Colorado Water Watch: real-time groundwater monitoring for possible contamination from oil and gas activities

Abstract

Currently, only a few states in the USA (e.g., Colorado and Ohio) require mandatory baseline groundwater sampling from nearby groundwater wells prior to drilling a new oil or gas well. Colorado is the first state to regulate groundwater testing before and after drilling, which requires one pre-drilling sample and two additional post-drilling samples within 6-12 months and 5-6 years of drilling. However, the monitoring method is limited to the state's regulatory agency and to ex situ sampling, which offers only a snapshot in time. To overcome the limitations and increase monitoring performance, a new groundwater monitoring system, Colorado Water Watch (CWW), was introduced as a decision-making tool to support the state's regulatory agency and also to provide real-time groundwater quality data to both the industry and the public. The CWW uses simple in situ water quality sensors based on the surrogate sensing technology that employs an event detection system to screen the incoming data in near real-time.

Setting the baseline for shale gas – Establishing effective sentinels for water quality impacts of unconventional hydrocarbon development

“…Unlike for spot sampling in-situ water quality sondes are subject to damage and vandalism and must be maintained and calibrated in-situ. Son et al (2015Son et al ( , 2018 have proposed the use of in-situ water quality sondes down borehole in areas of active hydraulic fracturing in northern Colorado to monitor for pollution events. The problem of interpretation would be equally true for high frequency as for low frequency data obtained from spot sampling, i.e.…”

Environmental screening of water associated with shale gas extraction by fluorescence excitation emission matrix

“…2 Second, monitoring contaminant incidences often requires real-time analyses and often wireless telemetry systems. 2,24 To date, many chemical, physical and microbiological tests to assess wastewater quality are unsuitable for real-time monitoring. 37 Beyond on-site implications, the connection between water and energy is multifaceted and includes facilities maintenance, longevity of equipment, weatherproofing, and other physical site considerations.…”

“…40,41 There are limitations or technical bottlenecks for existing detection technologies for the environmental screening of water quality and include technical and economic challenges due to the need for real-time analyses, building contaminant specific sensors and often wireless telemetry systems. 2 Because fluorescence spectroscopy has the potential to be used in water quality studies to determine the source and origin of detected organic compounds, 41 the oil and gas industry is beginning to use fluorescent spectroscopy as a natural tracer to identify contamination incidents during operations. 30,[39][40][41][42] Fluid-shale interactions are increasingly used to determine natural contributions of shale to produced water.…”

“…Water management during shale gas extraction operations is essential to minimise freshwater consumption while ensuring sufficient water supply for fracturing operations. 2 Water consumed for shale gas production over a 30 year life cycle can reach up to 100 million litres (L) of water per well. 3,4 Recycling and treating produced water therefore becomes an essential part of water management plans during operations.…”

Baseline Groundwater Quality before Shale Gas Development in Xishui, Southwest China: Analyses of Hydrochemistry and Multiple Environmental Isotopes (2H, 18O, 13C, 87Sr/86Sr, 11B, and Noble Gas Isotopes)

“…Thus, establishing geochemical baseline datasets of shallow groundwater systems before shale gas production is necessary, which can not only provide direct evidence when contamination occurs, but can also reduce controversies of shallow groundwater pollution after hydraulic fracturing [28][29][30]. Currently, a few sites, such as Pennsylvania, USA [31], Colorado, USA [32], Quebec, Canada [33], North Yorkshire, UK [34], and Chongqing, China [35,36], have developed baseline investigation of groundwater before drilling shale gas wells.…”