Predicting rock permeability from well logs in uncored wells is an important task in reservoir characterization. Due to the high costs of coring and laboratory analysis, typically cores are acquired in only a few wells. Since most wells are logged, the common practice is to estimate permeability from logs using correlation equations developed from limited core data. Most commonly, permeability is estimated from various well logs using statistical regression. For sandstones, often the logs of permeability can be correlated with porosity, but in carbonates the porosity permeability relationship tends to be much more complex and erratic. For this reason permeability prediction is a critical aspect of reservoir characterization in complex reservoirs such as carbonate reservoirs. In order to improve the permeability estimation in these reservoirs, several statistical regression techniques have already been tested in previous work to correlate permeability with different well logs. It has been shown that statistical regression for data correlation is quite promising in predicting complex reservoirs. But using all the possible well logs to predict permeability is not appropriate because the possibility of spurious correlation increases if you use more well logs. In statistics, variable selection is used to remove unnecessary independent variables and give a better prediction. So we apply variable selection to the permeability prediction procedures in order to further improve permeability estimation. We present three approaches to further improve reservoir permeability prediction based on well logs via data correlation and variable selection in this research. The first is a combination of stepwise algorithm with ACE technique. The second approach is the application of tree regression and cross-validation. The third is multivariate adaptive regression splines. Three methods are tested and compared at two complex carbonate reservoirs in west Texas: Salt Creek Field Unit (SCFU) and North Robertson Unit (NRU). The result of SCFU shows that permeability prediction is improved by applying variable selection to non-parametric regression ACE while tree regression is unable to predict permeability because it can not preserve the continuity of permeability. In NRU, none of these three methods can predict permeability accurately. This is due to the high complexity of NRU reservoir and measurement accuracy. In this reservoir, high permeability is discrete from low permeability, which makes prediction even more difficult. Permeability predictions based on well logs in complex carbonate reservoirs can be further improved by selecting appropriate well logs for data correlation. In comparing the relative predictive performance of the three regression methods, the stepwise with ACE method appears to outperform the other two methods.

Borehole imaging is one of the fastest and most precise methods for collecting subsurface data that provides high resolution information on layering, texture and dips, permitting a core-like description of the subsurface. Although the range of information recoverable from this technology is widely acknowledged, image logs are still used in a strictly qualitative manner. Interpreting image logs manually is cumbersome, time consuming and is subjective based on the experience of the interpreter. This thesis outlines new methods that automate image log interpretation and extract subsurface lithofacies information in a quantitative manner. We developed two methodologies based on advanced image analysis techniques successfully employed in remote sensing and medical imaging. The first one is a pixelbased pattern recognition technique applying textural analysis to quantify image textural properties. These properties together with standard logs and core-derived lithofacies information are used to train a back propagation Neural Network. In principle the trained and tested Neural Network is applicable for automated borehole image interpretation from similar geological settings. However, this pixel-based approach fails to make use explicitly of the spatial characteristics of a high resolution image. TAT second methodology is introduced which groups identical neighbouring pixels into objects. The resultant spectrally and spatially consistent objects are then related to geologically meaningful groups such as lithofacies by employing fuzzy classifiers. This method showed better results and is applied to outcrop photos, core photos and image logs, including a ‘difficult’ data set from a deviated well. The latter image log did not distinguish some of the conductive and resistive regions, as observed from standard logs and core photos. This is overcome by marking bed boundaries using standard logs. Bed orientations were estimated using an automated sinusoid fitting algorithm within a formal uncertainty framework in order to distinguish dipping beds and horizontal stratification. Integration of these derived logs in the methodology yields a complete automated lithofacies identification, even from the difficult dataset. The results were validated through the interpretation of cored intervals by a geologist. This is a supervised classification method which incorporates the expertise of one or several geologists, and hence includes human logic, reasoning, and current knowledge of the field heterogeneity. By including multiple geologists in the training, the results become less dependent on each individual’s subjectivity and prior experience. The method is also easily adaptable to other geological settings. In addition, it is applicable to several kinds of borehole images, for example wireline electrical borehole wall images, core photographs, and logging-while-drilling (LWD) images. Thus, the theme of this dissertation is the development of methodologies which makes image log interpretation simpler, faster, less subjective, and efficient such that it can be applied to large quantities of data.

