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.
On the PetroHawk Map for Haynesville Shale Overview, does each block represent one Township/Range (and all sections within)?
The larger squares are townships. The 36 (6X6) smaller squares indicate the sections.
It is the general practice of Haynesville operators to state a TVD in a permit that is intentionally deeper than the interval they plan to target. This way if they miss on their TVD assumption, they do not have to stop drilling and go to the state for an amended permit. So you are not looking for the permit TVD, you are looking for the "as drilled" TVD. Here is a good example, note the dates. 12,805' is the permitted TVD. Then three months later, the TVD is reported as 11,911'.
BOTTOM HOLE COORD
|EFFECTIVE DATE||END DATE||PLUGBACK TOTAL DEPTH||TRUE VERTICAL DEPTH||MEASURED DEPTH||LAT DEG||LAT MIN||LAT SEC||LONG DEG||LONG MIN||LONG SEC||COORDINATE SOURCE||LAMBERT X||LAMBERT Y||ZONE||COORDINATE SYSTEM|
Good example. Thanks for posting.
One could take any HV TVD and subtract "x" feet to get a TVD point in the middle of the Bossier if they want.
How could a person tell if they own Bossier or Haynesville existing wells on SONRIS since there is no TVD average range?
Is there a document in SONRIS that uses specific Bossier or Haynesville terminology?
Or is there a substantial TVD difference between the two.
Depending on the area, I would estimate that the TVD difference from Mid Bossier to Mid Haynesville is anywhere from 500' to 750'.
But I would have to pull some logs to confirm this. And that TVD difference may vary at different points in the basin - even within a single Parish or County.
Thanks - thought I was close! Got lucky!
Good example, OLDDOG. Now if you go west to the northwest corner of 11N-14W, the TVD for the Section 6 well is 11,239'. A 1327' difference. That's the slant in the down dip.
While we are talking about Desoto parish ....do any of you guys know why there are no HZ wells drilled yet in some sections in the far SW portion of Desoto near Toldeo Bend 11N 16W area? You mentioned the down dip is that a problem?
Betting lack of drilling is tied to reservoir differences
Thinner and/or poorer section = lower EUR and poor economics
11N-16W is only about 10 sections as the state line begins to follow the Sabine River there at Logansport. Those sections, all of the 11N-15W sections and the western half of 11N-14W is an area of low porosity. Therefore there is less Gas In Place (GIP). Chesapeake drilled a good many of the sections through that area in the early years of the play. We discussed it here on occasions because the wells were so poor, about a third of the IP compared to the same well design in other areas, but Chesapeake kept drilling them. Although Comstock has explored the far north section row of 11N-15&14W, with little success I might add, no other Haynesville operator is testing those sections.