They say a Macellus gas will produce Natural Gas for over 20 plus years.  What is the expect life of an oil well and does it have the same decline curve?

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BluFlame or MaddMan,

When you refer to the leg spacing of 1000 or 250' is that the spacing at the end of the bore from the nearest end of bore (other leg)?  I picture the legs radiating out form the well pad like spokes of a wheel, so where is the spacing measured.  Of course we have to think in 3D, so even at 250' then could be "on top" of another leg, just 250' higher or lower. I'm sure the surface/vertical start of the bore will be much closer that 250'.

Hello TheMap,

    I saw a post recently asserting the legs radiate from the pad like the spokes of a wheel. Actually, I believe that analogy is misleading. The laterals (legs) are drilled in parallel. As a former farmer, a better analogy would be "in parallel like the tines of a pitchfork". In the Utica, the laterals are drilled NW-SE or vice-versa in general parallel with the shale formation.

  So, the spacing between the horizontal parallel "tines" can be as close as 250 ft in Ohio. Most are currently at 500' or 1000'. Optimum horizontal spacing is still a "work in progress" in the Utica as is the vertical element. Obviously, the objective is to capture as much hydrocarbon content as possible from a particular lateral while drilling as few laterals as possible. The overall vertical thickness of the Utica-Pt. Pleasant shale formation is ~290'.

  I hope this helps!

BluFlame

BluFlame,

Thank you, that clarifies a lot.  I had seen the NW-SE leg directions, and I just didn't mesh with the "spokes' idea.  So there is not just a down and turn horizontal, but down, turn out (250' or so from existing leg) and then turn horizontal.  Parallel legs also are most efficient at capturing the area, a spoke pattern would end up leaving lots of untapped space at the ends of the legs.

Wow that's much closer than I expected.  What is the advantage of 250' spacing, more legs and better production?  Does head pressure have anything to do with the spacing?  In Monroe county our neighbor's well blew out the 5,000 psi head with just one leg drilled so I don't think they will be drilling more legs anytime soon.  The well currently has a 10,000 psi head sitting dormant  awaiting pipeline.   Here's something interesting I found; the world record for well head pressure is 10,100 psi from a well in Saudi Arabia.  In comparison BP's deep water rig was about 6,800 psi when it failed in the gulf.  We might see a utica well surpass that someday who knows.

-madd man

M m,

  Honestly, I can only speculate. Repeating, the objective is extract the maximum hydrocarbons with a minimum of laterals. Maybe the 250' spacing is required in the oil zone, where higher viscosity material and lower pressure from less gas presence makes extracting oil challenging. On the other hand, revenue generated by oil is higher than other hydrocarbons, and therefore justifies additional expensive laterals. I believe that currently only one well has been permitted at 250', and I do not know the location.

  The pressures you cite are staggering. When the wells are brought on stream, they should be good, long-lasting producers.

BluFlame

Not really related but check out this power point.  Good old fluid mechanics describing the flow and pressure differences in wells.


-Madd

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M m,

   Thanks for posting this interesting piece. It seems to confirm my speculation, although mine is the "Cliff Notes" version of your explanation!

BluFlame

Fang,

Thank you, but some others have given an answer.  A shale natural gas well will produce longer than an oil well.   What do you do now since you no longer a tomatoe?

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