Natural gas. Correlation between water content and water dew point

2015 ◽  
Keyword(s):  
1973 ◽  
Vol 13 (05) ◽  
pp. 297-306 ◽  
Author(s):  
A. Rosman

Abstract To develop reliable design data for glycol contactors, gas-liquid equilibria in the system water-methane-triethylene glycol (TEG) were investigated experimentally. Equilibrium values vary little at the very high TEG concentrations used in modern contactor design, but increase significantly with increasing water concentration in the contacting TEG, and with increasing equilibrium temperature. Various methods of data correlation are described and compared with experimental data. The correlation provides the means for extending the results of this investigation to other pressures and temperatures. Introduction Water removal is a fundamental operation in natural gas processing. Hydrate formation, corrosion, and the formation of liquid water that might separate in the transmission lines are some of the problems caused by an excess of water in the gas. Of the methods available for gas dehydration, water absorption is by far the most generally used. Glycols, especially triethylene glycol (TEG), are the preferred absorbents. A survey of the literature on the water dew point of natural gas over glycol solutions reveals point of natural gas over glycol solutions reveals significant disagreements. A sampling of published dewpoint data for gas in equilibrium with TEG (Fig. 7) illustrates the prevailing confusion. Scant, but still contradictory, information was published for glycol concentrations in excess of 99.8 weight percent. Data in that range are needed in designing percent. Data in that range are needed in designing modern glycol contactors where the water dewpoint temperature must be reduced by more than 100 deg. F. The main reason for discrepancies in experimental results is the difficulty of measuring accurately very small amounts of water in gas. Water is easily adsorbed on the surfaces of experimental apparatus. Normally acceptable data scatter looms large in relation to the low water concentrations that must be measured. Attempts to establish water dew points on the basis of plant performance have been points on the basis of plant performance have been more successful. However, accuracy is limited by the difficulty in establishing the relative contribution of various factors that interrelate in plant operation. plant operation. Faced with these doubts, contactor designers have chosen to provide for TEG circulation rates that are overly high so as to insure more than adequate water removal. Such a practice is undesirable, however, where space and power are at a premium, as on offshore production platforms. Thus, the range of this investigation was governed by the need to extend equilibrium information to the contact temperatures and TEG concentrations necessary m optimize glycol contactors on offshore production platforms. production platforms. New procedures were developed for sampling and analyzing very small concentrations of water in gas and in TEG. To avoid experimental difficulties encountered by previous authors, equilibrium was reached and samples were taken under dynamic conditions. Experimental equilibrium results were smoothed and correlated by several methods. Thermodynamic equations were used to check on the internal consistency of data and to calculate equilibrium constants at conditions outside the range of the investigation itself. The White expression, fitted to the COFRC experimental data, adequately describes the results within the range of temperatures and concentrations studied. DEFINITIONS AND METHODS At water dewpoint temperature, the water contained in a natural gas reaches saturation. Part of that water will condense if the gas is brought to a lower temperature or to a higher pressure. Thus, the "dewpoint temperature" describes the water content of the gas. When dewpoint gas contacts TEG, the water content of the gas decreases. The lower water content corresponds to saturation water at a lower temperature; that is, the dew point will be lower. The initial dewpoint temperature is the contacting temperature. The temperature corresponding to the lowered water content is the equilibrium dewpoint temperature, and the difference between the two temperatures is the dewpoint depression. SPEJ P. 297


2021 ◽  
Vol 651 (3) ◽  
pp. 032090
Author(s):  
Xiaomei Zou ◽  
Fengxia Huang ◽  
Liming Zhang ◽  
Tumeng Gele
Keyword(s):  

2016 ◽  
Author(s):  
V. J Aimikhe ◽  
O. F Joel ◽  
S. S Ikiensikimama ◽  
S Iyuke

2006 ◽  
Vol 45 (14) ◽  
pp. 5179-5184 ◽  
Author(s):  
S. Avila ◽  
A. Benito ◽  
C. Berro ◽  
S. T. Blanco ◽  
S. Otín ◽  
...  

2021 ◽  
Author(s):  
Adel Mohsin ◽  
Abdul Salam Abd ◽  
Ahmad Abushaikha

Abstract Condensate banking in natural gas reservoirs can hinder the productivity of production wells dramatically due to the multiphase flow behaviour around the wellbore. This phenomenon takes place when the reservoir pressure drops below the dew point pressure. In this work, we model this occurrence and investigate how the injection of CO2 can enhance the well productivity using novel discretization and linearization schemes such as mimetic finite difference and operator-based linearization from an in-house built compositional reservoir simulator. The injection of CO2 as an enhanced recovery technique is chosen to assess its value as a potential remedy to reduce carbon emissions associated with natural gas production. First, we model a base case with a single producer where we show the deposition of condensate banking around the well and the decline of pressure and production with time. In another case, we inject CO2 into the reservoir as an enhanced gas recovery mechanism. In both cases, we use fully tensor permeability and unstructured tetrahedral grids using mimetic finite difference (MFD) method. The results of the simulation show that the gas and condensate production rates drop after a certain production plateau, specifically the drop in the condensate rate by up to 46%. The introduction of a CO2 injector yields a positive impact on the productivity and pressure decline of the well, delaying the plateau by up to 1.5 years. It also improves the productivity index by above 35% on both the gas and condensate performance, thus reducing production rate loss on both gas and condensate by over 8% and the pressure, while in terms of pressure and drawdown, an improvement of 2.9 to 19.6% is observed per year.


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