Repository for Oil and Gas Energy Research (ROGER)

Abstract:
Worldwide, shale-gas development is becoming a feasible extraction practice and the northern Allegheny Plateau, USA is a region experiencing such development. We used a GIS to investigate topographic and soil characteristics across existing and permitted shale-gas pads in Pennsylvania, which could affect infrastructure development and reclamation success. Results from this analysis, while regionally specific, can contribute knowledge for successful management of all shale-gas extraction. Approximately 60% of existing and permitted pads occur on slopes at risk to some excess surface water movement and local erosion. Pad development occurs >90% of the time on backslope landscape positions and 37% of the time on soils with a fragipan subsoil horizon, which can contribute to soil drainage problems. Most pads (73%) are developed on soils without drainage problems, but 21% are on potentially wet soils. Shale-gas development related to one pad typically disturbed a 0.1- to 20.5-ha area (mean of 2.7 ha). Aerial photography analysis from 2010 indicates a small proportion of pads have undergone restoration, and restored pads were recontoured and planted with grass. Agricultural lands restored after infrastructure development were found to return to some crop production. Assuming perfect site reclamation, grass, herbaceous, hardwood, and conifer establishment appears suitable across the range of existing and permitted pads; however revegetation success may be limited by poor soil reclamation.

Abstract:
Worldwide shale-gas development has the potential to cause substantial landscape disturbance. The northeastern U.S., specifically the Allegheny Plateau in Pennsylvania, West Virginia, Ohio, and Kentucky, is experiencing rapid exploration. Using Pennsylvania as a proxy for regional development across the Plateau, we examine land cover change due to shale-gas exploration, with emphasis on forest fragmentation. Pennsylvania’s shale-gas development is greatest on private land, and is dominated by pads with 1–2 wells; less than 10 % of pads have five wells or more. Approximately 45–62 % of pads occur on agricultural land and 38–54 % in forest land (many in core forest on private land). Development of permits granted as of June 3, 2011, would convert at least 644–1072 ha of agricultural land and 536–894 ha of forest land. Agricultural land conversion suggests that drilling is somewhat competing with food production. Accounting for existing pads and development of all permits would result in at least 649 km of new road, which, along with pipelines, would fragment forest cover. The Susquehanna River basin (feeding the Chesapeake Bay), is most developed, with 885 pads (26 % in core forest); permit data suggests the basin will experience continued heavy development. The intensity of core forest disturbance, where many headwater streams occur, suggests that such streams should become a focus of aquatic monitoring. Given the intense development on private lands, we believe a regional strategy is needed to help guide infrastructure development, so that habitat loss, farmland conversion, and the risk to waterways are better managed.

Abstract:
When natural resources are exploited, environmental costs and economic benefits are often asymmetric. An example is apparent in the environmental impacts from fossil fuel extraction by hydraulic fracturing. So far, most scrutiny has been focused on water quality in affected aquifers, with less attention paid to broader ecological impacts beyond individual drilling operations. Marcellus Shale methane exploitation in New York State, USA, has been delayed because of a regulatory moratorium, pending evaluation that has been directed primarily at localized impacts. We developed a GIS-based model, built on a hexagonal grid underlay nested within the U.S. Environmental Protection Agency’s EMAP system, to examine potential cumulative ecological impacts. In a two-step process, we characterized > 19,000 hexagons, each sized to approximate the footprint of one drilling site (2.57 km²), using ecological attributes; we then developed a method for apportioning resource access that includes assessments of cumulative ecological costs. Over one-quarter of the hexagons were excluded as off-limits on the basis of six criteria: slope suitability, regulated wetland cover, protected-land cover, length of high-quality streams, mapped road density, and open water cover. Three additional criteria were applied to assess the estimated conservation vulnerability of the remaining sites: density of grassland birds (North American Breeding Bird Survey), percent core forest (Coastal Change Analysis Program), and total density of all state-mapped streams; these were determined and used in combination to rank the 14,000 potentially accessible sites. In a second step, an iterative process was used to distribute potential site access among all towns (sub-county governments) within the Marcellus Shale Formation. At each iteration, one site was selected per town, either randomly or in rank order of increasing vulnerability. Results were computed as percent cumulative impact versus the number of sites committed and compared to a most-conservative selection process (ranked by statewide conservation vulnerability). Random selection with proportional distribution by town resulted in larger cumulative ecological impacts, but rank-ordered selection by town was in many ways comparable to selection by statewide conservation vulnerability ranking. These outcomes allow for a political solution for managing resource access fairly, based on a balanced geographic distribution of economic benefits, coupled with an underlying scientific basis for assessing the ecological costs that are publicly shared.

Abstract:
In June 2008, 303,000 L of hydrofracturing fluid from a natural gas well were applied to a 0.20-ha area of mixed hardwood forest on the Fernow Experimental Forest, West Virginia. During application, severe damage and mortality of ground vegetation was observed, followed about 10 d later by premature leaf drop by the overstory trees. Two years after fluid application, 56% of the trees within the fluid application area were dead. Ehrh. was the tree species with the highest mortality, and L. was the least affected, although all tree species present on the site showed damage symptoms and mortality. Surface soils (0-10 cm) were sampled in July and October 2008, June and October 2009, and May 2010 on the fluid application area and an adjacent reference area to evaluate the effects of the hydrofracturing fluid on soil chemistry and to attempt to identify the main chemical constituents of the hydrofracturing fluid. Surface soil concentrations of sodium and chloride increased 50-fold as a result of the land application of hydrofracturing fluids and declined over time. Soil acidity in the fluid application area declined with time, perhaps from altered organic matter cycling. This case study identifies the need for further research to help understand the nature and the environmental impacts of hydrofracturing fluids to devise optimal, safe disposal strategies.

Abstract:
Background Many studies have quantified the indirect effect of hydrocarbon-based economies on climate change and biodiversity, concluding that a significant proportion of species will be threatened with extinction. However, few studies have measured the direct effect of new energy production infrastructure on species persistence. Methodology/Principal Findings We propose a systematic way to forecast patterns of future energy development and calculate impacts to species using spatially-explicit predictive modeling techniques to estimate oil and gas potential and create development build-out scenarios by seeding the landscape with oil and gas wells based on underlying potential. We illustrate our approach for the greater sage-grouse (Centrocercus urophasianus) in the western US and translate the build-out scenarios into estimated impacts on sage-grouse. We project that future oil and gas development will cause a 7–19 percent decline from 2007 sage-grouse lek population counts and impact 3.7 million ha of sagebrush shrublands and 1.1 million ha of grasslands in the study area. Conclusions/Significance Maps of where oil and gas development is anticipated in the US Intermountain West can be used by decision-makers intent on minimizing impacts to sage-grouse. This analysis also provides a general framework for using predictive models and build-out scenarios to anticipate impacts to species. These predictive models and build-out scenarios allow tradeoffs to be considered between species conservation and energy development prior to implementation.