Inorganic Scaling and Geochemical Formation Damage 357 (text continued from page 351) + lH 2 O<r*2Al(OH)~ 4 +2H 2 SiO 4 +2H + (13-48) A comparison of Figures 13-12A and B reveals that the Canyon Reef water is compatible with the JMU connate water with respect to kaolinite, whereas the Mule Shoe water becomes incompatible upon large volumes of water injection into the reservoir. Saturation Index Charts for Carbonates and Sulfates Using the SOLMINEQ.88 program, Schneider (1997) generated the saturation index curves for the mixing of waters for calcite, CaCO 3 , magnesite, MgCO 3 , dolomite, CaMg(CO 3 ) 2 , witherite, BaCO 3 , strontianite, SrCO 3 , anhydrite, CaSO 4 , gypsum, CaSO 4 -2H 2 O, barite, BaSO 4 , and celestine, SrSO 4 given in Figures 13-13 through 16, respectively. Figures 13-13A and B show the barite saturation index charts for mixing the JMU connate water with the Mule Shoe Ranch and Canyon Reef waters, respectively. It is apparent that mixing sufficient volumes of the Mule Shoe Ranch water with the JMU connate water will induce barite pre- cipitation. But, the mixtures of the Canyon Reef and JMU connate waters will not lead to any precipitation. Figures 13-14A and B show the celestine saturation index charts for mixing the JMU connate water with the Mule Shoe Ranch and Canyon Reef waters. Figure 13-14A shows that around 80% volume Mule Shoe Ranch water content, the water mixture is nearly saturated with celestine. However, the mixtures of the Canyon Reef and the JMU connate waters do not yield any precipitation. As indicated by the water analysis presented in Table 13-1, the JMU connate water is undersaturated by anhydrite and gypsum. Therefore, the saturation index charts shown in Figures 13-15A and B indicate no possibility of anhydrite or gypsum precipitation as a result of mixing JMU connate water with any portions of the Canyon Reef water. The water analysis given in Table 13-1 indicate that the JMU connate water is supersaturated by calcite and dolomite and undersaturated by witherite. Consequently, as indicated by Figures 13-16A, B, and C, mixing of this water with any portions of the Mule Shoe Ranch and Canyon Reef waters will not result in appreciable calcite and dolomite dissolution and any witherite precipitation. (text continued on page 362) 358 Reservoir Formation Damage a « £ 4 =. ? 2 J Z tf°« •o JE 9 o l + - « C «o •* 0 Barite Saturation in JMU Reservoir Mute S/ioe Water Infiltration (8.4 pH) SI > 0: Supersaturated „„. !•! ^— g SI < 0: Undersaturated _ ___ _ ^ ^ 1 i ^ ^_ __ ^ 20 40 60 80 Water Infiltration, % ~i «. 10 > 10 c, Log (lAP/Ksp) o M *. at I -2 1-* i.6 Barite Saturation in JMU Reservoir Infiltration by Amoco SWD #20 Water ! I ! ! ~* ~~~ "~ " "f -\ j _j I ! . _. . ._. _ |8t *-flfc Si JStt< Oft U^ j tpersaturatect ! rdereaturated | i i . i | t^ n I.I. « 6 0 20 40 60 80 Water Infiltration, % > 100 B Figure 13-13. Barite saturation for mixtures of connate and invasion waters (after Schneider, ©1997; reprinted by permission of G. W. Schneider). Inorganic Scaling and Geochemical Formation Damage 359 ? 6 | * A 9 O 9 -J * f o 9 o 2 A $•* 1.6 W 0 SrSO4 Saturation in JMU Reservoir Mule Shoe Water Infiltration (8.4 pH) i i SI > 0: Oversaturated 1 r * * SI < 0; Undereaturated — ._ ._„ . .^ . . ,.