The study area is situated along the obliquely converging boundary of the Caribbean and South American plates offshore eastern offshore Trinidad. Major structural elements in the shelf break and deep-water slope regions include normal and counter-normal faults to the south and large transpressional fault zones to the north. Well logs and biostratigraphic information were analyzed for twenty-four wells in the study area to refine previous depositional environment interpretations. For purposes of this net sand distribution analysis it was decided to consider the deltaic portion of the shelf transit cycle, against the marine portion of the shelf transit cycle and were named T and R cycles, respectively. T and R cycles were interpreted based on well log patterns and depositional facies shifts. Six T/R cycles were interpreted within the Pliocene to recent stratigraphic succession and shelf edge trajectories were also mapped for each of these cycles based on earlier stratigraphic correlations. Net-to-gross (NTG) ratios were calculated for each component of the T/R cycles and plotted against total thicknesses and net sand values. In addition, NTG trends were mapped for each interval and analyzed based on their proximity to the corresponding shelf edge. Mapping of the shelf edge trajectories (SET) revealed that (1) SET migrate northeasterly across the Columbus Basin through time and (2) shelf edge orientations are parallel to the strike of growth faults in the south but deflect to the northeast near the Darien Ridge indicating a strong underlying structural control. The NTG plots and maps also revealed that (1) For T cycles, NTG values never exceed 60% and are inversely proportional to total thickness, (2) For R cycles, NTG values are highly variably ranging from 35% to 90%, (3) NTG values increase as the shelf break is approached and (4) The distribution of NTG ratios is also controlled by accommodation space created by local structures. The Guiana current is believed to play an important role in the redistribution and reworking of sand in the Columbus Basin. Aggradation and progradation distances were computed for each interval and the results suggest that the younger Sequences C2 (T-R cycle E) and C3 (T-R cycle F) show a stronger progradational trend than the older C4, C5 and C6. This strong progradational trend might indicate delivery of sand basinwards, while for the older intervals; the aggradational trend suggests an increase in sediment storage. In long-term scale (1-2 m.y.) the Orinoco Delta seems to behave as an aggradational delta that increases sediment storage due to growth fault and high subsidence rates. However, in the short-term scale, the Orinoco delta seems to behave as a rapid progradational delta, for the younger sequences C2 and C3, where sediment bypass is more likely to occur; and as a rapid aggradational (slow prograding) margin for the older intervals C4, C5 and C6. / text

No description available.

