A good strategy to overcome this challenge is to increase the participation of gas lift in this process. As time goes oil and gas fields become more mature, the internal energy of the reservoirs decreases and consequently the natural gas production does as well. Getting natural gas out of the ground introduces new supply chain challenges because the wells decline more rapidly than traditional ones.
However, while the works related to the estimation of uncertainty of the calorific value and the hydrocarbon dew point are limited, this review represents a breakthrough in the path of research applied in the proper determination of these parameters and results with greater metrology reliability of chemical quantities of natural gas. This review gathers different forms of measurement of the gas quality parameters selected, from studies found in the literature both in the determination of its value and its associated uncertainty. Correct measurement is of vital importance, especially in the custody transfer points, since who delivered as who receives both are interested in knowing the quality of the gas marketed with a high accuracy. These requirements correspond to the parameters of gas quality inside which are the calorific value and the hydrocarbon dew point. Natural gas should meet certain requirements that ensure that their production, transport, distribution and consumption is carried out safely. This simplified methodology minimizes operator exposure, besides saving about US$ 50,000.00 per chromatograph. The results show that all samples that comply with Brazilian legislation can be analyzed by method B, because there are no metrological differences in terms of SCV and z, even though the allowed tolerance has been exceeded. From natural gas composition analyzed by both methods, exceeding the method B allowed tolerance SCV, z and its uncertainties are calculated and compared. The method B uses a single point calibration, with an allowed tolerance between the calibration gas mixture and sample mole fraction, so it is used to analyze constant natural gas streams. The method A uses an analytical curve with seven points that the best adjust is confirmed by Analysis of Variance (ANOVA) it is required when the composition of the natural gas varies.
The properties, superior calorific value (SCV) and the compressibility factor (z), of 77 natural gas (NG) samples are calculated from two different calibration approaches of gas chromatography, based on ISO 6974-2.