Pennsylvania Data Discrepancies

By Matt Kelso, Manager of Data & Technology

The Pennsylvania Department of Environmental Protection (PADEP) publishes oil and gas well data in two different places: on their own website’s Spud Data Report, and in the Oil and Gas Locations file published on the PA Spatial Data Access repository, also known as PASDA. Because these two sources are both ultimately published by PADEP, it would stand to reason that the data sources would match up. Unfortunately, that is not the case. Learn more about the data discrepancies we uncovered:

This map shows those wells in Pennsylvania that only show up on one of the two data sources. Pink dots show wells that appear on PASDA but not the PADEP site, while the reverse is true for blue wells. Click here for the full screen view with additional map tools.


Both of these data sources have existed for years. When FracTracker does analyses of PA, we usually use data directly from the PADEP site, because it includes far more information about the wells, such as the spud date, county, municipality, well configuration, and whether or not the well is classified as unconventional. Even though it has less information about each well, the data on PASDA is useful for expediently mapping the inventory of wells in the Keystone State. In this current analysis, we looked at both sources, and found significant discrepancies between the two.

Individual oil and gas wells have been given unique API numbers since the 1950’s. The overwhelming majority of items on both lists that we examined have these numbers, and those that do not have other numeric identifiers in their place. The uniqueness of the data in these columns is what we used to determine the number of wells on both lists. These columns in both data sources were then tested against one another using Microsoft Excel in order to determine which wells were included on both lists.

The data on PASDA is described as “Oil and Gas Locations,” and nothing in available metadata made it clear as to whether wells that were permitted but not yet drilled might be included in this or not. Additionally, we are mostly interested in wells that are still operational, assuming that there might be accuracy issues for historical wells in an industry that has been operational in the state since before the Civil War. We did, however, include orphaned and abandoned wells, as they remain a source of impact throughout the state.



Number of wells in PA in various categories. For brevity, “Total wells – Drilled and not plugged” is shown as “TW-DnP.”

We found 3,315 records of drilled, unplugged wells with location information on the PASDA dataset that are not on the PADEP search tool, and 96 such wells on the PADEP site that aren’t found on PASDA. Additionally, there are 35,434 drilled and unplugged wells in the PADEP data that lack location data, although six of these wells are actually on the PASDA site, meaning that there is some location data for them somewhere at PADEP.

For those of you who might be looking for discrepancies in our discrepancy table, one might expect the number of both wells that appear on both lists (the second to last row on the chart) to be identical. The biggest reason that they are not is that some wells appear in the PASDA dataset multiple times. There are 6,997 fewer unique wells than there are entries on the full file, or a 95.74% match rate. In comparison, the PADEP spud report only has 19 duplicates for over 204,000 wells, a 99.99% match between the number of wells and the number of records. Indeed, when we filter for unique wells, the difference between the two lists shrinks to only 40 records, which might be explained by differences is well statuses that were used to shape our analysis.

This chart shows the number of wells drilled per year in Susquehanna County, through 2/11/15.

Number of wells drilled per year in Susquehanna Co., through 2/11/15.

Undoubtedly, it will take some effort to get the two datasets to reflect the full set of wells in PA, but that is certainly a task than can be accomplished. The wells lacking location data are likely to be much more of a challenge. If we include all status types, there are 75,508 wells on the spud report that lack latitude and longitude values altogether, leaving us with only the county and municipality to determine where these wells are located. Hopefully, this crucial data exists somewhere in the PADEP inventory, and these wells are not in fact lost.

Finally, there are a couple of things to note about dates. Since the PASDA dataset does not include spud dates, it is impossible to determine the age of the majority of the mismatched wells. Looking at the pink dots on the interactive map above, though, it is clear that a large number of these mismatched PASDA wells are in the northeastern corner of the state that has been booming since the recent development of the Marcellus, but saw little to no development before that time – at least according to the spud report.

Of the 96 wells that are on the spud report but not PASDA, 67 are given the date “1/1/1800,” which seems to be a default date; over 94,000 wells on the report have this listed as the spud date. Most of the other wells that don’t match are relatively old wells, with spud dates ranging between 1960 and 1984. One of these wells was drilled on May 6, 1999 though, and four more were drilled on August 19, 2014.

