LECTURES ON GEOCHEMICAL !N1 ERPRETATION OF ...
LECTURES ON GEOCHEMICAL !N1 ERPRETATION OF ... LECTURES ON GEOCHEMICAL !N1 ERPRETATION OF ...
- 14 -FIGURE 5. The computed activity p~oduct of ca++ and CO) in geotherma lwaters during single- step adiabatic flashing in relation to the calcitesolubility curve (thick solid line). The solid lines assume maximumdegassing and the dashed lines 1/5 of maximum degassing.(From Arnorsson, 1918).
- 15 -,pH8~ .....\ ........ -NamafjallReykholt - --pHHveragerdi6150 200 2506Reykjabol150 200 250 °c, ,pH,_~.Nesjaverlir~,,pHB\\6Leira150 200 250150 200 250 ° CFIGURE 6. The va~iation in pH in geothermal waters during single- stepadiabatic flashing in relation to the calcite solubility curve (thicksolid line). The solid lines assume maximum degassing and the dashedlines 1/5 of maximum degassing. (Redrawn from Arnorsson, 1978).SUKl1ARYIn most natural waters heating will cause calcite to precipi tat e~ andcooling without boiling will cause it to dissolve (Fig. 4). However, wherean ascending solution boils as a result of decompression (cooling adiabatically).carbonate is likely to precipitate as a result of the boiling(Fig. 5). The cooling that tends to move a solution toward a condition ofundersaturation with respect to calcite is generally more than offset bythe strong partitioning of C02 into the vapor phase (and concomitantdecrease in partial pressure of C02) that decreases the solubility ofcalcite. At present, calculations that take account of all the physicalprocesses (mainly boiling) and chemical reactions that i nfluence thetransport and deposition of carbonate minerals can be carried out onlywith the aid of sophisticated computer programs . However, if only themost abundant dissolved species in natural waters are considered, andsimplifying assumptions are made about enthalpies of coexisting liquidsand gases (mainly steam), hand-held. programmable calculators can be usedeffectively to calculate the approximate conditions for transport anddeposition of calcite in hydrothermal solutions.
- Page 1 and 2: ,. ,O~KUSTOFNUNNATIONAL ENER GY AUT
- Page 3 and 4: PREFACESince the foundation of the
- Page 5 and 6: P~eTHE SOLUBILITY OF SILICA IV HYDR
- Page 7: - 1 -CARBONATE TRANSPORT AND DEPOSI
- Page 10 and 11: - 4ca~bonic acid (Table 3). Equatio
- Page 12 and 13: - 6 -Values of y a~ewater and the r
- Page 14 and 15: - 8 -The s implest equation ~ep~ese
- Page 16 and 17: - 10 -c0"0"'0>,'"0>>-.- .D"0"'Q)Q'"
- Page 18 and 19: - 12 -The effect of partitioning of
- Page 22 and 23: - 16 -REFEREYCESA~o~sson.S .• 191
- Page 24 and 25: TABLE 2.Coefficients for use with e
- Page 26 and 27: - 20 -TABLE 4. Values of ionie cnar
- Page 28 and 29: - 22 -vapor pressure of pure water
- Page 30 and 31: - 24 -Figure 2 shows the solubility
- Page 32 and 33: - 26 -TABLE 2. Temperatures, enthal
- Page 34 and 35: - 28 -800600~ci>E 400NoVi200o 500 1
- Page 36 and 37: - 30 -800~ 600"- 0>E 400NoVi200o 50
- Page 38 and 39: - 32 -has an enthalpy L , and the r
- Page 40 and 41: - 34 -tempe~atu~e in kelvins. Molal
- Page 42 and 43: - 36 -SILICA SCALING POT ENTIAL AS
- Page 44 and 45: - 38 -and no silica scaling will oc
- Page 46 and 47: - 41 -CATION GEOTHERKOKETRYRobert O
- Page 48 and 49: - 43 -fo~ dilute solutions). Thus,
- Page 50 and 51: - 45 -3.002.50~ 2.00Q-;"1.50z~g-' 1
- Page 52 and 53: - 47 -whe~e ~ is 1/3 fo~ wate~s equ
- Page 54 and 55: - 49 -Kg concent~ations in geotherm
- Page 56 and 57: - 51 -Na/l00070IMMATURE WATERSK/l00
- Page 58 and 59: - 53 -CONCLUSIONSIn evaluating cati
- Page 60 and 61: 55CONVECTION AS A MECHANISM FOR TRA
- Page 62 and 63: 57and mainly wi thin interconnectin
- Page 64 and 65: 59During drilling, the mud weight r
- Page 66 and 67: 61TABLE 2. Calculation of specific
- Page 68 and 69: 63REFERENCESG~iffiths.R.W., 1981. L
- 15 -,pH8~ .....\ ........ -NamafjallReykholt - --pHHveragerdi6150 200 2506Reykjabol150 200 250 °c, ,pH,_~.Nesjaverlir~,,pHB\\6Leira150 200 250150 200 250 ° CFIGURE 6. The va~iation in pH in geothermal waters during single- stepadiabatic flashing in relation to the calcite solubility curve (thicksolid line). The solid lines assume maximum degassing and the dashedlines 1/5 of maximum degassing. (Redrawn from Arnorsson, 1978).SUKl1ARYIn most natural waters heating will cause calcite to precipi tat e~ andcooling without boiling will cause it to dissolve (Fig. 4). However, wherean ascending solution boils as a result of decompression (cooling adiabatically).carbonate is likely to precipitate as a result of the boiling(Fig. 5). The cooling that tends to move a solution toward a condition ofundersaturation with respect to calcite is generally more than offset bythe strong partitioning of C02 into the vapor phase (and concomitantdecrease in partial pressure of C02) that decreases the solubility ofcalcite. At present, calculations that take account of all the physicalprocesses (mainly boiling) and chemical reactions that i nfluence thetransport and deposition of carbonate minerals can be carried out onlywith the aid of sophisticated computer programs . However, if only themost abundant dissolved species in natural waters are considered, andsimplifying assumptions are made about enthalpies of coexisting liquidsand gases (mainly steam), hand-held. programmable calculators can be usedeffectively to calculate the approximate conditions for transport anddeposition of calcite in hydrothermal solutions.
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