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Abdulaziz

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About Abdulaziz

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  1. Hi Brian, thanks again for your feedback. I have fixed the specific surface area to be 50 cm2/g in the coming scripts. Also, I have changed the flow filed to potential drop miming the acidizing pressure drop instead of the specific discharge and set them into different intervals. in regard to the diffusion constant, you are right I changed the value of the diffusion constant ( related to porous medium ) from 9e-11 to 9e-6 and there is no much of a difference was noted. however, I have adjusted the mechanical dispersion and changed the dispersivity to 3 cm and I noted the ca++ curve was elongated a bit. please see Aziz Model_8 script. It matched CA++ concentration but not pH measurement. pH went from a value 7 to 3 and I count not control that. it's true during carbonate acidizing, the produced CO2 (bubbles ) will remain in solution. so I added CO2 fugacity in the initial pane and set a fixed fugacity path since the exchange is rapid in the Aziz Model_9 script. I am not sure if I need to add CO2 fugacity to the fluid pan as well. the result of Aziz Model_9 script is pretty much similar to Aziz Model_8 script. I have also set a kinetic gas transfer model in Aziz Model_12 script and the same result was observed as in Aziz Model_9 script. the limestone Carbonate is mainly composed of calcite (98.2%) and Montmorillonite (1.8 %). in summary, with and without adding CO2 fugacity effect, the below scripts are either matching Ca++ ion concentration ( Aziz Model_8 & Aziz Model_9 ) mainly when rate constant is around 5e-12 or pH measurement (Aziz Model_10 & 13) when the rate constant is around 5e-6 (where the lab pH measurement went from 7 to 6.4 ). I couldn’t match both Ca++ ion concentration and pH measurement in one script. Can you please advise how to !!! Thank you for your help and support. Best Regards, Abdulaziz Aziz Model_8.x1t Aziz Model_9.x1t Aziz Model_10.x1t Aziz Model_12.x1t Aziz Model_13.x1t
  2. Hi Brian, thanks for your feedback. Sorry for the misundersatanding, the core daimater is 2.5 cm (Cylindrical Carbonate rock (97% Calcite (CaCo3), daimeter 2.5 cm ,length 5 cm, rock weight ( 58 g), Porosity ( 16% ) , Permeability (9 md) , Bulk volume ( 25 cm3)). So, I adjusted the porosity multiplier A to be 0.3 in order to see changes in permeability ( not constant )throughout the core flooding test. As you mentioned earlier, permeability is not much effected since I am using a specific discharge. I am still trying to match Ca++ lab result (120 mg/l) and pH measurements, where I find it very difficult to match. please see attached Aziz Model_2 script. Thank you for your help and support. Best Regards, Abdulaziz Aziz Model_2.x1t
  3. Hi Brian , Thanks for your quick fruitful reply. I have checked and updated Aziz Model_1(file). My main goal is to estimate Damköhler and Péclet numbers for each acidic core flooding experiment, where the diffusion coefficient and reaction rate constant are needed to be estimated. Yes, the carbonate rock sample was saturated with fresh water for a day at maximum, then flooded with freshwater to measure the brine permeability using Darcy’s law, then flooded with diluted HCl ( pH =2). After the acidic flooding of HCl ( pH =2), pH value dropped from 7 to 6.4 through the whole experiment. Now, I hope my initial rock-fluid conditions are right. I have checked the specific discharge as advised in your previous comment ( flow rate (cm3/min) divided by cross-sectional area (cm2) , which is in my case : 7 (cm3/min ) / 5.22 (cm2) = 1.33 cm/min ~ 0.022 cm/s). also, I have adjusted the permeability to be 9 md , but it seems the permeability is constant along the whole interval time. In the reactants pane, calcite specific surface area is not provided in the database. I have looked in the literature (https://www.onepetro.org/conference-paper/SPE-21044-MS ) and found 0.49 m2/g is the specific surface for Indiana limestone using BET method. Shall I use this value for the calcite specific surface area or specific surface area should be estimated else way? I am trying to mimic the ICP Lab results of the produced Ca++ ions effluent (that (Ca++ ) concentration reaches a value of 120 mg/l in the first 5 minutes then stabilizes at 120 mg/l afterwards ) using Ca++ vs time xtplot. But it appears that the dissolution of Ca++ ions is quite immediate from the first 2 minutes reaches and stabilizes at a concentration of 300 mg/l. how can I delay or elongate the production of Ca++ ions linearly and what are the parameters that would allow me to adjust the curve of the produced Ca++ ion ( e.g. specific surface area , diffusion coefficient and reaction rate constant though both factors are competing in the dissolution process) . please see attached Aziz Model_1 script. Thank you for your help and support. Best Regards, Abdulaziz Aziz Model_1.x1t
