Orientadores: José Ricardo Pelaquim Mendes, Kazuo Miura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-19T05:58:26Z (GMT). No. of bitstreams: 1 Ifekaibeya_WalterNkemjika_M.pdf: 2900574 bytes, checksum: e8d362a13403f80acfb2bf870662e5fd (MD5) Previous issue date: 2011 / Resumo: Na área de petróleo & gás, devido aos altos custos das sondas utilizados nas atividades de perfuração no mar, o aumento da velocidade de execução das operações torna-se imprescindível. A necessidade de se reduzir esses altos custos tem feito com que empresas de perfuração busquem métodos que permitam alcançar o objetivo almejado. Uma dessas formas é o aumento da taxa de penetração (ROP) da broca. Contudo, segundo pesquisas, os efeitos obtidos através dessa prática nem sempre tem resultado na redução dos custos operacionais. Embora pertinente essa constatação, não foram desenvolvidos estudos que pudessem dizer a real influência da taxa de penetração da broca sobre os custos de construção de poços. Essa deficiência motivou o desenvolvimento desta dissertação, que possui como objetivo estudar a influência da taxa de penetração da broca sobre os custos de construção de poços utilizando informações obtidas através da análise da análise de Boletins Diário de Perfuração, dados de mudlogging, entre outros. Para facilitar a avaliação desenvolveu-se um novo parâmetro de análise baseado no tradicional e difundido custo métrico da broca / Abstract: In the field of oil and gas, due to the high costs of rigs used in drilling activities, increasing the speed of operations execution becomes essential. The need to reduce these costs has made drilling companies seek methods to achieve the desired objective. One of those ways is to increase the rate of penetration (ROP) of the bit. However, according to surveys, the outcomes achieved through this practice have not always result in lower operating costs. Although relevant, studies that could tell the real influence of bit's penetration on the costs of well construction were not developed. This deficiency has motivated the development of this dissertation, which has as objective to study the influence of penetration rates on the well construction costs by using information obtained from daily drilling reports analysis, mudlogging data, among others. To facilitate the evaluation influence of bit's penetration on the costs of well construction has developed a new parameter of analysis based on the traditional and popular cost per foot / Mestrado / Explotação / Mestre em Engenharia Mecânica

