A dynamic model of CO2 diffusion coefficient in shale based on the whole process fitting

2021 ◽  
pp. 131151
Author(s):  
Hao Chen ◽  
Mingyang Yang ◽  
Chenyuan Huang ◽  
Yu Wang ◽  
Yuxiang Zhang ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Dynamic Model ◽  
Whole Process ◽  
Co2 Diffusion

scholarly journals The Effect of Oil Properties on the Supercritical CO2 Diffusion Coefficient under Tight Reservoir Conditions

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1495 ◽  
Author(s):  
Chao Zhang ◽  
Chenyu Qiao ◽  
Songyan Li ◽  
Zhaomin Li
Keyword(s):  
Diffusion Coefficient ◽  
Supercritical Co2 ◽  
Co2 Diffusion ◽  
Tight Reservoir ◽  
Reservoir Conditions

Measurement and modeling of CO2 diffusion coefficient in Saline Aquifer at reservoir conditions

2013 ◽  
Vol 3 (4) ◽  
Author(s):  
Reza Azin ◽  
Mohamad Mahmoudy ◽  
Seyed Raad ◽  
Shahriar Osfouri
Keyword(s):  
Diffusion Coefficient ◽  
Positive Impact ◽  
Compressibility Factor ◽  
Equilibrium Concentration ◽  
Initial Pressure ◽  
Oil Field ◽  
Saline Aquifers ◽  
Saline Aquifer ◽  
Full Field ◽  
Co2 Diffusion

AbstractStorage of CO2 in deep saline aquifers is a promising techniques to mitigate global warming and reduce greenhouse gases (GHG). Correct measurement of diffusivity is essential for predicting rate of transfer and cumulative amount of trapped gas. Little information is available on diffusion of GHG in saline aquifers. In this study, diffusivity of CO2 into a saline aquifer taken from oil field was measured and modeled. Equilibrium concentration of CO2 at gas-liquid interface was determined using Henry’s law. Experimental measurements were reported at temperature and pressure ranges of 32–50°C and 5900–6900 kPa, respectively. Results show that diffusivity of CO2 varies between 3.52–5.98×10−9 m2/s for 5900 kPa and 5.33–6.16×10−9 m2/s for 6900 kPa initial pressure. Also, it was found that both pressure and temperature have a positive impact on the measures of diffusion coefficient. Liquid swelling due to gas dissolution and variations in gas compressibility factor as a result of pressure decay was found negligible. Measured diffusivities were used model the physical model and develop concentration profile of dissolved gas in the liquid phase. Results of this study provide unique measures of CO2 diffusion coefficient in saline aquifer at high pressure and temperature conditions, which can be applied in full-field studies of carbon capture and sequestration projects.

Machine Learning Approach to Estimate the Diffusion Coefficient of CO2 in Hydrocarbons

2021 ◽  
Author(s):  
Nikhil Bagalkot ◽  
Arvind Keprate
Keyword(s):  
Machine Learning ◽  
Diffusion Coefficient ◽  
Computational Modelling ◽  
Gaussian Process Regression ◽  
Gradient Boosting ◽  
Co2 Diffusion ◽  
Machine Learning Approach ◽  
Multiphase Systems ◽  
Varied Range ◽  
Computational Part

Abstract Diffusion of the gas into the liquids is a critical part in understanding multiphase systems and engineering applications associated with these multiphase systems. The study couples multiphase pendant drop experiments and computational modelling to calculate the CO2 diffusion coefficient in n-decane. Experiments were carried out at a varied range of pressure and temperature 25–45°C and 25–65 bar. During the experiments, the change in the volume of the hydrocarbon drop due to CO2 diffusion was dynamically measured, and numerical model was developed which used the experimental data to estimate the diffusion coefficient. The current study brings in the capability of machine learning as a replacement of the computational part for prediction of the diffusion coefficient of the process. The feasibility of various machine learning models such as Gradient boosting, Gaussian Process Regression (GPR), k-NN, Decision tree etc. are checked. Firstly different algorithms were trained on the dataset and finally evaluated on the test dataset, using various statistical metrics). Finally, the most accurate algorithm is used as a surrogate model for predicting the diffusion coefficient. The chosen ML algorithm was fairly accurate in predicting the diffusion coefficient with a maximum inaccuracy of 7.5%. Therefore, ML may then be employed as an alternative to experiments and numerical methods. A case study is performed to demonstrate the proposed methodology.

