Natural gases containing sour components exhibit different gas compressibility factor （Z） behavior than do sweet gases. Therefore, a new accurate method should be developed to account for these differences. Several ...Natural gases containing sour components exhibit different gas compressibility factor （Z） behavior than do sweet gases. Therefore, a new accurate method should be developed to account for these differences. Several methods are available today for calculating the Z-factor from an equation of state. However, these equations are more complex than the foregoing correlations, involving a large number of parameters, which require more complicated and longer computations. The aim of this study is to develop a simplified calculation method for a rapid estimating Z-factor for sour natural gases containing as much as 90% total acid gas. In this article, two new correlations are first presented for calculating the pseudo- critical pressure and temperature of the gas mixture as a function of the gas specific gravity. Then, a simple correlation on the basis of the standard gas compressibility factor chart is introduced for a quick estimation of sweet gases＇ compressibility factor as a function of reduced pressure and temperature. Finally, a new corrective term related to the mole fractions of carbon dioxide and hydrogen sulfide is developed.展开更多
This paper extends the analysis of the fourth model of Exploration and Production Sharing Agreement(EPSA IV)and our proposed modification of the Libyan Exploration and Production Sharing Agreement(LEPSA I)to field app...This paper extends the analysis of the fourth model of Exploration and Production Sharing Agreement(EPSA IV)and our proposed modification of the Libyan Exploration and Production Sharing Agreement(LEPSA I)to field applications.The paper focuses on risk evaluation and analyzing the sensitivity of the fiscal terms of EPSA IV model(cost recovery,A factors,and B factors)and the fiscal terms of LEPSA I model(initial production share,the geologic probability of success,and the oil reference price)on the profitability indicators of Net Present Value(NPV)and Internal Rate of Return(IRR).The deterministic analysis method and stochastic analysis method using the Monte Carlo Simulation have been used in this study.The two methods were used to show the probability distribution of the NPV and IRR on the basis of the random variables of fiscal terms in the two models of EPSA IV and LEPSA I,respectively.The simulation output of the development field scenario of enhanced oil recovery using CO2 injection showed that the cost recovery is a very sensitive term on the NPV and IRR in the EPSA IV model.But,the A and B factors in the EPSA IV model have different sensitivities on the NPV and IRR.The B factor 3 and B factor 1 are more sensitive on the NPV and IRR than are other factors.The B factor 4 and A factor 4 have shown less effect on the NPV and IRR than the other factors.Moreover,the simulation output showed that the initial share and reference price are more sensitive to the NPV and IRR than the probability of success on the basis of the LEPSA I model.展开更多
文摘Natural gases containing sour components exhibit different gas compressibility factor （Z） behavior than do sweet gases. Therefore, a new accurate method should be developed to account for these differences. Several methods are available today for calculating the Z-factor from an equation of state. However, these equations are more complex than the foregoing correlations, involving a large number of parameters, which require more complicated and longer computations. The aim of this study is to develop a simplified calculation method for a rapid estimating Z-factor for sour natural gases containing as much as 90% total acid gas. In this article, two new correlations are first presented for calculating the pseudo- critical pressure and temperature of the gas mixture as a function of the gas specific gravity. Then, a simple correlation on the basis of the standard gas compressibility factor chart is introduced for a quick estimation of sweet gases＇ compressibility factor as a function of reduced pressure and temperature. Finally, a new corrective term related to the mole fractions of carbon dioxide and hydrogen sulfide is developed.
文摘This paper extends the analysis of the fourth model of Exploration and Production Sharing Agreement(EPSA IV)and our proposed modification of the Libyan Exploration and Production Sharing Agreement(LEPSA I)to field applications.The paper focuses on risk evaluation and analyzing the sensitivity of the fiscal terms of EPSA IV model(cost recovery,A factors,and B factors)and the fiscal terms of LEPSA I model(initial production share,the geologic probability of success,and the oil reference price)on the profitability indicators of Net Present Value(NPV)and Internal Rate of Return(IRR).The deterministic analysis method and stochastic analysis method using the Monte Carlo Simulation have been used in this study.The two methods were used to show the probability distribution of the NPV and IRR on the basis of the random variables of fiscal terms in the two models of EPSA IV and LEPSA I,respectively.The simulation output of the development field scenario of enhanced oil recovery using CO2 injection showed that the cost recovery is a very sensitive term on the NPV and IRR in the EPSA IV model.But,the A and B factors in the EPSA IV model have different sensitivities on the NPV and IRR.The B factor 3 and B factor 1 are more sensitive on the NPV and IRR than are other factors.The B factor 4 and A factor 4 have shown less effect on the NPV and IRR than the other factors.Moreover,the simulation output showed that the initial share and reference price are more sensitive to the NPV and IRR than the probability of success on the basis of the LEPSA I model.
