Publications
American Association of Petroleum Geologists
AAPG Annual Convention and Exhibition 2013 - Pittsburgh (to be presented)
Abstract Geological models for reservoir studies are built through interactive integration of information captured in several different scales of analysis. Several software tools support the analysis in each one of these scales, but usually the integration of this information across different scales results in manual work for the geologist. We describe here an approach to support the visualization and interactive data analysis to integrate three scales in which the data is captured by separated systems: meso-, macro- and micro-scales. The meso-scale corresponds to the overview of a set of wells in a 3D space, macro-scale to the individual well logs with associated core description, and the micro-scale is represented by petrographic description. In the meso-scale, the
Reservoir View, the user can select and plot a set of key wells, having a general view of all available information. The wells, displayed in a 3D space, provide different visualization styles showing the types of data available along the wells. The user can analyze an individual log or switch between logs in the reservoir view to compare the values of the same property across different wells. In the intervals where well has core descriptions, lithological symbols show the lithology and unit boundaries. From this broader view, the user can select a macro-scale of analysis. The
Well View shows all the information related to an individual well (logs and core descriptions, if available). Core description is based on the concept of facies. Each facies is determined according to lithology, texture and structures, using a standard set of icons and nomenclature for the different attributes. Whenever a petrographic description is available, the user can move into the micro-scale using the
Petrography View. This view is divided into sections that encompass the petrographic attributes. Textural and structural parameters are represented by icons, and the mineral composition is represented by bar charts. Ternary diagrams are used to represent the rock classification, and photomicrographs associated with the analysis are also shown. In the current version, the visualization environment integrates well log data from LAS files, information stored in Strataledge (core description) and in Petroledge (petrographic description). We believe that this approach will reduce the amount of time specialists spend generating interpretation and reports, thus optimizing the workflow in reservoir characterization.
Oscar Paesi da Silva(1,3), Carla Maria Dal Sasso Freitas (1), Alexandre Lorenzatti(1,3), Mara Abel(1,3), Luiz Fernando de Ros(2,3), Karin Goldberg(2,3)
(1) Informatics Institute, UFRGS, Porto Alegre, Brazil;
(2) Geosciences Institute , UFRGS, Porto Alegre, Brazil;
(3) Endeeper, Porto Alegre, Brazil.
American Association of Petroleum Geologists
AAPG Annual Convention and Exhibition 2012 - Long Beach
Abstract The definition of sedimentary facies through the description of cores and outcrops provides the basis for the construction of calibrated reservoir models, assembled by anchoring of 3D geological objects. The realism and accuracy of such models depends on systematic and substantial information about the lithologies, including detailed description of sedimentary structures and textures. The major obstacle for the systematic definition and representation of depositional facies, and mostly, for their processing within computer-generated reservoir models, resides in the lack of a formal nomenclature of sedimentary structures and of agreement about what each term means. An advanced computer application developed to support the detailed and systematic description of lithology, sedimentary structures and texture of cores and outcrops combines resources from knowledge systems and human-oriented interfaces. Systematic description is facilitated by the use of a visual, intuitive interface in touch-screen mobile devices, supported by standardized nomenclature and parameters. Depositional and post-depositional structures are associated to visual representations (icons, patterns and colors) that emulate the way in which geologists usually represent graphic logs, with a touch-select-draw interface. The descriptive nomenclature was formally defined based on ontology engineering methods and validated by a group of sedimentologists using a web collaborative portal. The application substantially reduces description time and errors, and allows capturing the information into a relational database for further processing and exportation to several standard formats, essential for the efficient construction of realistic reservoir models for optimized recovery and quality prediction.
Mara Abel(1), Alexandre Lorenzatti(1), Luiz Fernando De Ros(2), Karin Goldberg(2), Claiton Scherer(2), Oscar Paesi da Silva(3) e Ariane Bernardes(3)
(1) Informatics Institute, UFRGS, Porto Alegre, Brazil;
(2) Geosciences Institute , UFRGS, Porto Alegre, Brazil;
(3) Endeeper, Porto Alegre, Brazil.
AAPG Annual Convention and Exhibition 2011
AbstractThe quality of clastic reservoirs is impacted by the sequence and intensity of diagenetic processes. Characteristic paragenetic patterns and porosity and permeability values were distilled for 9 compositional petrofacies recognized from 121 cases. The porosity of non-marine
feldspathic sandstones depends on a balance among eogenetic clays, compaction, quartz or calcite cementation, and feldspar dissolution. Their permeability is controlled by intensity of compaction, quartz, illite or chlorite cementation. Marine arkoses-subarkoses commonly display less intense eodiagenesis and better reservoir quality, but may show stronger porosity reduction by mesogenetic calcite cementation than their continental equivalents. Non-marine
quartzose sandstones (quartzarenites) typically show eogenetic Fe-oxide, smectite and dolomite, and mesogenetic quartz, calcite or dolomite, dissolution, and illite or chlorite. Chlorite rims preserve porosity by inhibiting quartz overgrowths, but reduce permeability. Marine quartzarenites show limited eodiagenesis, and mesodiagenesis similar to non-marine equivalents, with reservoir quality controlled by quartz cementation and pressure dissolution.
