Borehole sampling

KEYWORDS geochemical sampling, carbon sequestration, borehole sampling, fluid sampling... 

Stuart, A. (1984). Borehole sampling techniques in groundwater pollution studies. British Geological Survey Technical Report, WE/FL/84/15. 

Table 15.2 Statistical parameters of the analytical data from the borehole samples of the phase I monitoring using a 100 m x 100 m network (statistics all lithologies)... 

Levinson et al. (1978) observed that organic-rich lake sediments from the vicinity of the Key Lake U deposit contained 18 times as much U as one would infer from the Ra content. Similarly, borehole samples from southern Africa (Levinson and Bland, 1978) had excess chemical U, whereas soils from Thailand contained excess radiometric U. Syromyatnikov et al. (1967) describe a gamma-ray anomaly over decomposed rhyolites which contained excess Th and Ra. Nikiforova and Yufa (1970) give a mean eUAJ ratio of 1.16 for 520 different soil samples, and 1.03 for 73 rocks, with the following... 

DBCP Sorption on Soil and Saprolite. For the Kunia site, sorption values were measured on samples from several depths in Boreholes 2 and 3 as well as from three shallow depths near the well. The borehole sorption data, obtained by flow equilibration, are given in Table I. Batch equilibration gave results which were about 20% higher for samples with the highest sorption, but the batch method had inadequate precision when sorption was low, as for samples 2-1, 2-3 and 3-2. The precision of the flow-equilibration method for DBCP is limited only by the GC analysis. Zero values in Table I indicate sorption Kd < 0.01 ml/gm. Of the several borehole samples, only sample 3-1 showed substantial sorption of DBCP. In both boreholes there was little sorption below 1 meter. The diminished sorption of DBCP with increasing depth appears to be related principally to a decrease in organic carbon with depth. 

Borehole Sample Depth (meter) Organic Carbon (%) Kd (ml/gm)... 

Charifo G, Almeida JA, Ferreira A (2013) Managing borehole samples of unequal lengths to construct a high-resolution mining model of mineral grades zoned by geological units. J Geochem Explor 132 209-223... 

FIGURE 9.4 Thermal conductivity of samples from the KTB borehole. Samples are gneiss from a depth of 1793 m, amphibolite from a depth of 147 m. (a) Conductivity as a function of uniaxial pressure, measured at T= 54 °C. (b) Conductivity as a function of temperature, measured at p = 10 MPa. Data from Huenges et at. (1990). 

In the pre-development stage, core samples can be used to test the compatibility of injection fluids with the formation, to predict borehole stability under various drilling conditions and to establish the probability of formation failure and sand production. 

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. 

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. 

Fig. 4.17 Samples of high-purity AZ31 (upper photographs) and ZW3 (lower photographs) magnesium-base alloys, fitted with mild-steel nuts and bolts and exposed to a variety of corrosion conditions, (a) 4-S hours immersion in 37 salt soln., (b) 180 days immersion in distilled water, (c) 4 days immersion in borehole water, (d) 180 days in humidity cabinet sea-water spray and (e) 180 days atmospheric exposure...

Once the soil cores have been collected, all boreholes must be backfilled with untreated soil (with frequent tamping) to prevent bypass flow that could transport residues into the lower soil profile. After backfilling, flags or stakes should be placed at the boreholes. This serves as an additional check to ensure that sub-plots are not sampled more than one time during the study. (Note that these boreholes should... 

Freifield B., Trautz R., et al. The U-tube a novel system for acquiring borehole fluid samples from a deep geologic C02 sequestration experiment. 2005 Journal of Geophysics Reservoir 110 B10203. 

Analytical problems continue to arise in new forms. Demands for analysis at long range by instrument packages steadily increase. Space probes, borehole logging and deep sea studies exemplify these requirements. In other fields, such as environmental and clinical studies, there is increasing recognition of the importance of the exact chemical form of an element in a sample rather than the mere level of its presence. Two well-known... 

The U-tube was developed to simplify the recovery of fluids from deep boreholes and allow flexibility for post-sampling analysis (Freifeld et al. 2005 Freifeld Trautz 2006). In particular, the ability to repeatedly collect large volume multiphase samples into high pressure cylinders facilitates both real-time field analysis as well as acquisition of sample splits for future laboratory based analysis. 

Freifeld, B.M. Trautz, R.C. 2006. Real-time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U-tube sampling methodology. Geofluids, 6, 217-224. doi 10.1111/j.1468-8123.2006.00138.x. 

Freifeld, B.M., Trautz, R.C., Yousif K.K., Phelps, T.J., Myer, L.R., Hovorka, S.D., Collins, D. 2005. The U-Tube A novel system for acquiring borehole fluid samples from a deep geologic CO2 sequestration experiment. Journal Geophysical Research, 110, B10203, doi 10.1029/2005JB003735. 

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