Title

Better Solutions for Produced Water Management in California Oilfields

Poster Number

3a

Lead Author Affiliation

Ecological Engineering Research Program

Lead Author Status

Faculty

Second Author Affiliation

Civil Engineering

Third Author Affiliation

Civil Engineering

Third Author Status

Masters Student

Fourth Author Affiliation

Ecological Engineering Research Program

Fourth Author Status

Faculty

Introduction

Oil production is important in California, as California is the third most productive oil-producing state in the U.S. During oil production, a liquid waste stream—termed produced water—is generated that must be treated and/or disposed properly. Historically, produced water has been managed by injection into deep wells or by surface infiltration. Changing regulations and concerns over current disposal practices have prompted review of management methods. Additionally, water scarcity in oil-producing regions have made use of reclaimed produced water more appealing.

Purpose

Over the past several years our research group has been assessing the environmental hazards of produced water and potential treatment technologies. While we have addressed environmental hazards posed by well stimulation practices (e.g. hydraulic fracturing), our work covers many aspects of oil production. Our purpose in doing this work is to better understand the hazards posed by oil production and to guide regulatory efforts to collect and disseminate data. We are also motivated to find appropriate treatment technologies that can make oilfield water reclamation feasible.

Method

Our assessment of produced water has taken several forms. We are reviewing records on oil production practices to better understand industry water and chemical use and to better understand the pollutants present in produced water. We are collecting and evaluating field samples of produced water to confirm water quality and treatability. We use the field samples in laboratory tests to confirm the suitability of different treatment approaches. We also use water quality data collected from available data sets and from field studies in geochemical models to further assess treatability.

Results

Evaluation of existing data sets has included review of data from the online, industry-sponsored chemistry registry FracFocus. Regulatory disclosure data sets reviewed include those from the South Coast Air Quality Management District in Southern California and from the California Division of Oil, Gas, and Geothermal Resources. These evaluations have elucidated chemical and water use by the oil industry in California, and have identified data gaps. Collection of field samples and analysis of these samples in laboratory tests has revealed amenability to biological treatment, even under saline conditions. Acclimation of a lab-scale biological reactor to an appropriate feedstock (sodium benzoate) appears useful in achieving biotreatability. Geochemical modeling has shown that precipitation of scale-forming chemicals can be controlled to limit impacts on downstream treatment processes. Piper plots and stiff diagrams have proven useful in evaluating the ionic contents of produced water.

Significance

The work that our research group has done provides clarity on water and chemical use in oil production in California. We have evaluated data sets that are now available as the result of new disclosure requirements. Our participation in field data collection has clarified oilfield practices and our laboratory tests highlight feasible treatment approaches for produced water. Additionally, our efforts to integrate geochemical modeling into treatment assessment are beneficial for better identifying feasible treatment approaches. Our goal is to continue assessing oilfield chemicals to better understand the fate and transport of these chemicals in treatment systems and in downstream water reclamation projects.

Location

DeRosa University Center

Format

Poster Presentation

Poster Session

Morning 10am-12pm

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Apr 28th, 10:00 AM Apr 28th, 12:00 PM

Better Solutions for Produced Water Management in California Oilfields

DeRosa University Center

Oil production is important in California, as California is the third most productive oil-producing state in the U.S. During oil production, a liquid waste stream—termed produced water—is generated that must be treated and/or disposed properly. Historically, produced water has been managed by injection into deep wells or by surface infiltration. Changing regulations and concerns over current disposal practices have prompted review of management methods. Additionally, water scarcity in oil-producing regions have made use of reclaimed produced water more appealing.