Powdermill Nature Reserve

Maps and Geographic Information Systems

Logo Carnegie Museum of Natural History

You are here: Home / Projects / Pennsylvania Unconventional Natural Gas Wells / Frequently Asked Questions

Frequently Asked Questions

Here is a list of some Frequently Asked Questions. If you have a question not included on this list, please contact the Carnegie Museum of Natural History GIS Lab at GIS@CarnegieMNH.Org.

  1. How many wells are Permitted? Drilled? Producing?

    VersionPermittedDrilledProducingPermit ExpiredUnknown StageTotal Wells
    2022 Q42001,98311,9739,02156123,738
    2022 Q32092,13311,6869,01644423,448
    2022 Q22512,01411,6498,99053623,440
    2022 Q12892,04411,4318,96947723,210
    2021 Q42581,96711,3988,93857523,136
    2021 Q33112,06511,1458,89645722,874
    2021 Q22872,00911,0908,87153022,787
    2021 Q13392,05710,9268,82345222,597
    2020 Q43822,00210,8448,76960022,597
    2020 Q34332,04810,6998,68955622,425
    2020 Q24812,08410,5528,60568922,407
    2020 Q15682,13310,3888,51546822,072
    2019 Q46882,10010,2768,38954421,997
    2019 Q37642,21910,0378,25648221,758
    2019 Q27982,2419,8788,17352521,615
    2019 Q17882,2969,6468,10757021,407
    2018 Q48792,1849,5617,93763821,199
    2018 Q31,0702,1789,3667,69983321,146
    2018 Q21,1562,2919,0837,54659820,674
    2018 Q11,2682,3398,8227,45073620,615
    2017 Q41,0092,2348,7317,4261,21320,613
    2017 Q37462,4228,3427,37385419,737
    2017 Q26222,2708,2877,3441,09419,617
    2017 Q15602,2668,0777,28081618,999
    2016 Q47142,1747,9857,12672518,724*
    2016 Q38322,2607,7236,95446618,235*
    2016 Q29692,1497,6886,78348418,073*
    2016 Q11,1312,3727,3926,54241417,851*
    2015 Q41,1862,3437,3146,30164117,785*
    2015 Q31,2082,5646,9376,07050917,288*
    2015 Q21,4072,4456,8375,76960417,062*
    2015 Q11,5222,7096,3835,52145716,592*
    2014 Q41,5722,5726,3005,31162216,388*
    2014 Q31,7132,9005,6205,10247115,806*
    2014 Q21,8072,5155,6204,87875115,571*
    2014 Q11,7132,7005,1014,63964514,798*
    * This total does not include wells without geographic coordinates because these wells were not included in the geodatabase feature class prior to 2017. For more information on the number of wells that are missing location information, see question two below.

    Note: Prior to 2015, production reports were released twice a year (for January-June and July-December), so the number of producing wells only changed in Q2 and Q4 updates.  Starting in 2015, production was reported monthly, 45 days after the end of the month. Therefore, Q1 and Q3 versions of the data include all wells that produced gas up to the end of January and July, respectively.  Data versions from Q2 and Q4 include all wells that produced gas up to the end of June and December, respectively.

  2. How many wells have discrepancies or errors associated with them? What do the discrepancies or errors mean?

    VersionPermit
    Errors    		SPUD
    Errors    		Unconventional Status
    Errors    		Location
    Errors    		Total
    Errors
    2022 Q45724723,17752524,368
    2022 Q3455461785251,204
    2022 Q2547471775191,290
    2022 Q1477471604711,155
    2021 Q4575471604591,241
    2021 Q3457471604471,111
    2021 Q2530471604191,156
    2021 Q145247160278937
    2020 Q4600471612931,101
    2020 Q3556471612571,021
    2020 Q2685471612731,166
    2020 Q146847162236913
    2019 Q4549471632781,037
    2019 Q348247167268964
    2019 Q252547171249992
    2019 Q157047170209996
    2018 Q4638461603451,189
    2018 Q3833481602511,292
    2018 Q2598471582051,008
    2018 Q1736471782211,182
    2017 Q41,213481593641,784
    2017 Q3854441561891,243
    2017 Q21,094441571891,484
    2017 Q1816421581921,208
    2016 Q47254616348*978
    2016 Q34664215945*707
    2016 Q24844216038*724
    2016 Q14144015238*643
    2015 Q4641381528*839
    2015 Q35093715030*722
    2015 Q26043714922*792
    2015 Q1457371487*649
    2014 Q46334914923*854
    2014 Q34714714820*686
    2014 Q27515714932*989
    2014 Q16673815423*855
    * Location error only includes wells without geographic coordinates. Prior to 2017, this error was determined using a different algorithm and may not be accurate.

    Because not every data source includes records for every unique well, discrepancies are inherent. It is recommended that every effort be made by users to investigate and/or disregard records that may skew one’s research or analysis.

