By definition, the isothermal compressibility of a substance is defined mathematically by the following expression: For a crude oil system, the isothermal compressibility coefficient of the oil phase B is defined for pressures above the bubble point by one of the following equivalent expressions: where V is volume of the fluid and K T is isothermal bulk modulus, respectively. The solubility of a gas in a liquid depends on temperature, the partial pressure of the gas over the liquid, the nature of the solvent and the nature of the gas. To submit chemistry assignments Click here, Petroleum Engineering | Petroleum Engineering Courses | Rotary Drilling | Gas Reservoirs | Behavior Of Ideal Gases | Online Tutoring, Fundamental properties Of Fluid Permeated Rocks, Classification Of Reservoir And Reservoir Fluids, Determination And Application of Reservoir Fluid Properties, Oil Recovery mechanisms And The material Balance Equation, Change in Pore Volume Due to Initial Water and Rock Expansion, Computational Mathematics Assignment Help. is always ready to help you when you need help in gas solubility, petroleum chemistry, bubble point pressure, crude oil viscosity, and oil formation volume factor related problems. Below the bubble point pressure, the solution gas is liberated and the value of Rs decreases with pressure. This behavior results in an increase in the oil formation volume factor and will continue until the bubble-point pressure is reached. For a particular gas and crude oil to exist at a constant temperature, the solubility increases with pressure until the saturation pressure is reached. The oil formation volume factor can be expressed mathematically as: Bo = Oil formation volume factor, bbl/STB, (Vo)p,T = Volume of oil under reservoir pressure p and temperature T, bbl, (Vo)sc = Volume of oil is measured under standard conditions, STB. CC BY-SA 3.0. This important property can be measured experimentally for a crude oil system by conducting a constant-composition expansion test. The viscosity, in general, is defined as the internal resistance of the fluid to flow. A typical oil formation factor curve, as a function of pressure for an under saturated crude oil (pi > pb), is shown in Figure. Suppose, when we insert sugar into water it will dissolve. Solubility The definition of solubility is the maximum quantity of solute that can dissolve in a certain quantity of solvent or quantity of solution at a specified temperature or pressure (in the case of gaseous solutes). Usually oil viscosity is determined by laboratory measurements at reservoir temperature. Wikispaces As the pressure is reduced below the initial reservoir pressure pi, the oil volume increases due to the oil expansion. The bubble point pressure pb of a hydrocarbon system is defined as the highest pressure at which a bubble of gas is first liberated from the oil. By clicking Submit, you read and agree to our new Privacy Policy and Cookies Policy. Boundless Learning Pressure has a negligible effect on the solubility of solid and liquid solutes, but it has a strong effect on solutions with gaseous solutes. For many solids dissolved in liquid water, solubility tends to correspond with increasing temperature. As water molecules heat up, they vibrate more quickly and are better able to interact with and break apart the solute. (adsbygoogle = window.adsbygoogle || []).push({}); Solubility is the ability of a solid, liquid, or gaseous chemical substance (referred to as the solute) to dissolve in solvent (usually a liquid) and form a solution. In CHM1045 we discussed solubility as a yes or no quality. A popular saying used for predicting solubility is “Like dissolves like.” This statement indicates that a solute will dissolve best in a solvent that has a similar chemical structure; the ability for a solvent to dissolve various compounds depends primarily on its polarity. The solubility of gases displays the opposite relationship with temperature; that is, as temperature increases, gas solubility tends to decrease. This is apparent every time you open a soda can; the hissing sound from the can is due to the fact that its contents are under pressure, which ensures that the soda stays carbonated (that is to say, that the carbon dioxide stays dissolved in solution). There are various factors affecting solubility namely; temperature, pressure, polarity, molecular size and stirring increases the speed of dissolving. Crude oil viscosity is an important physical property that controls and influences the flow of oil through porous media and pipes. Boundless Learning Under certain conditions, the equilibrium solubility can be exceeded, yielding a supersaturated solution. At the saturation pressure (bubble point pressure) all the available gases are dissolved in the oil and the gas solubility reaches its maximum value. The degree of solubility ranges widely depending on the substances, from infinitely soluble (fully miscible), such as ethanol in water, to poorly soluble, such as silver chloride in water. CC BY-SA 3.0. In this process: Generally, solubilities of solids in liquids increase with temperature and those of gases decrease with temperature and increase with pressure. Oil viscosity is a strong function of many thermodynamic and physical properties such as pressure, temperature, solution gas-oil ratio, bubble point pressure, gas gravity and oil gravity. A solution is considered saturated when adding additional solute no longer increases the concentration of the solution. Gas solubility is always limited by the equilibrium between the gas and a saturated solution of the gas. At pb, the oil reaches its maximum expansion and consequently attains a maximum value of Bob for the oil formation volume factor. CC BY-SA 3.0. Temperature often plays the largest role, although pressure can have a significant effect for gases. The dissolved gas will always follow Henry's law. This relationship is written as: Where k is a temperature-dependent constant, p is the partial pressure (atm) of the solute in the gas above the solution, and c is the concentration of the dissolved gas in the liquid (mol/L). The gas solubility Rs is defined as the number of standard cubic feet of gas which will dissolve in one stock-tank barrel of crude oil at certain pressure and temperature. In the absence of the experimentally measured bubble point pressure, it is necessary for the engineer to make an estimate of this crude oil property from the readily available measured producing parameters.