The mismatched data can be accessed here for those who are interested.

Drilling rig in Ohio, December 2015

Oil and Gas Drilling 101

Oil and Gas Drilling 101

While conventional oil and gas drilling (O&G) for commercial purposes has been occurring in the United States for over 150 years, recent processes utilize a variety of unconventional extraction techniques such as fracking to improve the return of hydrocarbons to the surface.

According to the U.S. Environmental Protection Agency (EPA):

Natural gas is a fossil fuel formed when layers of buried plants and animals are exposed to intense heat and pressure over thousands of years. The energy that the plants and animals originally obtained from the sun is stored in the form of carbon in natural gas. Natural gas is combusted to generate electricity, enabling this stored energy to be transformed into usable power.


As with other fossil fuels, oil is found in underground reservoirs. It is the end product of the decomposition of organic materials that have been subjected to geologic heat and pressure over millions of years.

Natural Gas

When first obtained from the ground, natural gas is composed of primarily methane with other alkanes typically mixed in, and possibly also carbon dioxide, nitrogen, and hydrogen sulfide. Shale gas, specifically, is natural gas trapped within shale geologic formations (a type of sedimentary rock).

Both oil and natural gas are considered non-renewable resources since they cannot be replenished on a human timeframe.

Current Methods of Extraction

Recently, oil and gas companies have been extracting these resources from unconventional reservoirs, such as shale formations. These “reservoirs” of gas do not connote underground lagoons; in fact, shale gas is held in tiny bubbles in the rock, and requires a combination of technologies to liberate that gas. The process typically involves directionally drilling wells, not just vertically, and often using additional techniques to “stimulate” the reservoir to increase production from the new or existing wells.

Hydraulic fracturing or “fracking” is one form of stimulation used to facilitate the production of underground resources such as oil and natural gas wells, geothermal energy, and water. Another form of well stimulation is called acidizing and will be discussed later.

For unconventional O&G drilling, the process begins with vertical drilling, and then turns horizontal (often at depths greater than 6,800 feet and below) traveling 6,300-6,400 lateral feet.

Explore this process by watching the following TED-Ed video by Mia Nacamulli, animation by Sharon Colman:

How many wells have been stimulated (e.g. fracked) in the U.S.?

This question is a common one that we receive here at FracTracker. Unfortunately, the answer is simple and not so simple at the same time.

Short Answer: No one knows – exactly.

Long Answer: We estimate that there are ~1.3 million active oil and gas facilities in the United States (map below). How many are being unconventionally drilled – utilizing technologies such as directional drilling, acidizing, or hydraulic fracturing – is a much tougher number to determine because of serious gaps in both reporting requirements and data formats. Most of these active wells are likely receiving some sort of advanced stimulation techniques, however. This article explains the topic and caveats in further detail.

If you notice an error or omission in this section, please let us know.

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Updated PA Data and Trends

By Matt Kelso, Manager of Data and Technology

The FracTracker Alliance periodically takes a deeper look into the unconventional oil and gas data in Pennsylvania, in order to provide updates for some frequently requested statistics on the industry. Here we provide updated PA data and trends as of December 4, 2014. Since unconventional drilling began in the Commonwealth permits have been issued to drill 15,573 unconventional wells, according to data from the Pennsylvania DEP. Many – 8,696 (56%) – of those permits have actually been drilled. In terms of violations, there have been 5,983 entries on the statewide Compliance Report for unconventional wells throughout the state, which are attributed to 1,790 distinct wells.

Pennsylvania Shale Viewer Map

Please click here for the full screen version, with additional map tools and controls.

Additional Stats

The number of permits, wells, and violations vary significantly from month to month, but each category is well off of its peak. The largest number of unconventional permits issued in a single month was 402, which was in December 2010, more than twice as many as were issued last month. In that year, there were six months with 300 or more permits issued, whereas there has only been one such month to date in 2014.

