It seemed like the description "Jurassic" was thought to be dropped &/or incorporated into the greater "Haynesville Play" that now contains both the Bossier & Haynesville Shales. On the Texas side, all of the 'Bossier' and 'Haynesville' fields were consolidated into the greater "Carthage (Haynesville Shale)" field & a 'parent-child' relationship was set up, so that two Hz wells (one 'Mid-Bossier Shale' and one 'Haynesville Shale') could be drilled under the same field name, and both produce from the same proration unit. Normally, only ONE well is allowed to drain hydrocarbons from a proration unit in a recognized field...
THAT IS - Let's take a field like the Ginormous (Woodbine) field. Spacing is 40 acres per well. 40 acres is described in a permit (by virtue of a surveyor's plat) & if more than one tract is included in the 40 acres, a P-12 form has to be provided, which shows that the operator has the right to POOL tracts in order to form a 40 acre PRORATION UNIT. If the operator doesn't have 40 acres of leases around the well it plans to drill, it might affect its allowable to produce - if a well is made. Ex. - if the operator only has 30 acres, it would theoretically only get 3/4ths of an 'open flow' allowable.
I have read where the name 'Jurassic' is still being used in Louisiana & Texas & am wondering if this rock unit could be - - - (a) the Gilmer Limestone, (b) a calcareous-shaley section of the Gilmer, (c) a shaley section below the Smackover, etc...?
It's driving me CRAZY ! ! Please make me (more) sane! - Thank you!
Thank you... I was wondering about that myself.
Both the Haynesville and the Bossier intervals were laid down during the Jurassic Period. So any of the formations/zones in the Jurassic portion (far left column) of the stratigraphic column could be called Jurassic. Encana was exploring the Haynesville Shale in 2006 as was Chesapeake and chose to use Jurassic as their name for the Haynesville/Bossier drilling units they formed in NW LA. The Commissioner of Conservation decided that all Haynesville units should have the same common name and Encana switched to using HA along with all other operators. Those Woodbine units are oil units, not gas units. That is why they are so much smaller on average. Natural gas being a smaller molecule than oil can migrate over a longer distance to reach a well bore. So a 640 acre gas unit might be effectively drained by one well while an oil well would only drain ~40 acres. This is the best I can do - hope it improves your sanity.
Thanks, Skip - my wife claims that NO MATTER WHAT, my sanity will never improve; - - but... yes; at the beginning of the play, some older language & Stratigraphic Columns preferred to use "Bossier" as the go-to description for thousands of feet of sediments [hence the now-defunct "Bossier" fields that were transferred into the Carthage (Haynesville Shale) Field].
I'm over here in Texas & don't know a lot about LA rules. As it would be in Texas, could I request copies of the LA Conservation Commission regarding the designated "Jurassic" activity?
I guess you could but you would be disappointed as they would say they have none. You see LA Haynesville drilling units have depth interval designations that include the Mid-Bossier so whether a horizontal unit well is landed in the Haynesville or the Bossier, the well designation is Haynesville. This is of course unlike Texas where the well name indicates the well is producing from the Haynesville or the Bossier. Over here the only other Jurassic formations with historic production are the Smackover in far north LA and the remainder of the Cotton Valley Sands (about 14 separate sands with historic production). The Cotton Valley group is a 1500 to 1800' interval. As you can see, the Bossier is actually part of the Cotton Valley Group, the basal or deepest member. Since the Haynesville and Bossier are both shale in a portion of NW LA, the Office of Conservation allows companies to create a single unit that includes both. For a little background on Texas, ask Julie (jffree1).
Well, that's the way it is in Texas, also. An operator can (and it is the 'norm') drill a Haynesville Shale well, then skid the rig over 15' and drill a "stacked lateral" Bossier Shale well on top of the Haynesville well. The Haynesville well is just a little deeper (vertically). The first Haynesville well in a large gas unit is commonly called the 1H or H1 & the Bossier well is called the 1B or the B1. out of .. let's say the 900 ac. unit. The combined output is reported under ONE Lease# & eventually, there might be something like a 140 acre PRORATION unit area designated along the path of the 'stacked' wells, and reported under the Carthage (Haynesville Shale) field. The reason for my question is that I've seen a play (?LA designated field?) called - "Jurassic" - and is apparently being drilled with Hz wells. Is this zone (?field?) a separate and - deeper than Haynesville Shale - horizon / play ?? - Thanks for the comments!
In NW LA, the Jurassic (JUR), as a drilling unit designation, and the Haynesville (HA) are one and the same. They are the exact same formation and depth interval. The Jurassic is not a separate horizon. Many don't realize that Encana was a step ahead of Chesapeake in testing the Haynesville Shale and they named their early units Jurassic possibly because they were including the Mid-Bossier Shale in the unit depth definition. The Commissioner of Conservation had to choose between JUR and HA as the official abbreviation for the Haynesville Shale drilling units and chose HA. In LA there is no well name designating the Haynesville from the Bossier. They are all Haynesville wells. You have to compare the lateral landing depth to tell which formation the well is producing from. I don't know how many ways I can explain this. There is not separate Jurassic formation or play. Period.
Thanks for the chart... that clears up a lot of questions that I had about the Plays they talk about.