Improvement of Thermodynamic Modeling of Calcium Carbonate and Calcium Sulfates at High Temperature and High Pressure in Mixed Electrolytes

Dai, Zhaoyi

doi:10.2118/169786-ms

Cited by 6 publications

(3 citation statements)

References 33 publications

(76 reference statements)

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“…The retention time is chosen when longer retention time will not result in higher outflow concentration to make sure the equilibrium has been reached. The details of the apparatus and measurement procedures for different systems can be found in the previous papers. ,,, …”

Section: Methodsmentioning

confidence: 99%

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi

et al. 2014

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Mineral solubility predictions are critical for estimating scaling risks at conditions of high temperature, pressure, and ionic strength (IS) in mixed electrolytes which occur in various industrial processes. On the basis of the Pitzer theory, this study establishes a thermodynamic model to predict the solubilities and scaling risks of barite, calcite, gypsum, and anhydrite under these extreme conditions. This study combines the related equilibrium constants, virial coefficients, and the solubilities of these minerals from 0 °C to 250 °C, from 14.7 psi to 22000 psi, with up to 6 mol NaCl/kg H 2 O with or without mixed electrolytes to determine the temperature and pressure dependences of the following virial coefficients for Ca 2+ , and Ca 2+ −Br − binary interactions used in the Pitzer theory. Using these virial coefficients, the solubilities of these four minerals can be accurately predicted with no apparent temperature, pressure, or IS bias in solutions under the extreme conditions. The association constants (K assoc ) for CaSO 4 (0) ion pairs calculated from the β CaSO 4(2)values derived in the model match well with experimental measurements at 25 °C and 1 atm, and show similar temperature and pressure dependence with those calculated from the Fuoss ion pair association theory and those listed in SOLMINEQ. 88.

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Section: Methodsmentioning

confidence: 99%

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi

et al. 2014

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“…First of all, it may be questioned whether or not the basic and common thermodynamic database (equilibrium constants) is applicable for predicting the solubility of anhydrite, gypsum and calcite over wide ranges of temperature, pressure, and ionic strength with mixed electrolytes (particularly at reservoir conditions with high temperature high pressure high brine salinity) (Dai et al, 2014). Some evidence from other studies suggests that when minerals first nucleate they have high log K values which later decrease with accumulation.…”

Section: Mineral Dissolution and Precipitation Reactions Chemical Equmentioning

confidence: 99%

Analysis of Mineral Reactions Occurring in the Gyda Field Under Seawater Injection with the Help of Geochemical Non-Isothermal Model and Produced Water Data

Hu¹,

Mackay²

2016

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The evidence from the produced brine chemistry suggests that the Gyda field has experienced a variety of geochemical reactions due to the high temperature and initial calcium concentration, and so it is worth reviewing the produced water dataset and studying what in situ geochemical reactions may be taking place.Produced brine chemistry data from 16 wells in the Gyda field are plotted and analysed in combination with general geological information and the reservoir description. A one dimensional reactive transport model is developed to identify the possible geochemical reactions occurring within the reservoir triggered by seawater injection, then extended with the inclusion of thermal modelling and also to be a two dimensional vertical cross section model.Three possible classes of formation water compositions in different regions of the Gyda field have been identified by analysis of the produced water dataset. Anhydrite and barite precipitation are the two dominant mineral reactions taking place deep within the reservoir. Magnesium stripping may be a result of multi-component ion exchange, dolomite precipitation or a combination of both. Reservoir temperature is lowered during cold water injection. The solubility of anhydrite increases at lower temperature, and anhydrite will gradually dissolve in response to the movement of the temperature front, which is much slower than the formation/injection water mixing front. The extent of mineral precipitation within the reservoir can be reduced by the heterogeneity; the modelling shows that the extent of ion stripping caused by mineral reactions in the reservoir is greatest when simulating a single uniform layer. Brine mixing and the occurrence of geochemical reactions due to vertical mixing are not observable, even when assigning a high vertical permeability in a heterogeneous model.Thermal modelling is included to evaluate the effect of non-isothermal processes and heat transport on the geochemical reactions, especially the anhydrite mineral reaction. We have investigated how the difference in horizontal permeability in the two layers affects brine mixing of formation and injection water and geochemical reactions.

