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Restoring anthropogenic footprints to pre-disturbance conditions or minimizing their long-term impacts is an important goal in conservation. Many footprints, particularly if left alone, have wide-ranging effects on biodiversity. In Canada, energy exploration footprints result in forest dissection and fragmentation contributing to declines in woodland caribou. Developing cost effective strategies to restore forests and thus conserving the woodland caribou habitat is a conservation priority. In this study, we compared the effects of wildfire and local variation in the amount of residual woody debris on natural regeneration in jack pine on exploratory well pads in Alberta’s boreal forest. Specifically, we investigated how footprint size, fire severity (overstory tree mortality), ground cover of fine and coarse woody debris, and adjacent stand characteristics (i.e., height, age, and cover), affected tree regeneration densities and height using negative binomial count and linear models (Gaussian), respectively. Regeneration density was 30% higher on exploratory well pads than adjacent forests, increased linearly with fire severity on the exploratory well pads (2.2% per 1% increase in fire severity), but non-linearly in adjacent forests (peaking at 51,000 stems/ha at 72% fire severity), and decreased with amount of woody debris on exploratory well pads (2.7% per 1% increase in woody debris cover). The height of regenerating trees on exploratory well pads decreased with fire severity (0.56 cm per 1% increase in fire severity) and was non-linearly related to coarse woody debris (peaking at 286 cm at 9.4% coarse woody debris cover). Heights of 3 and 5 m on exploratory well pads were predicted by 13- and 21-years post-fire, respectively. Our results demonstrate that wildfires can stimulate natural recovery of fire-adapted species, such as jack pine, on disturbances as large as exploratory well pads (500–1330 m2) and that the type and amount of woody debris affects these patterns.

Unconventional oil and gas (UOG) wells from the Marcellus and Utica shale plays have expanded greatly across the Appalachian region of the United States (US) since the early 2000s. This region is now the single largest natural gas producing area of the US. The local and regional impacts of this industry on the landscape make it critical to understand for future planning efforts. This study investigated land cover change associated with over 21,000 unconventional wells representing 4,240 well pads permitted from 2007 to 2017 in Pennsylvania, West Virginia, and Ohio. The goal was to characterize UOG disturbance to document development patterns and extents in the region. Supervised classification was used to map land use and land-cover changes within a 25-ha buffer of well pads identified in the region. On average, disturbance related to unconventional development impacted 6.2 ha in Pennsylvania, 4.7 ha in Ohio and 4.4 ha in West Virginia and 5.6 ha over the region. Forest and grassland were found to be the most impacted cover types, with increases in impervious surface areas being a significant contributor to land-use classification change. These conversions can contribute to increased forest fragmentation and edge, which can in turn adversely impact biodiversity indicators at the regional level. Additionally, increases in impervious surface in small headwater watersheds can lead to increased sediment and runoff loads in receiving streams. Local and regional land use planning should be implemented during the well pad permit review process to help minimize environmental impacts over larger geographic scales.

In order to study the engineering problems of shale oil horizontal well platform fracturing mode, a three-dimensional geological model and a three-dimensional geomechanical model were constructed according to the characteristics of Chang 7 section in Ordos Basin. The fracture propagation under different well spacing, cluster spacing, and fracturing sequence was simulated. The PEBI grid was used to refine the local grid of the fractures and predict the performance of the multi-well pad. The finite element model was used to analyze the change of induced stress field. The numerical simulation analysis shows that: 1) Comparing the simulation results of sequence fracturing and zipper fracturing under the condition of 300 m well spacing, the induced stress generated by zipper fracturing is more conducive to the formation of complex fractures, improving the effect of transformation and higher production after fracturing. 2) Under the condition of 200 meters or 300 meters well spacing, zipper fracturing is carried out, and the cluster spacing is reduced from 5 meters to 3 meters. The stress shadow between wells and sections leads to adverse effects, and the production will decrease after fracturing. Therefore, 5 meters is recommended as the cluster spacing.