Nos depósitos cenozóicos da Bacia de Taubaté são encontrados depósitos de folhelhos betuminosos (oleígenos) pertencentes à Formação Tremembé, de idade oligocênica, que durante alguns anos na década de 50 foram investigados com relação ao seu aproveitamento econômico através da extração industrial do óleo nele contido. Entretanto, em face de aspectos tecnológicos e conjunturais da época, esse aproveitamento industrial foi considerado inviável do ponto de vista econômico. Nesta dissertação é proposta uma aplicação da perfilagem geofísica para a caracterização da faciologia dos folhelhos betuminosos da Formação Tremembé, tendo como objetivo principal a identificação das eletrofácies nos perfis elétricos, através de uma metodologia robusta e consistente. A identificação de eletrofácies é importante para ajudar na determinação da caracterização de uma reserva não convencional e na análise da viabilidade econômica. Neste estudo foram utilizados os perfis convencionais de poço: Raio gama, resitividade, potencial espontâneo e sônico. Os dados de perfis de poços foram integrados com os testemunhos e dados geoquímicos, mais precisamente os dados de COT, S, IH, S2 para uma caracterização realística das eletrofácies. Os dados foram obtidos a partir de três sondagens rotativas realizadas na Bacia de Taubaté, resultantes de testemunhagem contínua e perfilagem a cabo ao longo do intervalo de folhelhos da Formação Tremembé. A partir disto, obtém-se como resposta um modelo específico para cada litologia, onde cada pico corresponde a uma eletrofácies, permitindo o estabelecimento de alguns padrões ou assinaturas geofísicas para as principais fácies ocorrentes. Como resultado deste trabalho, foi possível correlacionar as eletrofácies entre os poços numa seção modelo, a partir de similaridade lateral das eletrofácies entre os marcos estratigráficos representado, foi possível observar a continuidade de duas sequências de folhelhos betuminoso com alto teores de COT, S, IH, S2, considerados os mais importantes do ponto de vista econômico e gerado um modelo faciológico 2D e 3D dessas camadas. Os resultados obtidos neste trabalho são bastante promissores, apontando para a possibilidade de aplicação desta técnica a outros poços da Bacia de Taubaté, fornecendo subsídios relevantes à determinação da evolução sedimentar. / At the Cenozoic deposits in the Taubaté Basin are found deposits of bituminous shale (oil Shale) belonging to Tremembé Formation, Oligocene, which for some years in the 50s were investigated with respect to its economic exploitation by the industrial extraction of oil contained therein. However, in the face of technological issues and conjuncture of this time, the industrial use was considered unfeasible economically. This dissertation proposed an application of geophysical Well Log for the faciology characterization of bituminous shale in Tremembé Formation, having as main objective the identification of electrofacies on electric logs, through a robust and consistent methodology. The identification of electrofacies is important to help determine the characterization of an unconventional reserves and economic viability analysis. In this study we used the conventional Well Logs: Gama Ray, resistivity, spontaneous potential and sonic. Data from well logs were integrated with the core and geochemical data, specifically data from TOC, S, IH, S2 for a realistic characterization of electrofacies. Data were obtained from three Wells in Taubaté Basin, resulting from continuous coring and wireline log along the Tremembé Formation shales. From this response is obtained as a model for each lithology, where each peak corresponds to an electrofacies, allowing the establishment of some patterns geophysical for the main facies occurring. As a result of this study, it was possible to correlate the electrofacies between wells in a section model, from sideways similarity of electrofacies between the represented marks stratigraphic , It was possible to observe the continuity of two sequences of bituminous shales with high TOC, S, IH , S2, which are considered the most important of point of economic view, and generated a 2D and 3D facies model of these layers. The present results are very promising, pointing to the possibility of applying this technique to other wells in the Basin Taubaté, providing subsidies relevant to the determination of sedimentary evolution.

O trabalho aqui apresentado teve como objetivo, avaliar o método de Eaton (1975) aplicado ao cálculo de pressão de poros das formações rochosas em subsuperfície, utilizando dados de perfis de poços no que diz respeito a porosidade, tais como, o Tempo de Transito da onda compressional, Resistividade, Densidade e Neutrão. Posteriormente foi avaliado o resultado alcançado por esta técnica e confrontado com o dado obtido pelo registro de pressão real da formação, adquirido pela ferramenta de perfilagem MDT. Distribuídos em 6 poços perfurados na porção sul da Bacia de Campos, o intervalo cronoestratigráfico estudado está compreendido no período geológico Terciário, e os registros de pressão real da formação foram adquiridos nos reservatórios turbidíticos da Formação Carapebus (Eoceno). Apesar de existir um mecanismo causador de anomalia de pressão na bacia (Desequilíbrio de Compactação Difícil migração dos fluidos ao longo do tempo geológico) devido ao forte aporte sedimentar sustentado pelo soerguimento da Serra do Mar no Eoceno, os resultados encontrados não apontaram qualquer tipo de alteração nas respostas dos perfis utilizados, onde a referência foi a assinatura do perfil sônico em um trend normal de compactação compreendido por rochas argilosas dentro do intervalo cronoestratigráfico estudado. O presente trabalho atesta que a boa calibração do trend de ompactação normal em rochas argilosas, juntamente com a similaridade entre o resultado obtido pelo cálculo da pressão de poros a partir do perfil sônico, e os valores reais registrados diretamente na formação, pela ferramenta de registro de pressões (MDT), comprovam a aplicabilidade do método de Eaton (1975) para o cálculo de geopressões a partir de um conjunto básico de perfis de poços tais como: Raios Gama, Resistividade, Velocidade Acústica, Densidade e Neutrão / The work presented here aimed to assess the method of Eaton (1975) applied to the pore pressure calculation of rock formations in the subsurface, using well logs data regarding porosity, such as the Transit Time of compressional wave, resistivity, density and Neutron. Subsequently it evaluated the result achieved by this technique and confronted with the data obtained by the real pressure record of formation, acquired by logging tool MDT. Distributed in 6 wells drilled in the southern portion of the Campos Basin, the study chronostratigraphic range comes under Tertiary geological period, and the actual pressure records of the training was acquired in turbidite reservoirs Carapebus Formation (Eocene). Although there is a causative mechanism of pressure anomaly in the basin (Imbalance Compression - Hard migration of fluid over geological time) due to the strong contribution sedimentary supported by the Serra do Mar uplift in the Eocene, the results did not show any changes in the responses of used logs, where the reference was the signing of the sonic log in a normal compaction trend comprised of argillaceous rocks within the chronostratigraphic range studied. This study confirms that good calibration of the normal compaction trend in argillaceous rocks, along with the similarity between the results obtained by the pore pressure calculation from the sonic log, and actual amounts recorded directly in formation, the registration tool pressures (MDT), demonstrate the applicability of the method Eaton (1975) for calculating geopressões from a basic set of well logs such as gamma rays, resistivity, acoustic speed, density, and neutron

