Austin Chalk Drilling Activity--August, 15 2017
The "first" Austin Chalk well completed as a plug and perf completion in Giddings Field was the SM 1H Escheberger, now operated by Wildhorse, and completed in first quarter 2013 (See Figure 1). Prior to this, many wells were drilled horizontal and frac'd, but thru a slotted liner. The Escheberger well was frac'd with 662 lbs/ft sand and 814 gals/ft of fluid and had an IP of 8.7 MMCFGPD on a 16/64"ck and FTP of 6,668 psi. The SICP was 8010 psi and when corrected for a full gas column extrapolates to a minimum BHP of 9,714 psi, ~ 0.7 pressure gradient. This is significant in that it proves the presence of a "resource-like" reservoir in this area that has a significant over-pressure gradient; very key elements of a successful play except for a large modern completion. On cue, in walks Wildhorse Resources and Geosouthern Operating Companies...
Wildhorse Resources Development Co
Finally, there's something to write about! It took a public company with an incentive to promote their success (capitalist profit motive), to give me some good news to write about. For some time now I have been wanting to add a new page documenting the recent drilling and completion activity in the Giddings area, but unfortunately the results are only now trickling out. Wildhorse Resources announced the results of their Winkelmann well in Washington County last week. This announcement massively overshadowed their adequate Eagle Ford results, by reporting a 30 day average of 2,387 BOEPD . Based on their reported percentages, 26% oil, 38% gas and 36% ngl, this breaks down to 621 BOPD, 5.44 MMCFG and 859 BNGL. If you prefer two phase reporting for easy comparison it's 621 BOPD and ~7 MMCFG. Now we're talking! That's a great test from only a 4,700' lateral, but if you notice the location of the well on the above map (Figure 1), it is on the edge of the SoPhi-H thick. Can we expect better results in the future? I think so! Wildhorse alluded to the fracture parameters in their earnings call as being similar to their Eagle Ford completions, which are massive slickwater jobs using 3,700 lbs/ft sand. Considering their very large Giddings acreage position, I expect the market will dictate that Wildhorse expedite their Austin Chalk appraisal program.
Wildhorse 2nd quarter presentation: http://www.wildhorserd.com/wp-content/uploads/2017/08/WRD-Company-Presentation-Q2-2017-Earnings-vFINAL.pdf.
Geosouthern Operating Co
Geosouthern has been quietly leasing and drilling appraisal wells in their Fayette and Washington County position since last year. Geosouthern's Fowler well is a 5,104' lateral completed using 3,004 lbs/ft sand that has steadily produced between 8 and 10 MMCFGPD since completion in December 2016. Geosouthern recently reported IP's of 401 BOPD and 1.1 MMCFG in the Loughnane well and 433 BOPD & 1.8 MMCFG for the Kristof well. Good results considering they are in the lower SoPhi-H area of the map (Figure 1). The wells were 5,094' and 5,557' respectively with similar frac sizes to their Fowler well. Geosouthern, a private company with no incentive to publicize their success and invite competition, reported a low IP of 3.07 MMCGPD for their early Fowler well, so there’s reason to suspect they could be under reporting the results from their new wells. Nothing nefarious there, just smart business on their part. Be mindful that I am still calibrating the tests to the map and there is the uncertainty of completion designs between companies and different fluid windows that impact future productivity as much or more than rock quality. I am excited about additional locations that have been permitted in the SoPhi-H thick by Geosouthern. The Lehrmann, Winkelmann and Schlabach wells located in the thicker parts of the map in Washington and Fayette Counties are very high potential tests and warrant watchiing. Too bad it will take forever to find out the results...
Enervest owns and operates more Austin Chalk wells in the Giddings area than any other player. Theyare also very active drillers in the Karnes Trough area. Between the two areas they control significant amounts of acreage in the Austin Chalk play. Enervest is currently drilling the 2H McMahan Unit just west of the Geosouthern 1H Fowler well in Washington County. This location lies within the higher SoPhi-H area of the map (Figure 1) and is on trend with the Wildhorse 1H Winkelmann well. The reported spud date was July 31 and we should expect results within the next few months. This well has good potential given its location. Currently awaiting completion is the Enervest 2 Neva well also in Washington County but in a lower SoPhi-H area. The rig was released as of July 23, 2017.
Pallas (EOG) 1H Tonkawa Unit
In my mind, the most interesting well drilled to date is the Pallas (EOG) 1H Tonkawa Unit in Colorado County. To put the massive potential of the mapped SoPhi-H into perspective lets examine Figure 2 below. This cross section goes from the Marathon Oil Chalk development in southwestern Karnes and Live Oak Counties to the prolific Karnes Trough and finally to a nearby offset of the Pallas 1H Tonkawa Unit pilot well, see inset index map in Figure 2. As you can see the Marathon area is thin, 25'-100' at best, with a SoPhi-H less than 2.5. The results have been promising but mediocre as you would expect. Almost surely, some of the hydrocarbons are coming from the Eagle Ford below. The best IP I could find in the area was around 1,600 BOPD. The Karnes trough is a highly prolific area as evidenced by the impressive well results and also by the investment made by Enervest in the Gulftex and Blackbrush acquisitions. The log suite below is typical of the Karnes Trough Chalk with a good SoPHi-H of 3 to 5, however the results are tremendous. The typical well to date IP's around 2,000 BOPD, but some wells have exceeded 5,000 BOPD. Most of these wells should have an EUR approaching or exceeding 1 MMBOE. One has to wonder how you get all that oil out of that rock. Could an unseen fracture network be contributing to the productivity? Now lets examine the well drilled in the SoPhi-H thick near the Pallas well. The SoPhi-H is massive 17.2 and dwarfs whats seen on logs in any other area of the chalk. The well exhibits NPHI-DPHI crossover (gas effect) almost the entire Austin Chalk section, and has intervals that touch 10% porosity in the middle chalk. Also in the middle chalk, an interval approximately 70' thick exhibits mudcake development, see zoomed in log suite in Figure 3. In the old days of conventional exploration this was usually a sign of good permeability development. This is unheard of in the unconventional world. Given the fact that BHP should be ~9,300 psi this area has great potential! Another question to ponder is given the 300' thickness of the Austin Chalk, could a second layer of laterals be necessary to drain the entire section? We have so much to learn, but is it possible to drill wells similar to or exceeding those 30 BCF downdip wells? Many of the critical elements are certainly present. Time will tell. Tick, Tick, Tick...
Regional Austin Chalk Cross-Section
Near Pallas 1-Tonkawa Unit Pilot Hole