Well samples location

ERSA) samples of 59 wells in 29 oil, gas and gas-condensate fields were compiled from internal, proprietary Shell databases and Warren Smalley (1994). All data used were quality checked and contaminated samples or samples of dubious origin were excluded. Table 1 summarizes the fields, wells, sample location and formations from which the different types of sample were obtained. Field locations are shown in Fig. 1. Data were obtained from sandstone and sandstone/shale sequences at depths between 7300 and 19000 ft TVDSS. At these depths, reservoir temperatures and pressures are between 107 and 191 °C and between 323 and 1136 bars, respectively. 

Mumber Density and Volume Flux. The deterrnination of number density and volume dux requires accurate information on the sample volume cross-sectional area, droplet size and velocity, as well as the number of droplets passing through the sample volume at any given instant of time. Depending on the instmmentation, the sample volume may vary with the optical components and droplet sizes. The number density represents the number of droplets contained in a specified volume of space at a given instant. It can be expressed as follows, where u is the mean droplet velocity, t the sample time, andM the representative cross-sectional area at the sampling location. 

No water wells were located down gradient from the landfill and significant leaching past the landfill liner was not found hence no further hydrological assessments were undertaken. Airborne emissions from the landfill were characterized by air samples taken at the landfill and airborne concentrations were also measured at the nearest community. 

A commonly used method of sampling and analysis for volatile organic compounds In ambient air Is by concentration of the compounds on a solid sorbent such as Tenax and subsequent thermal desorption and GC/MS analysis of the collected compounds. The analysis phase, although not trivial, can be done well If proper care Is taken. However, the sampling phase of this process apparently Introduces artifacts and unusual results due to, as yet, unknown factors. A method to detect some sampling problems has been proposed and tested (7 ). This distributed air volume method requires a set of samples of different air volumes to be collected at different flow rates over the same time period at the sampling location. Each pollutant concentration for the samples should be equal within experimental error since the same parcel of air Is sampled In each case. Differences In results for the same pollutant In the various samples Indicates sampling problems. 

Alachlor was found In two wells out of 14 sampled In Nebraska at about 0.04 ppb In a monitoring study which focused on atretzlne high use areas (24). These corn growing areas were known to have sandy soils and a shallow, unconflned aquifer. The wells sampled were assumed to be representative of over 1,000 wells located In the study area. 

The sample locations are shown on the map in Figure 1. Euromonding (Port of Rotterdam) and the North Sea Canal (Port of Amsterdam) are well-known polluted areas. The sites in the North Sea are situated at the end of the estuarine harbour areas, except for Noordwijk (site 6), which is a t5 ical coastal location. Two relatively clean sites, the Oesterput in the Eastern Scheldt estuary (site 14) and Ussehneer near Enkhuizen (site 12), were also sampled and used as saltwater and freshwater reference sites respectively. In the Port of Rotterdam transect the salinity gradient is continuous whilst in the Port of Amsterdam transect the salinity gradient is interrupted and more complex due to canalisation. The numbers of the sampling sites correspond with the site numbers reported previously for the results of the chemical sediment and flounder liver analyses (De Boer 2001). The transects were sampled from 19 to 26 September 1996. 

Fig. 5. Variation of the Sl80 and 8D values of the fluid delivered from well 131, located 500 m away from the re-injection site, during an injection test conducted in the peripheral area of Serrazzano in the Larderello field (open squares). The figure also shows graphically, and in arbitrary units, the flow rate Q of water re-injected into the well as a function of time, and the position of each sample collected. Theoretical isotopic pattern of the steam produced by re-injected water, assuming continuous steam separation at depth, is also reported. Since the actual evaporation temperature and the fraction of residual water are unknown, calculations were made for three different temperatures (140, 160, and 180 °C) and fractions (/w) of residual liquid water after boiling. Dashed line represents the hypothetical mixing between deep geothermal steam (W) and completely evaporated re-injected water (R).

Air microbial monitoring should be performed in and around areas of high operator activity. It is not unusual to see settle plates and air sample locations well away from such areas. A typical example is where settle plates are located well to the rear of the filling machine where there is little or no operator activity. The same may be true for air sampling. It is important, therefore, to observe operator activity over a period of time and ensure that the monitoring sites are located so as to monitor operator activity. 