PA unconventional O&G activity per month from Jan. 2009 to Nov. 2014.  Source:  PADEP

PA unconventional O&G activity per month from Jan. 2009 to Nov. 2014. Source: PADEP

The 210 wells spudded (drilled) in August 2011 represents the high water mark, and is more than two times the amount of wells drilled last month. In the 28 months between March 2010 and June 2012, the industry failed to spud 100 wells only once, reaching 98 in April 2011. In the first 11 months of 2014, that plateau was missed three times, with a low of 58 spuds in February.

There was a significant spike in violations appearing on the compliance report from December 2009 through August 2011. More than 100 violations were issued in 17 out of 21 months, including 196 in March 2010. The number of violations issued has slowed down considerably since then, with November 2014 being the 34th straight month with fewer than 100 violations. Only 14 violations were issued in June 2014.

Violations per Well (VpW)

Unconventional violations per well by county in PA, showing the 10 counties with the largest number of violations.  Counties with an above average Violations per Well (VpW) score are highlighted in red.

Unconventional violations per well by county in PA, showing the 10 counties with the largest number of violations. Counties with an above average Violations per Well (VpW) score are highlighted in red.

We often ask whether drilling is more problematic in some areas than others. Since the number of wells varies depending upon the location, we must approach this question by looking at the number of violations issued per well drilled (VpW). However, there is an important caveat to consider. Put simply, what is a violation? The Pennsylvania DEP publishes a Compliance Report for unconventional wells, which has 5,983 incidents listed from 2000 through December 4, 2014. However, it used to be common for the DEP to lump several incidents into the same Violation ID number, although this is not the case for more recent infractions. When the DEP counts violations issued, they look at the total number of unique Violation ID numbers that have been issued, not the total number of incidents on the report. Here, we include the more inclusive list of items on the compliance report.

Of the 10 counties with the largest number of violations issued, only 3 counties have a violations per well mark below the statewide average. Notably, each of those three counties are located in Southwestern Pennsylvania. It is unclear from these numbers what is going on in Potter County, but clearly there is a significant problem in that location – with almost three violations issued per well drilled, Potter County has a VpW score 4.3 times the statewide average.

Operator Trends

Before we look at the operators with the most violations, there is an additional caveat to consider: It is relatively common for wells to change hands over their operational lifetimes. This characteristic could be due to one company buying another out, or simply transferring some of their assets. Still, wells changing from one operator to another is a normal aspect of the oil and gas industry. Such a fact matters for this analysis because while violations issued always stick with the responsible party in the DEP data, the name of the operator changes on the Spud Report to the current operator.

Unconventional violations per well by operator in PA, showing the 10 operators with the largest number of violations.  Operators with an above average Violations per Well (VpW) score are highlighted in red.

Unconventional violations per well by operator in PA, showing the 10 operators with the largest number of violations. Operators with an above average Violations per Well (VpW) score are highlighted in red.

Because of how these datasets are maintained, we see that East Resources has 261 violations for zero wells, which is of course an impossibly large ratio. That is because East sold off its stake in the Marcellus to Royal Dutch Shell, which does business as SWEPI in Pennsylvania. SWEPI, by the way, is 13th on the list of violations in its own right, with 154 violations for 675 wells, resulting in a 0.23 VpW. If the legacy violations for the old East wells were included, the result would be a 0.61 ViW score, which is almost three times as high, but still below the statewide average. FracTracker doesn’t do the analysis that way, both because it is unfair to the new operator to charge them with violations that they had nothing to do with, as well as being nearly impossible to keep track of the various transactions that result in wells changing hands over the years.

Cover image by Pete Stern, 2013.

Hydraulic fracturing, stimulations, & oil & gas drilling unjustly burden Hispanic & non-white students

By Kyle Ferrar, CA Program Coordinator, FracTracker Alliance

As my first year in The Bay Area of California comes to a conclusion and the summer once again turns into fall I realize how much more this time of year meant for me living on the east coast. For us lucky ducks living in the Bay Area, fall is perpetual. With the California drought seasons blur together, but back home in Pennsylvania and New York, fall marks a much appreciated relief from 90°F+ days. Regardless of where you live certain fall activities are universal, including hockey, postseason baseball, football, and most importantly for kids – going back to school.