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“…In the last several years, the author's research group has been engaged in both experimental and theoretical development of such a thermodynamic database [16,[68][69][70][71][72]. As of the end of 2014, we updated our scale prediction software with another massive modeling effort.…”

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confidence: 99%

Scale Prediction and Control at Ultra HTHP

Kan

Dai

Zhang

et al. 2015

Day 1 Mon, April 13, 2015

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Production from deepwater environment often encounter ultra high temperature, pressure (ultra HTHP) and with more exotic fluid compositions. Most scale prediction programs were developed by semiempirically modeling the thermodynamic parameters using experimentally measured mineral solubilities and other chemical properties. However, the experimental data were limited at temperature, pressure, and ionic strength that were clearly below that typically encountered in deepwater production. Therefore, extending the existing thermodynamic models to HTHP applications is of questionable accuracy. Furthermore, the partitioning of H 2 O, CO 2 , and H 2 S in and out of the gas/oil phases during production can have a significant impact on scaling tendency. The authors have published papers on experimental solubility measurements and thermodynamic modeling to extend the solubility data to HTHP condition. The new thermodynamic parameters and a flash calculator that integrate the latest development of Equation of State (EOS) to model the partition of H 2 O, CO 2 , and H 2 S in hydrocarbon/aqueous phases at temperature and pressure have been incorporated into a scale prediction software that is specifically tailored for oil and gas production application.The objective of this paper is to validate the software's application range with a set of critically evaluated peer-reviewed mineral solubility data for general oilfield produced water and deepwater HTHP application. A total of 73 selected papers and more than 2,500 individual experimental data points were included in this evaluation. Our model has been shown to be applicable to greater than 95% of produced water compositions with SI prediction of better than Ϯ0.03 for halite, Ϯ0.05 for gypsum, Ϯ0.1 for calcite and anhydrite, and Ϯ0.2 for barite at temperature between 32 -500°F, and and pressure between 14.7 to 22,000 psia. The newly incorporated flash calculator is capable of predicting how CO 2 , H 2 S, and H 2 O partition in and out of the gas phase during production. The partitioning of CO 2 , H 2 S, and H 2 O between the hydrocarbon and aqueous phases has significantly changed the ion composition and pH and therefore, impacted the scaling tendency of the fluids at the production temperature and pressure. This is a particularly important issue for newer wells with high volumes of gas and low water cuts and for CO 2 flooding.

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Improvement of Thermodynamic Modeling of Calcium Carbonate and Calcium Sulfates at High Temperature and High Pressure in Mixed Electrolytes

Cited by 6 publications

References 33 publications

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi

Analysis of Mineral Reactions Occurring in the Gyda Field Under Seawater Injection with the Help of Geochemical Non-Isothermal Model and Produced Water Data

Scale Prediction and Control at Ultra HTHP

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Improvement of Thermodynamic Modeling of Calcium Carbonate and Calcium Sulfates at High Temperature and High Pressure in Mixed Electrolytes

Cited by 6 publications

References 33 publications

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO4(0) Ion Pair up to 250 °C and 22000 psi

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO4(0) Ion Pair up to 250 °C and 22000 psi

Analysis of Mineral Reactions Occurring in the Gyda Field Under Seawater Injection with the Help of Geochemical Non-Isothermal Model and Produced Water Data

Scale Prediction and Control at Ultra HTHP

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A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi

A Thermodynamic Model for the Solubility Prediction of Barite, Calcite, Gypsum, and Anhydrite, and the Association Constant Estimation of CaSO₄⁽⁰⁾ Ion Pair up to 250 °C and 22000 psi