New Oil in Water Method Allows Onsite Analysis

New regulations governing the measurement of oil-in-water, a 15% hydrocarbon emission reduction target and Hydrocarbon Trading have all heightened the importance of monitoring, and as a result instrument supplier Quantitech has reported a rapid growth in demand for the ‘InfraCal’ portable hydrocarbon analyser.

The Oil Pollution Prevention and Control (OPPC) Regulations prohibit the discharge of oil into the sea unless it is in accordance with the schedule conditions of a permit issued to cover the discharge. In support of OPPC, the DTI has provided industry with technical guidance on suitable methods for the sampling and analysis of produced water and other samples containing hydrocarbons.

The determination of oil in produced water has been traditionally carried out using a standard reference method based on solvent extraction followed by Infrared analysis. However, the solvent Freon 113 is no longer permitted (Montreal Protocol) and there have been health and safety concerns with its replacement, Tetrachloroethylene, so there has been a drive to develop and adopt a new reference oil-in-water analysis method by both the authorities and the offshore industry.
As a result, an OSPAR modified version of the ISO 9377-2 GC-FID method (Gas Chromatography and Flame Ionisation Detection) has been adopted as the reference method and this comes into force 1st January 2007.

GC-FID analysis is generally undertaken in a laboratory; however, the DTI guidelines permit the use of other methods that have a crude oil specific validation against the GC-FID. As a result, many operators have exploited the facility to employ the InfraCal because it is a portable device providing faster results at a much lower cost.

The ‘InfraCal’ is a portable instrument, marketed in the UK by Quantitech Ltd, for the measurement of total hydrocarbons (both soluble and dispersed).

Sarah McGillivray, Operational Chemist for CETCO Oilfield, says “We use an InfraCal on every job that we undertake including produced water treatment, well interventions or acid stimulations. We use the InfraCal in each of these applications in order to determine the oil in water content of the treated fluids. This analysis allows the operator of our equipment to fully optimise the equipment and also to determine the point at which our consumable media has been exhausted. One of the key advantages of onsite analysis is the facility to demonstrate successful treatment quickly and easily. Also, without an InfraCal we would not be permitted to treat contaminated produced water and dispose of it directly overboard.”

R.U.M. Consultancy provides analytical services including mass spectrometry for organics and, commenting on the monitoring regulations, their Richard Morrison says “The InfraCal is now the main portable device for the measurement of oil in water; it is robust, easy to use and most people are familiar with it. We also provide the instrument validation service that is required under the new regulations. In summary, I believe that the new monitoring guidelines will help protect the environment without imposing a heavy cost burden.”