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[pt] A inversão sísmica é o processo de transformar dados de Sísmica de Reflexão em valores quantitativos de propriedades petroelásticas das rochas. Esses valores, por sua vez, podem ser correlacionados com outras propriedades ajudando os geocientistas a fazer uma melhor interpretação que resulta numa boa caracterização de um reservatório de petróleo. Existem vários algoritmos tradicionais para Inversão Sísmica. Neste trabalho revisitamos a Inversão Colorida (Impedância Relativa), a Inversão Recursiva, a Inversão Limitada em Banda e a Inversão Baseada em Modelos. Todos esses quatro algoritmos são baseados em processamento digital de sinais e otimização. O presente trabalho busca reproduzir os resultados desses algoritmos através de uma metodologia simples e eficiente baseada em Redes Neurais e na pseudo-impedância. Este trabalho apresenta uma implementação dos algoritmos propostos na metodologia e testa sua validade num dado sísmico público que tem uma inversão feita pelos métodos tradicionais. / [en] Seismic inversion is the process of transforming Reflection Seismic data into quantitative values of petroleum rock properties. These values, in turn, can be correlated with other properties helping geoscientists to make a better interpretation that results in a good characterization of an oil reservoir.There are several traditional algorithms for Seismic Inversion. In this work we revise Color Inversion (Relative Impedance), Recursive Inversion, Bandwidth Inversion and Model-Based Inversion. All four of these algorithms are based on digital signal processing and optimization. The present work seeks to reproduce the results of these algorithms through a simple and efficient methodology based on Neural Networks and pseudo-impedance. This work presents an implementation of the algorithms proposed in the methodology and tests its validity in a public seismic data that has an inversion made by the traditional methods.

Orientadores: Alexandre Campane Vidal, Jose Ricardo Pelaquim Mendes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-13T23:48:25Z (GMT). No. of bitstreams: 1 Ninci_BeatrizCristinaArmelin_M.pdf: 2930424 bytes, checksum: 2e7a09022cc56ed1f213537548845b25 (MD5) Previous issue date: 2009 / Resumo: Este trabalho foi direcionado para a caracterização de fácies do reservatório do Campo de Namorado, com a interpretação de três tipos de perfis geofísicos (raios gama, densidade e neutrão) de oito poços e a utilização da lógica nebulosa. A lógica nebulosa considera que um elemento pode pertencer a mais de um conjunto, mas com graus de pertinência diferentes. Baseiase em variáveis lingüísticas e manuseia valores entre 0 e 1, tolerando dados imprecisos. Com base na descrição dos testemunhos foi definida, por meio de estatística básica, a associação dos valores dos perfis com as litologias identificadas em testemunho. As 26 fácies foram classificadas em 4 grupos de acordo com critérios geológicos. Na etapa seguinte foram desenvolvidos dois sistemas nebulosos, considerando os métodos de inferência Mamdani e Sugeno. A validação dos resultados fornecidos pelos sistemas nebulosos foi feita através da comparação com os dados dos testemunhos. A identificação dos grupos de fácies pelos dois métodos utilizados foi satisfatória, principalmente em relação ao grupo 1, constituído apenas por arenitos. Os resultados decorrentes da aplicação da lógica nebulosa representam um papel importante na caracterização de um reservatório, desde que utilizado em análise conjunta com outros tipos de fontes de dados / Abstract: The research was directed to the facies characterization of Namorado Field reservoir, considering the interpretation of three types of geophysical well-logs (gamma ray, density and neutron) from eight wells, and the use of fuzzy logic. The fuzzy logic considers that an element can belong to more than one set, but with different membership degrees. It is based on linguistic variables and handling values from 0 to 1, tolerating inaccurate data. Based on the cores description, the combination of the values of well-logs with the lithology identified in cores was defined using statistical analysis. The 26 facies were classified into 4 groups according to geological criteria. In the next stage, two fuzzy systems were developed, considering Sugeno and Mamdani inference methods. The validation of results provided by fuzzy systems was made by comparing the results with core data. The identification of the groups was satisfactory in both methods, particularly regarded to group 1, which is formed by sands, predominantly. The results arising from the application of fuzzy logic represents an important role in reservoir characterization, since they are analysed with other types of data sources / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

