Sidewall sampling

The sidewall sampling tool (Sl/VS) can be used to obtain small plugs (2 cm diameter, 5 cm length, often less) directly from the borehole wall. The tool is run on wireline after the hole has been drilled. Some 20 to 30 individual bullets are fired from each gun (Fig. 5.35) at different depths. The hollow bullet will penetrate the formation and a rock sample will be trapped inside the steel cylinder. By pulling the tool upwards, wires connected to the gun pull the bullet and sample from the borehole wall. 

SWS are useful to obtain direct indications of hydrocarbons (under UV light) and to differentiate between oil and gas. The technique is applied extensively to sample microfossils and pollen for stratigraphic analysis (age dating, correlation, depositional environment). Qualitative inspection of porosity is possible, but very often the sampling process results in a severe crushing of the sample thus obscuring the true porosity and permeability. 

In a more recent development a new wireline tool has been developed that actually drills a plug out of the borehole wall. With sidewall coring (Fig. 5.36) some the main disadvantages of the SWS tool are mitigated, in particular the crushing of the sample. Up to 20 samples can be individually cut and are stored in a container inside the tool. 

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Keywords d rec methods, indirect methods, rock properties, coring, core barrel, standard core analysis, special core analysis, slabbed core, sidewall samples, direct indications, microfossils, sonde, logging unit, invasion, mudcake, formation pressure measurement, fluid sampling, measurement while drilling, formation evaluation while drilling. 

Porosity data can be obtained from laboratory measurements on sidewall samples and core samples from boreholes (e.g. Monicard, 1981), from geophysical well logs (sonic, density and neutron logs Serra, 1987) or from seismic data. 

Gas exits the vessel at the bottom through the vessel sidewall. This arrangement minimizes entrainment of fines. Additionally, a cone strainer should be included in the exit line. This line should also have a pressure tap and sample test tap. 

For reactions at atmospheric pressure, standard laboratory glassware such as round-bottomed flasks or simple beakers from 0.25 to 2 L can be used. A protective mount in the ceiling of the cavity enables the connection of reflux condensers or distillation equipment. An additional mount in the sidewall allows for sample withdrawal, flushing with gas to create inert atmospheres, or live monitoring of the reaction with a video camera. Most of the published results in controlled MAOS have been obtained from reactions in sealed vessels, and thus in the following mostly accessories for sealed-vessel reaction conditions are described. 

With time, however, the company encountered problems, including caving of the formation into the wellbore and the loss of permeability in zones that had accepted fluid. In June 1987, a number of sidewall cores were taken from the formation (Mehnert et al., 1990). Mineralogic analysis by x-ray diffraction showed that significant amounts of calcite (CaCCb) and brucite [Mg(OH)2], as well as some amorphous matter, had formed from the original dolomite. In some samples, the dolomite was completely consumed and the rock was found to be composed entirely of a mixture of brucite and calcite. 

COOH)2, swnt- phenyl-S03Na, underivi-tized SWNT stabilized in 1% Pluronic F108 (3 pg/ml-30 mg/ml) (HDF) cytotoxic as the degree of sidewall functionalization increases The sidewall functionalized SWNT samples are substantially less cytotoxic than surfactant stabilized SWNTs (2006)... 

Fig. 3.6 for hypothetical Si and SiO samples subjected to 150 eV positive ion bombardment. The —150 volt bias on the sample determines the etch rate of the bottom of the etched feature (V ) whereas the lateral etch rate can be approximated by the zero bias etch rate (V,). This latter quantity is dependent on the material being etched and is showed as zero for Si02 in Fig. 2.6. Consequently, the etched feature in the SiOj has vertical sidewalls. Since is not zero for the Si, the sidewalls are not vertical.

For systems in which is not zero, the shape of the etched profile can be controlled to a certain extent by adjusting the stoichiometry of the discharge. This is illustrated in Fig. 3-7 using an idealized Si sample. As hydrogen is added to a CF. discharge the etch rate of Si will decrease as we have seen earlier in Fig. 3.2. However, the etch rate will stop on surfaces not subjected to ion bombardment (point A in Fig. 3.7) before etching stops on surfaces which are exposed to energetic ion bombardment. This means that the lateral etch rate has been eliminated and features with vertical sidewalls can be etched if an etch gas mixture of CF. — 10% is used in this example. 

We use sampling grids mainly for surface soil sampling, however, it is not unusual to place soil borings and collect subsurface samples on a grid pattern. Grids are also used for soil sampling from the bottom and sidewalls of excavation pits and trenches. 

In the course of remediation projects we often need to sample from the bottom and sidewalls of excavation pits. A variation of excavation pit sampling is sampling from test pits and trenches. Test pits are small excavations usually made with a backhoe for a purpose of collecting a subsurface soil sample. A trench is a long and narrow excavation originating from a pipeline removal or placed with earth moving equipment for exploratory purposes. 

Collect undisturbed soil samples at the bottom and sidewalls of the pit. 

To sample with airtight coring devices, we must have access to exposed soil, which may be the ground surface, the bottom and sidewalls of an excavation, the stockpile face or side, or soil in the excavator bucket. We may also apply this technique for sampling of subsurface soil brought to the ground level in a split spoon sampler. 

The thickness of the coatings on the sidewall is 6 pm, and on the bottom a thickness of 2 pm was observed. The delamination of the catalyst coating is an artefact caused by sample preparation [86],... 

Jt-Stacking of 1-pyrenebutanoic acid succinimidyl ester on SWCNT sidewalls SWCNTs were suspended on meshed gold grids according to known methods and a grid sample was incubated in a 1-pyrenebutanoic acid succinimidyl ester solution (6 mM in DMF or 1 mM in methanol) for 1 h at room temperature, after which the sample was rinsed three times in pure DMF or methanol [196],... 

Again, the emission pattern from a glass substrate is also shown for reference. Figure 17.18 shows the fluorescence output as a function of incidence angle for the passivated sample. At the surface-plasmon incidence angle, the total fluorescence enhancement compared to the reference is 12 (normalized to the 3.1% fill-fraction of the bottom surface of the nanoapertures), which is comparable to the enhancement obtained under full interior surface coverage (Figure 17.14). Therefore, the fluorescence enhancement (per unit area) is comparable for fluorophores on the bottom as for fluorophores on the sidewalls with backside detection, as before with individual apertures. 

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