Sergio A.B. Fontoura

Sergio A.B. Fontoura
Pontifícia Universidade Católica do Rio de Janeiro · Department of Civil Engineering (CIV)

PhD

About

113
Publications
15,249
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332
Citations
Citations since 2017
7 Research Items
160 Citations
201720182019202020212022202305101520253035
201720182019202020212022202305101520253035
201720182019202020212022202305101520253035
201720182019202020212022202305101520253035

Publications

Publications (113)
Conference Paper
Full-text available
Some prolific basins have large deposit thicknesses of different saline types that are often treated as a homogeneous layer. However, for drilling purpose it is extremely important to predict the different salt types and their behaviors due to their particularities and direct influence in the development of well design. To characterize the differen...
Conference Paper
Full-text available
With the aim to pursue an improvement in the guidelines definition for rocks mechanical characterization, which can be easily incorporated to the geomechanical studies, such as reservoir modeling and well stability analysis, the development of this study was introduced. Following this approach, Petrobras began a research focusing on the geological...
Conference Paper
Full-text available
In this study, a wellbore stability model was built of the pre-salt area using analytical correlations to obtain an optimum mud window. The operational window assists in optimizing the fluid weight to be used while drilling and is defined by a lower limit (pore or collapse pressure) and an upper limit (fracture gradient). To build a geomechanical m...
Conference Paper
Full-text available
The mechanical properties of conglomeratic rocks are difficult to study by conventional laboratory tests. On the other hand, in-situ tests are more representative to establish the mechanical properties of these materials but, in general, take a long time to execute and represent a high cost for projects. This paper presents a methodology to obtain...
Article
Wells penetrate long intervals of salt to access hydrocarbon reservoirs in many locations. High mud weights are frequently used to stabilize the wellbore while drilling through salt formations. High borehole pressures reduce rates of penetration (ROPs) in many sedimentary rocks. This effect is significant and contributes greatly to the low ROPs and...
Conference Paper
Full-text available
This paper presents the results of numerical modeling through finite element method and discrete element method for single cutter drilling in carbonate samples. This work is relevant to understand the mechanics of drill bit – rock interaction while drilling deep wells and the results behavior were validated with experimental data raised under simul...
Conference Paper
Wells penetrate long intervals of salt to access hydrocarbon reservoirs in many locations. High mud weights are frequently used to stabilise the wellbore while drilling through salt formations. High borehole pressures reduce penetration rates in many sedimentary rocks. This effect is significant and contributes greatly to the low penetration rates...
Conference Paper
Full-text available
A indústria do petróleo realiza contínuas pesquisas para aperfeiçoar as operações de perfuração, aumentando a taxa de penetração e reduzindo o tempo não produtivo. Diversos estudos analisam o processo de corte em rocha utilizando brocas PDC (Polycrystalline Diamond Compact). Experimentos de laboratório como o ensaio de cortador único simulam a inte...
Conference Paper
Full-text available
Drilling and the development of oil and gas production in carbonate reservoirs have presented serious operational problems in the Brazilian Offshore oil fields. These problems are partly caused by difficulties in the characterization of carbonates whose structures have complex spatial distributions. This paper proposes to integrate the processing a...
Conference Paper
Full-text available
3D geological modeling is an important part of geomechanical models. Therefore, the knowledge of spatial distribution algorithms of geological properties is essential for the proper characterization of the subsurface. Generally, geostatistical and neural networks can be used as forecasting strategies of geological characteristics. One problem in fo...
Conference Paper
During the lifetime of an oil field, well integrity should be taken into account under the geomechanical perspective. This work shows the influence of geomechanical effects resulting from reservoir development over the integrity of a well, employing partially coupled fluid-mechanical simulations. This paper also presents a practical workflow, imple...
Conference Paper
Full-text available
The depletion of oil reservoirs causes significant effects on its surroundings. During the lifetime of an oil field, well integrity should be taken into account under the geomechanical perspective. The aim of this work is to show the influence of geomechanical effects over the integrity of an oil well, employing par-tially coupled fluid-mechanical...
Article
Rock cutting mechanics has been studied in order to better understand drilling process in cutter scale. The cutting energy is mainly dependent of cutter orientation and rock properties. It was previously reported in the literature that specific energy is strongly dependent of backrake and siderake. Although there have been good attempts to develop...
