Simple, Fast and Accurate Solvent-free Method for Produced Water Process Monitoring

What is produced water? Water that comes to the surface with oil and gas Contains many chemical constituents – Salt content (salinity, total dissolved solids, electrical conductivity) – Oil and grease Composite of many hydrocarbons and other organic materials – Toxics from various natural inorganic and organic compounds or chemical additives – NORM – Some oxygen demanding materials

U.S Oil and grease limit used as a “surrogate” for other pollutants – When oil and grease are controlled, other pollutants will also be controlled Limit is based on a statistical analysis of data from 60 U.S. platforms – Monthly average = 95th percentile = 29 mg/l – Daily maximum = 99th percentile = 42 mg/l Limits based on the Freon Extraction method

Method comparison Old protocol –IR Technique –Freon extraction – kept light ends D

Method comparison New Technique – EPA 1664 –Hexane extraction –Distill off the hexane Loss of light ends –Weigh the residue Hexane

A2 Test Methodology Filter water through a PTFE filter Mass loading Highly efficient Even distribution Quick drying

Filter Method Analysis time– 30 seconds No solvents Easy disposal Easy cleanup D

PAL Spectrometer

1. Place Sample on window 3. Analyze the sample 2. Rotate TumblIR into place 4. Cleaning is easy! No Sample Prep Required, No Training Required

Why FT-IR for Lubrication Analysis? Water Additive depletion –Antioxidant Phenolic Aminic EP/AW Oxidation Nitration –Varnish formation

IR Detector Scatter Large droplets => IR scattered A IR Detector Small droplets => IR absorbedB Water in oil Before surfactant

A B Surfactant effect Minimizes transfer loss from container to container Ensures consistency in amount of oil measured Before After

Absorbance Absorbance Before surfactant After surfactant Surfactant Effect

Gravimetrically Prepared Oil in Water Standards Used for FT- IR Calibration and Method Development 1.Oil dilution standards gravimetrically prepared in IPA 2.Appropriate volumes added to a thoroughly cleaned 1000mL volumetric flask 3.The IPA solvent is evaporated at 50°C under vacuum 4.Dried flask is filled to the mark with distilled water 5.250uL of Oil Stabilizer additive is added 6.Sample is vigorously shaken by inversion for 1-2min 7.Transfer solution to cleaned 1L sample jar, shaking the flask vigorously after ¾ of the solution is transferred

Methodology

Filter

FT-IR Spectrum of Mineral Oil

Wavenumber Absorbance

Actual Concentration Predicted Concentration R 2 =0.9957

Actual Concentration Predicted Concentration R 2 =0.9957

The limit of detection for this method is 0.10ppm (100ppb)

Wavenumber Absorbance

Additional capabilities Water in crude oil –0.1 – 0.3% level –Keeps pipes from corroding Water in crude oil –1% – 50% –Allows dewatering/production validation etc Water/Glycol mix analysis –Drilling fluid

Conclusions