Alfonso Benavides

Abstract Several factors determine the depositional characteristics of turbidite deposits. Important ones are the source area, as well as grain size and mineralogy, at the time that sediment bypasses the shelf break. Transport volume, frequency, and basin gradient(s) can very considerably between flows, which influences the areal extent, thickness, and location of succeeding layers. Many basins, especially those influenced by salt diapirs, are constantly in motion, causing their deep sand-rich zones to be tilted tectonically through time. Fine-grained sediments tend to form oblong deposits with the majority of the sand deposited in the distal outer fans (bypassing system). Coarse-grained sediment forms wider deposits that show a grain-fining in the downdip direction (prograding system). Later tectonics may contort the original basin shapes. Searching for hydrocarbons in these deposits should not be based solely on seismic interpretations, but should also utilize a combination of new seismic processing methods and other geological studies. The studies should include the source-to-sink concept, mineralogy, and grain size. A compilation of detailed seismic layering and lateral changes of sediment types should be produced. Structural studies should infer the original shape and size of the basin, as well as changes during and after deposition, temperature histories, and pressures. Although this method seems difficult and complex where experts work together, in reality less time is required than one might expect. Practically all companies conduct these different studies piece-meal through time. Completing these initial steps increases the chances of successfully discovering hydrocarbons and also provides for understanding the total depositional environment (vital for predicting production).

Several factors determine the depositional characteristics of turbidite deposits. Important ones are the source area, as well as grain size and mineralogy, at the time that sediment bypasses the shelf break. Transport volume, frequency, and basin gradient(s) can very considerably between flows, which influences the areal extent, thickness, and location of succeeding layers. Many basins, especially those influenced by salt diapirs, are constantly in motion, causing their deep sand-rich zones to be tilted tectonically through time. Fine-grained sediments tend to form oblong deposits with the majority of the sand deposited in the distal outer fans (bypassing system). Coarse-grained sediment forms wider deposits that show a grain-fining in the downdip direction (prograding system). Later tectonics may contort the original basin shapes. Searching for hydrocarbons in these deposits should not be based solely on seismic interpretations, but should also utilize a combination of new seismic ...

... detection improvements using EM63 synthetic multi-receiver array geometries Carl J. Pierce, Jr.*, Alfonso Benavides, Mark E. Everett and Jack Stalnaker, Department ... As shown in the above figure, a 2.0 x 3.0 m data acquisition template was designed using a heavy canvas tarp. ...

Numerical simulations of the nuclear magnetic relaxation process for fluids confined in the restricted geometry of the pore space were performed. The magnetic field fluctuations were calculated assuming an appropriate propagator for the molecules in the fluid and the geometry of the pore space. From the time series obtained, it was possible to calculate the spectral densities for the relaxation processes and the mean local magnetic field distribution function. The simulations are in accordance to experimental results.

A total of 21 coal samples, belonging to Los Cuervos Formation, were taken in Villa Páez, Táchira State, Venezuela, with the aim of establishing vertical variations in their geochemical parameters. The samples were subject to immediate (moisture, volatile matter, fixed ...

Classification of conductive targets using controlled-source electromagnetic induction (EMI) is an important task in near-surface applied geophysics. Target classification is sometimes required in near real-time, requiring efficient and fast data processing algorithms. We select empirical physics-based target parameters that are invariant under transmitter-receiver geometry. We used a modifed EM63 metal detector to construct a response database. The target collection consists

Controlled-source electromagnetic (CSEM) spatial profiles and 2-D conductivity maps were obtained on the Brazos Valley, TX floodplain to study the fractal statistics of geological signals and effects of man-made conductive targets using Geonics EM34, EM31 and EM63. Using target-free areas, a consistent power-law power spectrum (|A(k)| ~ k ^-beta) for the profiles was found with beta values typical of fractional