+. i i i if 20 40 60 80 Water Infiltration, % ^^>j 10 [ 0 B SrSO4 Saturation in JMU Reservoir Infiltration by Amoco SWD #28 Water 0) 40 60 Water Infiltration, % 60 100 Figure 13-14. Celestine saturation for mixtures of connate and invasion waters (after Schneider, ©1997; reprinted by permission of G. W. Schneider). 360 Reservoir Formation Damage B T? ft 4 W | 4 O> 9 I 2 It 1 c-2' I"* CO 0 "5? fi ^ £ A . D 9 , 5 2 2 I-2j mt JL , m o Anyhydrite Saturation in JMU Reservoir Infiltration by Amoco SWD #28 Water I _} SI > Q: SMpersaturated | 1 SI < 0: Undersaturatecl i j i 20 40 60 80 Water Infiltration, % Gypsum Saturation in JMU Reservoir Inmnrtton by Amoco SWD #28 Water ! ! i i SI > 0: Supersaturated i 1 ! 1" i ! j JBBIHII.J. _ . _. ™-4 ^.^ .{ f ._ SI < Qi UiJKij^iptgltyt^t'Mi ; 1 i ^ „ 1 ! 1 ! 20 40 60 80 Water Infiltration, % 10 •3MMB 1C 1 0 , 0 Figure 13-15. Saturation of various sulfate minerals for mixtures of connate and invasion waters (after Schneider, ©1997; reprinted by permission of G. W. Schneider). Inorganic Scaling and Geochemical Formation Damage 361 B Calcite Saturation in JMU Reservoir Intttaatton by Amoco SWD #28 Water p) (ft Log( i SI > Q: Supersaturated >: Uodersaturated 20 40 60 Water Infiltration, % 80 100 Dolomite Saturation in JMU Reservoir /nffittratfon toy Amoco SWD #28 Water a 6 40 60 Wftter Infiltration, % 100 BaCOS Saturation in JMU Reservoir InOtnOon by Amoco SWD #28 Water § 4 I 2 SJ<0: Ufderwturated , 20 40 60 Water Infiltration, % 80 100 Figure 13-16. Saturation of various carbonate minerals for mixtures of connate and invasion waters (after Schneider, ©1997; reprinted by permission of G. W. Schneider). 362 Reservoir Formation Damage f text continued from page 357) Activity-Activity Charts Schneider (1997) equilibrated the activities of the five connate water compositions given in Table 13-1 to the 135°F temperature of the Jo Mill Unit reservoir using the SOLMINEQ.88 program. He then plotted these activity values on the activity-activity charts. As can be seen in Fig- ures 13-17 through 13-20, all points appear inside the mineral stability fields of the types of clay minerals present in the sandstone formation of the Jo Mill Unit reservoir. Hence, this confirmed the validity of the geo-chemical model and the accuracy of the mineral stability field charts generated by the SOLMINEQ.88 program. Schneider (1997) explains that the formula (13-49) of the Rotliegendes illite is somewhat similar to the formula KA1 2 (AlSi 3 ]O lo (OH) 2 of the muscovite, which is an end-member com- position illite. Because the JMU reservoir contains a high amount of illite (6-10 volume %), the JMU reservoir connate water compositions should appear within the muscovite stability region as indicated by Figure 13-17 by Schneider (1997). Schneider (1997) constructed the illite-chlorite mineral stability charts shown in Figure 13-18 based on the following illite to chlorite incon- gruent reactions using the proper stoichiometric coefficients according to the compositional formulae of the illites and chlorites mentioned above: Illite + Mg +2 + Fe +2 + H 2 O <-> Chlorite (13-50) Again, as indicated by the mineral stability charts shown in Figure 13- 18 by Schneider (1997), all the JMU reservoir connate water composition appear inside the mineral stability regions of the illites. Schneider (1997) constructed the illite-kaolinite mineral stability charts shown in Figure 13-19 based on the following illite to kaolinite incongruent reactions using a proper set of stochiometric coefficients according to the compositional formulae