FORMATIONS · RRC WELLBORE FILE

Silurian (undifferentiated)

Reported as a top in 978 wells across 24 counties, at a median depth of 9,199 ft (5,586 to 12,944 ft in most wells). 16 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 →

978
wells reporting a top
16
permitted in last 3 years
24
counties
9,199
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
Crane
155
5,7245,422–9,8455
Andrews
126
8,3447,974–12,5203
Winkler
100
8,3507,300–15,8913
Ector
94
8,3827,274–11,3262
Crockett
84
8,3425,163–9,4780
Pecos
74
7,1525,552–17,9000
Upton
58
11,3648,102–12,1681
Martin
36
11,77611,056–12,1420
Ward
35
14,0507,650–17,0971
Howard
32
10,0919,850–10,3860
Midland
25
12,26511,634–12,4540
Terrell
25
12,2319,264–12,9260
Yoakum
25
11,8919,494–13,1240
Reagan
21
10,0069,320–10,1861
Reeves
18
14,01311,816–18,0040
Gaines
15
12,27210,898–13,4290
Glasscock
14
10,2989,795–11,0520
Dawson
12
12,05611,481–12,2630
Culberson
6
14,09313,472–14,8420
Irion
6
9,1699,088–9,2220
Loving
6
18,79517,360–19,7110
Terry
6
13,19212,625–13,3360

Operators

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

Recently permitted wells reporting the Silurian (undifferentiated)

BY LAST PERMIT ISSUED

Last permitLeaseOperatorCountyTop, ftAPI
Aug 6, 2026O'HarrowPetx Operating LLCUpton10,56346101157
Apr 9, 2026Pyote MonitorXTO Energy Inc.Ward13,51347530228
Feb 19, 2026Bashara, M. J. -E-Hilcorp Energy CompanyWinkler8,07049531942
Jan 30, 2026Mabee, Guy 'B'Texaco Inc.Andrews12,28800333438
Jul 30, 2025Waddell, W. N.Burlington Res O & G Co-MidlandCrane9,83510334536
May 23, 2025Waddell Bros + CoSlant Operating, LLCWinkler9,31049532414
May 9, 2025Ratliff & BedfordOccidental Permian Ltd.Andrews9,26200305107
Feb 20, 2025Waddell Bros + CoFormentera Operations LLCWinkler9,30949532403
Dec 11, 2024Ratliff & BedfordOccidental Permian Ltd.Andrews9,21300338560
Jul 26, 2024University -25-Superior Oil Company, TheCrane10,89810333066
Jun 27, 2024Millard 'C' SWDRing Energy, Inc.Ector7,16713507252
Jun 18, 2024Raptor 34 SWDEnvironmental Dspl Systems, LLCReagan11,90438341815
May 22, 2024R.B. -AB- CowdenFivestones Energy LLCEctor7,95013535014
Mar 4, 2024Waddell TR 1Blackbeard Operating, LLCCrane9,99010337429
Dec 11, 2023Waddell TR 1Blackbeard Operating, LLCCrane9,82210337380
Nov 14, 2023Waddell TR 3Blackbeard Operating, LLCCrane9,52010301246
Oct 18, 2023Waddell TR 3Blackbeard Operating, LLCCrane9,70010301129
Aug 22, 2023Waddell TR 3Blackbeard Operating, LLCCrane9,44010301599
Aug 22, 2023Waddell, W. N.Gulf Oil Corp.Crane9,55010332464
Jul 18, 2023Waddell, W. N.Gulf Oil Corp.Crane9,41010332328
Mar 20, 2023Waddell TR 3Blackbeard Operating, LLCCrane9,67010301347
Feb 27, 2023Waddell TR 3Blackbeard Operating, LLCCrane9,67510301309
Feb 13, 2023Waddell TR 1Blackbeard Operating, LLCCrane8,72610336995
Sep 26, 2022Connell, W.E. NCT-1XTO Energy Inc.Ector7,04113501450
Sep 19, 2022Blue EstateSlant Operating, LLCWinkler8,79049532185

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/silurian, documented in the API reference.