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In this study, the gamma-ray spectrum of single elemental capture spectrum log was simulated. By numerical simulation we obtain a single-element neutron capture gamma spectrum. The neutron and photon transportable processes were simulated using the Monte Carlo N-Particle Transport Code System (MCNP), where an Am-Be neutron source generated the neutrons and thermal neutron capture reactions with the stratigraphic elements. The characteristic gamma rays and the standard gamma spectra were recorded, from analyzing of the characteristic spectra analysis we obtain the ten elements in the stratum, such as Si, Ca, Fe, S, Ti, Al, K, Na, Cl, and Ba. Comparing with single elemental capture gamma spectrum of Schlumberger, the simulated characteristic peak and the spectral change results are in good agreement with Schlumberger. The characteristic peak positions observed also consistent with the data obtained from the National Nuclear Data Center of the International Atomic Energy Agency. The neutron gamma spectrum results calculated using this simple method have practical applications. They also serve as an reference for data processing using other types of element logging tools. [ABSTRACT FROM AUTHOR]

Calculating the mineral composition is a critical task in log interpretation. Elemental capture spectroscopy (ECS) log provides the weight percentages of twelve common elements, which lays the foundation for the accurate calculation of mineral compositions. Previous processing methods calculated the formation composition via the conversion relation between the formation chemistry and minerals. Thus, their applicability is limited and the method precision is relatively low. In this study, we present a multimineral optimization processing method based on the ECS log. We derived the ECS response equations for calculating the formation composition, then, determined the logging response values for the elements of common minerals using core data and theoretical calculations. Finally, a software module was developed. The results of the new method are consistent with core data and the mean absolute error is less than 10%. [ABSTRACT FROM AUTHOR]

We have established a set of laboratory measurements which is used for capturing element gammma spectrum. Standard captured gamma ray spectra for ten elements, including Si, Ca, Fe, are obtained using the measurements for the first time in China. We also simulated the capture gamma ray spectra of the ten elements using Monte Carlo methodology with the same parameters of our experimental measurements. Comparing the experiment and simulation results with the data from the International Atomic Energy Agency's Nuclear Data Center, we obtained the standard captured gamma ray spectra of the ten elements, which, as calibration spectra, are used to calibrate the raw spectrum in data processing. This method solved the key problem during the conversion from the original measuring spectrum to the yield of each element in the data processing. The method can effectively improve the accuracy of the element yield calculation. [ABSTRACT FROM AUTHOR]