An IR-Based Field Analytical Method For Total Petroleum Hydrocarbon Measurement — Field Deployment And Benefit In Site Remediation

SYNOPSIS

Total Petroleum Hydrocarbons (TPH) in soil is often measured to determine if soils have been impacted by crude oil. PT. Chevron Pacific Indonesia (PT. CPI) operates several oil fields in Sumatra, and during site investigations and recovery, soil samples must be analyzed. Traditional laboratory methods require five days to complete, and commercial labs often take two to four weeks to release the reporting results. This could delay decision making regarding soil delineation and site excavation as well as in determining when soil remediation has been completed. In the PT. CPI pilot studies, a portable handheld infrared (IR) instrument was pilot tested with over 500 soil samples from variable PT. CPI sites to generate site-specific models. These samples covered a wide range of soil type, oil content, and moisture content, and should, therefore, be representative of most PT. CPI sites conditions. The US EPA 8015 TPH-Gas Chromatography (GC) analytical method data of those soil samples were used to create two site-specific models with 15 – 20 double blinded samples to validate the modeling work. The key advantages of this rapid IR method are that the soil samples don’t use any chemicals, so no wastes are generated, and the method provides results in a few minutes. This results in saving valuable time for site-specific decision-making. After the deployment in PT. CPI fields in July 2016, continuous monitoring of incoming soil types vs. data accuracy has been set up to evaluate the performance of this instrument at variable field conditions. The post-deployment evaluation concluded a good accuracy and repeatability compared to the standard laboratory method. Potential cost savings can be more than 100,000 US$ in a scenario where 3000 samples are analyzed per month.