In California alone, almost 6.24 million students from kindergarten to 12th grade are enrolled and attend classes at one of the 10,366 state “campuses.” State-recognized schools range in size from under a dozen students to a maximum 2013/2014 enrollment of 5,229. When so many children are together in one space, they share much more than just the scholarship, social development, and the occasional but inevitable flu virus. They share the same environmental media (air, water, soil) and are therefore exposed to the same environmental contaminants.

To understand who among this vulnerable population is subject to potential health impacts, the FracTracker Alliance has put together a report analyzing the demographic characteristics of schools located near oil and gas extraction activity. An interactive map of the data that was analyzed is shown below, as are the points of the report. The full report can be found here:

 Disproportionate Burdens for Hispanic and Non-White Students in California

and here in Spanish:

Las Estimulaciones por Fracturación Hidráulica y la Perforación Petrolífera Cerca de las Escuelas y dentro de los Distritos Escolares de California son una Carga Desproporcionada para los Estudiantes Hispanos y Estudiantes No Blancos.

Fracked well near elementary school

Sequoia Elementary School located in Shafter, CA.

In the background, less than 1,200 feet from the school is
an oil well (API 403043765) that was hydraulically fractured.

Key Findings of School Analysis:

  • There are 485 active/new oil and gas wells within 1 mile of a school and 177 active/new oil and gas wells within 0.5 miles of a school.
  • There are 352,784 students who attend school within 1 mile of an oil or gas well, and 121,903 student who attend school within 0.5 miles of an oil or gas well.
  • There are 78 stimulated wells drilled within 1 mile of a school and 14 stimulated wells drilled within 0.5 miles of a school.
  • There are 61,612 students who attend school within 1 mile of a stimulated oil or gas well, and 12,362 students who attend school within 0.5 miles of a stimulated oil or gas well.
  • School Districts with greater Hispanic and non-white student enrollment are more likely to contain more oil and gas drilling and stimulation.
  • Schools campuses with greater Hispanic and non-white student enrollment are more likely to be closer to more oil and gas drilling and stimulation.
  • Students attending school within 1 mile of oil and gas wells are predominantly non-white (79.6%), and 60.3% are Hispanic.
  • The top 11 school districts with the highest well counts are located the San Joaquin Valley with 10 districts in Kern County and the other just north of Kern in Fresno County.
  • The two districts with the highest well counts are in Kern County; Taft Union High School District, host to 33,155 oil and gas wells, and Kern Union High School District, host to 19,800 oil and gas wells.
  • Of the schools with the most wells within a 1 mile radius, 8/10 are located in Los Angeles County.

Report Map

The interactive map below allows the user to compare the demographical profiles of school districts with oil and gas drilling and stimulation activity. Non-white enrollment percentages of school districts are displayed in shades of blue. Overlaid with red are the relative counts of stimulated and/or non-stimulated oil and gas wells. The highest counts of wells are hosted in school districts located in the Central (San Joaquin) Valley and along California’s south coast. Geologically, these areas lay above the Monterey Shale – the 50 million year sedimentary basin producing California’s oil reserves.

Comparison of Oil and Gas Violations and the Sale of Wells

Well pad spill, wetland. Photo courtesy of WV Host Farms Program (

Well pad spill, wetland. Photo courtesy of WV Host Farms Program

By Matt Unger, FracTracker GIS Intern

When the unconventional oil and gas extraction boom hit Pennsylvania in the mid-2000s small, local operators were among the first on the scene. As shale plays continued to develop, many of these smaller companies were bought out by larger, national corporations. Larger oil and gas development companies often maintain that they are better able to handle the expected regulatory requirements, and so FracTracker wanted to determine if there was a change in the compliance record for wells that changed hands. Does having more resources available to them translate into stronger compliance standards for oil and gas drillers, better training for their employees, and a greater burden to get things right? Investigating these questions by looking into compliance data and the sale of wells, however, was no easy task.