Orientador: Armando Zaupa Remacre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias / Made available in DSpace on 2018-08-03T18:08:29Z (GMT). No. of bitstreams: 1 Sancevero_SergioSacani_M.pdf: 11223861 bytes, checksum: 4e1d81a7b97619bdeec6c0a58da2e74b (MD5) Previous issue date: 2003 / Resumo: A modelagem de corpos geológicos que possuam caracteristicas de depósitos turbidíticos é uma tarefa muito importante para a indústria de petróleo, principalmente no Brasil, onde os principais reservatórios estão situados nesse tipo de ambiente deposicional. A simulação booleana de objetos e a simulação seqüencial gaussiana são técnicas geoestatísticas que permitem a construção de modelos de referência sintéticos, porém com caracteristicas geológicas, que podem ser submetidos ao processo de modelagem sísmica que num trabalho de caracterização de reservatórios, podem ser usados para testar algoritmos de interpretação, inversão sísmica. Uma vantagem no caso de utilizar dados sintéticos para a realização de estudos de caracterização de reservatórios está na facilidade de interpretar os resultados e gerar conclusões objetivas, uma vez que se pode isolar os diversos fenômenos que afetam o resultado, analisando-os separadamente. Outra caracteristica, bastante importante dos dados sintéticos é que se tem um conjunto de dados de referência para a validação dos resultados. Nesta dissertação propõe-se mostrar a criação de um modelo de referência sintético para ser utilizado em estudos de caracterização de reservatórios. Como resultados, obtém-se um modelo geológico e petrofisico que represente as heterogeneidades de reservatórios petrolíferos do tipo turbidítico, bem como um modelo sísmico sintético onde as ferramentas de interpretação e inversão sísmica possam ser testadas e seus resultados avaliados de maneira concreta já que se tem um controle sobre as estruturas que se deseja interpretar. Conclui-se então a importância de um modelo de referência para estudos de caracterização de reservatórios e propõem-se como trabalhos futuros estudos relativos à conectividade dos corpos reservatório gerado, modelagem de outros sistemas deposicionais e estudos sobre o comportamento do fluxo no modelo sintético / Abstract: The geological modeling of bodies that have characteristics of turbidite reservoir is a very important task for the industry of oil, main1y in Brazil, where the main reservoirs are situated in that kind of deposicional environment. The simulation based in objects by Boolean model and the sequential gaussian simulation are the geostatistics techniques that permit the construction of synthetic reference models, however with geological characteristics, that can be submitted to the seismic modeling that in a work of reservoirs characterization, can be used to test algorithms of seismic interpretation and inversion. An advantage in case of use synthetic dataset for the achievement of studies of reservoir characterization is in the facility of interpret the results and generate objective conc1usions, since it can be isolated the diverse phenomena that affect the result, analyzing them separately. Another important characteristic, of the synthetic dataset is that has a reference model for the validation of results. In this dissertation the propose is the creation of a synthetic reference model to be used in studies of reservoir characterization. As results, obtain a petrophysical and geological model that represent the heterogeneities of turbidites oil-producing reservoirs, as well as a synthetic seismic model where the tools of seismic interpretation and inversion can be tested and his results can be evaluated of effective way since has a control about the structures that is desired interpreto Conc1ude itself then the importance of a model of reference for studies of reservoir characterization and propose as future works studies about the connectivity of the reservo ir bodies generated, modeling of others depositionals systems, and studies about fluid flow behavior / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

The presence of subseismic scale faulting within high porosity sandstone reservoirs and aquifers represents a significant source of uncertainty for activities such as hydrocarbon production and the geologic sequestration of carbon dioxide. The inability to resolve geometrical properties of these smaller scale faults, such as size, connectivity and intensity, using conventional subsurface datasets (i.e. seismic reflection tomography, wireline log and core), leads to ambiguous representations within reservoir models and simulators. In addition, more fundamental questions still remain over the role of cataclastic faults in the trapping and transfer of mobile geofluids within the subsurface, particularly when two or more immiscible fluid phases are present, as is the case during hydrocarbon accumulation, waterflood operations and CO2 injection. By harnessing recent developments in 3D digital surface and volume imaging, this study addresses uncertainties pertaining to the geometrical and petrophysical properties of subseismic scale faults within porous sandstone reservoirs. A novel structural feature extraction and modelling framework is developed, which facilitates the restoration of fault and fracture architecture from digital rock surface models. This framework has been used to derive volumetric fault abundance and connectivity from a normal sense array of cataclastic shear bands developed within high porosity sandstones of the Vale of Eden Basin, UK. These spatially resolved measures of discontinuity abundance provide the basis for the geostatistical extrapolation of fracture/fault intensity into reservoir modelling grids, which promises the introduction of a much higher degree of geological realism into discrete fracture network models than can currently be achieved through purely stochastic methods. Moreover, by establishing spatial correspondences between volumetric faulting intensity and larger scale features of deformation observed at the study area (cataclastic shear zones), the work demonstrates the potential to relate reservoir equivalent measures of fault or fracture abundance obtained from outcrop to seismically resolvable structures within the subsurface, aiding the prediction of reservoir structure from oilfield datasets. In addition to the derivation of continuum scale properties of sub-seismic scale fault networks, a further investigation into the pore-scale controls which govern the transfer of fluids within cataclised sandstones has been conducted. Through X-ray tomographic imaging of experimental core flood (scCO2-brine primary drainage) through a cataclastic shear band bearing sandstone, insights into the influence that variations in fault structure exert over the intra-fault drainage pathway of an invading non-wetting fluid have been gained. Drainage across the fault occurs as a highly non-uniform and non-linear process, which calls into question the practice of using continuum methods to model cross fault flow. This work has also provided an improved understanding of the role that high capillary entry pressure cataclised regions play in modifying pore-fluid displacement processes within the surrounding matrix continuum. In particular, the high sweep efficiency and enhanced non-wetting phase pore-wall contact relating to elevated phase pressure observed during drainage points towards favourable conditions for wettability alteration within cataclised sandstones. This is likely to negatively impact upon the effectiveness of oil recovery and CO2 sequestration operations within equivalent reservoir and aquifer settings.

