Density gamma-ray

Findings with PDU. Work with the PDU largely paralleled the bench-scale reactor tests there was one important addition—extensive three-phase fluidization studies. As was mentioned, the PDU is equipped with a traversing gamma-ray density detector that is capable of measuring bed density to within dbO.Ol specific gravity units. Thus, we could measure and correlate fluidized bed expansion as a function of liquid and gas velocities and physical properties, and could also determine the... 

Sediment stratigraphy controls the hydrate distribution at Hydrate Ridge. The methane-rich migration pathway of Horizon A provides enriched hydrate formation relative to other sediments. In Figure 7.26, the remote sensing logs (gamma ray, density, RAB, and Archie water saturation) are most sensitive to hydrates. 

Other Methods, Gamma-ray attenuation measures the density of the sample, which is related to changing oil or water content. Gamma-ray density meters are quite common in process monitoring, but they are useful for emulsion characterization only in cases where the solids content is known to be zero or completely constant (33). Otherwise the density information obtained cannot be reliably related to oil or water content. 

Figure 5.37 depicts the basic set up of a wireline logging operation. A sonde is lowered downhole after the drill string has been removed. The sonde is connected via an insulated and reinforced electrical cable to a winch unit at the surface. At a speed of about 600m per hour the cable Is spooled upward and the sonde continuously records formation properties like natural gamma ray radiation, formation resistivity or formation density. The measured data is sent through the cable and is recorded and processed in a sophisticated logging unita the surface. Offshore, this unit will be located in a cabin, while on land it is truck mounted. In either situation data can be transmitted in real time via satellite to company headquarters if required. 

In the spring of 1989, it was announced that electrochemists at the University of Utah had produced a sustained nuclear fusion reaction at room temperature, using simple equipment available in any high school laboratory. The process, referred to as cold fusion, consists of loading deuterium into pieces of palladium metal by electrolysis of heavy water, E)20, thereby developing a sufficiently large density of deuterium nuclei in the metal lattice to cause fusion between these nuclei to occur. These results have proven extremely difficult to confirm (20,21). Neutrons usually have not been detected in cold fusion experiments, so that the D-D fusion reaction familiar to nuclear physicists does not seem to be the explanation for the experimental results, which typically involve the release of heat and sometimes gamma rays. 

A problem with the early MWD mud pulse systems was the very slow rate of data transmission. Several minutes were needed to transmit one set of directional data. Anadrill working with a Mobil patent [100] developed in the early 1980s a continuous wave system with a much faster data rate. It became possible to transmit many more drilling data, and also to transmit logging data making LWD possible. Today, as many as 16 parameters can be transmitted in 16 s. The dream of the early pioneers has been more than fulfilled since azimuth, inclination, tool face, downhole weight-on-bit, downhole torque, shocks, caliper, resistivity, gamma ray, neutron, density, Pe, sonic and more can be transmitted in realtime to the rig floor and the main office. 

A typical set of logs recorded while drilling is shown in Figure 4-280. The wireline caliper is shown in the gamma ray track. Displayed on this attachment are gamma ray, R curve, Pe curve, neutron and density curve. The delta-rho curve is the quality curve check for the density log. 

The density section of the tool, also seen in Figure 4-281, uses a 1.7 curie (Ci) of 137-cesium (Ce) gamma ray source in conjunction with two gain-stabilized scintillation detectors to provide a high-quality, borehole compensated density measurement. 

With the availability of the MWD/LWD drilling parameters, gamma ray resistivity, neutron-density Pe, a global approach of interpretation has been implemented by Anadrill when all measurements have been made in a given strata. A particular strata is first analyzed with the drilling data for a pressure at the bit estimate. Then, it is reanalyzed later when gamma ray resistivity data... 

Figure 4-335. Computations of the formation pressure, lithology, and fluid content made with MWD formation-strength, LWD resistivity, gamma ray, neutron, and density measurements. (Courtesy Anadrill [113].,)...

One of the limitations of the portable field survey instruments in the measurement of americium is that their quantitative accuracy depends on how well the lateral and vertical distribution of americium in the soil compares with the calibration parameters used. These methods can provide a rapid assessment of americium levels on or below surfaces in a particular environment however, laboratory-based analyses of samples procured from these environmental surfaces must be performed in order to ensure accurate quantification of americium (and other radionuclides). This is due, in part, to the strong self absorption of the 59.5 keV gamma-ray by environmental media, such as soil. Consequently, the uncertainty in the depth distribution of americium and the density of the environmental media may contribute to a >30% error in the field survey measurements. Currently, refinements in calibration strategies are being developed to improve both the precision and accuracy (10%) of gamma-ray spectroscopy measurements of americium within contaminated soils (Fong and Alvarez 1997). 

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