Growing energy demand has increased the need to manage conflicts between energy production and the environment. As an example, shale-gas extraction requires substantial surface infrastructure, which fragments habitats, erodes soils, degrades freshwater systems, and displaces rare species. Strategic planning of shale-gas infrastructure can reduce trade-offs between economic and environmental objectives, but the specific nature of these trade-offs is not known. We estimated the cost of avoiding impacts from land-use change on forests, wetlands, rare species, and streams from shale-energy development within leaseholds. We created software for optimally siting shale-gas surface infrastructure to minimize its environmental impacts at reasonable construction cost. We visually assessed sites before infrastructure optimization to test whether such inspection could be used to predict whether impacts could be avoided at the site. On average, up to 38% of aggregate environmental impacts of infrastructure could be avoided for 20% greater development costs by spatially optimizing infrastructure. However, we found trade-offs between environmental impacts and costs among sites. In visual inspections, we often distinguished between sites that could be developed to avoid impacts at relatively low cost (29%) and those that could not (20%). Reductions in a metric of aggregate environmental impact could be largely attributed to potential displacement of rare species, sedimentation, and forest fragmentation. Planners and regulators can estimate and use heterogeneous trade-offs among development sites to create industry-wide improvements in environmental performance and do so at reasonable costs by, for example, leveraging low-cost avoidance of impacts at some sites to offset others. This could require substantial effort, but the results and software we provide can facilitate the process. La creciente demanda de energía ha incrementado la necesidad de manejar los conflictos entre la producción de energía y el ambiente. Como ejemplo, la extracción de gas esquisto requiere de una infraestructura superficial sustancial, la cual fragmenta los habitats, erosiona el suelo, degrada los sistemas de agua dulce y desplaza a las especies raras. La planeación estratégica de la infraestructura de gas esquisto puede reducir las compensaciones entre los objetivos económicos y ambientales, pero la naturaleza específica de estas compensaciones no se conoce. Estimamos el costo de evitar los impactos del cambio de uso de suelo causado por el desarrollo de gas esquisto dentro de los arriendos sobre los bosques, humedales, especies raras y arroyos Creamos un software para sitiar óptimamente la infraestructura superficial de gas esquisto y minimizar su impacto ambiental a un costo de construcción razonable. Valoramos visualmente los sitios antes de la optimización de la infraestructura para probar si dicha inspección podría usarse para predecir si los impactos podrían evitarse en el sitio. En promedio, hasta el 38 % de los impactos ambientales agregados de la infraestructura podría evitarse por 20 % de costos de desarrollo mayores al optimizar espacialmente la infraestructura. Sin embargo, encontramos compensaciones entre los impactos ambientales y los costos entre los sitios. En las inspecciones visuales muchas veces distinguimos entre los sitios que podrían desarrollarse para evitar los impactos a un costo relativamente bajo (29 %) y aquellos que no podrían (20 %). Las reducciones en una medida de impacto ambiental agregado podrían atribuirse en su mayoría al desplazamiento potencial de las especies raras, la sedimentación y la fragmentación del bosque. Los planificadores y los reguladores pueden estimar y usar compensaciones heterogéneas entre los sitios de desarrollo para crear mejoras en el desempeño ambiental a lo largo de la industria y hacerlo a costos razonables al, por ejemplo, evitar los impactos en algunos sitios para compensar otros. Esto podría requerir un esfuerzo sustancial, pero los resultados y el software que proporcionamos pueden facilitar el proceso.

