Geothermal Fluids: Chemistry and Exploration Techniques

ISBN-13: 9783642778469 / Angielski / Miękka / 2011 / 263 str.

Keith Nicholson

Opis

This book provides a comprehensive introduction to the chemistry of geothermal water and gas discharges, including the application of isotope studies, and assumes no prior knowledge of geothermal fluid chemistry. The critical interpretation of discharge chemistry in terms of resource evaluation and the development of hydrological models are emphasized. The text is divided into two parts: following an introduction to the genesis of geothermal fluids, the first part deals with water, gas and isotope chemistry. The chemical behaviour of common constituents and the interpretation of the chemical signature of the fluids are discussed, with stress placed on the evaluation of reservoir conditions and subsurface flow regimes. The second part describes techniques in geochemical exploration for geothermal resources. Individual chapters deal with the planning, execution and critical evaluation of water, gas and soil surveys. Analytical methods, units and data presentation techniques are also covered in this section. Both students and experienced geothermal scientists will find this book of value both as an introductory text to the application of geothermal chemistry, and as a reference handbook to geochemical techniques. Part Two will also be of interest to exploration and environmental geochemists in general, as the survey techniques detailed have applications beyond geothermal resource evaluation

Spis treści

I Geothermal Fluid Chemistry.- 1 Geothermal Systems.- 1.1 System Types and Characteristics.- Classification.- 1.2 Genesis of Geothermal Fluids.- Origin of water and solutes.- Evolution of geothermal fluids.- Evolution of steam: boiling point-depth relations.- Age of geothermal fluids and geothermal systems.- 1.3 Thermal, Hydrological and Chemical Structure.- Liquid-dominated systems.- Vapour-dominated systems.- 2 Water Chemistry.- 2.1 Water Types.- Chloride.- Sulphate.- Bicarbonate.- Sulphate-chloride.- Dilute chloride-(bicarbonate).- A diagnostic plot of water chemistry.- 2.2 Processes Affecting Water Composition.- Mineral-fluid equilibria.- Boiling (adiabatic) cooling.- Conductive cooling.- Mixing (dilution) with other waters.- 2.3 Interpretation of Water Chemistry.- pH.- Common solutes.- Chemical behaviour of common species.- Chemical indicators of physico-chemical processes.- Statistical analysis of water chemistry.- 2.4 Mixing Models.- Enthalpy — Chloride diagrams.- Enthalpy — silica diagrams.- Carbonate — silica/chloride.- 2.5 Solute Geothermometers.- Silica.- Na/K geothermometer.- Na-K-Ca geothermometer.- Na/Li geothermometer.- K/Mg and Li/Mg geothermometers.- Na-K-Mg geothermometer.- Ca/Mg gt; SO4/F geothermometers for carbonate reservoirs.- 2.6 Calculattng Reservoir Fluid Chemistry.- Heat and mass balance equation.- Steam fraction calculation.- Weirbox composition.- Reservoir fluid composition.- Total discharge (TD) composition.- Reservoir fluid pH.- 3 Gas Chemistry.- 3.1 Introduction.- 3.2 Discharge Features.- 3.3 Processes Affecting Steam Composition.- Geothermal system.- Solubility.- Steam formation.- Condensation.- Oxidation.- Rock-steam reactions.- Mineral equilibria and buffering.- Seismicity.- Contamination.- 3.4 Interpretation of Gas Chemistry.- Behaviour of common geothermal gases.- Indicators of physico-chemical processes.- 3.5 Gas Geothermometers.- CO2-H2S-H2-CH4 geothermometer (D’Amore gt; Panichi).- CO-based geothermometer.- CO2-geothermometer.- H2 Ar geothermometer.- gas/?water - based geothermometers.- 4 Isotope Chemistry.- 4.1 Introduction.- Notation.- Standards.- 4.2 Geothermal Applications of Isotopes.- Stable isotope.- Radioactive isotopes.- 4.3 Isotope Geothermometers.- Isotope geothermometry equations.- Oxygen isotope geothermometers.- Hydrogen isotope geothermometers.- Carbon isotope geothermometers.- Sulphur isotope geothermometer.- II Exploration Techniques gt; Surveys.- 5 Exploration Techniques.- 5.1 Introduction.- 5.2 Exploration Surveys.- Active systems.- Fossil/epithermal systems.- 6 Water Surveys.- 6.1 Pre-Field Laboratory Preparation.- Collection bottles.- Bottie cleaning.- Sampling equipment.- 6.2 Field Survey.- Mapping springs.- Field notes.- Field measurements.- Selection and prioritizing springs for sampling.- 6.3 Sampling Methods.- Springs and pools.- Wells.- Specialised sampling requirements.- Sample storage.- 6.4 Analytical Methods.- Aluminium.- Ammonia.- Arsenic.- Bicarbonate, Carbonate.- Boron.- Caesium.- Calcium.- Chloride.- Fluoride.- Hydrogen sulphide.- Iodide, Bromide.- Iron.- Lithium.- Magnesium.- Mercury.- pH.- Potassium.- Rubidium.- Silica.- Sodium.- Sulphate.- Total Dissolved Solids.- 6.5 Data Quality and Presentation.- Quality control checks.- Ionic balance.- Mass balance.- Units.- Tabulation of results.- 7 Gas Surveys.- 7.1 Pre-Field Laboratory Preparation.- Sample flasks.- Flask cleaning and preparation.- Sampling equipment.- 7.2 Field Survey.- Selection and prioritizing fumaroles for sampling.- 7.3 Sampling Methods.- Fumaroles.- Gas discharges from pools.- Wells.- General notes on sampling gases Sample storage.- Sample storage.- 7.4 Analytical Methods.- Gas chromatographic determinations.- Wet chemical determinations.- Calculation of gas in the total discharge (TDgas).- 7.5 Gas Concentration Units.- 8 Soil and Soil-Gas Surveys.- 8.1 Introduction.- 8.2 Survey Organisation.- Orientation survey.- Sampling grid.- 8.3 Soil Surveys.- Soil sampling.- Sample preparation.- Ammonia.- Antimony.- Arsenic.- Boron.- Mercury.- 8.4 Soil-Gas Surveys.- Soil-gas sampling.- Carbon dioxide.- Helium.- Mercury vapour.- Radon.- 8.5 Data Quality, Presentation and Interpretation.- Presentation methods.- Anomaly identification and interpretation.- Appendices.- 1. Steam tables.- 2. Atomic weights.- References.