Modeling Water Saturation Points in Natural Gas Streams Containing CO2 and H2S—Comparisons with Different Equations of State

2015 ◽  
Vol 54 (2) ◽  
pp. 743-757 ◽  
Author(s):  
Letícia C. dos Santos ◽  
Samir S. Abunahman ◽  
Frederico W. Tavares ◽  
Victor R. R. Ahón ◽  
Georgios M. Kontogeorgis
Keyword(s):  
Natural Gas ◽  
Equations Of State ◽  
Water Saturation ◽  
Gas Streams

Technique and results of experimental determination of the compressibility factor of the natural gas

2021 ◽  
pp. 35-40
Author(s):  
Denis Y. Kutovoy ◽  
Igor A. Yatsenko ◽  
Vladimir B. Yavkin ◽  
Aydar N. Mukhametov ◽  
Petr V. Lovtsov ◽  
...  
Keyword(s):  
Natural Gas ◽  
Equations Of State ◽  
Compressibility Factor ◽  
High Accuracy ◽  
State Equations ◽  
Actual Problem ◽  
Temperature Range ◽  
Relative Value ◽  
Compressibility Coefficient

The actual problem of the possibility of using the equations of state for the gas phase of natural gas at temperatures below 250 K is considered. To solve it, the compressibility coefficients of natural gas obtained experimentally with high accuracy are required. The technique was developed and experimental study was carried out of compressibility factor aiming expanding temperature range of the state equations GERG-2004 and AGA8-DC92. The proposed technique is based on the fact that to assess the applicability of the equation of state, it is sufficient to obtain the relative value of the compressibility coefficient and not to determine its absolute value. The technique does not require complex equipment and provides high accuracy. The technique was tested on nitrogen, argon, air and methane. Uncertainty of determination of the compressibility factor is not greater than 0.1 %. For two different compositions of natural gas, obtained experimental data were demonstrated that the equations of state GERG-2004 and AGA8-92DC provide uncertainty of the calculation of the compressibility coefficient within 0.1 % in the temperature range from 220 K to 250 K and pressure below 5 MPa.

scholarly journals Utilization of CO2 as Cushion Gas for Depleted Gas Reservoir Transformed Gas Storage Reservoir

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 576 ◽  
Author(s):  
Cheng Cao ◽  
Jianxing Liao ◽  
Zhengmeng Hou ◽  
Hongcheng Xu ◽  
Faisal Mehmood ◽  
...  
Keyword(s):  
Natural Gas ◽  
Production Rate ◽  
Water Saturation ◽  
Gas Storage ◽  
Periodic Change ◽  
Residual Water ◽  
Reservoir Pressure ◽  
Gas Reservoir ◽  
Reservoir Permeability ◽  
Depleted Gas Reservoir

Underground gas storage reservoirs (UGSRs) are used to keep the natural gas supply smooth. Native natural gas is commonly used as cushion gas to maintain the reservoir pressure and cannot be extracted in the depleted gas reservoir transformed UGSR, which leads to wasting huge amounts of this natural energy resource. CO2 is an alternative gas to avoid this particular issue. However, the mixing of CO2 and CH4 in the UGSR challenges the application of CO2 as cushion gas. In this work, the Donghae gas reservoir is used to investigate the suitability of using CO2 as cushion gas in depleted gas reservoir transformed UGSR. The impact of the geological and engineering parameters, including the CO2 fraction for cushion gas, reservoir temperature, reservoir permeability, residual water and production rate, on the reservoir pressure, gas mixing behavior, and CO2 production are analyzed detailly based on the 15 years cyclic gas injection and production. The results showed that the maximum accepted CO2 concentration for cushion gas is 9% under the condition of production and injection for 120 d and 180 d in a production cycle at a rate of 4.05 kg/s and 2.7 kg/s, respectively. The typical curve of the mixing zone thickness can be divided into four stages, which include the increasing stage, the smooth stage, the suddenly increasing stage, and the periodic change stage. In the periodic change stage, the mixed zone increases with the increasing of CO2 fraction, temperature, production rate, and the decreasing of permeability and water saturation. The CO2 fraction in cushion gas, reservoir permeability, and production rate have a significant effect on the breakthrough of CO2 in the production well, while the effect of water saturation and temperature is limited.

