This is a continuation of the rare earth element sorption study for shaker bath tests on 2g media #1 in 150mL brine #1 with different starting pH's at 70C. In a previous submission we reported data for shaker bath tests for brine #1 with starting pH's of 3.5, 4.5 and 5.5. In this submission we these pH's compared to starting brine #1 pH's of 6, and 7. This pdf is a sorption study that shows the percentages of REE's (-50 100 media 1) removed from solution at different starting brine #1 pH's. In a previous submission we showed the comparison of REE's removed from solution at starting brine #1 pH's of 3.5, 4.5, and 5.5. In this submission we will compare those results with the results of brines with starting pH's of 6 and 7.
Groundwater flow model for West Maui. Data is from the following sources:
* Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014.
* Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume V – Island of Maui Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008. Groundwater flow model for West Maui. Data is in Excel format.
Rifts mapped through reviewing the location of dikes and vents on the USGS 2007 Geologic Map of the State of Hawaii, as well as our assessment of topography, and, to a small extent, gravity data. Data is in shapefile format. Hawaii rifts shapefile spatial index file
This is a continuation of the rare earth element sorption study for shaker bath tests on 2g media #1 in 150mL brine #1 with different starting pH's at 70C. In a previous submission we reported data for shaker bath tests for brine #1 with starting pH's of 3.5, 4.5 and 5.5. In this submission we these pH's compared to starting brine #1 pH's of 6, and 7. This is the raw data set for a shaker bath test with 2g of -50 +100 media #1 in 150mL of brine #1 with a starting pH of 6 and 7 shaking for 90 minutes. The concentration of REE's was 2ppm each of the REE7 metals.
geothermal reservoirs due to their high permeability compared to the surrounding rock matrix. The challenge in simulation of fractured reservoirs is to efficiently determine the grid based effective permeability tensor distribution. One of the powerful techniques presented to date to simulate fluid flow is the discrete fracture model. In this approach fluid flow is simulated through individual fractures, however, an enormous amount of computation time and resources are needed to solve flow equations for medium to high fracture density reservoirs. In this paper a numerical model to calculate grid based effective permeability for randomly oriented discrete fractured networks using boundary element method is presented. Laplace and Poisson equations are used for calculationof effective permeability tensor for each grid block efficiently. An innovative laboratory procedure was used to verify the numerically derived grid based effective permebaility. Glass bead models with very low matrix permeability and containing single and multiple interconnected fractures are constructed for this purpose. Displacement tests are carried out for single phase flow. Finally the grid based effective permeability tensor model is used to develop a k-tensor map for soultz geothermal reservoir. A range of pressure and production data for a given well orientation (injection and production wells) is presented.
Based on a continuum description, the effects of permeability heterogeneity on steady state, countercurrent, vapor-liquid flow in porous media are analyzed. It is shown that the capillary heterogeneity induced acts as a body force, that enhances or diminishes gravity effects on heat pipes. Selection rules that determine the particular steady states reached in homogeneous, gravity-driven heat pipes are formulated. It is shown that the iinfinitei two-phase zone terminates only if a substantial change in permeability occurs somewhere in the medium. The two possible sequences that result, namely liquid - liquid dominated - dry or liquid - vapor dominated - dry find applications in geothermal systems. Finally, it is shown that weak heterogeneity affects only gravity-driven flows, but stronger variations in permeability give rise to significant capillary effects.
A summary of ongoing geothermal projects and heat production from heat pumps is presented. The Lund project is still the largest geothermal plant in Sweden producing about 250 GWh/year and has been doing so for 25 years, Bjelm and Alm (2010). Utilization of heat pumps is by far the most common way of using geothermal energy in Sweden, Figure 1. With bedrock-soil- water source heat pumps about 12 TWh heat energy is extracted or about 15 % of the national heat demand is covered this way making Sweden a leading nation in heat pump based geothermal utilisation. The majority of the heat pumps are small and typically used in single houses, Nowacki (2007) and Lund, Bjelm and Bloomquist (2008).
Fracture stimulation (also known as hydraulic stimulation) involves pumping water at high pressure into a well, which causes fracturing of the rock. This additional fracturing enhances the permeability of the hot dry rock in order to create an efficient hydraulic loop for the purposes of harnessing geothermal energy. The process of fracturing the rock can also give rise to seismicity events that is, it can induce small earthquakes which have the potential to damage property and infrastructure not only within the exploration licence area but also on adjacent land and further afield.
A threshold issue in the development of geothermal heat supply systems is whether the system can penetrate existing utility monopoly service areas. The question is applicable to both single and multiple user/district heating systems and arises vis a vis competition with both private and public utilities. Special concerns related to the antitrust immunity of local governments are generated where the invaded utility is publicly owned. Reference to legal decisions in the natural gas arena is illustrative of the issue. Several state have addressed the problem with legislation.