This study assessed how hydraulic fracturing (HF) (water withdrawals from nearby river water source) and its associated activities (construction of well pads) would affect surface water and groundwater in 2021–2036 under changing climate (RCP4.5 and RCP8.5 scenarios of the CanESM2) in a shale gas and oil play area (23,984.9 km2) of northwestern Alberta, Canada. An integrated hydrologic model (MIKE-SHE and MIKE-11 models), and a cumulative effects landscape simulator (ALCES) were used for this assessment. The simulation results show an increase in stream flow and groundwater discharge in 2021–2036 under both RCP4.5 and RCP8.5 scenarios with respect to those under the base modeling period (2000–2012). This occurs because of the increased precipitation and temperature predicted in the study area under both RCP4.5 and RCP8.5 scenarios. The results found that HF has very small (less than 1%) subtractive impacts on stream flow in 2021–2036 because of the large size of the study area, although groundwater discharge would increase minimally (less than 1%) due to the increase in the gradient between groundwater and surface water systems. The simulation results also found that the construction of well pads related to HF have very small (less than 1%) additive impacts on stream flow and groundwater discharge due to the non-significant changes in land use. The obtained results from this study provide valuable information for effective long-term water resources decision making in terms of seasonal and annual water extractions from the river, and allocation of water to the oil and gas industries for HF in the study area to meet future energy demand considering future climate change.

Responses of boreal birds to changes in forest structure and composition caused by construction of well pads, seismic lines, and pipelines are poorly understood. Bird species associated with older forests are predicted to experience larger population declines with increased disturbance compared with species associated with younger or open habitats; however, point count methods may influence apparent outcomes because the proportional area of disturbed vegetation and the magnitude, uncertainty, and detection of a disturbance response by birds vary as a function of sampling area. We analyzed point count data from 12 energy sector studies and measured how disturbance type and point count radius interacted to affect 531 impact ratios (mean abundance at point counts centered within disturbances relative to abundance at point counts within forest 150–400 m from the nearest edge bordering those disturbances [59 species*3 disturbance types*3 point count radii]). We observed larger disturbance effects (impact ratios) within larger-radius point counts at well pads (100-m and unlimited-distance) and pipelines (unlimited-distance) compared with 50-m point counts at seismic lines, and within 50-m point counts at well pads relative to 50-m point counts at seismic lines. Effect uncertainty was higher at well pads and pipelines than seismic lines, and lower within larger-radius point counts. The probability of detecting a disturbance response was greater for larger-radius point counts at pipelines than for 50-m point counts at seismic lines, and within 50-m point counts at well pads relative to 50-m point counts at seismic lines. On average, a species was more likely to increase in abundance near an energy sector disturbance if the species was not associated with older (>75 yr) forest stages. While the effects of disturbance varied by species and with disturbance type, the effects of pipelines and seismic lines were better detected by larger-radius point counts, while the effects of well pads were better detected by smaller-radius point counts.

Hydraulic fracturing and related ground water issues are growing features in public discourse. Few have given much attention to surface impacts from shale gas development, which result from building necessary surface infrastructure. One way to reduce future impacts from gas surface development without radically changing industry practice is by formulating simple, conservation-oriented planning guidelines. We explore how four such guidelines affect the locations of well pads, access roads, and gathering pipelines on state lands in Pennsylvania. Our four guidelines aim to (1) reduce impacts on water, reduce impacts from (2) gathering pipelines and (3) access roads, and (4) reduce impacts on forests. We assessed whether the use of such guidelines accompanies tradeoffs among impacts, and if any guidelines perform better than others at avoiding impacts. We find that impacts are mostly synergistic, such that avoiding one impact will result in avoiding others. However, we found that avoiding forest fragmentation may result in increased impacts on other environmental features. We also found that single simple planning guidelines can be effective in targeted situations, but no one guideline was universally optimal in avoiding all impacts. As such, we suggest that when multiple environmental features are important in an area, more comprehensive planning strategies and tools should be used.