Article
The main purpose of casing cementing is to assure zonal isolation and borehole integrity. The aim of this paper is to describe the elements associated with borehole integrity in salt zones. To achieve this, a numerical analysis of the contacts amongst the rock salt, cement and casing was carried out using the finite element method. The problem was...
Article
Full-text available
Aiming to increase hydrocarbon production, the oil industry has developed recovery methods whose purpose is to get more production. Thus, several problems may be encountered when making use of these techniques, mainly the conventional one. In addition, consideration of geological structures in reservoir engineering, such as fault zones, has fundame...
Article
Oil wells are engineering structures that should last safe and sound for decades. Its integrity should be guaranteed not only during drilling but also throughout the life of the reservoir. Reservoir production generates stress changes within the reservoir as well as throughout the surrounding rocks. These stress changes cause displacements and stra...
Conference Paper
Full-text available
Aiming to increase hydrocarbon production, the oil industry has developed recovery methods whose purpose is to get more production. Thus, several problems may be encountered when making use of these techniques, mainly the conventional one. In addition, consideration of geological structures in reservoir engineering, such as fault zones, has fundame...
Data
This paper deals with the implementation and validation of a new hydromechanical partial coupling methodology conducted between two commercial simulators of flow and stress. Such configuration is based on a coupling methodology developed by the Computational Geomechanics Group – ATHENA/GTEP - PUC-Rio, based on the consistent inclusion of terms in f...
Conference Paper
Single cutter laboratory experiments are used for evaluating the drill bit - rock interaction mechanisms. These experiments can be simulated through numerical methods in order to analyze particular conditions of each borehole drilling operation. This paper describes the use of Finite Element Method for modeling single cutter experiments in evaporit...
Data
This paper was prepared for presentation at the North Africa Technical Conference & Exhibition held in Cairo, Egypt, 15–17 April 2013. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society o...
Data
This paper was prepared for presentation at the North Africa Technical Conference & Exhibition held in Cairo, Egypt, 15–17 April 2013. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society o...
Data
This paper was prepared for presentation at the North Africa Technical Conference & Exhibition held in Cairo, Egypt, 15–17 April 2013. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society o...
Data
This paper deals with the implementation and validation of a new hydromechanical partial coupling methodology conducted between two commercial simulators of flow and stress. Such configuration is based on a coupling methodology developed by the Computational Geomechanics Group - ATHENA/GTEP - PUC-Rio, based on the consistent inclusion of terms in f...
Data
Among the several mechanisms of producing an oil reservoir, the gas expansion mechanism is an important primary recovery process. During the depletion of the reservoir, the pore pressure may reach values below the bubble pressure of the oil, allowing the gas release. From the geomechanical point of view, the change in pore volume, due to production...
Article
This work presents some applications of partial fluid-mechanical coupling methodology developed by the Computational Geomechanics Group ATHENA/GTEP - PUC-Rio. The methodology consists in an interrelation between commercial simulators of flow and stress, based on the consistent inclusion of new terms in flow equation to approximate fully coupled res...
Article
Drilling through salt zones is an important current endeavor in many areas offshore of Brazil. The conventional well design workflow does not recognize the complex nature of the stress field near these salt bodies. Therefore, a reliable assessment of the in-situ stresses must be carried out considering a field (global) scale of the problem and the...
Article
Full-text available
Lade's failure criterion was initially developed for soils which present very low to no cohesion. The criterion uses a special relationship between the first and the third stress invariants. Lade failure criterion describes failure of rocks subjected to three different effective principal stresses. An important issue is the evaluation of the stress...
Data
Full-text available
This part describes the failure criterion known as Lade criterion (LC) and its variation, the so-called modified Lade criterion (MLC) as proposed by Ewy (1999). The two failure criteria are described first, including the material parameters involved. Next is shown how to determine these parameters from laboratory experiments conducted on rock sampl...
Article
This paper presents some closed-form solutions of the coupled thermo-chemo-hydraulic problem of pressure diffusion through shales. The solution is based on the Biot's poroelasticity theory that has been extended to incorporate temperature and solute diffusion and chemical osmosis into the constitutive equations. Explicit equations in the time domai...
