Posts

Changes to PA Maps feature image

Recent Changes to Pennsylvania Maps

Recently, the Pennsylvania Department of Environmental Protection (DEP) started to offer additional data resources with the introduction of the Open Data Portal. This development, along with the continued evolution of the ArcGIS Online mapping platform that we utilize has enabled some recent enhancements in our mapping of Pennsylvania oil and gas infrastructure. We’ve made changes to the existing Pennsylvania Shale Viewer for unconventional wells, and created a Conventional and Historical Wells in Pennsylvania map.

Unconventional Wells

Rather than defining the newer, industrial-scaled oil and gas wells by specific geological formations, configuration of the well, or the amount of fluid injected into the ground during the hydraulic fracturing process, Pennsylvania’s primary classification is based on whether or not they are considered to be unconventional.

Unconventional Wells – An unconventional gas well is a bore hole drilled or being drilled for the purpose of or to be used for the production of natural gas from an unconventional formation. An unconventional formation is defined as a geologic shale formation below the base of the Elk Sandstone or its geologic equivalent where natural gas generally cannot be produced except by horizontal or vertical well bores stimulated by hydraulic fracturing.

PA Shale Viewer (Unconventional Drilling)

View map fullscreen | How FracTracker maps work

The previous structure of the PA Shale Viewer had separate layers for permits, drilled wells, and violations. This version replaces the first two layers with a single layer of unconventional locations, which we have called “Unconventional Wells and Permits” for the sake of clarity. The violations layer appears in the same format as before. When users are zoomed out, they will see generalized layers showing the overall location of O&G infrastructure and violations in the state, which were formed by creating a one mile buffer around these features. As users zoom in, the generalized layers are then replaced with point data showing the specific wells and violations. At this point, users can click on individual points and learn more about the features they see on the map.

PA Shale Viewer Zoomed In

Figure 1. PA Shale Viewer zoomed in to see individual wells by status

O&G locations are displayed by their well status, as of the time that FracTracker processed the data, including: Abandoned, Active, Operator Reported Not Drilled, Plugged OG Well, Proposed but Never Materialized, and Regulatory Inactive Status. Note that just because a well is classified as Active does not mean that it has been drilled, or even necessarily permitted. These milestones, along with whether or not it has been plugged, can be determined by looking for entries in the permit issue date, spud date, and plug date entries in the well’s popup box.

Conventional and Historical Wells

The map below shows known conventional wells in Pennsylvania along with additional well locations that were digitized from historical mining maps.

Conventional Oil and Gas Wells Map

View map fullscreen | How FracTracker maps work

Although there are over 19,000 unconventional oil and gas locations in Pennsylvania, this figure amounts to just 11% of the total number of wells in the state that the DEP has location data for, the rest being classified as conventional wells. Furthermore, in a state that has been drilling for oil and gas since before the Civil War, there could be up to 750,000 abandoned wells statewide.

The DEP has been able to find the location of over 30,000 of these historical wells by digitizing records from old paper mining maps. This layer has records for 16 different counties, but well over half of these wells are in just three counties – Allegheny, Butler, and Washington. It looks like it would take a lot more work to digitize these historical wells throughout the rest of the state, but even when that happens, we will probably still not know where the majority of the old oil and gas wells in the state are located.


By Matt Kelso, Manager of Data & Technology

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: saveourstreamspa.org

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.

Conventional, Non-Vertical Wells in PA

Like most states, the data from the Pennsylvania Department of Environmental Protection do not explicitly tell you which wells have been hydraulically fractured. They do, however, designate some wells as unconventional, a definition based largely on the depth of the target formation:

An unconventional gas well is a well that is drilled into an Unconventional formation, which is defined as a geologic shale formation below the base of the Elk Sandstone or its geologic equivalent where natural gas generally cannot be produced except by horizontal or vertical well bores stimulated by hydraulic fracturing.


Naturally occurring karst in Cumberland County, PA. Photo by Randy Conger, via USGS.

While Pennsylvania has been producing oil and gas since before the Civil War, the arrival of unconventional techniques has brought greater media scrutiny, and at length, tougher regulations for Marcellus Shale and other deep wells. We know, however, that some companies are increasingly looking at using the combination of horizontal drilling and hydraulic fracturing in much shallower formations, which could be of greater concern to those reliant upon well water than wells drilled into deeper unconventional formations, such as the Marcellus Shale. The chance of methane or fluid migration through karst or other natural fissures in the underground rock formations increase as the distance between the hydraulic fracturing activity and groundwater sources decrease, but the new standards for unconventional wells in the state don’t apply.

The following chart summarizes data for wells through May 16, 2014 that are not drilled vertically, but that are considered to be conventional, based on depth:

These wells are listed as conventional, but are not drilled vertically.

These wells are listed as conventional, but are not drilled vertically.

Note that there have already been more horizontal wells in this group drilled in 2014 than any previous year, showing that the trend is increasing sharply.

Of the 26 horizontal wells, 12 are considered oil wells, five are gas wells, five are storage wells, three are combination oil and gas, and one is an injection well.  These 177 wells have been issued a total of 97 violations, which is a violation per well ratio of 62 percent.  429 permits in have been issued in Pennsylvania to date for non-vertical wells classified as conventional.  Greene county has the largest number of horizontal conventional wells, with eight, followed by Bradford (5) and Butler (4) counties.

We can also take a look at this data in a map view:


Conventional, non-vertical wells in Pennsylvania. Please click the expanding arrows icon at the top-right corner to access the legend and other map controls.  Please zoom in to access data for each location.