4 Feb, 2016
Correlations for Conversion between True and Reid Vapor Pressures (TVP and RVP)
Accurate measurement and prediction of crude oil and natural gas liquid (NGL) products vapor pressure are important for safe storage and transportation, custody transfer, minimizing vaporization losses and environmental protection. Vapor pressure specifications are typically stated in Reid Vapor Pressure (RVP) or/and True Vapor Pressure (TVP). In addition to the standard procedures for their measurements, there are rigorous and shortcut methods for their estimation and conversion.
Read More >20 Jan, 2016
What is the impact of Nitrogen on the Natural Gas Hydrate Formation Conditions?
Previously, we've discussed the hydrate phase behavior of sour natural gas mixtures. Specifically, we looked at carbon dioxide inhibits the hydrate formation slightly while hydrogen sulfide enhances hydrate formation considerably. This Tip of the Month (TOTM) will extend the previous study on the natural gas hydrate formation phase behavior. Specifically, it will study the impact of nitrogen on the formation of hydrate in a natural gas mixture.
Read More >6 Jan, 2016
How Do We Use the Results from Velocity Analysis in our Seismic Data?
Seismic velocities derived from moveout velocity analysis can be used to interpolate between wells or may be the only velocity information available in a new basin. This white paper will explore how we use the results from the velocity analyses, make corrections for lag, and account for floating datum.
Read More >7 Dec, 2015
Improvements in the Steels Used in Oil and Gas Processing Equipment over the Last Half Century
In the post-World war II period, the steels used in the oil and gas industry were quite different from what we use today. This tip of the month (TOTM) presents a brief overview of improvements in the steels used in oil and gas processing equipment for safer and more reliable operations.
Read More >9 Nov, 2015
Adsorption Dehydration: Two-Tower vs. Three-Tower System
There are different process configurations for adsorption dehydration systems. The most common arrangements are two-tower and three-tower configurations. In past articles, we have discussed the efficient operation of molecular sieve dehydration units. Specifically, the benefits of standby time in the adsorption dehydration processes and impact of feed gas conditions. This month’s Tip of the Month compares the required size of major equipment for the two-tower system with the three-tower system, considering a number of key parameters.
Read More >5 Oct, 2015
What is the Impact of Feed Gas Conditions on the Adsorption Dehydration System?
Adsorption dehydration units can reduce the water content of a gas stream to less than 0.1 ppmv. The gas industry normally uses adsorption dehydration units upstream of a liquefied natural gas (LNG) plant or a deep natural gas liquid (NGL) extraction plant where the gas temperature reduces to less than -160 °C (-256 °F) and -100 °C (-148 °F), respectively. Removal of water content to this very low level is essential to prevent freezing. This month’s article discusses feed gas flow rate, pressure, and temperature effect(s).
Read More >3 Sep, 2015
Gas-Liquid Separators Sizing Parameter
In this Tip of the Month (TOTM), we will focus on the application of Souders-Brown approach in gas-liquid separators and present diagram, simple correlations and tables to estimate the Souders-Brown equation constant, KS (the so called sizing parameter). We will consider both vertical and horizontal gas-liquid separators. Knowing the actual gas flow rate through the vessel, one can use KS parameter to determine the maximum allowable gas velocity through the vessel and determine the required separator diameter. One can also use the appropriate value of KS to size the mist extractor in the vessel. The performance of a gas-liquid separator is highly dependent on the value of KS; therefore, the choice of appropriate KS –values is important.
Read More >3 Aug, 2015
Effect of Relative Density (Specific Gravity) on the Saturated Water Content of Sweet Natural Gases
In this Tip of the Month (TOTM), we will study the effect of relative density (Specific Gravity, SG) on the saturated water content of sweet natural gases. The results of this study include the water content of sweet natural gases as a function of relative density in the range of 0.60 to 0.80. Four temperatures of 4.4, 23.9, 37.8 and 149 °C (40, 75, 100, and 300 °F) were considered. For each temperature, the saturated water content was calculated for pressures of 1724, 3448, 6897, and 13 793 kPaa (250, 400, 100 and 2000 psia).
Read More >6 Jul, 2015
How to Estimate Compressor Efficiency
In this article, we will demonstrate how to determine the efficiency of a compressor from measured flow rate, composition, suction and discharge temperatures and pressures. A rigorous calculation based on an equation of state and a shortcut method are considered and the results are compared. From a calculation viewpoint alone, the compressor power calculation is particularly sensitive to the specification of mass flow rate, suction temperature and pressure, and discharge temperature and pressure. A compressor is going to operate under varying values of the variables affecting its performance. Thus the most difficult part of a compressor calculation is specification of a reasonable range for each variable and not the calculation itself.
Read More >2 Jun, 2015
Effect of Chemical Additive on Crude Oil Pipeline Pressure Drop
For transportation of crude oil, the pumping power requirement varies as the crude oil viscosity changes. Increasing °API or line average temperature reduces the crude oil viscosity. The reduction of viscosity results in higher Reynolds number, lower friction factor and in effect, lower pumping power requirements. To reduce pressure drop and increase pipeline capacity, oil industry has utilized drag reducing agents. Drag-reducing agents, or drag-reducing polymers, are additives in pipelines that reduce turbulence in a pipe. Usually used in petroleum pipelines, they increase the pipeline capacity by reducing turbulence and therefore allowing the oil to flow more efficiently. In addition to drag reducing agents, another group of chemicals called “Incorporative Additives”, which reduces crude oil viscosity, may be used. In this Tip of the Month, we will demonstrate the effect of an incorporative additive on crude oil viscosity and consequently on pressure drop for crude oil pipeline transportation.
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