Environmental Chemistry Division - Case Studies...


Seabed Surveys for Oil Exploration/Production

In the current climate of environmental awareness and accountability, the impact of drilling operations on the environment has become a major focus for oil companies. GEOTECH frequently carries out analyses of seabed samples. These samples are analysed to determine a number of physical and chemical properties, including total petroleum hydrocarbons (TPH) (detection limit: ~ 20mg/kg), trace metals, including barium, cadmium, chromium, mercury and lead (detection limit: 10-50,000 mg/kg), particle size, total carbon (TC) and total organic carbon (TOC). The analyses provide an indication of the concentration of these compounds in an undisturbed natural setting. Companies often commission a base survey (conducted before drilling commences) and later analyse the same site to provide information as to the extent (if any) of possible contamination.


Study of Wood Samples from Offshore Ship Wrecks

The Maritime Museum of Western Australia commissioned GEOTECH to analyse a suite of wood samples from wrecks in the Indian Ocean. Pyrolysis gas chromatography-mass spectrometry (Py GC-MS) was used to distinguish the various stages of biodegradation in these samples, and the data were used to help select the appropriate preservation technique.


Investigation of Production Problems in a Fractured Reservoir

GEOTECH was asked to characterise an unknown slime (affectionately called "gloop") recovered from a hydrocarbon production well. This "gloop" was thought to be blocking stimulated fractures and preventing the production of commercial quantities of crude oil. The analytical programme was designed specifically for the client, including tests to determine the composition of the "gloop" and the reason for its formation. Once thses factors were determined, an antidote was developed to prevent the "gloop" from forming downhole, and the well resumed commercial activity.


Leachate Testing

Oil companies and other clients often need to assess the nature of sediments to be disposed of in respect to landfill criteria, as per Landfill Waste Classification and Waste Definitions.

In a first testing phase the concentration of contaminants such as BTEX, TPH and metals in the waste are determined according to ASTM methods. These contaminant concentrations are compared with contaminant thresholds (CT) values and the contaminant assigned a classification. If any contaminant concentration exceeds the relevant CT value, Australian Standard Leaching Procedures (ASLP) leachate concentrations for all relevant contaminants are determined.

GEOTECH regularly performs ASLP leachate analyses on sands recovered during shutdown of oil production wells on the North West Shelf to allow operators to dispose of the sand according to legislative requirements.

Biodegradation of Base Fluid - August 2006
Oil Mist Monitoring - August 2006