scholarly journals CO2 diffusion in polar ice: observations from naturally formed CO2 spikes in the Siple Dome (Antarctica) ice core

2008 ◽  
Vol 54 (187) ◽  
pp. 685-695 ◽  
Author(s):  
Jinho Ahn ◽  
Melissa Headly ◽  
Martin Wahlen ◽  
Edward J. Brook ◽  
Paul A. Mayewski ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Diffusion Coefficient ◽  
Concentration Profile ◽  
Ice Core ◽  
Polar Ice ◽  
Common Assumption ◽  
Ion Concentrations ◽  
Co2 Diffusion ◽  
Siple Dome ◽  
Diffusion Rates

AbstractOne common assumption in interpreting ice-core CO2 records is that diffusion in the ice does not affect the concentration profile. However, this assumption remains untested because the extremely small CO2 diffusion coefficient in ice has not been accurately determined in the laboratory. In this study we take advantage of high levels of CO2 associated with refrozen layers in an ice core from Siple Dome, Antarctica, to study CO2 diffusion rates. We use noble gases (Xe/Ar and Kr/Ar), electrical conductivity and Ca2+ ion concentrations to show that substantial CO2 diffusion may occur in ice on timescales of thousands of years. We estimate the permeation coefficient for CO2 in ice is ∼4 × 10−21 mol m−1 s−1 Pa−1 at −23°C in the top 287 m (corresponding to 2.74 kyr). Smoothing of the CO2 record by diffusion at this depth/age is one or two orders of magnitude smaller than the smoothing in the firn. However, simulations for depths of ∼930–950 m (∼60–70 kyr) indicate that smoothing of the CO2 record by diffusion in deep ice is comparable to smoothing in the firn. Other types of diffusion (e.g. via liquid in ice grain boundaries or veins) may also be important but their influence has not been quantified.

scholarly journals Experimental Determination of CO2 Diffusion Coefficient in a Brine-Saturated Core Simulating Reservoir Condition

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 540
Author(s):  
Zerong Li ◽  
Lei Yuan ◽  
Guodong Sun ◽  
Junchen Lv ◽  
Yi Zhang
Keyword(s):  
Diffusion Coefficient ◽  
Co2 Storage ◽  
Co2 Diffusion ◽  
Nacl Concentration ◽  
Reservoir Conditions ◽  
Temperature And Pressure ◽  
The Relationship ◽  
Crucial Part

CO2 diffusion coefficient plays a crucial part in saline aquifers for the CO2 storage and the safety of long-term sequestration. Therefore, it is particularly important to measure the diffusion coefficient accurately. As far as we know, there are currently no CO2 brine diffusion data in real cores under reservoir temperature and pressure conditions. In this paper, a study on the CO2 diffusion coefficient diffused in a brine-saturated Berea core along the radial direction was conducted at temperatures of 313.15 K to 373.15 K and pressures of 8 MPa to 30 MPa. On account of the experimental results, the effect of permeability, NaCl concentration, temperature and pressure on the CO2 diffusivity is analyzed. The results in this study indicate that the diffusion coefficient increases with increasing permeability, pressure and temperature and decreases with increasing NaCl concentration. However, the relationship between pressure and the diffusion coefficient is not linear. As the pressure gradually increases, the effect of pressure will become weak. In addition, an empirical correlation of the relationship between temperature–pressure and the CO2 diffusion coefficient could be obtained based on the experimental data. The data in this paper fill the blank on the study of the CO2 diffusivity in brine under reservoir conditions, which has positive significance for the study of supercritical CO2 diffusion in a brine-saturated core.

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