Nos depósitos cenozóicos da Bacia de Taubaté são encontrados depósitos de folhelhos betuminosos (oleígenos) pertencentes à Formação Tremembé, de idade oligocênica, que durante alguns anos na década de 50 foram investigados com relação ao seu aproveitamento econômico através da extração industrial do óleo nele contido. Entretanto, em face de aspectos tecnológicos e conjunturais da época, esse aproveitamento industrial foi considerado inviável do ponto de vista econômico. Nesta dissertação é proposta uma aplicação da perfilagem geofísica para a caracterização da faciologia dos folhelhos betuminosos da Formação Tremembé, tendo como objetivo principal a identificação das eletrofácies nos perfis elétricos, através de uma metodologia robusta e consistente. A identificação de eletrofácies é importante para ajudar na determinação da caracterização de uma reserva não convencional e na análise da viabilidade econômica. Neste estudo foram utilizados os perfis convencionais de poço: Raio gama, resitividade, potencial espontâneo e sônico. Os dados de perfis de poços foram integrados com os testemunhos e dados geoquímicos, mais precisamente os dados de COT, S, IH, S2 para uma caracterização realística das eletrofácies. Os dados foram obtidos a partir de três sondagens rotativas realizadas na Bacia de Taubaté, resultantes de testemunhagem contínua e perfilagem a cabo ao longo do intervalo de folhelhos da Formação Tremembé. A partir disto, obtém-se como resposta um modelo específico para cada litologia, onde cada pico corresponde a uma eletrofácies, permitindo o estabelecimento de alguns padrões ou assinaturas geofísicas para as principais fácies ocorrentes. Como resultado deste trabalho, foi possível correlacionar as eletrofácies entre os poços numa seção modelo, a partir de similaridade lateral das eletrofácies entre os marcos estratigráficos representado, foi possível observar a continuidade de duas sequências de folhelhos betuminoso com alto teores de COT, S, IH, S2, considerados os mais importantes do ponto de vista econômico e gerado um modelo faciológico 2D e 3D dessas camadas. Os resultados obtidos neste trabalho são bastante promissores, apontando para a possibilidade de aplicação desta técnica a outros poços da Bacia de Taubaté, fornecendo subsídios relevantes à determinação da evolução sedimentar. / At the Cenozoic deposits in the Taubaté Basin are found deposits of bituminous shale (oil Shale) belonging to Tremembé Formation, Oligocene, which for some years in the 50s were investigated with respect to its economic exploitation by the industrial extraction of oil contained therein. However, in the face of technological issues and conjuncture of this time, the industrial use was considered unfeasible economically. This dissertation proposed an application of geophysical Well Log for the faciology characterization of bituminous shale in Tremembé Formation, having as main objective the identification of electrofacies on electric logs, through a robust and consistent methodology. The identification of electrofacies is important to help determine the characterization of an unconventional reserves and economic viability analysis. In this study we used the conventional Well Logs: Gama Ray, resistivity, spontaneous potential and sonic. Data from well logs were integrated with the core and geochemical data, specifically data from TOC, S, IH, S2 for a realistic characterization of electrofacies. Data were obtained from three Wells in Taubaté Basin, resulting from continuous coring and wireline log along the Tremembé Formation shales. From this response is obtained as a model for each lithology, where each peak corresponds to an electrofacies, allowing the establishment of some patterns geophysical for the main facies occurring. As a result of this study, it was possible to correlate the electrofacies between wells in a section model, from sideways similarity of electrofacies between the represented marks stratigraphic , It was possible to observe the continuity of two sequences of bituminous shales with high TOC, S, IH , S2, which are considered the most important of point of economic view, and generated a 2D and 3D facies model of these layers. The present results are very promising, pointing to the possibility of applying this technique to other wells in the Basin Taubaté, providing subsidies relevant to the determination of sedimentary evolution.

