Flowback water quality data from the Kyalla-117 and Tanumbirini-1 well sites, Northern Territory

Abstract

As part of the GBA program, CSIRO has undertaken an investigation of flowback water quality at two shale gas sites in the Beetaloo Sub-basin, Northern Territory. The study was conducted between late 2019 and early 2021 at the Tanumbirini-1 and Kyalla-117 well sites in the Beetaloo Sub-basin, NT, where the organic-rich shale units within the Velkerri and Kyalla formations are the primary unconventional hydrocarbon targets. The study involved measuring the concentrations of a comprehensive range of chemicals in flowback waters at periodic intervals over a 3 month period from the commencement of flowback, which followed the completion of hydraulic fracturing. Water samples from on-site flowback water storage tanks were also taken in order to provide an indication of the composition of the accumulated wastewater prior to its treatment. The chemical analyses conducted covered over 60 trace elements (e.g. arsenic, manganese, barium, boron and zinc), seven radionuclides (e.g. isotopes of radium, thorium, and uranium) and over 160 organic chemicals (e.g. hydrocarbons and phenols). The dataset is organised into four spreadsheets. Inorganics and organics data are contained in separate spreadsheets for each well site. Quality control data (e.g. blanks, replicate measurements, reference materials) are also included. The dataset also contains a copy of the report: Apte SC, Kirby J, Williams M, King JJ, Hayward J, Johnston C, Schatz J, Jarolimek CV (2021) Assessing the potential impacts of hydraulic fracturing on water quality at well sites in the Northern Territory. CSIRO Land and Water technical report.

Attribution

Geological and Bioregional Assessment Program

History

The water sampling and laboratory analytical methods used to create this dataset are described in the report “Assessing the potential impacts of hydraulic fracturing on water quality at well sites in the Northern Territory”. The report also includes a full interpretation of the data. Field work including water sample collection, were conducted at Tanumbirini from late November 2019 to late March 2020 and at Kyalla from October 2020 to January 2021. All water samples were collected and processed using internationally accepted protocols. The sampling design employed involved initial intensive (daily) sampling as soon as possible after the well had been hydraulically fractured, then weekly sampling for the first month, followed by monthly sampling until flowback or well operations ceased (between 3 and 4 months). Additional samples were also taken from the flowback retention ponds at both well sites. These samples gave an indication of the water quality of the combined flowback waters prior to their treatment/disposal. This list of chemicals to be analysed was developed following a review of relevant published literature on shale gas operations. Wherever possible, sample analyses were conducted in NATA (National Association of Testing Authorities, Australia) accredited laboratories which includes the CSIRO laboratory at Lucas Heights. The quality control (QA/QC) program adopted in the study included field duplicates, laboratory replicates, blanks, spike recovery tests and where available, analysis of certified reference materials. Analysis for organic target compounds was conducted by the National Measurement Institute, Sydney (NMI) which is NATA accredited facility. All radiochemical analyses were conducted by the Australian Nuclear Science and Technology Organisation (ANSTO). Biocide analysis was conducted at the CSIRO Land and Water laboratory in Adelaide.