Análise computacional de imagens de lâminas delgadas na predição dos parâmetros hidráulicos porosidade e condutividade hidráulica do aquífero Barreiras-RN

The understanding of the occurrence and flow of groundwater in the subsurface is of fundamental importance in the exploitation of water, just like knowledge of all associated hydrogeological context. These factors are primarily controlled by geometry of a certain pore system, given the nature of sedimentary aquifers. Thus, the microstructural characterization, as the interconnectivity of the system, it is essential to know the macro properties porosity and permeability of reservoir rock, in which can be done on a statistical characterization by twodimensional analysis. The latter is being held on a computing platform, using image thin sections of reservoir rock, allowing the prediction of the properties effective porosity and hydraulic conductivity. For Barreiras Aquifer to obtain such parameters derived primarily from the interpretation of tests of aquifers, a practice that usually involves a fairly complex logistics in terms of equipment and personnel required in addition to high cost of operation. Thus, the analysis and digital image processing is presented as an alternative tool for the characterization of hydraulic parameters, showing up as a practical and inexpensive method. This methodology is based on a flowchart work involving sampling, preparation of thin sections and their respective images, segmentation and geometric characterization, three-dimensional reconstruction and flow simulation. In this research, computational image analysis of thin sections of rocks has shown that aquifer storage coefficients ranging from 0,035 to 0,12 with an average of 0,076, while its hydrogeological substrate (associated with the top of the carbonate sequence outcropping not region) presents effective porosities of the order of 2%. For the transport regime, it is evidenced that the methodology presents results below of those found in the bibliographic data relating to hydraulic conductivity, mean values of 1,04 x10-6 m/s, with fluctuations between 2,94 x10-6 m/s and 3,61x10-8 m/s, probably due to the larger scale study and the heterogeneity of the medium studied.

Sistema inteligente para estimar a porosidade em sedimentos a partir da análise de sinais GPR

This Thesis presents the elaboration of a methodological propose for the development of an intelligent system, able to automatically achieve the effective porosity, in sedimentary layers, from a data bank built with information from the Ground Penetrating Radar GPR. The intelligent system was built to model the relation between the porosity (response variable) and the electromagnetic attribute from the GPR (explicative variables). Using it, the porosity was estimated using the artificial neural network (Multilayer Perceptron MLP) and the multiple linear regression. The data from the response variable and from the explicative variables were achieved in laboratory and in GPR surveys outlined in controlled sites, on site and in laboratory. The proposed intelligent system has the capacity of estimating the porosity from any available data bank, which has the same variables used in this Thesis. The architecture of the neural network used can be modified according to the existing necessity, adapting to the available data bank. The use of the multiple linear regression model allowed the identification and quantification of the influence (level of effect) from each explicative variable in the estimation of the porosity. The proposed methodology can revolutionize the use of the GPR, not only for the imaging of the sedimentary geometry and faces, but mainly for the automatically achievement of the porosity one of the most important parameters for the characterization of reservoir rocks (from petroleum or water)

O sistema aquífero Barreiras na região de Parnamirim, RN: uso das águas e potencialidades

The study area is within the Pirangi River Basin, eastern sector of Rio Grande do Norte state, where is located of the Parnamirim city. It has an area of approximately 370 km². Urbanization has developed much fast without an appropriate infrastructure, mainly by the lack of sewage systems, with risks of contamination of groundwater that may cause serious damage to the health of the population. The Barreiras Aquifer System groundwater in the area represents the main source of water supply for urban and rural populations. The use of groundwater occurs without adequate planning and therefore, important recharge areas are being occupied. This study was conducted to quantify the use and evaluation of the potential of groundwater, in order to increase good water quality supply and lower risks of being affected by polluting activities. With these objectives, the following activities were carried out: 268 points of water have been registered; characterization of the lithological, thickness and hydrogeological structure of the Barreiras aquifer, based on the correlation of well logs; and evaluation of hydrodynamic parameters of the aquifer, from the interpretation of results well pumping tests. It was found that the saturated thickness increases from west to east towards the sea, with values ranging from 15,47-56,5 m with an average of 32,45 m. The hydrodynamic parameters using Cooper-Jacob method were: average transmissivity of 5,9x10-3 m²/s and average hydraulic conductivity 2,82x10-4 m/s. The effective porosity is of 15%, obtained by applying Biecinski equation. The potentiometric map shows the main direction of groundwater flow, from west to east, and identifies the recharge areas corresponding to the region of the tablelands of the "Barreiras". The river valleys refer to the discharge areas of the aquifer system. The Recharge was estimated at 253 mm/year, which corresponds to the 16.4% rate of infiltration.

