The University of Hawaii at Manoa conducted a Play Fairway Analysis of the state of geothermal potential for the islands. Phase I included the aggregation of all existing geologic, geophysical and geochemical data available. A probability model incorporating heat, fluid, and permeability was then created to assess the probability of viable geothermal development. Phase II is the focus of this paper, with new data collection as the goal for this funding period. The Play Fairway Project collected new geothermal groundwater data from 60 wells and 1 spring across the State of Hawaii. Geochemical geothermal indicators used previously in Hawaii, and around the world, were investigated for the newly acquired data in Phase II. These indicators include groundwater temperature, chloride:magnesium ratios, sulfate:chloride ratios, and silica concentrations. All chemical analyses were collected by ... the Play Fairway team and analyzed at various labs at the University of Hawaii at Manoa. Of the ten target areas identified for Phase II, two of the sites provide encouraging groundwater geochemical results for potential geothermal resources. These sites include the Southwest Rift Zone of Haleakala, Maui, and the Palawai Basin, Lanai. Multiple geothermal indicators have been observed in these areas and, therefore, provide encouragement to further explore for subsurface heat. Further investigation is recommended in these target areas through geological, geophysical, and geochemical exploration. The Hawaii Play Fairway project was funded by the U.S. Department of Energy Geothermal Technologies Office, and the Hawaii Groundwater and Geothermal Resources Center (Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa) executed the project. For more information, go to HGGRC's website that is linked in the resources.

In enhanced geothermal systems (EGS) the reservoir permeability is often enhanced or created using hydraulic fracturing. In hydraulic fracturing, high fluid pressures are applied to confined zones in the subsurface usually using packers to fracture the host rock. This enhances rock permeability and therefore conductive heat transfer to the circulating geothermal fluid (e.g. water or supercritical carbon dioxide). The ultimate goal is to increase or improve the thermal energy production from the subsurface by either optimal designs of injection and production wells or by altering the fracture permeability to create different zones of circulation that can be exploited in geothermal heat extraction. Moreover, hydraulic fracturing can lead to the creation of undesirable short-circuits or fast flow-paths between the injection and extraction wells leading to a short thermal residence time, low heat recovery, and thus a short-life of the EGS. A potential remedy to these problems is to deploy a cementing (blocking, diverting) agent to minimize short-cuts and/or create new circulation cells for heat extraction. A potential diverting agent is the colloidal silica by-product that can be co-produced from geothermal fluids. Silica gels are abundant in various surface and subsurface applications, yet they have not been evaluated for EGS applications. In this study we are investigating the benefits of silica gel deployment on thermal response of an EGS, either by blocking short-circuiting undesirable pathways as a result of diverting the geofluid to other fractures; or creating, within fractures, new circulation cells for harvesting heat through newly active surface area contact. A significant advantage of colloidal silica is that it can be co-produced from geothermal fluids using an inexpensive membrane-based separation technology that was developed previously using DOE-GTP funding. This co-produced silica has properties that potentially make it useful as a fluid diversion agent for subsurface applications. Colloidal silica solutions exist as low-viscosity fluids during their "induction period" but then undergo a rapid increase in viscosity (gelation) to form a solid gel. The length of the induction period can be manipulated by varying the properties of the solution, such as silica concentration and colloid size. We believe it is possible to produce colloidal silica gels suitable for use as diverting agents for blocking undesirable fast-paths which result in short-circuiting the EGS once hydraulic fracturing has been deployed. In addition, the gels could be used in conventional geothermal fields to increase overall energy recovery by modifying flow.

Results from a nanofiltration study utilizing simulated geothermal brines. The data includes a PDF documenting the process used to remove Calcium, Magnesium, Sodium, Silica, Lithium, Chlorine, and Sulfate from simulated geothermal brines. Three different membranes were evaluated. The results were analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

This submission contains geospatial (GIS) data on water table gradient and depth, subcrop gravity and magnetic, propsectivity, heat flow, physiographic, boron and BHT for the Southwest New Mexico Geothermal Play Fairway Analysis by LANL Earth & Environmental Sciences. GIS data is in ArcGIS map package format.

Compilation of boron, lithium, bromine, and silica data from wells and springs throughout New Mexico from a wide variety of sources. The chalcedony geothermometry calculation is included in this file.

This file contains silica precipitation and lithium sorption data from the project. The silica removal data is corrected from the previous submission. The previous submission did not take into account the limit of detection of the ICP-MS procedure.

This document provides results of experiments aimed at removing silica from geothermal brines. All experiments were conducted with simulated brines. The data presented shows the effect of iron addition, kinetics, temperature, pH and brine concentration.

This is a compilation of logs and data from Well 9-1 in the Roosevelt Hot Springs area in Utah. This well is also in the Utah FORGE study area. The file is in a compressed .zip format and there is a data inventory table (Excel spreadsheet) in the root folder that is a guide to the data that is accessible in subfolders.