Willian A. Trevizan

Petróleo Brasileiro S.A. | PETROBRAS · Research and Development Center (CENPES)

In the domain of formation evaluation through well logging techniques, Nuclear Magnetic Resonance (NMR) stands out for its capacity to explore the geometrical characteristics of porous media under specific conditions. In the case of a core sample saturated with a single fluid, a robust correlation exists between relaxation times (T1 or T2) and the...

Calculating log-scale petrophysical properties is essential in formation evaluation, since it directly impacts the estimates of hydrocarbon reserves and reservoir flow capacity. These calculations traditionally use the nuclear magnetic resonance (NMR) log through cutoffs in the transverse relaxation time (T2) in the Brazilian pre-salt carbonates. T...

High-resolution computed micro-tomography is an important area of science, which correlates well with several experimental methodologies and serves as a basis for advanced computational physics studies, in which high-resolution images are used as input to different scientific simulation models. The dataset presented herein includes (raw) grayscale...

Permeability is the key parameter for quantifying fluid flow in porous rocks. Knowledge of the spatial distribution of the connected pore space allows, in principle, to predict the permeability of a rock sample. However, limitations in feature resolution and approximations at microscopic scales have so far precluded systematic upscaling of permeabi...

This article was written in honor of Prof. Bernhard Blümich, who has heavily impacted many areas of Magnetic Resonance and, in particular, low-field and portable NMR with numerous advances, concepts, innovations, and applications of this impressive technology. Many years ago, we decided to research and develop single-sided magnets for the area of p...

Permeability is the key parameter for quantifying fluid flow in porous rocks. Knowledge of the spatial distribution of the connected pore space allows, in principle, to predict the permeability of a rock sample. However, limitations in feature resolution and approximations at microscopic scales have so far precluded systematic upscaling of permeabi...

Many of the world's oil reservoirs are sandstones and some equations have been widely explored to estimate their permeability from NMR measurements, especially those based on the Schlumberger Doll Research (SDR) and Timur–Coates models. In both cases, the permeability is assumed to be related to pore sizes. Brownstein and Tarr showed that, under fa...

Network Extraction algorithms from X-ray microcomputed tomography have become a routine method to obtain pore connectivity and pore morphology information from porous media. The main approaches for this extraction are either based on Max Ball Algorithm or Medial Axis Extraction. The first is a robust method to separate the pore space into pore and...

Nowadays, most of the efforts in NMR applied to porous media are dedicated to studying the molecular fluid dynamics within and among the pores. These analyses have a higher complexity due to morphology and chemical composition of rocks, besides dynamic effects as restricted diffusion, diffusional coupling, and exchange processes. Since the translat...

The Presalt carbonate wells of Lula Field, Santos Basin, Offshore Brazil, are currently producing high quality, 28 to 30° API oil at an average rate of 30,000 BOPD. With reservoir pressures over 8,000 psi, and a downhole oil viscosity of 1 cP, the proli¿c Àow rates from these high permeability, lacustrine carbonates have shown no signi¿cant decline...

Complex pore structure in carbonate rocks causes the petrophysical characterization and formation evaluation a challenge. Permeability is one of the main evaluation parameters for determining the potential production of a reservoir because it defines the ability of fluids to flow through rocks. It is not possible to directly measure permeability us...

Summary Nuclear magnetic resonance (NMR) transverse relaxation times (T2) were measured for carbonate rocks saturated with brine and crude oil under different saturation conditions. The NMR measurements were intercalated within the stages of standard wettability core analyses, which monitor imbibition and drainage processes after restoring in situ...

Nuclear magnetic resonance (NMR) measurements have been used as a way to evaluate reservoir rocks based, on the longitudinal and transverse relaxation times, T 1 and T 2 , and the time dependent diffusion coefficient, D(t). Relaxation time distributions can be related to pore sizes and to the free and bound fluid fractions. In addition, there are w...

Nuclear magnetic resonance (NMR) measurements have been used as a way to evaluate reservoir rocks based, on the longitudinal and transverse relaxation times, T1 and T2, and the time dependent diffusion coefficient, D(t). Relaxation time distributions can be related to pore sizes and to the free and bound fluid fractions. In addition, there are well...

In this paper, the Nuclear Magnetic Resonance response of three sedimentary rocks (one sandstone and two carbonates) is modeled through random walk simulations. With this modeling, we aim to improve micro-porosity content and pore size estimation, by taking into account both surface relaxation and diffusive coupling. Experimental Magnetic Resonance...

When estimating permeability (k) from NMR logs, a key assumption is that the surface relaxivity (rho2) parameter, which scales the relationship between transverse relaxation time (T2) and the surface-to-volume ratio (S/V) of the pore system, remains constant. With this assumption, the rho2 parameter can be accounted for in the premultiplier of the...