    Wells are analyzed for errors based on the following criteria:

    • Permit Error – Identifies wells that have a SPUD record and/or a production record indicating production greater than 0 Mcf but are missing permit information.
      • This error is concerned with drilling and production and the lack of a permit. Production and SPUD records indicate with more confidence that a particular well exists and is operating. If no permit records exist, then data is incomplete for that particular well.
      • To query for wells without permits, use the PERMIT_COUNT field.
    • SPUD Error – Identifies wells that show natural gas production but do not have a SPUD record.
      • Wells producing gas should have a record of when drilling commenced. If no SPUD records exist, then data is incomplete for that particular well.
    • Unconventional Status Error – Identifies wells that are inconsistently classified as unconventional wells across all datasets.
      • Well records that are inconsistently classified as unconventional wells cannot be verified. Any analysis including these wells should have strong cause to include such wells. Although, such wells should not be ignored, as the wells can be reported to the PA DEP for clarification.
    • Location Error – Identifies wells without geographic coordinates in any data source (indicated with the value ‘YES’ in the feature class) or wells with different geographic coordinates between data sources (indicated with ‘Coordinate Inconsistent, Mean Used: x° Max Error’.
      • Without geographic coordinates, a well is not able to be mapped or used in spatial analyses and wells with differing geographic coordinates may not be accurately mapped.
      • For most inconsistent records, this error is minimal, as an error of less than 0.00001° will be less than ~3 ft (1 m). However, a few records may include errors up to 1° or more, which is very significant at more than 50 mi (80 km) of error. If all datasets report the same geographic coordinates, no inconsistency is reported.
      • Prior to 2017, records with location errors will not be present in GIS feature classes, while for versions published in 2017 and after will include wells without geographic locations, but contain a null point geometry.

  3. How many unconventional wells have been reported to the PUC by the PA DEP? How many wells does the geodatabase classify as unconventional wells? Why is there a difference?

    This is a tricky question! To answer this question, we need to concentrate on drilled and producing wells only, as this is what the PUC report is concerned with.

    VersionPUCPA Unconventional Wells
    Geodatabase    		Difference
    2022 Q413,89413,95662
    2022 Q313,75813,81961
    2022 Q213,60213,66361
    2022 Q113,42613,47549
    2021 Q413,31613,36549
    2021 Q313,16113,21049
    2021 Q213,05013,09949
    2021 Q112,93412,98349
    2020 Q412,84612,79749
    2020 Q312,69812,74749
    2020 Q212,58712,63649
    2020 Q112,47112,52150
    2019 Q412,32212,37654
    2019 Q312,20112,25655
    2019 Q212,06712,11952
    2019 Q111,89111,94251
    2018 Q411,69911,74546
    2018 Q311,49811,54446
    2018 Q211,32711,37447
    2018 Q111,11211,16149
    2017 Q410,91610,96549
    2017 Q310,71910,76445
    2017 Q210,51110,55746
    2017 Q110,29410,34349
    2016 Q410,11010,15949
    2016 Q39,9379,98346
    2016 Q29,7909,83747
    2016 Q19,7229,76442
    2015 Q49,6189,65739
    2015 Q39,4629,50139
    2015 Q29,2529,28230
    2015 Q19,0519,09241
    2014 Q48,8228,87250
    2014 Q38,4808,52040
    2014 Q27,7598,135376
    2014 Q17,7597,80142

    The discrepancy in values lies in how unconventional wells are defined for the purposes of reporting them to the PUC, which is described in Act 13.

    For the purpose of the Pennsylvania Unconventional Wells Geodatabase, an unconventional natural gas well is defined as any well classified as such in any of the eight PA DEP data sources used in the compilation of this dataset. Some records in the individual data sources may not be classified as unconventional. If this is the case, at least one other record in any of the eight data sources indicates the well as unconventional. This inclusive approach allows for questionable wells to be subject to further scrutiny and to allow for a greatest-number of wells scenario. It is recommended that every effort be made by users to investigate and/or disregard records that may skew one’s research or analysis.

  4. How often is the Pennsylvania Unconventional Natural Gas Wells geodatabase updated?

    The geodatabase is updated quarterly.

    QuarterData End DatePADEP Data
    Download Date**    		UNCGDB
    Release Date**
    Q1March 31April 7April 15
    Q2June 30August 22August 31
    Q3September 30October 7October 15
    Q4December 31February 22February 28
    **Date represents the week of the corresponding date. Actual download/release may occur earlier or later.

  5. Does the data contain fracking information, such as when the wells were hydraulically fractured?

    No. this information is not distributed by the PA DEP through Oil ad Gas Reports.

  6. How should I cite the Pennsylvania Unconventional Natural Gas Wells geodatabase?

    Whitacre, J. V., and Slyder, J.B. YYYY. Carnegie Museum of Natural History Pennsylvania Unconventional Natural Gas Wells Geodatabase (v.YYYY-Q#) [computer file]. Pittsburgh, PA: Carnegie Museum of Natural History. Available download: URL: https://maps.carnegiemnh.org/index.php/projects/unconventional-wells/. Accessed: Date of Download.

