Giovanna Carneiro

• PhD
• Senior Researcher at Schlumberger Limited

Fluid composition has a direct impact on predicted petrophysical properties, mainly on those related to reserves estimation, such as total porosity, water saturation and volume of oil. However, most formation evaluation workflows use properties from literature or black oil models with built-in fluid properties, not considering the effects of differ...

The harsh conditions presented in Brazilian presalt, summed up with the complexity of its reservoir, generate a series of challenges to improve reservoir recovery. Routinely, we have used intelligent completion systems to address the major part of the challenges; however, with the new production rates new problems have arrived and the usual ones ha...

The complexity of carbonate reservoir in pre-salt plays dictates the use of advanced inflow devices to enable optimized reservoir recovery. Intelligent Completions are considered one of the most effective systems for flow control for a production interval. Depending on the actual design and geometry of the intelligent completion tool, inorganic sca...

In a previous work, we showed how to obtain the surface relaxivity as a function of pore size. In the present work, we take a step further and introduce a formulation that uses this surface relaxivity function to convert a T2 distribution into a pore size distribution. We then compare the pore size distribution obtained with the aid of this formula...

Relative permeability is a key input for multiphase reservoir simulations. Challenges related to the validation and interpretation of the laboratory core measurements are associated with the restoration processes and resulting wettability states, the heterogeneities and multi-scale aspects of complex rocks, as well as the limitations of core floodi...

Permeability is a key property to state if producing fluids from a hydrocarbon reservoir will be feasible or not. Nevertheless, the accurate estimation of permeability in carbonate rock reservoirs is considered a challenging task. This is due to two main reasons: (i) the extreme heterogeneity typically contained in these kinds of rocks; (ii) the fa...

In the present work, we formulate and solve an inverse problem to recover the surface relaxivity as a function of pore size. The input data for our technique are the distribution measurement and the micro-tomographic image of the rock sample under investigation. We simulate the NMR relaxation signal for a given surface relaxivity function using the...

Recent studies have indicated that the accurate identification of carbonate rock types in a reservoir can be employed as a preliminary step to enhance the effectiveness of petrophysical property modeling. Furthermore, rock typing activity has been shown to be of key importance in several steps of formation evaluation, such as the study of sedimenta...

Irreducible water saturation is a key property for the estimation of original oil and gas-in-place. It is also key to end-point scaling of capillary pressure and relative permeability, with significant impact on simulation results of reservoirs under improved/enhanced oil recovery (IOR/EOR). Several definitions of irreducible water saturation exist...

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...

Rock-pore-space geometry and network topology have a great impact on dynamic reservoir characteristics, in particular on capillary pressure and relative permeability curves. Hydraulic tortuosity is a key independent measurement relating the pore-space geometry and topology to the rock's effective porosity and absolute permeability. Therefore, hydra...

Spin relaxation based nuclear magnetic resonance (NMR) methods have been used extensively to determine pore size distributions in a variety of materials. This approach is based on the assumption that each pore is in the fast diffusion limit but that diffusion between pores can be neglected. However, in complex materials these assumptions may be vio...

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...

Low-field (1) H NMR was used in this work for the analysis of mixtures involving crude oils and water. CPMG experiments were performed to determine the transverse relaxation time (T(2) ) distribution curves, which were computed by the inverse Laplace transform of the echo decay data. The instrument's ability of quantifying water and petroleum in bi...