This dataset contains active fault features compiled by the Arizona Geological Survey, and published as a Web feature service for the National Geothermal Data System. Fields in the Active Fault Feature Content Model will become XML elements in interchange documents for WMS simple features provided by a node in the USGIN network. Each feature includes a Fault Name, Symbol and Source. The dataset is spatially referenced to EPSG: 4326 (for interoperability). The data contained in the submitted dataset is available as an Excel Spreadsheet, Access Database (.mdb), ESRI service, WMS and WFS service. Link to Active (Quaternary) Fault Feature Content Model: http://stategeothermaldata.org/data_delivery/content_models/active_faultquaternary_fault.

To prioritize information for archiving and to determine the applicability of the Fenton Hill experience to the future development of Enhanced Geothermal Systems (EGS), an integrated review was made of five categories of Fenton Hill information: hydraulic fracturing data, well logs, seismic data, flow test data and tracer test data. Major experiments were identified, the methods of data collection and analysis were determined, the location and format of the data were determined, and further analyses that would yield information of value to EGS developers were suggested. Such analyses would be directed toward the determination of: I) if and how the state of stress in the reservoir changed during sequential fracturing jobs; 2) how the orientation of fractures changed with depth and location; 3) how the reservoir size increased as fracturing and flow testing operations proceeded; 4) how the hydraulic properties and heat-transfer characteristics of the reservoir varied with changes in operating conditions; and 5) how the Phase II reservoir (the deeper and hotter of the two reservoirs developed) would behave over the long term under various operating conditions.

The publicly available database on oil and gas fields in California provides a significant and consistent source of information which can be used to evaluate geopressure. A total of 410 pools have pressure gradients exceeding 0.45 psi/foot; these are considered to be potentially geopressured. At least 70 of these have pressures distinctly higher than predicted by the regional hydrostatic gradient, and 8 pools are super pressured.

Some proponents of geothermal energy have described this energy source as renewable, but many geothermal fields show declines in output as exploitation proceeds. On the other hand, those who would call geothermal a depletable energy source have to explain how some mature fields are able to produce with negligible declines and no apparent limit to the amount of recoverable energy. The confusion arises out of the attempt to describe geothermal resources using inappropriate conceptual models of how resources behave. This paper presents a conceptual model that is better suited to describe the expected performance of a geothermal field over its entire life cycle. The paper also describes a set of terms that can be used to quantify geothermal resources and to guide plans for development.

For the purposes of this paper, sustainability is defined as the ability to economically maintain the installed capacity, over the amortized life of a power plant, by taking practical steps (such as, make-up well drilling) to compensate for resource degradation (pressure drawdown and/or cooling). Renewability is defined here as the ability to maintain the installed power capacity indefinitely without encountering any resource degradation; renewable capacity is, however, often too small for commercial development. This paper also considers an additional level of commercial capacity (above the sustainable level) that is not planned to be maintained fully over the entire plant life as mitigation of resource degradation would become uneconomic or otherwise impractical at some point. This declining capacity above the sustainable level is considered commercial only if the levelized power cost is lower than that from alternative renewable, or environmentally benign, energy sources. Even if power cost at this unsustained commercial generation level proves higher than that from fossil fuels, this additional capacity can reduce fossil fuel usage if power from renewable or environmentally benign energy resources is given adequate tax breaks or price support. Displacement of fossil fuel usage is a social imperative that would reduce environmental pollution today and preserve these fuels as raw material for organic chemicals, and for potentially cleaner power generation in the future.

This paper presents the results of a continuing study of geopressured resources in California. Three aspects of geopressured resources were examined in this study: the identification of geopressured zones in wells; quantification of the excess pressure from well logs; and the quantity of dissolved methane in California geopressured fluids.

Under the premise that the behavior of enhanced geothermal systems (EGS) will be dominated by fracture flow, this paper reviews the special features that would be required of any practical numerical simulator for EGS. These features, required in addition to the basic features of conventional geothermal simulators, namely, the ability to handle two-phase fluid flow, heat transfer and tracer transp0l1 in porous and fractured media, are: explicit representation of fractures, change in fracture aperture due to effective stress and shear, thermo-elastic effects, relation between fracture aperture and conductivity, and channeling of fluid flow within fractures. Chemical reaction between water and rock and coupling of the reservoir model with a well bore model would also be desirable features.

This spreadsheet is a compilation of thermal well features and temperature observations compiled by the Utah Geological Survey, published as a Web feature service for the National Geothermal Data System. The document contains 7 worksheets, including information about the template, notes related to revisions of the template, Resource provider information, the data, a field list (data mapping view), a key for UT abbreviations and a worksheet with vocabularies for use in populating the spreadsheet (data valid terms). Data from 846 wells are included. Fields in the data table include ObservationURI, WellName, APINo, HeaderURI, OtherID, OtherName, BoreholeName, Operator, LeaseOwner, LeaseNo, SpudDate, EndedDrillingDate, WellType, Status, CommodityOfInterest, StatusDate, Function, Production, Field, County, State, PLSS_Meridians, TWP, RGE, Section, SectionPart, Parcel, UTM_E, UTM_N, UTMDatumZone, LatDegree, LongDegree, SRS, LocationUncertaintyStatement, DrillerTotalDepth, DepthReferencePoint, Shape, TrueVerticalDepth, LengthUnits, ElevationKB, ElevationDF, ElevationGL, BitDiameterCollar, BitDiameterTD, DiameterUnits, Notes, MaximumRecordedTemperature, MeasuredTemperature, CorrectedTemperature, TemperatureUnits, TimeSinceCirculation, MeasurementProcedure, CorrectionType, DepthOfMeasurement, MeasurementDateTime, MeasurementFormation, MeasurementSource, CasingLogger, CasingDepthDriller, CasingPipeDiameter, CasingWeight, CasingWeightUnits, CasingThickness, InformationSource, DrillingFluid, Salinity, MudResisitivity, Density, FluidLevel, pH, Viscosity, FluidLoss and MeasurementNotes.

The purpose of this study was to verify quantitatively and to refine the conceptual hydrogeological model of the Mofete Geothermal field near Naples, Italy, using a numerical simulator. A three-dimensional, two-phase numerical simulation model of the reservoir was developed based on the conceptual model and the interpretation of the long-term interference test data. The measured temperature distribution was matched, by trial and error, with the temperature distribution calculated by the model after a simulated geological time, without any production, thus validating the conceptual model. The locations and extent of recharge and discharge and the permeability distribution were the main fitting parameters. The numerical modeling of the initial state helped refine the conceptual model by indicating that: (a) there is very little communication between the layers; (b) fluid flows from NE to S through the system in. the 275 to 850 m level; and (c) the heat source underneath the field is of a limited areal extent.

An industry-DOE cost-shared project is underway to evaluate the technical feasibility of developing an EGS power generation project on the eastern side of the Desert Peak geothermal field. Analysis of existing geological and geophysical data is complemented by new geologic mapping and gravity work in the Hot Springs Mountains undertaken by researchers with funding from the Great Basin Center for Geothermal Energy at the University of Nevada Reno (UNR). An existing well (DP 23-1) is the focus of much of the Phase I investigation, including re-interpretation of lithology, acquisition and analysis of a well bore imaging log, and conducting and analyzing a step-rate injection test. As of June 2003, the project is about half complete; results are summarized below. Phase I work remaining to modeling, numerical modeling and the development of a be completed includes conceptual detailed plan to guide upcoming field activities.