In contrast to the atmosphere, where much can be learned from a relatively small number of 14C sampling locations, the sea presents a formidable sampling problem. The sea does not achieve the nice vertical and zonal uniformity characteristic of the troposphere. The well-mixed surface layer of the sea, generally 50-100 meters deep but occasionally deeper, appears to achieve a uniform concentration but only vertically the levels of excess 14C in the mixed layer varies considerably from place to place. This arises partly from the upwelling of subsurface water of lower 14C content which perturbs the concentration of surface water in many areas of the ocean, adding to the difficulty of interpreting sea water 14C measurements. 

Table VI summarizes the sampling location and time, surface-water salinity, the measured surface-water H202 concentration, the decay rate constants, and bacterial cell counts for the five samples obtained on the transect. Although the ambient concentration of H202 remained similar throughout the transect, the decay rate decreased to give H202 half-lives of 2.5-12 h. The cell numbers were similar at all sampling locations, and the decay rate did not appear to correlate well. For some unexplained reason the increase...

Airborne micro-organisms are not free-floating or single cells, but they frequently associate with particles of 10 to 20 pm. Particulate counts as well as microbial counts within controlled environments vary with the sampling location and the activities being conducted during sampling. 

Location of hot spring or well sample (number of samples) Temperature (°C) PH Arsenic concentration (mg kg x)a Reference... 

Where it is not possible to move a pile, there is no choice but to sample it as is, and the sampling regime usually involves incremental spacing of samples over the entire surface. The reliability of the data is still in doubt. However, without any attempt at incremental spacing of the sample locations, any sample taken directly from an unmoved storage pile is a grab sample that suffers from the errors that are inherent in the structure of the pile as well as in the method by which the sample is obtained. 

The paper that best summarizes these midwestern groundwater studies is Kolpin et al. (1993), which describes the exact locations, detailed land use, and local features surrounding the 303 wells sampled. All of the Kolpin groundwater studies, which address a 12-state area in the Com Belt, use procedures described in this key paper. 

Figure 30.3 Location of wells in the USGS midwestern groundwater monitoring network. (A) Location of wells (mostly drinking water) sampled in the USGS midwestern groundwater monitoring network during 1991-1994. (B) Location of municipal drinking water wells sampled in Iowa during 1995-1998.

Sample location (soil boring, depth, monitoring well, grid unit, etc.)... 

Sampling point identification (soil boring, grab sample location, monitoring well... 

Ground water samples can be collected from monitoring or supply wells. Their location is not always straightforward—generally such water is sampled over hot spots and near locations following the subterranean stream in order to detect plume profile movements.19 The depth of the well and the characteristics of the surrounding land surface and upstream activities can help in the interpretation of results. 

SOM visualization can indicate outliers, that is, those chemical variables or sampling locations that do not belong to a well-organized group. 

Thirty crude oils from the BCF were collected (1) along two parallel and generally southwest-northeast trends. The areal extent of the BCF showing locations of wells sampled is shown in Figure 1. These oils were characterized by their API gravity, percent saturates, aromatics, NSO and asphaltene compounds, gas chromatograms for whole oils, CA-C7 fractions, and aromatics. Concurrently, 24 associated waters were also sampled and analyzed for Ca++, Mg++, Na+, HC03, C03 , SOA , pH, and total dissolved solids (TDS) (1). 

Figure 1. Areal extent of Bolivar Coastal Fields showing locations of wells sampled (Reprinted with permission from Ref, 1. Copyright 1983 Bockmeulen et al.)...

Figure 7.32. Geochemistry of the Devonshire, Bermuda groundwater lens. (A) Well samples and location of freshwater, (B) percentage of seawater in the groundwater, (C) saturation with respect to aragonite, (D) saturation with respect to calcite. SI (= Q) is the saturation index. (After Plummer et al., 1976.)...

Proposed probabilistic sampling location Soil borings by marin, 1998 Soil borings byTRC, 1988 Monitoring well byTRC, 1988 Sediment sample by TRC, 1988 Surface soil sample byTRC, 1988... 

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