As a number of mineral companies focused on acquiring Haynesville Shale acreage have become newly active players, I find myself having to explain the relationship between Haynesville and Mid-Bossier reserves. Since all Haynesville (HA) drilling and production units have depth interval ranges that include both the Mid-Bossier and the Haynesville, it can be hard to know when some horizontal laterals are landed in the Haynesville interval and others in the Bossier. For Texas mineral buyers familiar with the East Texas portion of the fairway, this can be an elusive question to answer. In Texas Haynesville units, well names distinguish which are Haynesville and which are Bossier. Not so here.
Now that portions of the LA side of the fairway have units with wells targeting both intervals, those that have learned how to navigate basic SONRIS database searches can compare the True Vertical Depth (TVD) of wells in the same or adjacent units to see the difference. Although it varies over the fairway, the depth difference is approximately 500 to 600' TVD. The shallower wells are Bossier, the deeper Haynesville.
Understanding this is important to the value of minerals. Roughly the north half of the fairway has only Haynesville reserves, no Bossier. The southern half has both. The state requires all Haynesville well laterals, whether truly Haynesville or Bossier, to be spaced 660' apart, as a minimum set back, and no closer than 330' from a unit boundary. Long lateral cross unit wells are not required to observe the 330' set back (no frac zone) on the north and south end of each section/unit. This results in approximately 80 acres of productive rock in each section that used to be off limits. This minimum spacing was followed through most of the Haynesville Shale development period producing eight wells, or lateral slots, per one mile wide section. Then Chesapeake declared "Propageddon" in late 2016 ushering the practice of "high intensity" fracs. See link at the bottom.
With high intensity fracs came larger frac cylinders and the ability to drain a common ~640 acre section with six wells instead of eight. That is the common practice now although no operator that I am aware of pumps 5000# per foot of perforated lateral as Chesapeake did in their two Propageddon wells.
The bottom line for mineral owners is that if you are in the Haynesville only portion of the play fairway, your section will accommodate six wells. If your minerals are located in the Haynesville and Bossier portion of the play fairway, your section will accommodate twelve wells. Think of these as slots that the state approves and that represent the intended path of each horizontal lateral. Much of the play fairway as it is currently defined by production has many sections with significant unrecovered reserves. Most sections have at least one well. The original unit wells likely drilled between 2008 and 2012. However many wells you currently have, you can subtract that from six or from twelve, depending on your location, to determine the number of well slots undrilled. A back of the envelope estimation of the recoverable reserves remaining.
Some buyers don't acknowledge this in their offers and hope to acquire minerals for the same offer price regardless of the location of the minerals. Obviously, the more proven reserves that remain, the greater the value of the minerals. A fact that a savvy seller should know.
Skip: thanks for this very helpful reminder. At some point in the past, there was a map of NW La and the relevant portion of East Texas that had the proven areas of both the HA and the Mid-Bossier. I've looked in my hard drive, and can't locate a copy of that map. That map was from the fairly early days of the play, and I assume that there is a better map now available.
If you had one to post, that would also be helpful.
I have a small interest in minerals in north Sabine Parish. Vine has recently drilled CULs in this area that include wells in both reservoirs. It isn't easy for me to try and compare the production from the different formations, although it seems like it should be. The 3 recent wells show a TVD as 12080, 12,167 and 12,395. Presumably the well at 12,080 is the Mid-Bossier, and the well at 12,395 is an HA. The 12,167 is in the middle, but closer to the Mid-Bossier.
Steve, you're thinking of the old Petrohawk Bossier contour map. I don't have a copy in my computer from a prior crash but I've kept a paper copy on my desk for twelve or so years. It was a reasonable good depiction when there was little well control to inform the map. There is a lot more data now but it has never been used for a more up to date map as far as I have found. Although there is some variation across township rows, the dividing line from west to east is roughly the top section row of the 13N townships. I have run across at least one exception for one or more sections in the lower portion of 14N.
It depends on the specific location in north Sabine but in that area the Haynesville is thinning and picking up contaminants that do not meet pipeline specs. At some point the Bossier becomes the better reservoir. I have run across information that where the Haynesville has levels of H2S and CO2 that would not meet pipeline specs, a least one operator drilled 2 Bossier and 1 Haynesville in the same unit and by co-mingling the production, the contaminants in the Haynesville flow were diluted sufficiently by the Bossier flow that together they met pipeline specs without the cost of treatment.
yes, it was the old Petrohawk map. Insofar as it was based on early data, it was still a pretty helpful map.
My Sabine minerals are in the north part of 9N, 12W. there's a ton of drilling going on down in that area by multiple operators, so I'm assuming that the contaminants aren't in this area.
I don't have enough specifics about the area with the contaminants but I know there are wells being drilled where they exist. There may be sufficient production volume to overcome the additional cost of treating the contaminants. You know what can happen when we assume, Steve! LOL!
Thanks, OldDog. The Bossier map is a little later version that doesn't have as many contour lines but is still a pretty accurate depiction. The 200 net porosity contour line is about the dividing line between economic and non-economic Mid-Bossier shale as far as that is defined by where operators are applying for Bossier wells. The Haynesville map is more dated as the play has grown around the edges in a number of areas. The trick with both maps is to be able to identify the township lines for a more detailed understanding of the areas defined.
You can use the Sonris Range/Township map and compare it to the one above. Follow the bottom line of Panola County. T12N/R16w is the section directly east and has the same bottom line. You can count sections from there.
Samson had some good maps, more recent than Petrohawk - 2017 vintage,
prior to their pull out from the play
Following is their Haynesville & Bossier outline map
& a good ownership map of 2017 vintage
1.What is the average range of TVD for Bossier HZ wells?
2.What is the average range of TVD for the Haynesville Shale HZ wells?
DeSoto Parish for example.
3. Would all of DeSoto Parish be 12 wells per section since it appears to fall within the Bossier fairway on the Samson maps?
Both are down dipping as they go south. There are two challenges with trying to establish an average over that large an area. First, DeSoto is about 26 miles north to south and the rate of down dip is unlikely to be consistent over that entire distance. The second is that the down dip tilts from west to east so you could say there is a twist in it. On the west near Toledo Bend might be 1000' more shallow than on the east near the Natchitoches line. Mother nature did not lay down the stratigraphic sequence along straight lines. As made obvious in all the maps we use and share that have contour lines.
Outside of having maps that have structural contours for both the Bossier and HV sections, the best way to understand TVD range in any one area is to start digging into Sonris and looking at the directional surveys for the various lateral targets by area.
Tedious work - yes. But also the most accurate if one is looking for a good range of depth.
One may be able to look at permitted depths which should show the approximate TVD of planned lateral. But my personal experiences have taught me that these depths can be very inaccurate and misleading. Personally, I don't trust permit depths very much.