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Wednesday, July 13, 2016

Possible Halo Effect Of A Horizontal Well On Very Old Vertical Wells -- July 13, 2016

Hang on buckaroos. This certainly looks interesting. There may be other explanations but I'll post it and see what folks think.

First, the production profile for this particular well which I will identify later on in the post. But first, some data.
  • an old CLR well
  • a vertical well (not a horizontal)
  • proposed:pay thickness: 5'; zone of interest, 10,652 to 10,660 feet (8 feet)
  • proposed:the pool targeted was the Sanish (Three Forks?); top of Three Forks at 10,648 ft; TD at 10,772 feet
  • actual: the Three Forks was entered at 10,648 feet; the Sanish was encountered at 10,655 feet; drill stem test #1 was conducted exclusively over the Sanish sand from 10,642' to 10,660' (18 feet)
  • actual: perforation record: 10,650' to 10,660'
  • this well has never produced more than about 800 bbls/month since it was first drilled back in 1990
  • exception: first full month: 2,363 bbls; and then quickly dropped to 700 bbls/month over the next few months; since then about 500 - 750 bbls/month for 15 years, day in, day out
  • then note: it was taken off line 6/15? Why? A neighboring horizontal was being fracked -- see graphic down below
  • note the spectacular jump in production for the next 8 months
  • also note the amount of water produced after it was placed back on line; after the neighboring well was fracked
  • again, this was an old, old vertical well -- probably met definition of a stripper well 
  • more recently it was taken off line again because of neighboring wells that were being fracked 
Monthly Production Data of an old vertical well, partial spreadsheet, only recent data:
PoolDateDaysBBLS OilRunsBBLS WaterMCF ProdMCF SoldVent/Flare
SANISH5-201622110775075
SANISH4-2016231280000
SANISH3-201615706696656990699
SANISH2-20162935143579485349503495
SANISH1-20163138043869678373303733
SANISH12-20153133043074901330803308
SANISH11-201530353538321220357503575
SANISH10-201531424242201547426304263
SANISH9-201530605262801722599105991
SANISH8-201531634061392202639406394
SANISH7-201523402236882753393503935
SANISH6-2015002030000
SANISH5-20152763661110575075
SANISH4-20152976464114051051
SANISH3-2015317641067105000
SANISH2-201528690651105000
SANISH1-201531796916122000
SANISH12-201420553449103000


Okay, so what well was it?
  • 12979, 192, CLR, Gudbranson 1, Antelope, Sanish pool, vertical, t11/1990; cum 152K 5/16; 
Coming up: the screen shot of this area.  When you look at the screen shot, note: 
  • first, note the "index" well, a vertical well, #12979, drilled back in 1990
  • also, note three other vertical wells in the immediate area that are just as old (red arrows).
  • now, note how closely the horizontal from #28332 passes by the old vertical well, #12979



So, when was #28332 fracked? I'll answer that after we look at the production profile.

The production profile of #28332, the horizontal well:
PoolDateDaysBBLS OilRunsBBLS WaterMCF ProdMCF SoldVent/Flare
SANISH5-20163122325221734144287012859393
SANISH4-20163023647236554199317773167290
SANISH3-20163126693266564441351803507193
SANISH2-20162919669199074034236972359687
SANISH1-2016312068520444456325673240641593
SANISH12-201531186851868546382346122727718
SANISH11-201530217892206364732652826312201
SANISH10-201531179411737569052418423324845
SANISH9-20150000000
SANISH8-20150000000
SANISH7-20153136013600258502585
SANISH6-20150000000


This well was fracked 6/6/2015, the very month that the Gudbranson vertical well was taken off-line and then the spectacular jump in production the very next month. 
  • 28332, 1,373, CLR, Salers Federal 4-27H1, Antelope, Sanish pool, 30 stages, 6.1 million lbs sand/ceramic, fracked 6/15; t10/15; cum 173K 5/15; 
Let's look at the production profile for the other vertical wells in the immediate area, but just for a few months of note. All wells are Antelop, Sanish pool vertical wells:

#4168, production profile, drilled in 1966, still active:
SANISH11-2015221614860000
SANISH10-20152821800000
SANISH9-2015121714660000
SANISH8-20151725800000
SANISH7-20151321800000
SANISH6-201573084440000
SANISH5-20150000000
SANISH4-20150000000
SANISH3-2015215000000
SANISH2-20150000000


#12198, production profile, drilled in 1988, still active:
SANISH10-20153121862149215244802200
SANISH9-20153024412389194254502305
SANISH8-20153123862417356255602308
SANISH7-2015259211045807133001148
SANISH6-20150000000
SANISH5-201527529441752712481
SANISH4-2015305894451246317251


#12643, production profile, drilled in 1989, still active (blue bold is water):
SANISH4-2016301168133938140501165
SANISH3-20163124562345146269002442
SANISH2-20162929342837257311002879
SANISH1-20163126892892317290302655
SANISH12-20153125602381222278902541
SANISH11-20153028323040360305402814
SANISH10-20153138293733253409803866
SANISH9-20153059246313369587205632
SANISH8-20153169136557772694606698
SANISH7-201529331431221568348103299
SANISH6-201521052370000
SANISH5-2015897238076721
SANISH4-201591850092119
SANISH3-20152802250800
SANISH2-2015255002260
SANISH1-20151331124609600
SANISH12-20142101001600
SANISH11-201426533702019200


I only looked at the data of one horizontal well; there are many other horizontal wells in the immediate area that were also fracked at various times. 

Note: in a long note like this, there will be typographical and factual errors. I may be seeing things that do not exist. I may be "over-reading" things. I may be misinterpreting data. I may be cherry picking data. If this information is important to you, go to the source.

In the big scheme of things, this is not a big deal. The increased production only lasts a few months, maybe up to a year. But if one has mineral rights, one might be surprised at a jump in one's "mailbox money." In addition, it helps me understand, or at least think about, water flooding in the middle Bakken and Three Forks (sandstone, dolomite, NOT shale).  One can also get a feel for how far -- radially -- fracking is effective. I continue to opine that fracking "only goes out about 500 feet radially." This helps one understand how close the horizontals can be / should be placed.

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