Energy development is one of the most rapidly increasing land uses in North America, so understanding how wildlife respond to different types of energy infrastructure is crucial for informing land‐use policies. Effects of energy development on wildlife habitat use and selection can vary depending on infrastructure type, level of industrial activity, and density. I examined seasonal habitat use and selection of greater sage‐grouse in relation to energy development in a high‐elevation oil and gas field in western Colorado by linking spatially and temporally explicit energy infrastructure layers with telemetry locations of marked females from 2006 to 2014. Objectives were to (1) quantify energy infrastructure around seasonal use locations; (2) examine how seasonal resource selection is affected by energy infrastructure with disturbed versus reclaimed surface and different levels of industrial activity; and (3) assess current surface disturbance and infrastructure density caps. Between 92% and 97% of seasonal use locations had <3% disturbed surface within 1000 m. After accounting for landcover and topography, breeding and wintering females selected locations with less disturbed, reclaimed, and total anthropogenic surface. Breeding females selected locations farther from high‐activity well pads and facilities. In contrast, females selected locations with low to intermediate values of disturbed and reclaimed surface and locations closer to pipelines and roads in summer–fall. This is the first evidence that greater sage‐grouse select locations with energy infrastructure in any season and suggests that responses to energy development may differ between mesic and arid sagebrush ecosystems. Females avoided locations with >1.1%–2.5% disturbed surface during breeding and winter and selected locations with lower densities of active energy features during breeding and roads in winter. Density caps of one active energy feature and 1.5 mi (2.41 km) of road per section were adequate to prevent avoidance except during the breeding season. Disturbance caps should be set at 1.1% disturbed surface and 1.8% total anthropogenic surface in breeding habitat and 2.5% disturbed surface and 3.5% total anthropogenic surface in winter habitat to minimize negative impacts on female habitat selection in this population. Results also support timing restrictions on construction and drilling during breeding and rapid transitioning of well pads from drilling to production.

Drilling and completion platform construction is a fundamental part of oil and gas reservoir development, and the location of construction directly affects the whole process of shale gas drilling and development. Due to the complex surface conditions and fragile ecological environment in mountainous areas, having an appropriate platform location can significantly reduce shale gas development and environmental costs. The DEM (digital elevation model) includes geographic elevation, surface complexity, land use type, and other data, so it can be used for rapid site selection for shale gas multi-well pad drilling. In this study, first, research results related to drilling platform site selection were analyzed and summarized, and then a platform site selection method aiming to minimize the total well construction cost was developed. Second, the well construction costs were decomposed into the surface construction costs and the underground construction costs, and the site selection model with the lowest total multi-well pad construction costs was established. Third, ground feature data obtained from DEM (digital elevation model) processing were substituted into the site selection model and solved using the genetic clustering algorithm. Finally, two practical cases were used to verify the research method developed in this study. The results show that the platform site selection results can be used to not only guide the formulation of development plans, but also to reduce the scope of the field investigation in the process of site selection, reduce the intensity of field work, and improve the work efficiency.

Multi-well pad has been considered the most efficient horizontal well development technique in unconventional reservoirs since it does not only maximize oil production but also significantly reduces operation costs and environmental footprints by drilling a group of wells on a single pad. To optimize both well placement and hydraulic fracture parameters simultaneously in a multi-well pad is still largely unexplored and remains to be a challenging task. In this study, we develop a global optimization framework based on generalized differential evolution (GDE) algorithm to maximize the expected net present value (NPV) in a constrained well-pad production optimization. More specifically, differential evolution (DE) algorithm is extended for constrained optimization problem through a generalized selection operation. Unlike the penalty functions, the GDE is capable of handling the constraints without introducing any extra parameters. Subsequently, a new well completion economic model is firstly proposed based on a 200 well completion dataset. This enables us to integrate the available field information into the optimization framework and obtain a practical optimum scenario for the multi-well pad development. Furthermore, a geological model is generated and matched to the field production data and operation costs of a four-well pad in Cardium tight oil formation. Based on the newly developed economic model and well-tuned simulation model, the well spacing, well length, fracture spacing, fracture half-length, and fracture conductivity of each well in a multi-well pad are optimized and a highest NPV is achieved. The oil recovery and NPV of the optimum scenario derived through the GDE are increased by 37.2 and 63.7% respectively in comparison with the field reference case.