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Reservoir Fluids

Compositional-Analysis


Compositional analysis generally refers to the measurement of the distribution of hydrocarbons and other components present in oil and gas samples. Using modern chromatography techniques samples are analyzed to determine the breakdown of the components in the sample. The analysis can be used to determine the value of a sales gas, it can be calculated to determine emissions. Compositional analysis can be used to assess the quality of samples, it can also help determine resevoir continuty and investigate leakage.


Compositional Analysis

Sample Assesment
The composition of the gas and oil samples taken from a surface separator can be used as a quality check. Once the compositions of the separator products are determined, the K-values of those equilibrium products are calculated and plotted.

The values, when plotted alongside theoretical values based on separator conditions, help reinforce the confidence of the validity of the samples.


Compositional Analysis

Drilling Mud Contamination
A sample of circulated oil-base mud is squeezed in a mud press and the collected filtrate is also injected onto a gas chromatograph column to be used as a reference.

Once both the reservoir fluid and oil-base compositions have been determined, the resulting molar compositions are input into proprietary software that determines the level of contamination of oil-base mud in the stock tank liquid.



Compositional Analysis

Fingerprint
In some cases there is a need to profile or "fingerprint" a petroleum sample to determine whether two hydrocarbons have come from a common source.

This technique can also be used to check for lubricants and other refined products.


C60 Paraffin
Another specialized chromatography analysis is the C60 paraffin analysis. This analysis is used to determine the distribution of the paraffin components of a hydrocarbon system. A sample of stock tank liquid is injected onto a capillary column of a high temperature chromatograph and the normal paraffin components from Heptadecanes (C17) through Pentacontanes (C60) are identified and quantified.


Compositional Analysis

Compositional Analysis

Distillations
Distillation, or volatility characteristics, of petroleum products are an indication of their performance in their intended applications.

Petroleum product specifications generally include distillation limits to assure products of suitable volatility performance