Computer Calculation Of Natural Gas Compressibility Factors Using The Standing And Katz Correlation

1973 ◽  
Author(s):  
P.M. Dranchuk ◽  
R.A. Purvis ◽  
D.B. Robinson
Keyword(s):  
Natural Gas ◽  
Computer Calculation ◽  
Compressibility Factors ◽  
Gas Compressibility

scholarly journals A Novel Simplification for the Prediction of Natural Gas Compressibility Factor

2021 ◽  
pp. 63-76
Author(s):  
OMOBOLANLE Oluwasegun Cornelious ◽  
AKINSETE Oluwatoyin Olakunle ◽  
AROMOKEYE Niyi
Keyword(s):  
Natural Gas ◽  
Compressibility Factor ◽  
Reservoir Properties ◽  
Predictive Tool ◽  
Deviation Factor ◽  
Temperature And Pressure ◽  
Explicit Correlation ◽  
Compressibility Factors ◽  
Gas Compressibility ◽  
Reduced Temperature

The need for a simpler, effective and less expensive predictive tool for the estimation of natural gas compressibility factor cannot be exaggerated. An accurate prediction of gas compressibility factor is essential because it plays a definitive role in evaluating gas reservoir properties used in the estimation of gas reserves, custody transfer and design of surface equipment. In this present work, a novel explicit correlation and a highly sophisticated computer program were developed to accurately predict natural gas deviation factor. The research also aims to effectively capture the relationship between Pseudo-reduced temperature and pressure in relations to the Z-factor. In this study, 3972 digitized data points extracted from Standing and Katz’s Chart were regressed and analyzed using Microsoft Excel Spreadsheet, the extraction of this data was done using WebPlotDigitizer developed by Ankit Rohatgi of GitHub, Pacifica, CA, USA. The correlation was developed as a function of Pseudo-reduced temperature and pressure with tuned parameters distributed across 1.05 ≤ Tpr ≤ 3.0 and 0 < Ppr ≤ 8.0. Subsequently, the input (Tpr and Ppr values) of the feed data was used to validate the correlation and compare it with other known and published correlations. Statistical analysis of the results showed that a 99.8% agreement exists between the predicted and actual compressibility factors for the various test scenarios and case studies involving both sweet and sour gases. Also, the correlation was observed to outperform other models. Finally, the results were observed to perfectly mimic the Standing and Katz charts with an overall correlation coefficient of 99.76% and an adjusted R2 of 99.75%. The proposed correlation was subsequently used to develop a software using JavaScript. Undoubtedly, the proposed correlation and software are suitable for rapid and accurate simplification and prediction of natural gas compressibility factor.

A corresponding states-based method for the estimation of natural gas compressibility factors

2016 ◽  
Vol 216 ◽  
pp. 25-34 ◽  
Author(s):  
Arash Kamari ◽  
Farhad Gharagheizi ◽  
Amir H. Mohammadi ◽  
Deresh Ramjugernath
Keyword(s):  
Natural Gas ◽  
Corresponding States ◽  
Compressibility Factors ◽  
Gas Compressibility

Performance Testing of Centrifugal Compressors: Schultz Compressibility Factors

2015 ◽  
Author(s):  
Matt Taher
Keyword(s):  
Equation Of State ◽  
Natural Gas ◽  
Performance Testing ◽  
Centrifugal Compressors ◽  
Real Gas ◽  
Gas Compression ◽  
Compressibility Factors

ASME PTC-10 [2009] recognizes inaccuracies involved in using the generalized charts to calculate Schultz compressibility factors for real gas compression. However, it neither addresses a method to develop the compressibility factors, nor does it specify when to use calculated compressibility factors rather than using generalized values. Using inaccurate generalized values for Schultz compressibility factors may lead to erroneous calculation of polytropic exponents and polytropic work. This paper employs the LKP equation of state to directly calculate Schultz compressibility factors for a mixture of hydrocarbons typically found in natural gas. The results are compared with the values of compressibility factors from the generalized compressibility charts.

Calculation Method of Natural Gas Compressibility Factor and its Application in Pipeline Trade

2014 ◽  
Author(s):  
Xiaocui Tian ◽  
Xiaokai Xing ◽  
Rui Chen ◽  
Shubao Pang ◽  
Liu Yang
Keyword(s):  
Natural Gas ◽  
Compressibility Factor ◽  
Economic Benefits ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Pipeline System ◽  
Natural Gas Pipeline ◽  
Gas Volume ◽  
Gas Compressibility ◽  
Simplified Formula

In the custody transfer metering of natural gas, it’s necessary to transform gas volume from metering state into standard state. Natural gas is non-ideal gas, and its compressibility factor varies with different components, temperature and pressure. So the accuracy of its calculation has direct impact on that of natural gas metering, and then affects the economic benefits of the enterprise [1]. According to related standard of China, in the custody transfer metering of natural gas, the formula stipulated by AGA NO.8 should be adopted to calculate compressibility factor. But the components of natural gas must be monitored at all times when this method is used, and the calculation process is complicated. In practical operation of natural gas trade, compressibility factor changes because of frequent adjustment of pipeline operating conditions. In order to simplify the calculation, simplified formula is applied to calculate compressibility factor generally, but it’s difficult to guarantee the accuracy at the same time. In this paper, the simplified formula, which is used for calculating natural gas compressibility factor of a joint-stock natural gas pipeline of CNPC, is modified with the standard formula stipulated by AGA NO.8. After the modification, an empirical formula of compressibility factor calculation applicable to this pipeline system is proposed, whereby the accuracy of compressibility factor calculation is improved. When the modified one is applied to natural gas trade, the accuracy of metering is improved likewise.

scholarly journals THE INFLUENCE OF PRESSURE AND TEMPERATURE ON THE COMPRESSIBILITY FACTOR

2021 ◽  
Vol 2(73) (2) ◽  
pp. 13-21
Author(s):  
George Iulian Oprea ◽  
◽  
Artemis Aidoni ◽  
Ioana Cornelia Mitrea ◽  
Florinel Dinu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Entire Range ◽  
Compressibility Factor ◽  
Ideal Gas ◽  
Calculation Methods ◽  
Natural Gases ◽  
Canadian Association ◽  
Compression And Expansion ◽  
Gas Compressibility ◽  
Reduced Pressures

The natural gas compressibility factor indicates the compression and expansion characteristics of natural gas under different conditions. It is a thermodynamic property used to take into account the deviation of the behaviour of real natural gases from that of an ideal gas. Compressibility factor, Z, values of natural gases are necessary for most petroleum gas engineering calculations. In this study, a comparison between five different calculation methods is presented to determine this critical parameter for the same natural gas at different conditions (pressure and temperature), using Canadian Association of Petroleum Producers, Azizi, Behbahani and Isazadeh, Dranchuk- Purvis- Robinson, Dranchuk-Abu-Kassem and Standing- Katz methods. The correlations are based on the equation of state are often implicit because they require iteration. Many correlations have been derived to enhance simplicity; however, no correlation has been developed for the entire range of pseudo-reduced pressures and temperatures. Azizi, Behbahani and Isazadeh’s method was found to have the biggest error as a result obtained for T=20° C, and p=20 bar is no longer in the field of applicability.

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