An outlier detection approach for water footprint assessments in shale formations: case Eagle Ford play (Texas)
- PDF / 3,058,451 Bytes
- 18 Pages / 595.276 x 790.866 pts Page_size
- 90 Downloads / 169 Views
ORIGINAL ARTICLE
An outlier detection approach for water footprint assessments in shale formations: case Eagle Ford play (Texas) Saúl Arciniega‑Esparza1,3 · Antonio Hernández‑Espriú2 · J. Agustín Breña‑Naranjo3 · Michael H. Young4 · Adrián Pedrozo‑Acuña3 Received: 19 November 2019 / Accepted: 12 September 2020 / Published online: 25 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The increasing trend on water use for hydraulic fracturing (HF) in multiple plays across the U.S. has raised the need to improve the HF water management model. Such approaches require good-quality datasets, particularly in water-stressed regions. In this work, we presented a QA/QC framework for HF data using an outlier detection methodology based on five univariate techniques: two interquartile ranges at 95 and 90% (PCTL95, PCTL90), the median absolute deviation (MAD) and Z score with thresholds of two and three times the standard deviation (2STD, 3STD). The cleaning techniques were tested using multiple variables from two data sources centered on the Eagle Ford play (EFP), Texas, for the period 2011–2017. Results suggest that the PCTL95 and MAD techniques are the best choices to remove long-tailed statistical distributions of different variables, classifying the minimum number of records as outliers. Overall, outliers represent 13–23% of the total HF water volume in the EFP. In addition, outliers highly impacted minimum and maximum HF water use values (min–max range of 0–47 m 3/m and 5.3–24.6 m 3/m of frac length, before and after the outlier removal process, respectively), that are frequently used as a proxy to develop future water–energy scenarios in early-stage plays. The data and framework presented here can be extended to other plays to improve water footprint estimates with similar conditions. Keywords Outliers · Geospatial analysis · Water use · Hydraulic fracturing · Eagle Ford · Shale gas
Introduction Quantifying water use for hydraulic fracturing (HF) has become a key issue related to water security in many regions where shale (or tight rock)-based energy are located, because shale development has been perceived as a water-intensive practice (Pacsi et al. 2014; Scanlon et al. 2014, 2017; Walker et al. 2017). HF and horizontal drilling techniques have been * Antonio Hernández‑Espriú [email protected] 1
Programa de Maestría y Doctorado en Ingeniería, Universidad Nacional Autónoma de México, Mexico City, Mexico
2
Hydrogeology Group, Faculty of Engineering, Universidad Nacional Autónoma de México, Mexico City, Mexico
3
Institute of Engineering, Universidad Nacional Autónoma de México, Mexico City, Mexico
4
Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
used to increase oil and gas production from U.S. shale formations during the last decade, contributing to the country’s energy independence (Lin et al. 2018; Nicot and Scanlon 2012). Nevertheless, production from unconventional reservoirs using HF has been
Data Loading...
