Kirkoff Xn

Hi there I am trying to redo the alkali flooding simulation on page range 443-447 in Geochemical and Biogeochemical Reaction modeling book. Is the volume change on Y axis (Fig. 30.4) expressed as "delta"? If yes, I have a couple of questions on values found in Table 30.2 Consider NaOH flood, how did you calculate the change in pore volume (delta % and Alkali consumed (%)? Thanks

Hi Jia I don't know if I misunderstood what's offered in GWB online academy https://academy.gwb.com/mixing_and_scaling.php Here's what's said about proportions "The horizontal axis shows the extent of mixing from purely the first fluid (seawater, on the left) to purely the second (brine, on the right); a mixing value of 0.4, for example, represents a mixture of 60% of the first fluid and 40% of the second." The first fluid is the reactant and the 2nd is in the basis pane...It looks like what you wrote is the reverse of what's written from the GWB online academy. Can you further explain this? And the Cl- concentration in fluid component looks not "geochemically sound"...I don't know if the flash scenario is the appropriate one...but that's what I think! Thank you

Hi When modeling injection of fluid A (oxidizing) into an aquifer having fluid B using flash model, I am a bit confused seeing the results yielded. The native groundwater has high TDS while the injectate is a freshwater. When plotting mineral saturation versus mixing ratio, there is a pattern of mineral saturation decrease with calcite dissolution (more likely)[I assume it's quite sound geochemically]. However, when plotting components in fluids that would define mineral stability being seen, I find some inconsistency. I have high Cl- concentration at 0% mixing fraction, implying that Cl- concentration is higher in the injectate water than in the native groundwater—which is not the case! Part of what I am trying to demonstrate is how groundwater get refreshed, and the hydrochemical facies evolution being seen in piper diagram can be backed up by the mixing using "flash model". Also, evaporites (gypsum and anhydrite) are more likely to increase with mixing ratio since the mixing ratio increases towards the native groundwater. In GSS file, It is possible to know the saturation index of minerals and these two minerals have high SI in the native groundwater than in the surface freshwater. Also, if I mix 50% fluid A with 50% fluid B in GSS (analysis > mix sample >mix by volume), I am wondering if the results yielded is the same as at 0.5 mixing fraction in react. Attached, you'll find both the GSS & react files. Thank you

After several tries , I found that reaction progress of 0 to 80% matches the time series data of all cations and anions. Now my question: I have time series of Ca, Mg, HCO3...concentrations varying with time...while in react, the simulation the reaction progress of one fluid mixing with another...while this reaction progress intuitively can translate into time, is it really "geochemically" sound to compare both data?

For more information on this, please refer to..., what's the reference? Sorry for the question.. I see where I made a mistake. I put the unit of mass reacted in mol instead of kg; and you are right on the constraints I did make! My main question is to what extent mixing both fluids would precipitate minerals....Is the pattern I am seeing on the time series species data controlled by simple mixing (dilution?) or also precipitation..and to what extend the precipitation starts to impact the concentration in the mixed aqueous fluid... Dolomite would be more likely in equilibrium with the native groundwater. If I mix for example 70% surface water with 30% native groundwater, where can I see the end result of different constituents in the mixed surface water-groundwater (other than plotting them? Is it on "view results" Step #100 , aqueous species? And If I want to simulate freshening of groundwater around the ASR well, I think the proper process should start with surface water composition(injectate)..basis..run> pick up >reactant...reactant times..70 times(to mimic high % surface water mixing or flashed into the native water in the vicinity of the well)... For example, I simulate mixing of 70% surface freshwater with 30% native groundwater, taking into account your recommendation(check precipitation). Y is in log..see the snapshot below. From the figure below, anhydrite and gypsum tend to dissolve more than calcite and dolomite, dolomite being the most stable(in equilibrium with the mixed fluid)...does it mean that the dissolution of both minerals(anhydrite and gypsum) and calcite is the main controlling factor of the mixing process? It is also possible that dolomite precipitated as I checked precipitation..how can I get the estimate of the dolomite that has precipitated? And if I add minerals, there are two carbonates, calcite and dolomite,...I can swap Ca2+ with Calcite...what about dolomite? can I swap HCO3- with dolomite?

I am working on data from monitoring well on an Aquifer storage and recovery project. With injection of surface water, there is a trend in freshening of the native "brackish" groundwater based on TDS values. I am wondering whether the geochemical evolution of hydrochemical facies result from simple mixing or from dissolution/precipitation of aquifer minerals. I did try to work with React by mixing both fluids ,with the surface water being the reactant and trace the evolution of mineral saturation versus mass of freshwater that is being flashed into the aquifer. It a two-layered aquifer separated by an unconfined layer(~semi confining layer). I did mixed fresh surface water with native groundwater from both aquifers(upper and lower aquifer layers). I have got different results based on mineral saturation vs Mass reacted H2O.My question is why it takes much water injected to the lower aquifer than the upper aquifer? As gypsum and anhydrite are undersaturated from Mass reacted 0(zero) does it mean that the lower decreased trend results from mixing(~dilution?). Thanks

If surface water is injected into an aquifer with a known composition (which may change with injection time) and at X distance from the injection well, groundwater data (considered a mixed surface water-native groundwater) is collected every day from a monitoring well. How is it possible to infer/know mineralogical assemblages of the aquifer that are dissolved or precipitated based on the time series of groundwater data collected from the monitoring well? Aquifer type: Carbonates with small amount of evaporites. Thanks