When injecting produced water into a formation, oil will bind up solids and can prevent water from being injectable into the formation as a result of changing the formation to oil-wet.  We recommend testing for total oil and grease (TOG), as the reporting values are very similar to total petroleum hydrocarbons (TPH) in brine water.  Since these are produced water samples, we do not anticipate a significant presence of polar hydrocarbons such as vegetable oils or animal fats.  The testing procedure for TOG also allows for a higher sample throughput volume without sacrificing accuracy.  In a case where an oil in soil measurement is needed, we would be required to run a TPH measurement to eliminate any plant or animal components.

J&L Laboratories utilizes the Spectro Scientific InfraCal 2 ATR-SP IR to perform TOG analysis.  Spike analyses are performed routinely to ensure that the instrument is within calibration.  The TOG method uses a 1:10 extraction with n-hexane.  A very small aliquot of n-hexane extract is then placed on the measurement window and allowed to evaporate.  The oil will leave a film on the window that interacts with the IR beam in a way that is proportionate to its concentration.

Customer notes:

An oil sample from the formation should be turned in for our analysts to determine which method parameter to use for that area.  We have a range of calibration curves that we will apply to the customer’s oil, or a calibration curve can be custom built for a specific field or formation.  Results are expressed in ppm.