The image to the right is a Top Cotton Valley structure map from DrillingInfo’s LA Unitization Geology file from Johnson Branch field in Caddo Parish. The lack of structural expression at Top Cotton Valley implies that structural trapping isn’t required for success in the Haynesville in this area.
We targeted Johnson Branch because it recently starting producing from the Haynesville and it provides a meaningful comparison between vertical and horizontal production profiles.
Chesapeake’s initial vertical well in the area –VUA:SRLT 29 #1 was perf’d from 11,284-11,458 in the Haynesville. Initial production was modest and the well rapidly declined. It was offset by the directional well HA RA SUA;SRLT 29, which after being perf’d 11,600’-15, 824’ potentialed at 2647 MCFD.
The comparison between the two wells and leases is shown below:
Look at the log below. Note that the vertical well was perforated in low SP sections that looked to have high Rwa spikes. Not your traditional LA clastic reservoir. Since the horizontal offset appears to have targeted the same section, it’s pretty clear that in this case horizontal drilling improved the recovery to a significant degree.
So, low resistivity shale with meager SP can be drilled horizontally and frac’d and produce commercial gas. What a concept!
Interestingly, a lot of operators in this fairway are also applying to LA DNR to expand the amount of Cotton Valley section ( directly above the Haynesville ) subject to pre-existing DNR unit orders. And the “nominated” Cotton Valley section looks relatively shaley as well. Check out the log below in from Johnson Branch field.
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