Next year the extra light crude market will continue to see a glut. Using api gravity, the conventional crude oils can be generally considered as light api30, medium 30api22, and heavy api american petroleum institute gravity is a term often used to measure how heavy or light a petroleum liquid is comparing to water. For example, if one petroleum liquid is less dense than another, it has a greater api gravity. Using the following formula, api gravity can also be used to calculate how many barrels of crude oil can be produced per metric ton. The api gravity is the form usually employed in petroleum exploration and production sector to represent the density. Figure 1a 1 depicts the change in specific gravity with temperature for crude oils of varying api gravity. Effects of crude price formula may be unexpected oil. There have been successive price regimes since the beginnings of the 20th century.
Specific gravity can be calculated from api gravity. A crude oil will typically have an api between 15 and 45 degrees. The only information required to calculate the api gravity is the specific gravity or density of the hydrocarbon. Washington, may 20, 2014 a comprehensive thirdparty study released today by the north dakota petroleum council ndpc shows that bakken crude oil is very similar to other light crudes and meets all federal regulations and tank car design standards for shipping flammable liquids by rail. Totals may not equal sum of components due to independent rounding. Calibrated in api degrees or degrees api, it is used universally to expresses a crudes relative density in an inverse measure lighter the crude, higher the api gravity, and vice versa because. Jan 27, 20 here is what i can remember from a class i had on this topic last year. When subjected to the simplest an d least costly form of refin ing, a high gravity crude oil will yield a larger proportion of light, high value products such as gasoline than will a low gravity crude oil. An api gravity of 10 means the petroleumbased liquid being measured has about the same density mass per unit volume as water.
The arbitrary formula used to obtain this effect is. Api gravity is thus an inverse measure of a petroleum liquids density relative to that of water also known as specific gravity. Values of specific gravity vary widely, but by using this formula, api gravity values of petroleum products are closer together than specific gravity values, making engineers lives a little. Api gravity can be calculated using specific gravity, which is a. The crude oil price escalation and deescalation formula for change in api gravity may result in payment of a higher price for a crude oil as a result of the increase in api gravity, when the. Api gravity is the oil industry standard used to determine and classify the density of oil. Corrected api gravity for temperature other than 60 deg f. Feb 16, 2010 formula given for specific gravity in slide no. Percentages of total imported crude oil by api gravity percent by interval period.
Api is calculated from a hydrocarbons specific gravity using this formula. Based on the mix of their respective crude oil production streams, the distribution by api gravity of crude oils produced in texas, north dakota, and california differs significantly. The greater the api gravity, the less dense the liquid. Physical and chemical properties of crude oil and oil products. Standard test method for density, relative density speci. Api american petroleum institute gravity is a dimensionless measure of the density of a petroleum liquid e. Simple equations to approximate changes to the properties. Api gravity, weighted average refinery crude oil input qualities. The result is an arbitrary scale for measuring gravity, expressed in degrees api. For example, the market price of crude oil is primarily based on american petroleum institute api gravity, a measure of density relative to that of water, and sulfur content with low sulfur. Api gravity can be calculated using specific gravity, which is a ratio of the density of the sample liquid in comparison to a reference liquid, usually water. Density is a state function and for a pure compound depends on both temperature and pressure and is shown by liquid. A specific gravity scale developed by the american petroleum institute for measuring the relative density of various petroleum liquids, expressed in degrees. Api gravity is one of the key characteristics of crude oil that, along with other characteristics such as sulfur content, is used by refiners when evaluating different crude streams for processing into petroleum products.
If api gravity is less than 10 it will sink in water. Api gravity, sulfur content, and desulfurization of crude. Specific gravity of oil calculator convert api to specific. The api gravity or american petroleum institute gravity is a term often used to measure how heavy or light a petroleum liquid is comparing to water. Oil has one fatal weakness by tsvetana paraskova nov 28. Learn about oil industry conversions crude petroleum, and the refined products made from crude oil, are normally measured either by volume in gallons and us barrels, or by weight in tons or tonnes.
Exxonmobil develops and applies nextgeneration technologies to help safely and responsibly meet the worlds growing needs for energy and highquality chemical products. The left and right margins of the table are annotated with the temperature. Using the gas pycnometer to determine api gravity in crude. Api gravity is a commonly used index of the density of a crude oil or refined products. The relative density of petroleum liquids can also be uncovered by using api gravity value. This measurement reflects how light or heavy a crude oil is compared to water. Api gravity calculator crude oil api gravity chart. The api gravity is calculated from the following equation. Crude oil that has a high api gravity, and low viscosity is generally easier to produce than lowgravity, highviscosity oil that may require stimulation to maintain production rates. Api gravity, sulfur content, and desulfurization of crude oil. Percentages of total imported crude oil by api gravity. Bitumen derived from the oil sands deposits in the alberta, canada area has an api gravity of around 8 api.