Analysis Methods

There are no indications in either the drilled wells or permits datasets available from the DEP that a well has changed hands; in both of these sources, one operator’s name is simply substituted for the other. It is possible to comb through old news stories, and find that East Resources sold its assets to Shell in 2010, for example. However, this approach is piecemeal, and would not lead to satisfactory results on an industry-wide analysis.

Major obstacles to our analysis included:

  • Lack of information on the transfer of oil and gas wells from one operator to another
  • There is often a lag time between the time violations occur and when they are reported
  • Errors in compliance reporting. For example, one API Number was found to have the operator listed as “Not Assigned” (It was later discovered that this well was never sold).


Unlike wells and permits, any items on the compliance dataset are attributed to whichever company was operating the well at the time the violation was issued. So while FracTracker could not do the analysis that we wanted to because of the limitations of available data, we were able to isolate 30 wells that have changed hands between January 1, 2000 and November 4, 2014 (Table 1). One well has been bought and sold twice, with each of the three operators being issued violations.

In some instances the original well owner was reported to be out of compliance more times than the second owner. For example, API Number 013-20012 had 11 violations reported under its first owner and only 1 since it has been sold. The contrary also occurred, however, such as in the case of API Number 065-26481, which had 4 violations reported under its first owner and 14 under its second owner. There are not enough data points to determine which scenario is the trend in the data – if in fact there is one.

Due to limitations in the data, we cannot currently evaluate whether the notion that larger companies can improve the track record of problematic wells. In fact, many of the wells that were issued violations for multiple operators really just changed hands from one big operator who wanted to get out of the Marcellus to another big operator who wanted to get in. Our small sample doesn’t include any of the wells that were issued violations to only one company, of all the wells that changed hands over the years. To accurately assess the scenario, more data would have to be released, specifically the date when wells changed hands from one company to another.

Table 1. Wells with violations by API number that have changed ownership

API Number First Owner Last Known Date Of Ownership Second Owner First Known Date Of Ownership Third Owner First Known Date Of Ownership
013-20012 Chief Oil & Gas LLC 5/24/10 Chevron Appalachia LLC 2/5/13
015-20033 Belden & Blake Corp 4/10/09 Chesapeake Appalachia LLC 12/7/11
015-20051 Consol Gas Co 6/16/04 Range Resources Appalachia LLC 8/9/05 Talisman Energy USA Inc 11/16/11
019-21494 Phillips Exploration Inc 6/10/08 XTO Energy Inc 7/24/13
019-21680 Phillips Exploration Inc 4/6/10 XTO Energy Inc 3/13/13
065-26481 Dannic Energy Corp 5/11/11 Mieka LLC 11/10/11
065-26832 Dannic Energy Corp 3/2/11 Mieka LLC 4/11/12
081-20062 Chief Oil & Gas LLC 1/6/09 Exco Resources Pa LLC 8/16/11
081-20069 Chief Oil & Gas LLC 5/21/08 Exco Resources Pa LLC 3/28/11
081-20128 Chief Oil & Gas LLC 11/15/10 Exco Resources Pa LLC 6/27/11
081-20144 Chief Oil & Gas LLC 7/21/10 Exco Resources Pa LLC 3/15/12
081-20149 Chief Oil & Gas LLC 1/10/11 Exco Resources Pa LLC 2/21/12
081-20244 Chief Oil & Gas LLC 5/20/10 Exco Resources Pa LLC 11/15/12
081-20255 Chief Oil & Gas LLC 11/15/10 Exco Resources Pa LLC 11/29/11
081-20279 Chief Oil & Gas LLC 12/3/10 Exco Resources Pa LLC 4/20/12
081-20298 Chief Oil & Gas LLC 5/26/10 Exco Resources Pa LLC 6/27/11
083-53843 Anschutz Exploration Corp 4/7/09 Chesapeake Appalachia LLC 3/20/13
113-20025 Chief Oil & Gas LLC 2/15/11 Exco Resources Pa LLC 3/16/11
113-20049 Chief Oil & Gas LLC 11/30/10 Exco Resources Pa LLC 4/13/11
115-20052 Turm Oil Inc 9/24/08 Chesapeake Appalachia LLC 8/21/14
115-20169 Alta Opr Co LLC 11/24/09 WPX Energy Appalachia LLC 4/13/11
115-20174 Alta Opr Co LLC 4/16/10 Wpx Energy Appalachia LLC 4/29/11
115-20191 Alta Opr Co LLC 12/1/09 Wpx Energy Appalachia LLC 6/1/11
115-20214 Alta Opr Co LLC 7/19/10 Wpx Energy Appalachia LLC 8/16/10
115-20231 Alta Opr Co LLC 4/8/10 Wpx Energy Appalachia LLC 6/1/11
117-20197 East Resources Inc 4/8/08 Talisman Energy USA Inc 1/26/11
117-20280 East Resources Inc 5/19/10 Swepi LP 8/28/14
117-20330 East Resources Inc 12/18/09 Talisman Energy USA Inc 2/20/13
117-20394 East Resources Inc 12/14/09 Swepi LP 10/25/11
117-20538 East Resources Inc 12/18/10 Swepi LP 5/27/10