Ultra-high-resolution subsurface stratigraphy mapped from 3D ground-penetrating radar (GPR) can provide insights into the fine-scale heterogeneity of reservoirs and other geologic features. Analog models derived from 3D GPR aid in understanding reservoir compartmentalization that may be sub-seismic but still affect fluid flow. We integrate 2D profiles and 3D GPR volumes with measured stratigraphic sections from outcrop exposure to characterize the fine-scale stratigraphy of an ancient Lake Bonneville shoreline deposit (locally, circa 20 ka based on carbon-14 dating) in the Great Basin (northwestern Utah). The heterogeneity of the deposit is expressed as multiple discordant patterns, separated by unconformities that likely were influenced by fluctuating lake levels on the lake margin. Although the study site is only ~8,000 square meters in area, the detailed stratigraphic relationships can be scaled up to inform the characterization of larger sedimentary deposits with economic reservoir potential. The sands, gravels, and marls composing the stratigraphy were deposited during the transgressive phase of the pluvial lake, which preserved shoreline features such as spits and barrier bars. We interpret our site as a spit that extended out into the Pleistocene lake, at times connecting to a nearby persistently subaerially exposed island to form a tombolo. The deposited strata are well-exposed in a fortuitously located gravel quarry. The site provides an excellent natural laboratory for detailed 3D imaging due to the mostly flat ground surface (the quarry floor), low-clay, low-salinity, and low-moisture content of the site. The GPR data were acquired with a 200-MHz antenna (for 2D profiles) and a 400-MHz antenna (for 3D volumes). For the latter, the line spacing was about 0.3 meters with a trace spacing of 2.5 cm. The GPR dataset offers high-resolution images of clinoform sequence stratigraphy down to about 3 meters below the surface of the quarry. The vertical resolution (Rayleigh criterion) of the data is about 6 cm (for 3D volumes) and 13 cm (for 2D profiles). Migration collapsed diffractions and re-positioned dipping reflectors correctly. Deconvolution suppressed multiple reflections and tightened the waveforms. Using petroleum industry mapping software, amplitudes were binned into voxels to create precise 3D volumes, which facilitated more accurate geometrical interpretation (e.g., true dip direction of reflectors). Facies associations from stratigraphic sections measured just above the GPR acquisition level (quarry floor) help to describe and reconstruct the depositional history of the spit. The lithologic interpretation of the GPR reflectors is constrained by the correlation (or extrapolation) of the measured sections to the subsurface data volumes. Reflectivity is controlled by variations in porosity and matrix content (e.g., quartz vs. clays vs. calcite). Our study furnishes a model of transgressive deposits in a lacustrine environment and an analog for clastic sediments deposited on a larger scale in such environments.