Article
Probabilistic and deterministic stability analyses of the progress of a large mine pit excavation in Brazil are presented herein. A simple method of reliability analysis for quantifying the probability of failure of slopes has been considered and its advantages and limitations are briefly discussed. The variance of the factor of safety is computed...
Article
Image characterization of rocks is generally carried out by optical and scanning electron microscopy techniques. In this paper, the non-destructive technique of X-Ray micro tomography (μCT) was used in order to obtain microstructural parameters. The experimental program consisted in obtaining these properties from three different carbonate rocks: t...
Article
Rock Mass must be characterized prior to the evaluation of slope stability. Therefore, geological, structural and rock mass models, components making up the geotechnical model, were constructed as per the recommendations of the Large Open Pit project (LOP), an international research project dedicated to open pit mine stability research. The rock ma...
Article
Rock cutting is an important operation in some rock engineering works such as oil well construction and machine driven excavation of rock tunnels. The selection of drill bits and drilling parameters is crucial for the economics of the operation. It can be very important to evaluate both rate of penetration and drill bit life during the planning the...
Chapter
Image characterization of rocks is generally carried out by optical and scanning electron microscopy techniques. In this paper, the non-destructive technique of X-Ray micro tomography (μCT) was used in order to obtain microstructural parameters. The experimental program consisted in obtaining these properties from three different carbonate rocks: t...
Article
A good knowledge of subsurface distribution of rock properties and its associated uncertainties is very useful for developing satisfactory geo-engineering projects. Traditional geotechnical engineering works are usually based on the so-called geotechnical cross-sections of the sub strata but recently, some efforts have been made to replace this pra...
Article
Among the many operational tecniques related to well drilling, hole cleaning is considered a very important one. An occasional failure in the process may cause serious problems, such as a significant increase in the annular pressure, high drag, stuck pipe and eventually, the loss of the well itself. Numerical simulation techniques have been used to...
Article
In recent years operators have shown great interest in the coupling between the multiphase fluid flow and the rock deformation in oil reservoirs and surrounding rocks. Frequently, the geomechanical effects are approximated in a conventional reservoir simulation through only the rock compressibility. This means that the stresses in the reservoir and...
Data
Full-text available
RESUMO No projeto de perfuração, um dos fatores de maior relevância é a limpeza do poço. A ineficiência do mesmo acarreta vários problemas, entre eles o aumento de pressão no anular, aprisionamento de coluna e eventualmente a perda do poço. Devido a isto, foram feitos inúmeros estudos em torno de simulações numéricas a respeito do transporte de sól...
Data
Full-text available
Currently, there is a great interest in the coupling between multiphase fluid flow and geomechanical effects in hydrocarbon reservoirs and surrounding rocks. The ideal solution for this coupled problem is to introduce the geomechanical effects through the stress analysis solution and implement an algorithm, which assures that the equations governin...
Article
Among the costs considered on an oil field exploration, the drilling process related ones constitute a significant share. Consequently, the focus on the removal of cuttings generated by the drilling process, or the hole cleaning operation, is essential. This operation remains a critical issue in the drilling of high inclination-wells, since the cut...
Article
Santos Basin is one of the most promising basins of Brazil, recently it was discovered light crude oil of 30º API (American Petroleum Institute), this reservoir of high productivity is located below a salt layer of two thousand meters (6561,7 ft) of thickness. Salt also known as an evaporite rock is found in many hydrocarbon basins around the world...
Article
A pore scale model, incorporating particle and pore size distributions, and the corresponding averaged equations are discussed and applied to predict pore blocking and permeability reduction during dead-end and cross-flow microfiltration in membranes. The model assumes that size exclusion is the dominant particle retention mechanism and accounts fo...
Article
Full-text available
The presence of saline structures (evaporite rock) in deepwater oilfield reservoirs provides favorable conditions for hydrocarbon imprisonment. Santos basin is one of the most promising basins in Brazil, recently it was discovered light crude oil. This highly productive reservoir is located below a salt layer of 2000 m (6,561.7 ft) in thickness. In...
Article
Full-text available
Na próxima década uma parte considerável da exploração de petróleo será realizada em bacias dominadas por estruturas salinas. Sal também chamado de rocha evaporito é encontrado em muitas bacias de hidrocarbonetos no mundo. Existem depósitos significativos no golfo do México, nas costas leste do Brasil e oeste da África, no sul do Mar do Norte e no...