Api gravity also known as the american petroleum institute gravity, is the measure of the density of a petroleum liquid in relation to the density of water. It is upgraded to an api gravity of 31 api to 33 api, citation needed and the upgraded oil is known as synthetic crude. Average dbe dbeavg and slope of planar limit equation sl for the. Api gravity is a system developed by the american petroleum institute to measure how light or heavy a petroleumbased liquid is in comparison to water. Api gravity change with temperature for crude oils. Alkenes with one double bond have the general formula cnh2n. Api gravity can also tell us whether the fluid will float or sink in the water. Between 1930 and 1970, it was the so called seven sisters pricing regime, where the pr. The general formula for paraffin or alkane hydrocarbon molecules. Using api gravity, the conventional crude oils can be generally considered as light. Now that we know how to calculate these measurements, lets take a look at a reallife example with a.
Penentuan specific gravity sg dan api gravity penentuan specific gravity berat jenis minyak crude oil dilakukan dengan alat hydrometer, dimana penunjuk specific gravity dapat dibaca langsung pada alat. The american petroleum institute established api gravity measure as a measure of the density of petroleum liquids relative to water. D28712b2019 standard test method for api gravity of crude petroleum and petroleum products. Api gravity correction for temperature in this spreadsheet, just type in the required information and press the compute button. Api gravity express the gravity or density of crude oil and liquid petroleum products. Jan 25, 2019 divide the days crude oil price by 42. Where ev weight percent evaporated, t surface temperature c, t time min. Application of the onethird rule in hydrocarbon and crude. How to calculate gasoline price from crude oil price. Use the online api to specific gravity converter to. Api gravity is a measure of the density of hydrocarbon fluid that has been used widely for long period of time. Changes in crude oil density and specific heat, or heat capacity, can be estimated from graphs andor more elaborate computer simulation. Simple equations to approximate changes to the properties of.
The american petroleum institute gravity, or api gravity, is a measure of how heavy or light a petroleum liquid is compared to water. Crude oil price differentials and differences in oil. Main characteristic of crude oil is api american petroleum institute gravity which shows how. In general, viscosity characteristics are predictable. If that seems arbitrary, it is because the equation was designed for conveniences sake. If an oils api gravity is less than 10, it is heavier than water and will sink.
The formula used to obtain the api gravity of petroleum liquids is thus. As the weight of an oil is the largest determinant of its market value, api gravity is exceptionally important. Apr 22, 2014 this article describes simple equations to approximate changes to the properties of crude oil with changing temperature. Temperature and pressure volume correction factors for generalised crude oils, refined products and lubricating oils. Specific gravity sp gr measures the ratio of density of the substance to the density of water in a given temperature, i. Generally, lighter high api crudes are more valuable because they yield more highvalue light products when run through a refinery. Jul 23, 2007 api gravity is graduated in degrees on a hydrometer instrument and was designed so that most values would fall between 10 and 70 api gravity degrees. Use our api gravity to density to convert to specific gravity.
Api is devised jointly by the american petroleum institute and the nist national institute of standards and technology. Energy statistics manual uc berkeley college of natural. Conversely, an api gravity less than 10, will cause petroleum liquid to sink in. Astm d287 12b2019 standard test method for api gravity of. This tip of the month describes simple equations to approximate changes to the properties of crude oil with changing temperature.
Here, we use the greek symbol rho to indicate density. The formula to calculate api gravity from specific gravity sg. Appendix a the oil properties data appendix wiley online library. Api is calculated from a hydrocarbons specific gravity using this formula api 141. The official formula used to derive the gravity of petroleum liquids from the specific gravity sg is presented. Use our api gravity at 60f temperature correction calculator online.
In fact, even opec countries often rely upon formulas using prices determined on. The term api gravitya standard adopted by the american petroleum institute is commonly used to express the specific gravity of petroleum. Dec 09, 2016 the formula to calculate api gravity from specific gravity sg is. Crude oil with api gravity less than 10 api is referred to as extra heavy oil or bitumen. Api gravity is gradated in degrees on a hydrometer instrument and was. The higher the api gravity, the lower the density of the petroleum liquid, so light oils have high api gravities. Penentuan specific gravity berat jenis minyak crude oil dilakukan dengan alat hydrometer, dimana penunjuk specific gravity dapat dibaca langsung pada alat.
