Recuperação De Atributos Sísmicos Utilizando A Migração Para Afastamento Nulo

A conventional processing, without a reliable adjustment in order to preserve the seismic amplitudes, could damage the mapping of the petrophysical properties, jeopardizing the correlation between the seismic data and the well profile. A manner to estimate correctly the amplitudes and, therefore, the reflection coefficients is to perform a pre-stack migration in true amplitude, where an amplitude distortion caused by the geometrical spreading throughout the ray path is compensated by the migration calculation. Nevertheless, this process has an expensive cost as well as is dependent from the velocity model. A routine less expensive than the other one and also more stable taking into account the velocity model, is to transform the seismic section obtained from the acquisition in common offsets in simulated section in zero offset with true amplitudes. This transformation is called true amplitude Zero Offset migration (TA MZO). In a media with constant velocity, the stack curve for the MZO and the weight function are reduced in analytic formulas, mitigating the computational effort. This work has two main objects: the first is to verify the TA MZO algorithm efficiency for a constant velocity in a synthetic model to a complex geology based on a Neo-Albian turbidity reservoir, where the assumption of constant velocity is not respected. The second one is to perform quantitative studies as results of the technique described above. Likewise, the study tries to analyze how useful is the methodology to compute the graphics for AVO and AVA analyses, helping the reservoir characterization.2015965Bleistein, N., Two and one half dimensional in plane wave propagation (1986) Geophysical Prospecting, 34, pp. 686-703. , S.IBleistein, N., Cohen, J., Jaramillo, H., True-amplitude transformation to zero offset of data from curved reflectors (1999) Geophysics, 64, pp. 112-129. , TulsaHubral, P., Tygel, M., Zien, H., Three-dimensional true-amplitude zero-offset migration (1991) Geophysics, 56, pp. 18-26. , TulsaSchleicher, J., A unified approach to 3D seismic reflection imaging. Part I: Basic concepts (1996) Geophysics, 61, pp. 742-758. , TulsaOliveira, A.S., Tygel, M., Filpo, E., On the application of true-amplitude DMO (1997) Journal of Seismic Exploration, 6, pp. 279-289. , Castelnau-le-LezRamos, A.C.B., True amplitude MZO and AVO: Application to real data (1997) International Congress of the Brazilian Geophysical Society, 1, pp. 223-226. , 5., 1997, Rio de Janeiro. Proceedings. [Rio de Janeiro: SBGf], Expanded AbstractTygel, M., Multiple Weights in diffraction stack migration (1993) Geophysics, 59, pp. 1820-1830. , TulsaTygel, M., Schleicher, J., Hubral, P., Kirchhoff-Helmholtz theory in modelling and migration (1994) Journal of Seismic Exploration, 3, pp. 203-214. , Castelnau-le-LezP. Pulse distortion in deph migration (1994) Geophysics, 59, pp. 1561-1569. , TulsaTygel, M., Schleicher, J., Hubral, P., Dualities involving reflectors and reflection-time surfaces (1995) Journal of Seismic Exploration, 4, pp. 123-150. , Castelnau-le-LezTygel, M., Schleicher, J., Hubral, P., A unified approach to 3D seismic reflection imaging Part II: Theory (1996) Geophysics, 61, pp. 759-775. , TulsaTygel, M., Schleicher, J., Hubral, P., 2,5D Kirchhoff MZO in laterally inhomogeneous media (1998) Geophysics, 63, pp. 557-573. , TulsaTygel, M., Kirchhoff imaging for AVO/AVA (1999) The Leading Edge, 18, pp. 940-945. , S.

Elephant grass silage inoculated with cellulolytic fungi isolated from rumen

ABSTRACT The objective was to evaluate the inoculation with Aspergillus terreus and/or Trichoderma longibrachiatum on fermentation, chemical and microbiological composition of elephant grass ‘Cameroon’ silage (Cenchrus purpureus). Treatments were A. terreus at 105 colony forming units (CFU)/g (AT15), T. longibrachiatum at 105 CFU/g (TL20), a mixture of both at 105 CFU/g (MIX), and a control group without inoculation (CONTR). The design was completely randomized with seven replicates. The MIX silage was most stable, while CONTR, AT15, and TL20, had lower dry matter losses. There was no effect of inoculation in the chemical composition of silages. Only MIX silage (4.40) had pH above the minimum of 4.2 for humid grass silage and above the control (4.05). Bacteria from Diplococcus genus was identified at the opening of TL20 and CONTR silages. After air exposure, the population of rods, Lactobacillus, and total lactic acid bacteria was higher in theTL20 and MIX. The inclusion of a T. longibrachiatum and A. terreus mixture increases dry mater loss and silage pH. T. longibrachiatum was more efficient in maintaining populations of total lactic acid bacteria after opening; therefore, this strain has potential as an additive for elephant grass ‘Cameroon’ silage

Diet of two syntopic species of Crenuchidae (Ostariophysi: Characiformes) in an Amazonian rocky stream

Abstract This study assessed the diet of two poorly known syntopic fish species of the family Crenuchidae, Characidium aff. declivirostre and Leptocharacidium omospilus, in a Presidente Figueiredo´ rocky stream, Amazonas, Brazil. The stomach contents were analyzed and their Frequency of Occurrence (FO %) and Relative Volume (Vol %) were combined in a Feeding Index (IAi). We examined 20 individuals of C. aff. declivirostre and 23 of L. omospilus. The Morisita-Horn Index was used to estimate the overlap between the diets of these species. Immature insects were the most valuable items consumed by both fish species. The diet of C. aff. declivirostre was mainly composed of larvae and pupae of Chironomidae, while L. omospilus predominantly consumed larvae of Hydroptilidae, Hydropyschidae and Pyralidae. Thus, both species were classified as autochthonous insectivorous. Characidium aff. declivirostre was considered a more specialized species, probably reflecting lower feeding plasticity or the use of more restricted microhabitats compared to L. omospilus. When the food items were analyzed at the family taxonomic level, the diet overlap between these species was considered moderate (Morisita-Horn Index = 0.4). However, a more thorough analysis, at the genus level, indicates a very low diet overlap. Therefore, we conclude that the feeding segregation between C. aff. declivirostre and L. omospilus may favor their co-existence, despite their high phylogenetic closeness