Article
Full-text available
A determinação exata do ponto de conversão (PC) do modo convertido PS é um aspecto relevante da sismologia da onda convertida. Geralmente, este problema é abordado considerando-se modelos isotrópicos. Mas esta simplificação pode induzir erros significativos devido à desconsideração das características anisotrópicas do subsolo. O presente artigo apr...
Article
This paper presents a coupled thermochemoporoelastic model to compute solute concentration, temperature, pore pressure and stress around a wellbore drilled through shales using water-based fluids. Although the model has both an analytical and a numerical solution, herein we present only the former and its application to wellbore stability analysis...
Conference Paper
This aim of this work is to investigate the errors generated when VTI anisotropy is not considered for normal moveout correction of seismic data. Synthetic data (with different degrees of anisotropy) were processed and the errors on layer depth and NMO velocity were quantified. The results show that NMO velocity is more sensible to δ than e (as exp...
Article
The existence of non-zero reflectivity for zero-offset PS waves in horizontally layered media is discussed. Field measurements have suggested the occurrence of this phenomenon. We show that, in some cases, if anisotropy is considered in the problem, this reflectivity can be predicted. By using an approximated formulation to determine the coefficien...
Article
Shales, in general, are the major source of wellbore stability problems. A particularly critical drilling scenario is the one that combines deepwater and shallow overburden, typical of ultra deepwater fields in Brazil. This scenario is characterized by high pore fluid pressure, low effective stresses, low fracturing gradients and narrow mud weight...
Article
This paper presents a new set of rock-drilling fluid interaction tests carried out in the diffusion cell using saline solutions and mineral oil on a Brazilian offshore shale. The diffusion cell was designed to apply hydraulic and chemical gradients through shale samples in order to evaluate shale-fluid interaction. The proposed test allows the dete...
Conference Paper
Full-text available
Resumo Subcompactação e baixos gradientes geotérmicos são características de ambientes de água profunda. Tais características são responsáveis pela geração de espessas camadas de folhelhos cuja composição é rica em argilomineral esmectita. Tais rochas representam a maior fonte dos problemas de estabilidade encontrados durante a perfuração de poços...
Conference Paper
Full-text available
Resumo Este artigo apresenta a caracterização petrográfica de folhelhos oriundos dos campos de Albacora, Marlim e Marlim Sul (Bacia de Campos, Brasil). O programa de caracterização incluiu a análise de lâminas delgadas, microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de energia (EDS). Os ensaios foram realizados com o objeti...
Article
Here, we analyze two aspects related to converted-wave seismology: the conversion point problem and the zero-offset energy phenomenon. We show the anisotropy effect on the conversion point position and evaluate the error introduced in data processing due to neglecting anisotropy. We demonstrate that the location of the conversion point depends stro...
Conference Paper
Lithology recognition is a common task found in the petroleum exploration field. Roughly speaking, it is a problem of classifying rock types, based on core samples obtained from well drilling programs. In this paper we evaluate the performance of different ensemble systems, specially developed for the task of lithology recognition, based on well da...
Conference Paper
Full-text available
This paper present a study of changes in physic-chemical properties of preserved shale samples when immersed in organic salt solutions. The changes in the immersion fluid are also discussed. An offshore Brazilian shale was used throughout the study. the lab tests were conducted with three kinds of formate brimes. The obtained results indicated that...
Conference Paper
Full-text available
Problemas de instabilidade são encontrados durante a perfuração através de folhelhos, onde, tais problemas são o maior fator responsável pelo aumento de custos que ocorrem durante a perfuração de poços de óleo e gás. Tais problemas são creditados, em geral, à interação entre os fluidos de perfuração e as referidas rochas. Para um maior entendimento...
Conference Paper
Full-text available
Este artigo apresenta um estudo das variações nas propriedades físico-químicas de amostras preservadas de folhelhos quando imersas em sais orgânicos. As mudanças nas propriedades dos fluidos também são apresentadas. Um folhelho brasileiro de origem offshore foi utilizado para a realização da campanha experimental. Os ensaios laboratoriais foram rea...
Conference Paper
Full-text available