The heavy crude oils with the api gravity of lower 22. For an api gravity greater than 10, a petroleum liquid will float on water. The official formula used to derive the gravity of petroleum liquids from the specific gravity sg, as follows. The relationship between volume and weight is usually measured by density in the united kingdom the alternative measure is relative density or. This application allows you to perform any of the following operations. Penentuan specific gravity sg dan api gravity teknik. A specific gravity scale developed by the american petroleum institute api for measuring the relative density of various petroleum liquids, expressed in degrees. After decades of decline, crude oil production in the united states has recently. If the gravity is less than 10, the petroleum liquid is heavier and thus it sinks and if the gravity is greater than 10, the liquid is lighter, so it floats on water. The api gravity scale acts as an inverse relationship to density and specific gravity, that is, as density increases, the api gravity decreases. Definition of api gravity of water provided by wikipedia. They are many common crude types like west texas, brent api gravity is a measure of how light or heavy the crude oil compared to water. Viscosity increases with decreases in crude oil api gravity assuming a constant watson characterization factor and decreases in temperature. Determination of api gravity, kinematic viscosity and.
Comparing crude oils with different api gravities on a molecular. Using the api to specific gravity conversion formula, the oil specific gravity is calculated. Figure 1a crude oil specific gravity vs temperature 1 this graph was compared with densitytemperature data from table d1, api publication 421, monographs on refinery environmental control management of water discharges 2. A library of exxonmobil crude oil blends sorted by api gravity and by sulfur content. The measuring scale is calibrated in terms of degrees api. Correlations for crude oil density and temperature are found by use of tools based on astm d 125004 and ip 20004 api manual of petroleum measurement standards, chapter 11 physical properties data, section 1. The api gravity may be calculated using the following formula. Crude oil blends by api gravity and by sulfur content. Higher api indicates a lighter lower density crude. To convert an api gravity reading to 60f, we usually use astm table 5b. Api is a specific gravity scale developed by the american petroleum institute for measuring the relative density of various petroleum liquids 8. What is the major property that effects the api gravity of a crude oil. Standard test method for api gravity of crude petroleum and. Each colored line represents a crude oil with a given density at a.
Oil used during the socsex experiment evaporation equation. The formula for specific gravity, given that the reference substance is water, is the density of the object divided by the density of the water. Api gravity is thus an inverse measure of the relative density of a petroleum liquid and the density of water, but it is used to compare the. The scale of api gravity was adjusted so that most petroleum liquids fall between 10 and 70 degrees api gravity. Api stands for the american petroleum institute, which is the industry organization that created this measure calculation of api gravity.
Chapman b department of chemical and biomolecular engineering, rice university. If an oils api gravity is greater than 10 the gravity of water, it is lighter than water and will float on it. Use the online api to specific gravity converter to find the sp gr of an oil by providing the api gravity. If its api gravity is greater than 10, it is lighter and floats on water. Api gravity is gradated in degrees on a hydrometer instrument and was designed so that most values would fall between 10 and 70 api gravity. Impressive api gravity temperature correction calculator.
Physical and chemical properties of crude oil and oil products 1 density, specific gravity, and api gravity density is defined as mass per unit volume of a fluid. It is used to compare densities of petroleum liquids. The api gravity is used to classify oils as light, medium, heavy, or extra heavy. The characteristics of the oil can, and often do, influence everything from well spacing to pump size to life of production all of which has an impact on the. Api gravity crude oil samples can be classified as medium or heavylight, according to their api gravity. Api gravity to specific gravity and density chart if you need need to convert other value use our online api gravity calculator on the top.
Density is an integral part of determining the value of oil, where light oils command a higher price due to the ease with which they are converted to gasoline. Oil gravity is usually 40 api or higher and increases during production after the. Exhibit 2 indicates the quality of a typical light crude 35 api and a typical heavy crude 25 api. An api of 10 is equivalent to water, which means any oil with an api above 10 will float on water while any with an api below 10 will sink. The density of crude oil and liquid hydrocarbons is usually reported in terms of specific gravity sg. This will tell you the dollar amount per gallon of refined gasoline attributed to crude. American petroleum institute s inverted scale for denoting the lightness or heaviness of crude oils and other liquid hydrocarbons. W withheld to avoid disclosure of individual company data.
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