Conventional and unconventional wells in PA

Over 1.2 Million Pennsylvanians Within 1/2 Mile of a Well

Aging well in McKean County, PA. Source:

One of the potentially troubling aspects of oil and gas development is that there are usually people who live in the vicinity of the wells. Pennsylvania now has over 8,000 active unconventional wells; there are any number of issues that can occur with these modern, industrial-scale sites, including road degradation, contaminated water, and health impacts, among others. In addition, there are over 93,000 of the smaller, conventional wells in operation throughout the Commonwealth. While these garner far less attention than their unconventional counterparts, they are also prone to producing similar impacts, not to mention that since many of them are older wells, they not only have potentially been subject to deterioration and occasional neglect, but were constructed during a period with less stringent requirements than are currently expected.

Petroleum engineers are now capable of drilling horizontally for tens of thousands of feet. For the most part, however, this technology is employed to maximize production, rather than to ameliorate impacts on people who live near the product. But who are these people? To help to answer this question, the FracTracker Alliance calculated the number of people living in a half-mile radius around active wells in the state.

More than 1.2 million Pennsylvanians live within the impact area.

Of the 93,754 wells that have been drilled in the state since 1950 that have not yet been plugged, the Pennsylvania DEP only has location data for 79,118 of them. All but one of the 14,636 missing locations are for wells that are categorized as Conventional. While one must presume that there is some overlap in coverage within the half-mile zone, the extent of this region – and therefore the population that lives within it – cannot be determined.

Fig. 1. PA Populations Near Oil and Gas Wells. Click here to access written description and additional map tools.

To maximize the reliability of our calculations, this map was created using a custom Albers equal-area projection centered on Pennsylvania. A half-mile buffer around each well type was created, and the resulting layer was clipped to Census tract data. The ratio of the smaller clipped area to the full Census tract area was calculated, and that ratio was then multiplied by the population totals from the 2010 Census to obtain our population estimates of the half-mile zone. The area in the study area is larger than six states, while the calculated population is larger than that of eight states.

Of the 79,118 active oil and gas wells in PA for which location data are available, we determined the area and estimated the population within a half mile radius. Note that some regions are with a half-mile of both conventional and unconventional wells.

Fig. 2. Number of people in PA near oil and gas wells (79,118 active wells for which location data are available). Note that some regions are with a half-mile of both conventional and unconventional wells.

The county most impacted, in terms of area, for unconventional wells is Bradford, with 353 square miles (See Figure 2). Washington County had the most people living in the zone, however, with 20,566. For conventional wells, the drilling landscape is the largest in Indiana County, affecting 761 square miles, while Erie County has the most people in the half-mile zone, with 212,900. When considering all wells together, the numbers are almost identical to conventional wells. Indiana County leads with 762 square miles, while the drill zone in Erie County represents 211,903 people, or 76% of the county’s population in 2010.

West Virginia shale viewer

West Virginia

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