scholarly journals The second law analysis of natural gas behavior within a vortex tube

2013 ◽  
Vol 17 (4) ◽  
pp. 1079-1092 ◽  
Author(s):  
Mahyar Kargaran ◽  
A. Arabkoohsar ◽  
S.J. Hagighat-Hosini ◽  
V. Farzaneh-Kord ◽  
Mahmood Farzaneh-Gord
Keyword(s):  
Natural Gas ◽  
Entropy Generation ◽  
Vortex Tube ◽  
Tube Length ◽  
Orifice Diameter ◽  
Working Fluid ◽  
Energy Separation ◽  
Second Law ◽  
Gas Streams ◽  
Mass Fractions

Vortex tube is a simple device without a moving part which is capable of separating hot and cold gas streams from a higher pressure inlet gas stream. The mechanism of energy separation has been investigated by several scientists and second law approach has emerged as an important tool for optimizing the vortex tube performance. Here, a thermodynamic model has been used to investigate vortex tube energy separation. Further, a method has been proposed for optimizing the vortex tube based on the rate of entropy generation obtained from experiments. Also, an experimental study has been carried out to investigate the effects of the hot tube length and cold orifice diameter on entropy generation within a vortex tube with natural gas as working fluid. A comparison has been made between air and natural gas as working fluids. The results show that the longest tube generates lowest entropy for NG. For air, it is middle tube which generates lowest entropy. Integration of entropy generation for all available cold mass fractions unveiled that an optimized value for hot tube length and cold orifice diameter is exist.

A Comparison Between PSRK and GERG-2004 Equation of State for Simulation of Non-Isothermal Compressible Natural Gases Mixed with Hydrogen in Pipelines / Porównanie równań stanu opracowanych według metody PSRK oraz GERG-2004 wykorzystanych do symulacji zachowania ściśliwych mieszanin gazu ziemnego i wodoru w rurociągach, w warunkach przepływów nie-izotermicznych

2013 ◽  
Vol 58 (2) ◽  
pp. 579-590
Author(s):  
Frits E. Uilhoorn
Keyword(s):  
Equation Of State ◽  
Natural Gas ◽  
Gas Flow ◽  
Transient Flow ◽  
Equations Of State ◽  
Group Contribution Method ◽  
Flow Conditions ◽  
Fluid Approximation ◽  
Natural Gases

In this work, the GERG-2004 equation of state based on a multi-fluid approximation explicit in the reduced Helmholtz energy is compared with the predictive Soave-Redlich-Kwong group contribution method. In the analysis, both equations of state are compared by simulating a non-isothermal transient flow of natural gas and mixed hydrogen-natural gas in pipelines. Besides the flow conditions also linepack-energy and energy consumption of the compressor station are computed. The gas flow is described by a set of partial differential equations resulting from the conservation of mass, momentum and energy. A pipeline section of the Yamal-Europe gas pipeline on Polish territory has been selected for the case study.

Impact Factors of Natural Gas Hydrate Dissociation by Depressurization: A Review

2013 ◽  
Vol 868 ◽  
pp. 564-567 ◽  
Author(s):  
Da Yong Wang ◽  
Xiao Jing Ma ◽  
Juan Qiao
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Water Saturation ◽  
Spatial Scales ◽  
Potential Effect ◽  
Impact Factors ◽  
Chemical Components ◽  
Production Well ◽  
Natural Gas Hydrate ◽  
Production Wells

Several geological factors can have a potential effect on dissociation of natural gas hydrate (NGH). It is important to understand their roles in safe exploitation of NGH deposits. This paper accordingly reviews experimental and numerical-modeling researches on impact factors of NGHs dissociation by depressurization. NGHs dissociation usually increases with increasing temperature, permeability, water saturation, thermal conductivity of sediments and depressurization rate of production well, whereas it is reverse for pressure, hydrate saturation, production wells pressure, gas saturation and particle size. Comparably, the effect of porosity and the heat conduction of production well can be reasonably ignored at different spatial scales. The heterogeneity of NGH deposits, chemical components of pore fluids, relative permeability and capillary pressure can also play a role in NGHs dissociation. However, their influencing mechanisms still need further studies in future.

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