O sistema aquífero Barreiras na região de Parnamirim, RN: uso das águas e potencialidades

The study area is within the Pirangi River Basin, eastern sector of Rio Grande do Norte state, where is located of the Parnamirim city. It has an area of approximately 370 km². Urbanization has developed much fast without an appropriate infrastructure, mainly by the lack of sewage systems, with risks of contamination of groundwater that may cause serious damage to the health of the population. The Barreiras Aquifer System groundwater in the area represents the main source of water supply for urban and rural populations. The use of groundwater occurs without adequate planning and therefore, important recharge areas are being occupied. This study was conducted to quantify the use and evaluation of the potential of groundwater, in order to increase good water quality supply and lower risks of being affected by polluting activities. With these objectives, the following activities were carried out: 268 points of water have been registered; characterization of the lithological, thickness and hydrogeological structure of the Barreiras aquifer, based on the correlation of well logs; and evaluation of hydrodynamic parameters of the aquifer, from the interpretation of results well pumping tests. It was found that the saturated thickness increases from west to east towards the sea, with values ranging from 15,47-56,5 m with an average of 32,45 m. The hydrodynamic parameters using Cooper-Jacob method were: average transmissivity of 5,9x10-3 m²/s and average hydraulic conductivity 2,82x10-4 m/s. The effective porosity is of 15%, obtained by applying Biecinski equation. The potentiometric map shows the main direction of groundwater flow, from west to east, and identifies the recharge areas corresponding to the region of the tablelands of the "Barreiras". The river valleys refer to the discharge areas of the aquifer system. The Recharge was estimated at 253 mm/year, which corresponds to the 16.4% rate of infiltration.

Sistema inteligente para estimar a porosidade em sedimentos a partir da análise de sinais GPR

This Thesis presents the elaboration of a methodological propose for the development of an intelligent system, able to automatically achieve the effective porosity, in sedimentary layers, from a data bank built with information from the Ground Penetrating Radar GPR. The intelligent system was built to model the relation between the porosity (response variable) and the electromagnetic attribute from the GPR (explicative variables). Using it, the porosity was estimated using the artificial neural network (Multilayer Perceptron MLP) and the multiple linear regression. The data from the response variable and from the explicative variables were achieved in laboratory and in GPR surveys outlined in controlled sites, on site and in laboratory. The proposed intelligent system has the capacity of estimating the porosity from any available data bank, which has the same variables used in this Thesis. The architecture of the neural network used can be modified according to the existing necessity, adapting to the available data bank. The use of the multiple linear regression model allowed the identification and quantification of the influence (level of effect) from each explicative variable in the estimation of the porosity. The proposed methodology can revolutionize the use of the GPR, not only for the imaging of the sedimentary geometry and faces, but mainly for the automatically achievement of the porosity one of the most important parameters for the characterization of reservoir rocks (from petroleum or water)

Desenvolvimento de sistemas a base de tensoativos para recuperação avançada de petróleo

Petroleum is a complex combination of various classes of hydrocarbons, with paraffinic, naphtenic and aromatic compounds being those more commonly found in its composition. The recent changes in the world scenario, the large reserves of heavy oils and also the lack of new discoveries of large petroleum fields are indications that, in the near future, the oil recovery by conventional methods will be limited. In order to increase the efficiency of the extraction process, enhanced recovery methods are cited in applications where conventional techniques have proven to be little effective. The injection of surfactant solutions as an enhanced recovery method is advantageous in that surfactants are able to reduce the interfacial tensions between water and oil, thus augmenting the displacement efficiency and, as a consequence, increasing the recovery factor. This work aims to investigate the effects of some parameters that influence the surfactant behavior in solution, namely the type of surfactant, the critical micelle concentration (CMC) and the surface and interface tensions between fluids. Seawater solutions containing the surfactants PAN, PHN and PJN have been prepared for presenting lower interfacial tensions with petroleum and higher stability under increasing temperature and salinity. They were examined in an experimental apparatus designed to assess the recovery factor. Botucatu (Brazil) sandstone plug samples were submitted to assay steps comprising saturation with seawater and petroleum, conventional recovery with seawater and enhanced recovery with surfactant solutions. The plugs had porosity between 29.6 and 32.0%, with average effective permeability to water of 83 mD. The PJN surfactant, at a concentration 1000% above CMC in water, had a higher recovery factor, causing the original oil in place to be recovered by an extra 20.97%, after conventional recovery with seawater