Api Gravity

TOM MCKEOWNFRANKLIN HAMILTON

API GRAVITY

What is API Graivty?

The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water.

If API Gravity > 10 lighter than water, floats on water.

If API Gravity < 10 heavier than water, sinks.

It is a measure of the relative density of a petroleum liquid and the density of water.

It is used to compare the relative densities of petroleum liquids

Example of API Gravity

If one petroleum liquid floats on another and is therefore less dense, it has a greater API gravity.

Liquid 1 floats on Liquid 2. Liquid 1 is less dense than Liquid 2. Liquid 1> Liquid 2 in API Gravity

How is API Gravity Measured?

Mathematically API gravity has no units , it is nevertheless referred to as being in degrees. 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.

Mostly 10< API GRAVITY VALUES <70. Mainly measured by the Baumé scalethe standard for

measuring specific gravity of liquids less dense than water. How does the Baumé scale work? Formula to measure API Gravity 141.5/SG-131.5 Formula to Measure Specific Gravity 141.5+ API/131.5 Therefore, a heavy oil with a specific gravity of 1.0 (i.e., with the

same density as pure water at 60°F) would have an API gravity of:

141.5/1.0-131.5= 10 .0 API

How is API Gravity Measured? (con’t)

One other alternative to measure API Gravity is via the density of Oil

SG=Oil/H20The API Gravity is of course measured after

the SG (specific gravity) is measured.

Components effecting API Gravity

How to view the grades of API GRAVITY

Crude Oil: is classified as light, medium or heavy, according to its measured API gravity.

Oil with: API gravity 40 > and < 45 IDEAL the highest prices. API gravity > 45 degrees UNDESIRABLE the molecular

chains become shorter and less valuable to refineries. Light crude oil API gravity > 31.1 °API Medium oil API gravity 22.3 °API < and > 31.1 °API Heavy oil API gravity < 22.3 °API. Extra Heavy <10 °API (bitumen) Bitumen derived from the oil sands deposits in the Alberta,

Canada area has an API gravity of around 8 °API. It is 'upgraded' to an API gravity of 31 °API to 33 °API and the upgraded oil is known as synthetic crude

Q&A From LA State O&G Dept. Considering that the price of crude in the 40 to 45 degree API gravity range is posted at

a premium over crude above or below that range, the Mineral Board has posed two questions to the Royalty Oil Task Force concerning gravity adjustment deductions to state royalty oil.

Question A Can the state increase royalty revenue by taking its crude in-kind and blending low

gravity and high gravity crudes to produce blends in the 40 to 45 degree API range? Simple Answer The answer is almost always no because the mixture that has the desirable API

gravity will not have the same chemical composition as that of a naturally occurring crude of the same API gravity. Refiners are ultimately paying for the composition of the crude rather than for its density as measured in degrees API.

Question B Why is crude lighter than 45 degree API penalized with a gravity deduction similar to

the gravity deduction for crude heavier than 40 degrees API? Simple Answer The answer lies in realizing that although light crude (i.e., 40-45 degree API) is good,

lighter crude (i.e., 46 degree API and above) is not necessarily better for a typical refinery. Looking at the chemical composition of crude, as the crude gets lighter than 40-45 degrees API, it contains shorter molecules, or less of the desired compounds useful as high octane gasoline and diesel fuel, the production of which most refiners try to maximize. Likewise, as crude gets heavier than 40 degrees API, it contains more longer and bigger molecules that are not useful as high octane gasoline and diesel fuel. It is, thus, consistent from the perspective of a chemical engineer at a refinery to penalize these lighter and heavier crudes similarly.

API GRAVITY PRICE ADJUSTMENT

Gravity

A B C D F G H

Per Degree

Cumulative Below 40

API Per

Degree

Cumulative Below 40

API

60.1 & Above

Above 45.0 API Deduct $0.015 Per Barrel Per 0.1 API

Gravity

$0.00

Above 60 API Gravity

Deduction Based on Quality

Analysis of Condensate

Above 45.0 API Deduct $0.015 Per

Barrel Per 0.1 API Gravity

Above 45.0 API Gravity Deduct

$0.015 Per Barrel Per 0.1 API Gravity

Above 45.0 API Gravity

Deduct $0.015 Per


$0.00

50.1-60.0

Above 50.0 to 60 API Gravity

Deduct $0.01 Per Barrel Per

0.1 API Gravity

45.1-50.0

$0.00

40-45.0 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 39-39.9 $0.02 $0.02 Below 40.0

API Deduct $0.02 Per


$0.02 $0.02 Below 40.0 API Deduct $0.015 Per


38-38.9 $0.02 $0.04 $0.02 $0.04 37-37.9 $0.02 $0.06 $0.02 $0.06 36-36.9 $0.02 $0.08 $0.02 $0.08 35-35.9 $0.02 $0.10 $0.04 $0.012 34-34.9

Below 35.0 API Deduct $0.015 Per Barrel Per 0.1 API

Gravity

Below 35.0 to 30.0 API

Deduct $0.01 Per Barrel Per

0.1 API Gravity

$0.04 $0.16 33-33.9

Below 34 Deduct

$0.015 Per Barrel Per 0.1 Degree API

Below 34.0 API Deduct $0.02 Per Barrel Per 0.1 API

Gravity

Below 34 Deduct

$0.015 Per Barrel Per 0.1 Degree API

32-32.9 31-31.9 30-30.9 29.9 & Below

Below 30.0 API Deduct $0.015 Per


Examples: Deductions From 40

API Gravity Price

Examples: Deductions

From 34 API Gravity Price





Examples: Deductions From 40

API Gravity Price





Gravity $/Bbl Gravity $/Bbl Gravity $/Bbl Gravity $/Bbl Gravity $/Bbl Gravity $/Bbl 33 $0.40 33 $0.15 Gravity $/Bbl 33 $0.14 33 $0.36 33 $1.05 33 $0.15 29.5 $0.93 29.5 $0.68 29.5 $0.58 29.5 $0.22 29.5 $1.06 29.5 $1.58 29.5 $0.68 24 $1.75 24 $1.50 24 $1.40 24 $0.32 24 $2.16 24 $2.40 24 $1.50 18 $2.65 18 $2.40 18 $2.30 18 $0.44 18 $3.36 18 $3.30 18 $2.40

Sources via Web

http://www.conocophillips.com/products/business/crude_oil/gravityscale/index.htm

http://www.freepatentsonline.com/4248599.html

http://en.wikipedia.org/wiki/API_gravity

Documents

Api Gravity