Orientadores: José Ricardo Pelaquim Mendes, Kazuo Miura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-21T13:11:36Z (GMT). No. of bitstreams: 1 DaFonseca_TiagoCardoso_M.pdf: 2105397 bytes, checksum: 938187b300de7b315fa5e2dcca4fef13 (MD5) Previous issue date: 2012 / Resumo: Integridade de poço pode ser entendida como sua capacidade de evitar vazamentos para o meio ambiente e é uma importante característica de um poço de petróleo. Uma das formas de evitar vazamentos durante a fase de produção é realizar intervenções de manutenção que conservem os poços em situações seguras e com barreiras de segurança sobressalentes. A previsão de custos relativos às intervenções para manutenção deve ser levada em conta nas fases iniciais dos projetos de Desenvolvimento da Produção, quando se planeja e se avalia técnica e economicamente a campanha de construção de poços. Este trabalho apresenta uma metodologia para análise de integridade de poços de Desenvolvimento da Produção que considera a existência de estados intermediários, onde não há perda de integridade, mas o sistema poço encontra-se degradado, fundamentando-se nos conceitos de Conjuntos Solidários de Barreiras (CSB) propostos por Miura (2004) e em técnicas de Engenharia de Confiabilidade. A metodologia pode ser utilizada na previsão de recursos para as intervenções de manutenção de uma campanha de construção e operação de poços. Através do tempo esperado para falha de cada um dos CSB presentes na configuração de completação é possível se estimar quando o estado de integridade do poço passará a depender de um único Conjunto Solidário de Barreiras e qual a expectativa para que haja vazamento (ausência de CSB) / Abstract: Well integrity may be defined as its capability to prevent leaks to the environment and is therefore a very important feature for oil and gas wells. One way to avoid leaks during the well operation is to perform maintenance interventions, seeking to keep redundancy in the well's safety barriers. Cost assessment regarding the wells maintenance interventions shall be done during the initial phases of the Production Development project, when the wells construction campaign is both technically and economically evaluated. This work presents a methodology for petroleum wells integrity analysis considering the existence of intermediate stages, when the integrity has not been lost but the well is considered to be in a degraded status. The method is based on the Barrier Integrated Sets (BIS), proposed by Miura (2004, in Portuguese) and described by Miura et al. (2006 [1]), and on Reliability Engineering techniques. The methodology may be used for maintenance interventions resource assessment considering a well construction campaign. Through the computation of the mean time to failure of each BIS identified in the completion configuration it is possible to estimate when the well is in a degraded status, relying in a single Barrier Integrated Set and well the well is expected to leak (no BIS) / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Reservoir management strategies traditionally attempt to combine and balance complex geophysical, petrophysical, thermodynamic and economic factors to determine an optimal method to recover hydrocarbons from a given reservoir. Reservoir simulators have traditionally been too large and run times too long to allow for rigorous solution in conjunction with an optimization algorithm. It has also proven very difficult to marry an optimizer with the large set of nonlinear partial differential equations required for accurate reservoir simulation. A simple capacitance-resistance model (CRM) that characterizes the connectivity between injection and production wells can determine an injection scheme maximizes the value of the reservoir asset. Model parameters are identified using linear and nonlinear regression. The model is then used together with a nonlinear optimization algorithm to compute a set of future injection rates which maximize discounted net profit. This research demonstrates that this simple dynamic model provides an excellent match to historic data. Based on three case studies examining actual reservoirs, the optimal injection schemes based on the capacitance-resistive model yield a predicted increase in hydrocarbon recovery of up to 60% over the extrapolated exponential historic decline. An advantage of using a simple model is its ability to describe large reservoirs in a straightforward way with computation times that are short to moderate. However, applying the CRM to large reservoirs with many wells presents several new challenges. Reservoirs with hundreds of wells have longer production histories – new wells are created, wells are shut in for varying periods of time and production wells are converted to injection wells. Additionally, ensuring that the production data to which the CRM is fit are free from contamination or corruption is important. Several modeling techniques and heuristics are presented that provide a simple, accurate reservoir model that can be used to optimize the value of the reservoir over future time periods. In addition to optimizing reservoir performance by allocating injection, this research presents a few methods that use the CRM to find optimal well locations for new injectors. These algorithms are still in their infancy and represent the best ideas for future research. / text

[pt] Materiais viscoplásticos, os quais apresentam tensão limite de escoamento, podem ser encontrados em vários processos naturais e em diversas indústrias, tais como: alimentícia, de cosméticos, farmacêutica e do petróleo. Nessas indústrias o conhecimento preciso das propriedades reológicas dos materiais viscoplásticos e do comportamento desses materiais em diferentes escoamentos é fundamental para o sucesso de várias operações. Todavia, a reometria desse tipo de material ainda apresenta alguns desafios como as medidas de tensão limite de escoamento, deslizamento aparente, tixotropia e a quebra da microestrutura na colocação da amostra no reômetro. Alémm disso, existe o fato de que até hoje alguns fenômenos em diferentes escoamentos envolvendo materiais viscoplásticos ainda permanecem não tão bem compreendidos, o que requer uma investigação mais profunda. Nesse trabalho, uma abordagem dos materiais que apresentam comportamento viscoplástico, dos métodos utilizados para as medições de suas propriedades reológicas e do comportamento desses materiais em diferentes tipos de escoamento é realizada. Além disso, é executada uma análise detalhada de escoamentos, tais como: viscométricos, através de expansões-contrações, envolvendo deslocamentos em tubos capilares e de escoamentos envolvendo deslocamentos em poços de petróleo. / [en] Viscoplastic or yield stress materials are found in a lot of natural processes, and in a wide variety of industries such as food, cosmetic, farmaceutical and petroleum. In these industries, knowing the accurate rheological properties of a viscoplastic material and its behavior in different flows are fundamental for the success of many operations. Nevertheless, the rheometry of this kind of material still presents some challenges, such as yield stress measurements, apparent wall slip, thixotropy and the breakdown of structure on loading the material into the rheometer geometry used. In addition to that, until now some phenomena in different flows involving viscoplastic materials are not well understood, and therefore more investigation is required. This thesis deals with viscoplastic materials, their rheological properties measurements, and their behavior in different kinds of flow. Moreover, a detailed analysis of flows such as viscometric, expansions-contractions, the displacements in capillary tubes, and the displacements inside oil wells was performed.

