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A series of column transport experiments ranging from 25ºC to 275ºC, as well as batch sorption experiments at 25ºC, were conducted to estimate cation exchange parameters for lithium and cesium at the Newberry Crater Enhanced Geothermal System demonstration site.. The experiments were designed to facilitate interpretation of single-well field tracer tests to interrogate fracture surface area. Lithium column transport from 125ºC to 275ºC showed a strong temperature dependence, with much greater cation exchange at higher temperatures than in 25ºC experiments. Cesium column transport at 225ºC indicated a weaker temperature dependence, and unlike Li + , its exchange decreased at higher temperatures.

Algal growth demands a continuous source of water of appropriate salinity and nutritional content. Fresh water sources are scarce in the deserts of the Southwestern United States, hence, salt water algae species are being investigated as a renewable biofuel source. The use of produced water from oil wells (PW) could offset the demand for fresh water in cultivation. Produced water can contain various concentrations of dissolved solids, metals and organic contaminants and often requires treatment beyond oil/water separation to make it suitable for algae cultivation. The produced water used in this study was taken from an oil well in Jal, New Mexico. An F/2-Si (minus silica) growth media commonly used to cultivate Nannochloropsis salina 1776 (NS 1776) was prepared using the produced water (F/2-Si PW) taking into account the metals and salts already present in the water. NS 1776 was seeded into a bioreactor containing 5L of the (F/2-Si PW media. After eleven days the optical density at 750 nm (an indicator of algal growth) increased from 0 to 2.52. These results indicate algae are able to grow, though inhibited when compared with non-PW media, in the complex chemical Neal 2 conditions found in produced water. Savings from using nutrients present in the PW, such as P, K, and HCO 3-, results in a 44.38% cost savings over fresh water to mix the F/2-Si media.

A comprehensive 2006 Massachusetts Institute of Technology (MIT) report found that electrical power derived from engineered (or enhanced) geothermal systems (EGSs) "represents a large, indigenous resource that could provide base-load electric power and heat that can have a major impact on the United States, while incurring minimal environmental impacts." EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear project review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program, emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single-or multi-well tests.This project was a collaborative effort between Brookhaven National Laboratory (BNL), Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL), and the Energy and Geoscience Institute (EGI) at the University of Utah. The project covered a wide array of activities including bench-scale testing of tracers, numerical modeling, interpretation of existing tracer tests, and design and conducting field tracer tests at a demonstration EGS site. The initial PFT development was led by BNL along with high temperature column studies by LANL. Various numerical models described in this study were applied by PNNL and LANL to bench-scale batch and column testing results of conservative and reactive tracers with different mineralogy, temperature regimes, and flow rates. These models were also used to 1) analyze an existing field reactive and conservative tracer test data set at a naturally fractured geothermal site at Soda Lake, Nevada, and 2) design the reactive and conservative tracer tests for an EGS demonstration site near Newberry Crater, Oregon, that was led by Alta Rock Energy, Inc. PNNL and EGI led tracer testing operations during this EGS demonstration that was conducted from October to December 2012. The numerical models developed under this project for the Newberry Crater EGS test will provide a useful tool for interpreting tracer test respon...

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