Lithofacies characteristics discovery from well log data using association rules

This paper reports the use of association rules for the discovery of lithofacies characteristics from well log data. Well log data are used extensively in the exploration and evaluation of petroleum reservoirs. Traditionally, discriminant analysis, statistical and graphical methods have been used for the establishment of well log data interpretation models. Recently, computational intelligence techniques such as artificial neural networks and fuzzy logic have also been employed. In these techniques, prior knowledge of the log analysts is required. This paper investigated the application of association rules to the problem of knowledge discovery. A case study has been used to illustrate the proposed approach. Based on 96 data points for four lithofacies, twenty association rules were established and they were further reduced to six explicit statements. It was found that the execution time is fast and the method can be integrated with other techniques for building intelligent interpretation models

Ab initio study on elastic and thermodynamical properties of Ti 1-x Zr xC

71.20.-b Electron density of states and band structure of crystalline solids, 71.15.Mb Density functional theory, local density approximation, gradient and other corrections, 71.20.Lp Intermetallic compounds, 62.20.de Elastic moduli,

Dielectric phase-transition and polarization studies in stepped and compositionally graded lead magnesium niobate-lead titanate relaxor thin films

Ferroelectric properties of chemically heterogeneous multilayers and graded composition thin films of $(1-x)Pb(Mg_{1/3}Nb_{2/3})O_{3}-xPbTiO_{3}$, a well-known relaxor, were prepared using a multitarget pulsed laser ablation system. Target materials with different values of x (0.0, 0.1,0.2, and 0.3) were used for ablation growth. Films with sharp interfaces and graded interfaces were prepared and were characterized for their electrical properties. The stepped films were found to have a phase-transition behavior dominated by the individual layer behavior with their corresponding local dielectric maxima. The graded films showed an overall averaged effect of the system. The graded films showed an enhanced diffusiveness in the phase transition and the gamma value was found to be 2.43, which is a measure of diffusivity. The tunability of these graded films was found to be high around 60% and was twice that of any of the film of homogeneous composition films. The room-temperature polarization hysteresis curves exhibited slim loop characteristics with a saturation polarization of about 40 mu C/cm(2) in the case of both stepped and graded films

Dielectric phase-transition and polarization studies in stepped and compositionally graded lead magnesium niobate-lead titanate relaxor thin films

Ferroelectric properties of chemically heterogeneous multilayers and graded composition thin films of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3, a well-known relaxor, were prepared using a multitarget pulsed laser ablation system. Target materials with different values of x (0.0, 0.1, 0.2, and 0.3) were used for ablation growth. Films with sharp interfaces and graded interfaces were prepared and were characterized for their electrical properties. The stepped films were found to have a phase-transition behavior dominated by the individual layer behavior with their corresponding local dielectric maxima. The graded films showed an overall averaged effect of the system. The graded films showed an enhanced diffusiveness in the phase transition and the γ value was found to be 2.43, which is a measure of diffusivity. The tunability of these graded films was found to be high around 60% and was twice that of any of the film of homogeneous composition films. The room-temperature polarization hysteresis curves exhibited slim loop characteristics with a saturation polarization of about 40 µ C/cm2 in the case of both stepped and graded films