[pt] Em geral, a análise da estabilidade e a análise das respostas de poços de petróleo são realizadas de forma determinística em relação às propriedades mecânicas e hidráulicas do meio rochoso. No entanto, sabe- se que os meios rochosos e em particular rochas sedimentares, podem mostrar um considerável grau de heterogeneidades, em micro, meso e macro-escala. Essas heterogeneidades produzem variabilidade espacial nas propriedades mecânicas e hidráulicas dos meios rochosos. Essa variabilidade mostra em geral um caráter espacial pronunciado. O presente estudo propõe o desenvolvimento de procedimentos de análise numérica, utilizando elementos finitos, de processos fluido mecânicos acoplados, monofásicos e bifásicos, que levem em conta a variabilidade espacial de propriedades hidráulicas e mecânicas e a variabilidade das condições iniciais de tensões e poro pressões. Nesse estudo, empregam-se os procedimentos numéricos desenvolvidos em duas fases distintas. Na análise probabilística da estabilidade de poços e na análise probabilística das respostas dos poços durante a produção, considerando o acoplamento fluido mecânico com fluxo bifásico. / [en] In general, borehole stability analysis and borehole response analysis are carried out considering that both hydraulic and mechanical parameters of the rock mass are deterministic. However, it is a well known fact, that rock masses and in particular sedimentary rock masses may show a considerable degree of heterogeneity, in micro, meso and macro scale. These heterogeneities produce spatial variability in mechanical and hydraulic properties of the rock medium. This variability can be very pronounced. The present work proposes the development of numerical analysis procedures, using finite elements, in order to analyze single and two phases flow, coupled fluid mechanical processes that take into account the spatial variability of hydraulic and mechanical properties and the variability of the initial stresses and pore pressures. In this study, the developed numerical procedures are used in two distinct phases. In the borehole stochastic stability analysis and in the borehole stochastic response analysis during the production, considering fluid mechanical coupling and two phase flow.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Donald Ralph Petersen. / M.S.

This work addresses the poroelastic effect on the processes involved in hydraulic fracturing and post-fracture production using a finite element based fully coupled poroelastic model which includes a triple system of wellbore-fracture-reservoir. A novel numerical procedure for modeling hydraulic fracture propagation in a poroelastic medium is introduced. The model directly takes into account the interaction of wellbore, hydraulic fracture and reservoir in a fully coupled manner. This allows realistic simulation of near fracture phenomena such as back stress and leak-off. In addition, fluid leak-off is numerically modeled based on the concept of fluid flow in porous media using a new technique for evaluating local pressure gradient. Besides, the model is capable of accommodating the zone of reduced pressure (including intermediate and fluid lag zones) at the fracture front so as to capture the behavior of fracture tip region more realistically. A fully coupled poroelastic model for gas reservoirs has been also developed using an innovative numerical technique. From the results of this study it has been found that fracture propagation pressure is higher in poroelastic media compared to that of elastic media. Also high formation permeability (in the direction normal to the hydraulic fracture) and large difference between minimum horizontal stress (in case of it being the smallest principal stress) and reservoir pressure reduce the rate of fracture growth. Besides, high pumping rate is more beneficial in elongating a hydraulic fracture whereas high viscous fracturing fluid is advantageous in widening a hydraulic fracture. It has been also shown that rock deformation, permeability anisotropy and modulus of elasticity can have a significant effect on fluid flow in a hydraulically fractured reservoir. Furthermore, it has been shown that long stress reversal time window and large size of stress reversal region can be caused by high initial pressure differential (i.e. the difference between flowing bottomhole pressure and reservoir pressure), low initial differential stress (i.e. the difference between maximum and minimum horizontal stresses) and low formation permeability in tight gas reservoirs. By taking advantage of production induced change in stress state of a reservoir, this study has also shown that a refracture treatment, if carried out in an optimal time window, can lead to higher economic gain. Besides, analysis of stress reversal region has depicted that a small region with high stress concentration in the vicinity of the wellbore could impede refracture from initiating at the desired place. Moreover, re-pressurization of the wellbore can result in further propagation of the initial fracture before initiation or during propagation of the secondary fracture.

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