of the illites and kaolinites considered for the study: Illite + H + + H 2 O o Al 2 Si 2 O 5 (OH) 4 + + Mg +2 + Fe +2 + H 4 Si0 4 (13-51) Inorganic Scaling and Geochemical Formation Damage 363 JMU Connate Water Compositions -4 -3 Log {H4SIO4} -2 -1 Figure 13-17. Stability chart for aluminosilicate minerals (after Schneider, ©1997; reprinted by permission of G. W. Schneider). Because of the existence of a large quantity of illite (6-10 volume %) and a negligible amount of kaolinite in the JMU sandstone reservoir formations, all the JMU connate waters appear inside the illite stability region. Schneider (1997) constructed the chlorite-kaolinite mineral stability charts shown in Figure 13-20 based on the following chlorite to kaolinite incongruent reactions using the proper set of stoichiometric coefficients according to the compositional formulae of the chlorites considered for the study Chlorite + H + + H 4 SiO 4 <-» Al 2 Si 2 O 5 (OH} 4 + Mg +2 + Fe +2 + H 2 O (13-52) Because of a relatively larger quantity of the chlorite (1-2 volume %) compared to the negligible amount of kaolinite present in the JMU sandstone formation, all the JMU connate waters appear inside the chlorite stability region. (text continued on page 367) 364 Reservoir Formation Damage B I -70 40 -50 Log {H4Si04}*1.37x{H+}*6.46 -40 40-50-40 Log {H4SKM}*1.0857x{H+}*«.3428 40 -60 -40 Log {H4SK34}*.«8S7x{H+}»6.»4» Figure 13-18. Illite-chlorite mineral stability chart (after Schneider, ©1997; reprinted by permission of G. W. Schneider). Inorganic Scaling and Geochemical Formation Damage 365 B -6-4-20 Log {H4SKM}M X {H+}*8.8 4-4-20 Log ({H+}*1.2 / {H4SJO4}) -12.6 •10 -7.6 -6 Log ({H+}*1.6) / ({H4SK34} A .9) -2.6 Figure 13-19. Illite-kaolinite mineral stability chart (after Schneider, ©1997; reprinted by permission of G. W. Schneider). 366 Reservoir Formation Damage B •10 f-20 '•40 -60 JMU Connate Water Compositions QUtF COAST CHLQRIfrE -90 -40 -80 -80 -70 -60 Log {H4Si04}\2 X {H+} A 9.2 -50 JMU Connate Water Compositions •70 -60 Log {H4St04}M X Figure 13-20. Chlorite-kaolinite mineral stability chart (after Schneider, ©1997; reprinted by permission of G. W. Schneider). [...]... +, £? _ /—s t> & +2 ( 1 1 f*'l\ \*"J—\jj) Fe2O3+6H+ (13 -64 ) +6H+ + 2e~ 2Fe +2 + 3H2O (13 -65 ) Fe2O3+2HCO3+4H++2e (13 -66 ) FeCO3 +H+ Fe +2 + HCO3 (13 -67 ) + 5H+ + 2e~ ^ 3FeCO3 + 4H2O + 2e~ 3Fe +2 + 4H2O 3Fe2O3 + 2H+ + 2e~ 2Fe3O4 + H2O (13 -68 ) (13 -69 ) (13-70) from which he wrote the following pe - pH relationships: \og{Fe +2} -3pH (13-71) (13- 72) (13-73) 370 Reservoir Formation Damage Schneider... and Geochemical Formation Damage 371 pe-pH DIAGRAM: Sulfate and Sulfide Species 20 U Jo M/// i/iitf Reservoir Temperature 16 O2 fugacity > 1 12 8 SO4 ( -2) • 0 -4 -8 - 12 20 JMU Connate Water Compositions I H2 fugacity > 1 S (c) H2S (aq) -H— 6 PH 10 pe - pH DIAGRAM: Pyrite-Hematite Stability Fields JMU Reservoir Temperature I O2 fugacity > 1 Fe2O3 B Figure 13 -22 pe - pH chart for Fe - O - H2O - S system... system (after Schneider, ©1997; reprinted by permission of G W Schneider) 3 72 Reservoir Formation Damage f + Fe +2 + 16H+ + Ue~ t=> FeS2 + 8/ /20 Fe^O3 2 + 38/T + 30e~ & 2FeS- + 19HQ + 6H+ + 2e~ d 2Fe +2 + 3/ /20 (13-80) (13-81) (13- 82) from which he wrote the following relationships pe = ^ log Keq + i log [SO? } + ± log [Fe +2 }-*pH 2 pe = — log /Teq + — logl{SO:;}- — pH 30 30 30 (13-83) (13-84) These equations... Geochemical