API PUBL 4711:2001 pdf download.Methods for Determining Inputs to Environmental Petroleum Hydrocarbon Mobility and Recovery Models
3.1 Sample Collection
Analysis of product properties begins with obtaining representative product samples. Typically this is accomplished by bailing free product from monitoring wells or collecting samples from active free-product recovery systems. Samples should be collected from a sufficient number of points to characterize the product present. Spatial variations in product properties commonly occur due to releases of different products and/or differential in situ weathering. A minimum volume of 250 mL of product (free of water) should be collected. Samples should be stored in brown glass containers with minimal head space and kept cool. No preservatives are required. In all cases the in situ temperature of the product should be determined. This reflects the dependence of fluid properties on temperature. In the case of bailed product samples, temperature should be measured immediately after collection. In the case of active recovery systems, the temperature should be measured in fluids that are ÒfreshÓ from the well (as opposed to stagnant fluids from piping or tanks). A third option is to lower a thermometer in a secure housing down a well to the water table. In all cases the thermometer should have a minimum accuracy of 1-degree Celsius. After sources of representative product samples have been identified, additional product and water samples should be collected for laboratory core studies. The volume of water and product needed to conduct core studies should be determined by asking the laboratory. Again, samples should be stored in brown glass containers with minimal head space and kept cool.
In general, the density of site water should also be measured. This reflects the fact that both dissolved organic and inorganic compounds can effect water density. The density of water is significant in that capillary pressure is a function of the difference in density between water and product. Ideally, measurements should be made using liquids at their in situ temperature. Sensitivity to temperature is illustrated by considering fuel oil which varies in density by 2 percent over the range of 0 to 25 degrees Celsius (Charbeneau et al., 1999).
4.1 Sample Collection
Sediments – Analysis of soil properties at a laboratory scale begins with obtaining representative soil samples. Ideally, soil samples should be undisturbed. This reflects the fact that parameters of interest are dependent on the geometry of pore bodies and throats. Preservation of these features or reproducing these features represents a significant challenge. At one extreme, soil samples can be recovered using hollow stem auger and split spoon sampling equipment [see ASTM D1586-99 or ASTM D1452-80(1995)e1]. After extraction of product, samples can be dried and sieved to remove larger materials (e.g., gravel) that would block flow in a standard core holder (diameters of a few centimeters). Lastly, samples can be placed in coreholders with confining pressure similar to the in situ overburden pressure. The assumption associated with this approach is that the procedure will result in pore bodies and throats representative of the in situ conditions. In general, this approach should be avoided when possible due to potential biases associated with disturbing the architecture of the sediments
API PUBL 4711:2001 pdf download
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