3D time-lapse seismics, also known as 4D seismics, have great potential for monitoring the migration of CO2 at underground storage sites. This thesis focuses on time-lapse analysis of 3D seismic reflection data acquired at the Ketzin CO2 geological storage site in order to improve understanding of the reservoir and how CO2 migrates within it. Four 3D seismic surveys have been acquired to date at the site, one baseline survey in 2005 prior to injection, two repeat surveys in 2009 and 2012 during the injection period, and one post-injection survey in 2015. To accurately simulate time-lapse seismic signatures in the subsurface, detailed 3D seismic property models for the baseline and repeat surveys were constructed by integrating borehole data and the 3D seismic data. Pseudo-boreholes between and beyond well control were built. A zero-offset convolution seismic modeling approach was used to generate synthetic time-lapse seismograms. This allowed simulations to be performed quickly and limited the introduction of artifacts in the seismic responses. Conventional seismic data have two limitations, uncertainty in detecting the CO2 plume in the reservoir and limited temporal resolution. In order to overcome these limitations, complex spectral decomposition was applied to the 3D time-lapse seismic data. Monochromatic wavelet phase and reflectivity amplitude components were decomposed from the 3D time-lapse seismic data. Wavelet phase anomalies associated with the CO2 plume were observed in the time-lapse data and verified by a series of seismic modeling studies. Tuning frequencies were determined from the balanced amplitude spectra in an attempt to discriminate between pressure effects and CO2 saturation. Quantitative assessment of the reservoir thickness and CO2 mass were performed. Time-lapse analysis on the post-injection survey was carried out and the results showed a consistent tendency with the previous repeat surveys in the CO2 migration, but with a decrease in the size of the amplitude anomaly. No systematic anomalies above the caprock were detected. Analysis of the signal to noise ratio and seismic simulations using the detailed 3D property models were performed to explain the observations. Estimation of the CO2 mass and uncertainties in it were investigated using two different approaches based on different velocity-saturation models.

This thesis investigates methane emissions and methane production potentials from abandoned longwall panels produced or emitted due to mining activities either from coal seam or any underlying or overlying formations. These emissions can increase greenhouse gas concentrations and also pose a danger to the underground working environment and to miners. In addition to the safety issues, recovery and utilization of this gas is an additional source of energy. In this study, methane concentrations measured from ventilation air ways in Yeni &Ccedil / eltek Coal Mine, which is located in Suluova basin, Amasya, and contains thick, laterally extensive Lower Eocene coal seams, were integrated within a numerical vi reservoir model. Key reservoir parameters for history matching are cleat permeabilities, cleat porosity, diffusion time and Langmuir volume and Langmuir pressure. Thirteen cases were studied. According to the results, Case-10 determined as the best fitted case for both of the production wells. Cleat permeabilities and Langmuir pressure were the most effective parameters. Reservoir parameters matched are cleat permeabilities of 5, 4 and 1 md and fracture dimensions of 0.8, 0.4, and 0.1 m in x, y and z direction respectively, 2 % cleat porosity, 0.3 % water saturation. Diffusion time was determined as 400 days and 2000 kPa Langmuir volume and 6.24279 m3 /tone gas content estimated. According to these results it can be said that methane production will not be economically feasible, however / to remedy underground working conditions and safety of workers methane management should be taken into consideration.

“History matching” (model calibration, parameter identification) is an established method for determination of representative reservoir properties such as permeability, porosity, relative permeability and fault transmissibility from a measured production history; however the uniqueness of selected model is always a challenge in a successful history matching. Up to now, the uniqueness of history matching results in practice can be assessed only after individual and technical experience and/or by repeating history matching with different reservoir models (different sets of parameters as the starting guess). The present study has been used the stochastical theory of Kullback & Leibler (K-L) and its further development by Akaike (AIC) for the first time to solve the uniqueness problem in reservoir engineering. In addition - based on the AIC principle and the principle of parsimony - a penalty term for OF has been empirically formulated regarding geoscientific and technical considerations. Finally a new formulation (Penalized Objective Function, POF) has been developed for model selection in reservoir history matching and has been tested successfully in a North German gas field. / „History Matching“ (Modell-Kalibrierung, Parameter Identifikation) ist eine bewährte Methode zur Bestimmung repräsentativer Reservoireigenschaften, wie Permeabilität, Porosität, relative Permeabilitätsfunktionen und Störungs-Transmissibilitäten aus einer gemessenen Produktionsgeschichte (history). Bis heute kann die Eindeutigkeit der identifizierten Parameter in der Praxis nicht konstruktiv nachgewiesen werden. Die Resultate eines History-Match können nur nach individueller Erfahrung und/oder durch vielmalige History-Match-Versuche mit verschiedenen Reservoirmodellen (verschiedenen Parametersätzen als Startposition) auf ihre Eindeutigkeit bewertet werden. Die vorliegende Studie hat die im Reservoir Engineering erstmals eingesetzte stochastische Theorie von Kullback & Leibler (K-L) und ihre Weiterentwicklung nach Akaike (AIC) als Basis für die Bewertung des Eindeutigkeitsproblems genutzt. Schließlich wurde das AIC-Prinzip als empirischer Strafterm aus geowissenschaftlichen und technischen Überlegungen formuliert. Der neu formulierte Strafterm (Penalized Objective Function, POF) wurde für das History Matching eines norddeutschen Erdgasfeldes erfolgreich getestet.