Eight wells per section configuration
I've been trying to think what the configuration of wells would be if they ever drill the famed "8 wells per section."
Current wells seem to oriented towards drilling near the corner of a section, and running one lateral parallel to one edge of the section.
I'm assuming that there is an advantage to using superpads vs. 8 separate pads. However, when the laterals are near to each other, they scavenge each others gas, and produce less than an isolated well.
It seems to make a lateral along each edge of the section, and then, perhaps a lateral running along each diagonal, but that's only 6 wells per section. it also requires 3 superpads.
It occurs to me that a superpad in opposite corner with 4 wells per pad gets you a somewhat spread out pattern of 8 laterals with only 2 superpads. You could actually use a superpad on the section corners, and drill 4 wells into each section and get 16 wells on a superpad, and only have to have a superpad on every 2 sections.
Has anyone really thought things out to this level of organization and optimization? Is there some "better" layout of pads and wells on a section?
Do they ever use multiple laterals per "vertical" bore?
All the laterals I see are straight. Do they ever curve a lateral? If you can go down vertically, and turn 90 degrees to be horizontal, can you go North for a while, then turn 90 degrees to the right and go East for a while? As a silly example, drill just one well in the middle of a section, and run it around in a spiral pattern to drain the whole section in just one well?
Current wells seem to oriented towards drilling near the corner of a section, and running one lateral parallel to one edge of the section.
I'm assuming that there is an advantage to using superpads vs. 8 separate pads. However, when the laterals are near to each other, they scavenge each others gas, and produce less than an isolated well.
It seems to make a lateral along each edge of the section, and then, perhaps a lateral running along each diagonal, but that's only 6 wells per section. it also requires 3 superpads.
It occurs to me that a superpad in opposite corner with 4 wells per pad gets you a somewhat spread out pattern of 8 laterals with only 2 superpads. You could actually use a superpad on the section corners, and drill 4 wells into each section and get 16 wells on a superpad, and only have to have a superpad on every 2 sections.
Has anyone really thought things out to this level of organization and optimization? Is there some "better" layout of pads and wells on a section?
Do they ever use multiple laterals per "vertical" bore?
All the laterals I see are straight. Do they ever curve a lateral? If you can go down vertically, and turn 90 degrees to be horizontal, can you go North for a while, then turn 90 degrees to the right and go East for a while? As a silly example, drill just one well in the middle of a section, and run it around in a spiral pattern to drain the whole section in just one well?
Views: 375
Replies to This Discussion
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Permalink Reply by Les Bamburg on -
Mac, the configuration for the wells are eight horizontal laterals spaced 660' apart with perforated lengths of 4620'. The laterals on the east & west edge are 330' from the section line. This would equate to ~ 80 acre spacing (660 * 5280 / 43560). Because the Haynesville Shale has very low permeability there would be minimal production interference from adajacent laterals. In the Barnett Shale they actually do simultaneous fracs of adjacent wells.
Regarding superpads, one concept is to locate two 8-well superpads directly on the east-west section lines ~ 1760' apart. Then drill 4 wells into the north section and 4 wells into the south section from each pad.
There are no current plans to drill multiple horizontal laterals from the same vertical wellbore.
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Permalink Reply by Mac Davis on
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Thanks,
So basically, 8 North-South laterals each about 1 mile long.
If I understand the superpad you're describing, the superpads would have angled boreholes down to the 8 perforation points. Wouldn't 2640' spacing make more sense? That would be equally spaced between 4 laterals with 1/8 mile spacing.
That makes a lot of sense. You only need 1 superpad with 8 wells per section.
A little calculation shows that the angled borehole is less than 1% longer than a vertical borehole to 10,000 feet. Interestingly enough, If you drilled all 8 wells from one pad on the middle of the middle of an east/west section line, the angled borehole is less than 4% longer than a vertical borehole. 16 well superpads anyone?
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Permalink Reply by Les Bamburg on
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Mac, I just think it is more efficient to drill in both a north and south direction from the superpad. A 16 well pad is probably just too difficult.
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Permalink Reply by Grillin' - MmmMmm on
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Les B: great explanation and spot on.
I have seen in the Marcellus where they are doing multi laterals, with one lateral in one shale member and then a second lateral a bit deeper in a second shale member. The shale members are separated by enough depth and a few impermeable layers that should prevent frac migration/communication. I don't know if any have been completed, but there have been a few proposed. Don't think the HS geology sets up for this type of an approach, though.
Placement of the superpad will probably be driven by surface issues as well. There could be a pad built that could drill 16 wells, either 8 in a northern unit and 8 in a southern unit or 4 in 4 units each, but that would take considerable surface acreage for the pad. It would be the most efficient, though. As more wells are drilled, the creativity of the drilling engineering groups will drive better and better solutions, resulting in lower costs and better recoveries.
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Permalink Reply by Mac Davis on
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I'm sure there are multiple issues, but it seems to me that one pad drilling, for instance, 4 wells is going to be a lot cheaper than 4 separate pads. It seems a completed well takes up less space than one being drilled, so you wouldn't need 4 times the space for a 4 well superpad vs. 4 normal pads. You wouldn't have more than one rig drilling at one time. You might be able to drill multiple wells without moving the drilling rig, or you wouldn't have to move it far. You'd have to build fewer roads, pipeline connections, etc. Fewer disputes with the neighbors. Fewer site prep issues to deal with.
What's surprising to me is how little the length of the drill string increases when you drill down at an angle to hit a perforation point away from the drilling rig location. The 10,000 foot depth is so large that even going halfway across the section (2640') at an angle only adds 400' of pipe.
I'm trying to figure out what disadvantage there is to drilling more than one well from a surface pad. The only things I see are that you have slightly longer drill strings, and that you might have to drill the wells one after another, rather than multiple wells at a time.
Why don't they do more superpad sites? Am I missing something?
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Permalink Reply by hogeyes on
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Les, interesting information. Is 8-wells per sections currently happening and/or do you really see this happening in the future? Also, is your last statement saying that there are no current plans to build superpads ( i.e. "multiple horizontal laterals from the same vertical wellbore" ) on the HS play?
We have a proposed plat on the table that is a 4.5 acres well pad. Is that a standard size well pad for a single horizontal well?
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Permalink Reply by Les Bamburg on
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Hogeyes, most operators are still in the hold acreage drilling mode so it will be a number of years before you see any sections have 8 wells.
A superpad involves multiple wells including both the vertical and horizontal sections. My statement was regarding another matter - ie using a single vertical well section for multiple
horizontal legs.
I will have to let someone else comment on the well pad size as I am not knowledgable on that topic. 4.5 acres definitely seems to be larger than a single well pad.
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Permalink Reply by Spring Branch,mineral owner on
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Encana's well pads on the Jackson Davis land in Section 26 of 15/14 are 1000' by 500". Put a pencil to that!
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Permalink Reply by The_Baron on
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CHK has drilled some wells with laterals that went diagonally, but have since reverted to drilling north-south. They have stated before that tthe shale has a "grain" that fracs better when the well is drilled north-south. It will be interesting to see what happens when a well is drilled "against the grain".
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