Most recent interest in the injection of cold water into a geothermal reservoir has been related to the disposal of geothermal brines. Injection also offers the potential benefit of prolonging the useful life of a vapor-dominated system by providing additional water to extract energy out of the rock matrix. In a liquid-dominated reservoir injection may help to maintain pressures near the production wells by pushing the hot water toward them and preventing too much local boiling. Pressure maintenance can also be achieved for superheated steam zones, because injection will cause pressures to increase towards the saturation pressure (Schroeder et al. (1980)). The general physical principles governing these processes are understood but no quantitative informat ion is available. The present work is aimed at helping to improve the qualitative and quantitative understanding of injection into a geothermal reservoir by considering a few idealized problems. First a vapor-dominated, single layer reservoir is considered, next a vapor-dominated, four layer reservoir, and finally a liquid-dominated, single layer reservoir. In each case varying injection rates are considered and in some cases the injection is changed at different times. The SHAFT79 simulator ( see Pruess and Schroeder (1979) for example) is used to calculate there servoir behavior in each case. It is only with the advent of efficient geothermal reservoir simulators, such as SHAFT79 and other codes ( fee Coats (1977), Faust and Mercer (1979) and Brownell et al. (1975), for example), that it is possible to calculate the behavior of a two-phase reservoir during injection. The condensation of steam and the movement of thermal and hydrodynamic fronts through the reservoir as a cold zone around an injection well expands are severe tests of the capabilities of a simulator and are very difficult phenomena to model accurately. Previous work by the authors (0i Sullivan and Pruess (1980), Schroeder et al. (1980)) has demonstrated the accuracy of SHAFT79 in modeling injection problems.
The well casings (most of which are of carbon steel) of geothermal plants exploiting the Dogger aquifer in the Paris Basin experience problems of corrosion and scaling related to the of the geothermal fluid and to the precipitation of iron sulphides, mainly as mackinawite A chemical code, MODEP, using a predetermined uniform corrosion rate and a simulation of scaling on the casing wall is proposed. Calculations based on mass conservation and mass balance enable us to: calculate the distribution of dissolved or degassed chemical species in the fluid as a function of temperature and pressure; (ii) calculate the saturation indexes of the fluid with respect to the various minerals; evaluate the excess of ferrous iron precipitated as mackinawite and (iv) calculate the new diameter of the casing. The basic data necessary for this model is the borehole fluid chemical composition. Two methods were used to sample the fluid: sampling with an inert bottom sampler and at the wellhead with a special composite tubing. Dissolved iron and total sulphide, measured in the production wellhead and calculated by MODEP are in a good agreement. This work continues in order to study diffusion phenomena and concentration gradients near the well wall and to improve knowledge of iron sulphide precipitation kinetics.
Ocean Ridges are areas with extremely high heat flow, where temperatures above 300 C can be reached at shallow depths. These high temperatures make them a good target for exploitation of geothermal energy. Therefore, innovating designs to generate electricity installing a little submarine on top of the vent with a binary cycle plant have been developed as part of the activities of the IMPULSA project of the Universidad Nacional Autonoma de Mexico (UNAM), which is focused on the utilization of renewable energy sources for desalination of seawater. Here, we present the results generated by the project for the exploitation of submarine vents and describe the designs that include calculations of the efficiency of every component.The plants were designed based on typical values of the vent parameters, and a rough calculation is made about the electricity that could be generated from this renewable resource. The importance of the vents from the ecological and biological point of view restricts the amount of areas that could be used to generate electricity without any drilling, and it is considered that only 1% of the already known sites might be exploited. Under those conservative assumptions, some 130 000 MW of electricity could be generated. That is almost the same amount of geothermal power that could be generated inland with all the actual and new techniques to generate electricity. We conclude that prototypes must be tested and exploration of suitable sites must be performed for future electricity generation from hydrothermal vents. One important result, obtained with this research, is that from one hydrothermal vent, up to 20 MW of electricity can be produced with a simple method that does not affect the ecosystem.
Continental rifts form mainly as half grabens with a border fault system down one side. Heat flow is highest in the centre of the half graben, but deep recharge is likely to be mainly associated with the border fault system. A volcanic centre must therefore form on the edge of the half graben or crosscutting permeable structures must exist for a significant geothermal system to form. Alternatively where there is permeability in pre-rift rocks, a geothermal system may form where they intersect the border fault system. Cross cutting structures can form in rifts where there has been a change in tectonic forces. This is the case in the East Africa rift where basement faults have been reactivated as NW strike slip faults which have produced associated tensional features. Where there is permeability in pre-rift rocks, permeable targets at depth are where the pre-rift permeable feature intersects the border fault system. Where there are strike slip faults, the associated tensional features are the targets at depth, otherwise normal faults parallel to the rift are the main target.
The modeling of the geothermal well reservoir system and plant design makes it necessary to use the thermodynamic properties of the geothermal fluids. Such properties for salt solutions may be found in tabular form. The increasing use of computers for the prediction of the state of the fluid at the wellhead requires the use of simpler and accurate functional expressions for the properties of the salt solutions. For that matter, correlations of density, enthalpy, entropy and viscosity were established in a simpler form and of tolerable accurate (3%) for both the liquid and vapor phase of the brines. Expressions for the elevation of boiling point are derive and the influence of non-condensable gases on the properties is also discussed.