  7. Who is citing the Pennsylvania Unconventional Natural Gas Wells geodatabase?

    The list below is not exhaustive. If you have have cited the geodatabase and would like to include your article, please contact the Carnegie Museum of Natural History GIS Lab at GIS@CarnegieMNH.Org.

    • Dennis LE, Richardson SJ, Miles N, Woda J, Brantley SL, Davis KJ. 2022. Measurements of Atmospheric Methane Emissions from Stray Gas Migration: A Case Study from the Marcellus Shale. American Chemical Society. doi:10.1021/acsearthspacechem.1c00312
    • Denham A, Willis M, Zavez A, and Hill E. 2019. Unconventional natural gas development and hospitalizations: evidence from Pennsylvania, United States, 2003–2014. Public Health 168: 17-25. doi:10.1016/j.puhe.2018.11.020
    • Phan TT, Hakala JA, Lopano CL, and Sharma S. 2019. Rare earth elements and radiogenic strontium isotopes in carbonate minerals reveal diagenetic influence in shales and limestones in the Appalachian Basin. Chemical Geology. doi:10.1016/j.chemgeo.2019.01.018
    • Chalfant BA and Corrigan CC. 2018. Governing Unconventional Oil and Gas Extraction: The Case of Pennsylvania. Review of Policy Research 36: 75-98. doi:10.1111/ropr.12319
    • Platt RV, Manthos D, and Amos J. 2018. Estimating the Creation and Removal Date of Fracking Ponds Using Trend Analysis of Landsat Imagery. Environmental Management 61: 310. doi:10.1007/s00267-017-0983-4
    • Hill E L, and Ma L. 2017. Does Shale Gas Development Impact Infant Health through Drinking Water?. working paper. https://pdfs.semanticscholar.org/d29a/9be6077ffc5add2b4adbef86a36ca722668e.pdf
    • Milt AW, Gagnolet T, and Armsworth PR. 2016. Synergies and tradeoffs among environmental impacts under conservation planning of shale gas surface infrastructure. Environmental management, 57(1), pp.21-30. doi:10.1007/s00267-015-0592-z
    • Phan TT, Capo RC, Stewart BW, Macpherson GL, Rowan EL, and Hammack RW. 2016. Factors controlling Li concentration and isotopic composition in formation waters and host rocks of Marcellus Shale, Appalachian Basin. Chemical Geology, 420, pp.162-179. doi:10.1016/j.chemgeo.2015.11.003
    • Dieterich M. 2015. Physicochemical Effects of Synthetic Hydraulic Fracturing Fluid on Core Samples Of The Middle Devonian Marcellus Shale and Underlying Huntersville Chert, Greene County, Pennsylvania, USA. Doctoral Dissertation, University Of Pittsburgh. http://d-scholarship.pitt.edu/id/eprint/24963
    • Milt AW. 2015. Conservation Planning in a Changing World. PhD Dissertation, University of Tennessee. http://trace.tennessee.edu/utk_graddiss/3514
    • Phan TT, Capo RC, Stewart BW, Graney JR, Johnson JD, Sharma S, and Toro J. 2015. Trace metal distribution and mobility in drill cuttings and produced waters from Marcellus Shale gas extraction: Uranium, arsenic, barium. Applied Geochemistry, 60, pp.89-103. doi:10.1016/j.apgeochem.2015.01.013
    • Rahm BG, Vedachalam S, Bertoia LR, Mehta D, Vanka VS, and Riha SJ. 2015. Shale gas operator violations in the Marcellus and what they tell us about water resource risks. Energy Policy, 82, pp.1-11. doi:10.1016/j.enpol.2015.02.033
    • Gamper‐Rabindran S. 2014. Information Collection, Access, and Dissemination to Support Evidence‐Based Shale Gas Policies. Energy Technology 2: 977-987. doi:10.1002/ente.201402114
    • Slyder J, Whitacre J, and Wenzel J. 2015. Painting a Clearer Picture of Shale Gas Development. ArcNews Vol. 37, No. 1: 20-21. https://www.esri.com/about/newsroom/arcnews/painting-a-clearer-picture-of-shale-gas-development/
    • Mitchell AL. 2013. Analysis of health and environmental risks associated with Marcellus Shale development. figshare. Thesis. doi:10.1184/R1/6714752.v1

  8. Why does the Carnegie Museum of Natural History produce the Pennsylvania Unconventional Natural Gas Wells geodatabase? How is it different from the PA DEP data or other data products?

    The Carnegie Museum of Natural History produces the Pennsylvania Unconventional Natural Gas Wells geodatabase to be used primarily for research purposes and to have one dataset that many researchers can use to provide reliable comparisons between different studies. The project began in response to the need to unify the PA DEP data sources (i.e. Permit, Spud, and Production reports) and check for discrepancies between the reports. We found that researchers were using the different reports inappropriately in some studies and that very few were checking the different reports for congruency and reliability in regards to a well’s unconventional status. We found that among the different reports, some wells were classified as unconventional in one report, but not in another. Therefore, we set out to identify those wells to provide researchers with data that has been pre-analyzed for the discrepancies, thus providing an authoritative dataset.