  4. Hi Brain , Thanks for your feedback. I have thoroughly read GWB documentations (Essentials, React and x1t ) and forum questions, but I must be missing something. I am trying to reproduce acidic core flooding experiment of fresh water saturated carbonate rock using x1t to match the produced Ca++ ions (ICP ) and estimate diffusion coefficient and reaction rate constant. the chemical equation is as follows : CaCO3 + 2HCl ---> CaCl2 + CO2 + H2O Here are the summary info of the fluid -rock system and the core flooding experiments : Cylindrical Carbonate rock (97% Calcite (CaCo3), radius 2.5 cm ,length 5 cm, rock weight ( 58 g), Porosity ( 16% ) , Permeability (9 md) , Bulk volume ( 25 cm3) Carbonate rock was saturated and flooded with Fresh Water Then saturated carbonate rock was flooded with HCl as intel fluid ( pH=2) at injection rate ( 7 cm3/min) till wormhole channel was formed and pressure drop fall to near zero value. I have tried to mimic the fluid-rock properties into the model, but I am not sure. My concerns are the following : How can I add the rock mineral ( carbonate calcite (CaCo3) ) and at what units (97 vol% or 58g , 58g/kg ) to the fluid system?I tried 2 methods. Method 1 (Aziz Model file) : I added calcite in the kinetic reactant pane (meaning calcite is not in equilibrium with the fresh water ) , but I couldn’t add calcite in 58 g unit as its weighted (97% of core sample weight ) which will be reflected in calcite specific surface area . Method 2 (Calcite swapped with Ca++ file) : I swapped calcite with Ca++ ( stating equilibrium condition with fluid) in the initial fluid pane plus adding the calcite in the kinetic reactant pane, but calcite concertation appeared to start producing from 350 mg/l instead from 0 mg/l . Do I need to equilibrate the fluid and the rock in the initial pane ? I did try Calcite mineral swapped with Ca++ in the fluid pane with React script ( Ca++_3 file). Sometimes I get this Error: -- Error: Porosity of node 0 is too small: -0.269011 . I can’t change much in the domain pane that semi-represents cylindrical core sample ( dimensions ) . Any help with setting this up would be much appreciated. Please see attached files. Regards Abdulaziz Ca++_3.rea Aziz Model.x1t Calcite swapped with Ca++.x1t
  5. Hi Melika, Thanks for your reply. when I submitted my case in the forum, an error message appeared and I ended up submitting the question 4 times without knowing it was posted at the first attempt. sorry about that. I used X1t app to simulate the acidized core flooding experiments and match the laboratory ICP result. the chemical equation is as follows : CaCO3 + 2HCl ---> CaCl2 + CO2 + H2O my concerns are the followings : How precisely can I put the constraints on the initial system for the rock sample and the injected acid solution? I am a little bit confused about the input units ( mg/kg, free kg, mmol/kg, ..etc). I am only aware of the limestone rock sample weight ( 50 g) , porosity (22%) and the concentration of the injected acid (pH, wt% ). how would I put the value of the followings with their units: H2O .... free kg H+ ..... 4 (pH) .. for example ! Cl- ... Ca++ ( mineral or ... ) ... HCO3- .... do I need to equilibrate the fluid and the rock in the initial pane in constraints on the initial system, and if so, how would I equilibrate them? injection rate was 10 cm3/min. how would I mimic the laboratory injection rate within the X1t the discharge ( injection rate) unit (cm/s, cm3/cm2/s, ..etc)? The laboratory domain was a cylindrical core sample (2.5 cm in diameter ⨉ 5 cm long) , how would I simulate that domain in the model, I used a spherical domain with r1: 1.25 cm, r2: 1.26 cm and nodes (Nx) = 5, please advise the appropriate way. I have attached 2 different files. please advise which one of them i should be simulating my lab work with. Carbonate acdizing.x1t Aziz HCl.x1t
  6. Greetings all, I conducted HCl ( acid ) core flooding experiments at room temperature on cylindrical limestone rock samples (2.5 cm in diameter ⨉ 5 cm long) which are mainly composed of ( ~ 97 % calcite from XRD analysis ) and the produced water (effluent) was chemically analyzed for cations using Inductively Coupled Plasma (ICP) spectroscopy to assess the dissolution reaction phenomena. the chemical equation is as follows : CaCO3 + 2HCl ---> CaCl2 + CO2 + H2O My aim is to get the dissolution reaction rate constant and the diffusion coefficient for the conducted experiment by matching laboratory ICP result (Ca++) with the model (X1t). I have read transport reactive and other documentation but I am missing something. I used X1t app to simulate the acidized core flooding experiments and match the laboratory ICP result. my concerns are the followings : How precisely can I put the constraints on the initial system for the rock sample and the injected acid solution? I am a little bit confused about the input units ( mg/kg, free kg, mmol/kg, ..etc). I am only aware of the limestone rock sample weight ( 50 g) , porosity (22%) and the concentration of the injected acid (pH, wt% ). how would I put the value of the followings with their units: H2O .... free kg H+ ..... 4 (pH) .. for example ! Cl- ... Ca++ ( mineral ) ... HCO3- .... do I need to equilibrate the fluid and the rock in the initial pane in constraints on the initial system, and if so, how would I equilibrate them? injection rate was 10 cm3/min. how would I mimic the laboratory injection rate within the X1t the discharge ( injection rate) unit (cm/s, cm3/cm2/s, ..etc)? The laboratory domain was a cylindrical core sample (2.5 cm in diameter ⨉ 5 cm long) , how would I simulate that domain in the model, I used a spherical domain with r1: 1.25 cm, r2: 1.26 cm and nodes (Nx) = 5, please advise the appropriate way. Your support in this matter is highly appreciated. regards Abdulaziz
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