Formation Damage 367 (text continued from page 3 62 ) pe - pH Charts Aqueous Species of the Fe - O - H2O System Schneider (1997) constructed the pe - pH charts for the aqueous species involving the following half-reactions of the Fe-O-H2O system: Fe+3 + e~ Fe +2 Fe(OH}3 + 3H+ (13-53) + 3H2O (13-54) Fe (OH\ + 3H+ + e~ Fe +2 + 3H2O (13-55) FeOH+ + H+ Fe +2 + H2O (13- 56) FeOH+ + 2H2O ... oxygenated waters at the JMU reservoir temperature as shown in Figure 13 -23 , based on the stability boundaries developed for the reduction of oxygen according to the following reactions given by Drever (1988): + 2H+ + 2e HO 2 + 2H+ + 2e 2 (13-85) H2O2 2HO (13- 86) Figure 13 -23 shows the range of the pe values for the oxygenated waters at the JMU reservoir temperature References Aja, S U., Rosenberg, P E., & Kittrick,... September 26 -29 , 19 82 Shaughnessy, C M., & Kline, W E., "EDTA Removes Formation Damage at Prudhoe Bay," Journal of Petroleum Technology, October 1983, pp 1783-17 92 Steefel, C I., & Lasaga, A C., "Evolution of Dissolution PatternsPermeability Change Due to Coupled Flow and Reaction," Chemical Modeling of Aqueous Systems II, Chapter 16, pp 21 2 -22 5, D.C Melchior & R L Basset (Eds.), ACS Symposium Series 4 16, ... F., "Modeling of Formation Damage due to Physical and Chemical Interactions between Fluids and Reservoir Rocks," SPE 22 8 56 paper, Proceedings of the 66 th Annual Technical Conference and Exhibition of the Society of Petroleum Engineers, October 6- 9, 1991, Dallas, Texas Chang, F F., & Civan, F., "Predictability of Formation Damage by Modeling Chemical and Mechanical Processes," SPE 23 793 paper, Proceedings... Processes," SPE 23 793 paper, Proceedings of the SPE International Symposium on Formation Damage Control, February 26 -27 , 19 92, Lafayette, Louisiana, pp 29 3-3 12 Chang, F F., & Civan, F., "Practical Model for Chemically Induced Formation Damage, " Journal of Petroleum Science and Engineering, Vol 17, No 1 /2, February 1997, pp 123 -137 Curtis, C D., Ireland, B J., Whiteman, J A., Mulvaney, R., & Whittle,... 181-1 96 Liu, X., & Ortoleva, P., "A Coupled Reaction and Transport Model for Assessing the Injection, Migration, and Fate of Waste Fluids," SPE 366 40 paper, Proceedings of the 19 96 SPE Annual Technical Conference and Exhibition, Denver, Colorado, October 6- 9, 19 96, pp 66 1 -67 3 Liu, X., & Ortoleva, P., "A General-Purpose, Geochemical Reservoir Simulator," SPE 367 00 paper, Proceedings of the 19 96 SPE... 2H2O Fe(OH)3 + 2H+ + e~ (13-57) for which he wrote the following pe - pH relationships: pe = log KeQ - log (13-58) (13-59) pe= log Keq - log{Fe + 2 }- 3pH pH = log K pe= - log {FeOH+} -\ogKeq-2pH-\og{FeOH+} (13 -60 ) (13 -61 ) (13- 62 ) Schneider (1997) then applied the SOLMINEQ.88 program and constructed the charts shown in Figure 13 -21 A by plotting Eqs 13-58 368 Reservoir Formation Damage pe - pH DIAGRAM: . *"J—jj) Fe 2 O 3 +6H + +6H + + 2e~ <=>2Fe +2 + 3H 2 O Fe 2 O 3 +2HCO 3 +4H + +2e FeCO 3 +H + <=> Fe +2 + HCO 3 + 5H + + 2e~ ^ 3FeCO 3 + 4H 2 O + 2e~ <=> 3Fe +2 . Schneider). 3 72 Reservoir Formation Damage f + Fe +2 + 16H + + Ue~ t=> FeS 2 + 8// 2 0 Fe^O 23 + 38/T + 30e~ & 2FeS- + 19HQ + 6H + + 2e~ d 2Fe +2 + 3// 2 0 from . Scaling and Geochemical Formation Damage 365 B -6- 4 -20 Log {H4SKM}M X {H+}*8.8 4-4 -20 Log ({H+}*1 .2 / {H4SJO4}) - 12. 6 •10 -7 .6 -6 Log ({H+}*1 .6) / ({H4SK34} A .9) -2. 6 Figure 13-19. Illite-kaolinite