Shell has done up to 8 zippered. current best practice financially and geologically.
And, yes, in case I wasn't clear, the pads will have wells going in both directions as long as the designated Drilling Unit - or Pennsylvania's equivalent - will enable it to be done.
General basin trend for natural fractures is NE-SW, wellbore cuts this going SE-NW, now fracturing can open & prop natural fracture.
One aspect of wellbore orientation is the type artificial lift for liquid recovery later on. To remove liquids efficiently and allow unimpeded gas flow, a toe up borehole (NW) will drain toward the heel were lift equipment is easily positioned from the vertical wellbore. A toe down completion would require running tubing to the toe thru the horizontal section. This will be more expensive. Again, this is just one of many conflicting considerations for wellbore orientations. Dry gas production much less impacted, but water and oil production more so.