Petrora

FORMATIONS · RRC WELLBORE FILE

Viola

Reported as a top in 2,504 wells across 28 counties, at a median depth of 8,080 ft (7,179 to 8,891 ft in most wells). 4 of those wells were permitted in the last three years.

A well counts if any of its completion filings report this formation, whether it produces from it or drilled through it. Depths are measured depth as filed; typo depths exist, which is why ranges are percentiles, not extremes. About completion reports →

2.5K
wells reporting a top
4
permitted in last 3 years
28
counties
8,080
median top, ft

COMPUTED OCT 29, 2026 · REBUILT DAILY

Depth by county

Counties with at least five wells reporting the top. Bars are well counts.

CountyWellsMedian, ftP10–P90Last 3 yrs
Denton
1,011
8,5707,813–8,9760
Wise
518
7,8527,219–8,2311
Tarrant
402
7,3817,118–7,7180
Montague
195
7,3446,580–8,5050
Grayson
120
8,3537,599–11,7581
Cooke
102
8,7038,367–8,8380
Clay
22
6,1746,090–6,4351
Dallas
20
8,8728,872–8,8770
Johnson
17
8,3676,977–8,6820
Hemphill
12
17,59216,715–19,8660
Hutchinson
11
7,9107,625–9,3500
Ochiltree
9
10,4069,743–10,6040
Parker
9
6,6006,367–6,8030
Wheeler
9
15,56411,723–21,7540
Ellis
8
8,9158,678–9,0240
Hansford
8
9,1947,994–9,6170
Hill
6
8,3658,166–9,2340
Roberts
6
9,8409,840–10,7780

Operators

Current operator of record for wells reporting the top, ranked by wells permitted in the last three years.

OperatorLast 3 yrsAll
Chief Oil & Gas LLC *1236
Jetta Operating Company, Inc.114
Scout Energy Management LLC12
Muirfield Exploration, Ltd.11
Burlington Resources O & G Co LP0394
Republic Energy Inc.0138
Antero Resources I, LP0116
Tejas Western Corp.098
Mitchell Energy Corporation095
Dallas Production, Inc.094
EOG Resources, Inc.061
Winchester Production Company060
Enre, L.P.057
Rife Energy Operating, Inc.057
Western Chief Oil & Gas Company049
Mitchell Energy Company L.P.045
Aruba Petroleum, Inc.043
Enre, L.P.041
Four Sevens Operating Co., Ltd.039
Lakota Energy, Ltd.038
Adkins, R. L. Corp.036
Threshold Development Co.034
Joint Resources Company030
Osborn,w.b. Oil & Gas Operations028
Precision Operating Inc.026

Recently permitted wells reporting the Viola

BY LAST PERMIT ISSUED

Last permitLeaseOperatorCountyTop, ftAPI
Jan 27, 2026Rawle 'A'Chief Oil & Gas LLC *Wise7,29649735666
May 7, 2024BonnieScout Energy Management LLCMoore6,24034133769
Nov 27, 2023Swanda NWMuirfield Exploration, Ltd.Clay1,83207735376
Nov 6, 2023Withrow (V)Jetta Operating Company, Inc.Grayson9,85418131527
Jun 13, 2023Oliver 'a' UnitChief Oil & Gas LLCTarrant7,00243930630
May 5, 2023Kathryn 'A'Scout Energy Management LLCSherman6,74442130302
Jun 22, 2022GadwallJetta Operating Company, Inc.Grayson8,48618131490
Jun 2, 2022HazlipAtoka Operating, Inc.Grayson7,69018131478
May 10, 2022Hinkle TrustEOG SPG Holdings, Inc.Montague7,05533735480
May 3, 2022Cobra Palomino UnitGha Barnett, LLCDallas8,87211330299
May 3, 2022Appaloosa Cobra UnitGha Barnett, LLCDallas8,87211330301
Apr 25, 2022Cobra Appaloosa Palomino UnitGha Barnett, LLCDallas8,87211330298
Apr 19, 2022AppaloosaGha Barnett, LLCDallas8,87211330300
Feb 11, 2022Gatlin (V)Jetta Operating Company, Inc.Grayson12,21518131520
Feb 11, 2022Gowans (V)Jetta Operating Company, Inc.Grayson11,75618131533
Feb 7, 2022Quarter Horse - DLSGha Barnett, LLCDallas8,87211330294
Jan 12, 2022Quarter Horse - DLSGha Barnett, LLCDallas8,87211330293
Jan 11, 2022Quarter Horse - DLSGha Barnett, LLCDallas8,87211330292
Jan 7, 2022Quarter Horse - DLSGha Barnett, LLCDallas8,87211330291
Dec 22, 2021Caddell 'B' AH1Lime Rock Resources IV-a, L.P.Denton8,59512134591
Dec 22, 2021Caddell 'B' AH5Lime Rock Resources IV-a, L.P.Denton8,59512134595
Dec 15, 2021BrockWatson Energy Investments, LLCMontague8,15433734003
Oct 6, 2021AppaloosaGha Barnett, LLCDallas8,87211330288
Oct 6, 2021AppaloosaGha Barnett, LLCDallas8,87211330290
Oct 5, 2021AppaloosaGha Barnett, LLCDallas9,07211330287

About this data

Formation tops, elevations, perforations, and casing from the RRC dbf900 wellbore file, refreshed weekly, with reported names normalized to Petrora's formation registry. County and operator breakdowns are rebuilt nightly.

Developers: this page as JSON is GET /v1/data/formations/viola, documented in the API reference.