... count base cases at each neutron detector for borehole diameters equal to 21.6 cm (8.5 in), 24.1 cm (9.5 in), and 26.7 cm (10.5 in). Figure 1 shows the calibration between MCNP detector counts for each base case and the inverse of formation migration length. Table 1. Homogeneous base case formations...

... logging speed. Figure 6. Epithermal flux at near and far locations, which at, respectively, 10 inches and 22 inches from the source. Slowing Down, Diffusion, and Migration Lengths: The Near/Far ratio behavior and hence the porosity response can be understood by considering the three processes...

...). Various nuclear properties, including density, Sigma (neutron capture cross-section), hydrogen index, inverse of migration length, PEF, and neutron porosity, were used for inversions. This paper describes a new method for estimating hydrocarbon properties from both nuclear and NMR measurements. Figure 1...

... of gamma rays. MCNP calculations are CPU time consuming, taking as long as 20 hours to simulate a single depth measurement, rendering the method inefficient for its application in an inversion algorithm. A faster approximation method was developed based on effective migration length using a library of pre...

... for petrophysical, geometrical, and borehole environmental effects. In gamma-gamma tools, electron density and photoelectric factor govern the basis of bulk density and Pe measurements with a linear relationship. Migration length is an important formation property tightly related to the measurement principle...

... boundaries, the first step of the method is to perform separate inversion of individual well logs to estimate bed properties such as density, migration length, electrical conductivity, PEF (Photo Electric Factor), and Th (Thorium), U (Uranium), and K (Potassium) volumetric concentrations. Next, a multi-layer...

... parameters for the formation. These parameters are the slowing down length, migration length, diffusion length and diffusion coefficient. N3LIP treats the formation regardless of its lithological composition as two regions: the pore space and the matrix. The matrix is considered as a black box where its four...

... or migration length, i. e. with the rock properties characterizing it in its homogeneous part undisturbed by the presence of a borehole or tool. This way of calibration to some extent eliminates the influence of the rock lithology but also has a serious handicap because it is valid for a fixed tool-borehole...

... in limestone test formations. This paper details how this process can be made more accurate by also including matrix density and sigma data. A tool model uses basic nuclear cross sections and calculations of effective neutron migration lengths in order to correct measured ratios for observed matrix density...

... Schlumberger interpretation Upstream Oil & Gas neutron anhydrite porosity migration length application Symposium fraction standoff spectral density spectral GR dual porosity neutron correction SPWLA TWENTY-SEVENTH ANNUAL LOGGING SYMPOSIUM, JUNE g-13.1986 OPEN-HOLE NUCLEAR LOGGING - STATE...

... Upstream Oil & Gas apparent porosity porosity hydrogen index log analysis detector gin cc migration length well logging calculation volumetric porosity tool response hydrocarbon Porosity effect Symposium carbon density crude oil cross section experiment hydrogen density...