# Recent Advances in Scale Prediction, Approach, and Limitations

- Authors
- Amy T. Kan (Rice University) | Joey Zhaoyi Dai (Rice University) | Guannan Deng (Rice University) | Gedeng Ruan (Rice University) | Wei Li (Rice University) | Khadouja Harouaka (Rice University) | Yi-Tsung Lu (Rice University) | Xin Wang (Rice University) | Yue Zhao (Rice University) | Mason B. Tomson (Rice University)
- DOI
- https://doi.org/10.2118/190754-MS
- Document ID
- SPE-190754-MS
- Publisher
- Society of Petroleum Engineers
- Source
- SPE International Oilfield Scale Conference and Exhibition, 20-21 June, Aberdeen, Scotland, UK
- Publication Date
- 2018

- Document Type
- Conference Paper
- Language
- English
- ISBN
- 978-1-61399-598-3
- Copyright
- 2018. Society of Petroleum Engineers
- Disciplines
- 4.2.3 Materials and Corrosion, 7 Management and Information, 5 Reservoir Desciption & Dynamics, 5.2.2 Fluid Modeling, Equations of State, 7.2 Risk Management and Decision-Making, 7.2.1 Risk, Uncertainty and Risk Assessment, 5.2 Fluid Characterization
- Keywords
- sulfate scale, carbonate scale, sulfide scale
- Downloads
- 5 in the last 30 days
- 197 since 2007

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SPE Member Price: | USD 9.50 |

SPE Non-Member Price: | USD 28.00 |

Numerous saturation indices and computer algorithms have been developed to determine if, when, and where scale will form, but scale prediction can still be challenging since the predictions from different models often differ significantly at extreme conditions. Furthermore, there is a great need to accurately interpret the partitioning of H_{2}O, CO_{2}, and H_{2}S in different phases, and the speciations of CO_{2} and H_{2}S. This presentation is to summarize current developments in the Equation of State and the Pitzer models to accurately model the partitioning of H_{2}O, CO_{2}, and H_{2}S in hydrocarbon/aqueous phases and the aqueous ion activities at ultra high temperature, pressure and mixed electrolytes conditions. The equations derived from the Pitzer ion-interaction theory have been parametrized by regression of over 10,000 experimental data from publications in the last 170+ years using a genetic algorithm on the super computer, DAVinCI. With this new model, the 95% confidence intervals of the estimation errors for solution density are within 4*10'^{4} g/cm^{3}. The relative errors of CO_{2} solubility prediction are within 0.75%. The estimation errors of the saturation index mean values for calcite, barite, gypsum, anhydrite, and celestite are within ± 0.1, and that for halite is within ± 0.01, most of which are within experimental uncertainties. This model accurately defines the pH of the production tubing at various temperature and pressure regimes and the risk of H_{2}S exposure and corrosion. The developed model is able to predict the density of soluble chloride and sulfate salt solutions within ±0.1% relative error. The ability to accurately predict the density of a given solution at temperature and pressure allows one to deduce when freshwater breakthrough will occur. Lastly, accurate predictions can only be reliable with accurate data input. The need to improve accuracy of scale prediction with quality data will also be discussed.

File Size | 1 MB | Number of Pages | 17 |

Honeywell 2017. UniSim Design Suite Honeywell Process Solution, https://www.honeywellprocess.com/en-US/explore/products/advanced-applications/unisim/Pages/unisim-design-suite.aspx.

Laursen, T. 2017. VLXE Advance PVT Simplified. VLXE ApS, http://www.vlxe.com/.

OLI 2017. OLI Studio Scalechem. OLI Systems, https://www.olisystems.com/oli-studio-analyzers-scalechem.

Aqueous Solutions 2017. The Geochemist's workbench. Aqueous Solutions LLC, Champaign, IL, https://www.gwb.com/.

Dai, Z., Kan, A.T., Shi, W.. 2017a. Calcite and barite solubility measurements in mixed electrolyte solutions and the development of a comprehensive model for water-mineral-gas equilibrium of the Na-K-Mg-Ca-Ba-Sr-Cl-SO4-CO3-HCO3-CO2 (aq)-H2O system at up to 250 oC and 1,500 bars. IndEng Chem Res 56: 6548-6561.

USGS 2017. PHREEQC (Version 3)--A Computer Program for Speciation, Batch-Reaction, One-Dimensional Transport, and Inverse Geochemical Calculations US Geological Survey, https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/.

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**28** downloads in the last 30 days

**135** downloads since 2007