O trabalho aqui apresentado teve como objetivo, avaliar o método de Eaton (1975) aplicado ao cálculo de pressão de poros das formações rochosas em subsuperfície, utilizando dados de perfis de poços no que diz respeito a porosidade, tais como, o Tempo de Transito da onda compressional, Resistividade, Densidade e Neutrão. Posteriormente foi avaliado o resultado alcançado por esta técnica e confrontado com o dado obtido pelo registro de pressão real da formação, adquirido pela ferramenta de perfilagem MDT. Distribuídos em 6 poços perfurados na porção sul da Bacia de Campos, o intervalo cronoestratigráfico estudado está compreendido no período geológico Terciário, e os registros de pressão real da formação foram adquiridos nos reservatórios turbidíticos da Formação Carapebus (Eoceno). Apesar de existir um mecanismo causador de anomalia de pressão na bacia (Desequilíbrio de Compactação Difícil migração dos fluidos ao longo do tempo geológico) devido ao forte aporte sedimentar sustentado pelo soerguimento da Serra do Mar no Eoceno, os resultados encontrados não apontaram qualquer tipo de alteração nas respostas dos perfis utilizados, onde a referência foi a assinatura do perfil sônico em um trend normal de compactação compreendido por rochas argilosas dentro do intervalo cronoestratigráfico estudado. O presente trabalho atesta que a boa calibração do trend de ompactação normal em rochas argilosas, juntamente com a similaridade entre o resultado obtido pelo cálculo da pressão de poros a partir do perfil sônico, e os valores reais registrados diretamente na formação, pela ferramenta de registro de pressões (MDT), comprovam a aplicabilidade do método de Eaton (1975) para o cálculo de geopressões a partir de um conjunto básico de perfis de poços tais como: Raios Gama, Resistividade, Velocidade Acústica, Densidade e Neutrão / The work presented here aimed to assess the method of Eaton (1975) applied to the pore pressure calculation of rock formations in the subsurface, using well logs data regarding porosity, such as the Transit Time of compressional wave, resistivity, density and Neutron. Subsequently it evaluated the result achieved by this technique and confronted with the data obtained by the real pressure record of formation, acquired by logging tool MDT. Distributed in 6 wells drilled in the southern portion of the Campos Basin, the study chronostratigraphic range comes under Tertiary geological period, and the actual pressure records of the training was acquired in turbidite reservoirs Carapebus Formation (Eocene). Although there is a causative mechanism of pressure anomaly in the basin (Imbalance Compression - Hard migration of fluid over geological time) due to the strong contribution sedimentary supported by the Serra do Mar uplift in the Eocene, the results did not show any changes in the responses of used logs, where the reference was the signing of the sonic log in a normal compaction trend comprised of argillaceous rocks within the chronostratigraphic range studied. This study confirms that good calibration of the normal compaction trend in argillaceous rocks, along with the similarity between the results obtained by the pore pressure calculation from the sonic log, and actual amounts recorded directly in formation, the registration tool pressures (MDT), demonstrate the applicability of the method Eaton (1975) for calculating geopressões from a basic set of well logs such as gamma rays, resistivity, acoustic speed, density, and neutron

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

No description available.