The wettability of the rock surface plays a very important role in the transport of fluid in porous media. The combined Amott-USBM method currently used for the determination of these values is not able to produce reliable estimates when the surface has an intermediate wettability. The nuclear magnetic resonance (NMR) technique could provide an efficient method if the parameters affected by the wettability could be established in well defined model systems. To obtain information about the effect of wettability changes upon the NMR parameters, T1 relaxation time measurements were carried out on 1H and 2H at two different magnetic fields. A large number of well defined consolidated and unconsolidated samples, with different degrees of wettability were used in this study. The results obtained showed that the T1 values, as well as the relaxation rate distribution parameters, such as the distribution width, are affected by changes in the wettability. A dependence of the T1 wettability data on the magnetic field intensity was also observed.

A total of 21 coal samples, belonging to Los Cuervos Formation, were taken in Villa Páez, Táchira State, Venezuela, with the aim of establishing vertical variations in their geochemical parameters. The samples were subject to immediate (moisture, volatile matter, fixed ...

A total of 21 coal samples, belonging to Los Cuervos Formation, were taken in Villa Páez, Táchira State, Venezuela, with the aim of establishing vertical variations in their geochemical parameters. The samples were subject to immediate (moisture, volatile matter, fixed ...

El presente trabajo describe las características principales de un transmisor switching de 1.5 KW para resistividades eléctricas y polarización inducida (IP). El diseño y desarrollo fue llevado a cabo utilizando dispositivos electrónicos de punta. El control y monitoreo de las funciones del transmisor se realiza mediante una computadora portátil, lo que permite un control completo del transmisor y receptor desde el lugar del receptor, reduciendo número de personas y los problemas de acoplamiento.

Classification of conductive targets using controlled-source electromagnetic induction (EMI) is an important task in near-surface applied geophysics. Target classification is sometimes required in near real-time, requiring efficient and fast data processing algorithms. We select empirical physics-based target parameters that are invariant under transmitter-receiver geometry. We used a modifed EM63 metal detector to construct a response database. The target collection consists of hollow and solid spheres, cylinders, plates and inert ordnance. The inversion method is based on non-linear least-squares combined with numerical continuation. The spatiotemporal forward response is that of a body whose induced magnetization tensor undergoes a stretched-exponential transient decay. The early-time background response and late-time system noise produce a rough objective function. In such cases, gradient descent methods can stop at sub-optimal solutions. Nevertheless, we observe model-space clu...

The experiments performed up to now in porous systems of glass beads, silica glass or sedimentary rocks have shown that stretched-exponential magnetic relaxation only occurs in sedimentary rocks. These systems differ from former in their pore structures and their pore-grain interfaces. We have carried out NMR experiments on some models in order to find the mechanism involving this type of relaxation in porous rocks. Some models such as different size glass beads packed so that the pore space is completely disordered and packing of sands with highly rough surfaces were used. 1H longitudinal relaxation preliminary measurements in these systems point out a close connection between the stretched-exponential relaxation function and the non-euclidean properties of pore geometry of sedimentary rocks. This suggests that stretched-exponential relaxation has a physical basis and is not simply and alternative way of fitting the data.

We performed Inversion-recovery and Carr-Purcell-Melboom-Gill experiments upon a wide variety of samples including sand and sedimentary rocks. To obtain the relaxation rate distnbutions. we used a simulated annealing algorithm, which gives the inverse Laplace transform. A complex evolution of the transversal distribution function was obtained.

Abstract Self-organizing maps (SOM) are implemented for discrimination of geologic noise, buried metal objects and unexploded ordnance using the geophysical method of time-domain electromagnetic induction. The learning and misfit measures are based on a Euclidean metric. The ...

Abstract The wettability of the rock surface plays a very important role in the transport of fluid in porous media. The combined Amott‐USBM method currently used for the determination of these values is not able to produce reliable estimates when the surface has an intermediate wettability. The nuclear magnetic resonance (NMR) technique could provide an efficient method if the parameters affected by the wettability could be established in well defined model systems. To obtain information about the effect of wettability changes upon the ...