Acid and
basic-intermediate volcanic litharenites commonly display eogenetic smectite, zeolites and silica or calcite, and mesodiagenesis inhibited by intense compaction of altered volcanic fragments, implying in low porosity and permeability. Intense eogenetic carbonate cementation, dissolution and chemical compaction of aragonite and Mg-calcite grains characteristic of
carbonate hybrid arenites promotes limited mesodiagenesis, and low porosity and permeability values. This same effect is also observed in carbonate litharenites (
calclithites). Berthierine, glauconite, silica and carbonates form during the eodiagenesis of
non-carbonate hybrid arenites. Their mesodiagenesis is commonly inhibited by strong compaction of clay ooids, peloids or intraclasts, with consequent very low porosity and permeability. The diagenesis in
chertarenites is characterized by microquartz rims, inhibition of quartz overgrowths and pressure dissolution, and consequent porosity preservation. The evolution of litharenites rich in low-grade metamorphic fragments (
phyllarenites) is abbreviated due to the intense compaction, promoting very low porosity and permeability. The systematic record and interpretation of paragenetic patterns offer a valuable guideline for the development of reservoir quality predictive models.
L. F. De Ros(1), K. Goldberg(1) and A. R. D. Elias(2)
(1) Geosciences Institute, UFRGS, Brazil;
(2) Petrobras UN/Rio, Rio de Janeiro, Brazil;
GSW GeoScience World 2010 Journals
Paper at AAPG Bulletin (August 2010), 94(8):1267-1309
Abstract Diagenesis exerts a strong control on the quality and heterogeneity of most clastic reservoirs. Variations in the distribution of diagenetic alterations usually accentuate the variations in depositional porosity and permeability. Linking the types and distribution of diagenetic processes to the depositional facies and sequence-stratigraphic framework of clastic successions provides a powerful tool to predict the distribution of diagenetic alterations controlling quality and heterogeneity. The heterogeneity patterns of sandstone reservoirs, which determine the volumes, flow rates, and recovery of hydrocarbons, are controlled by geometry and internal structures of sand bodies, grain size, sorting, degree of bioturbation, provenance, and by the types, volumes, and distribution of diagenetic alterations. Variations in the pathways of diagenetic evolution are linked to (1) depositional facies, hence pore-water chemistry, depositional porosity and permeability, types and amounts of intrabasinal grains, and extent of bioturbation; (2) detrital sand composition; (3) rate of deposition (controlling residence time of sediments at specific near-surface, geochemical conditions); and (4) burial thermal history of the basin. The amounts and types of intrabasinal grains are also controlled by changes in the relative sea level and, therefore, can be predicted in the context of sequence stratigraphy, particularly in paralic and shallow marine environments. Changes in the relative sea level exert significant control on the types and extent of near-surface shallow burial diagenetic alterations, which in turn influence the pathways of burial diagenetic and reservoir quality evolution of clastic reservoirs. Carbonate cementation is more extensive in transgressive systems tract (TST) sandstones, particularly below parasequence boundaries, transgressive surface , andmaximum flooding surface because of the abundance of carbonate bioclasts and organic matter, bioturbation, and prolonged residence time of the sediments at and immediately below the sea floor caused by low sedimentation rates, which also enhance the formation of glaucony. Eogenetic grain- coating berthierine, odinite, and smectite, formed mostly in TST and arly highstand systems tract deltaic and estuarine sandstones, are transformed into ferrous chlorite during mesodiagenesis, helping preserve reservoir quality through the inhibition of quartz cementation. The infiltration of grain-coating smectitic clays is more extensive in braided than in meandering fluvial sandstones, forming flow barriers in braided amalgamated reservoirs, and may either help preserve porosity during burial because of quartz overgrowth inhibition or reduce it by enhancing intergranular pressure dissolution. Diagenetic modifications along sequence boundaries are characterized by considerable dissolution and kaolinization of feldspars, micas, and mud intraclasts under wet and warm climates, whereas a semiarid climate may lead to the formation of calcrete dolocrete cemented layers. Turbidite sandstones are typically cemented by carbonate along the contacts with interbedded mudrocks or carbonate mudstones and marls, as well as along layers of concentration of carbonate bioclasts and intraclasts. Commonly, hybrid carbonate turbidite arenites are pervasively cemented. Proximal, massive turbidites normally show only scattered spherical or ovoid carbonate concretions. Improved geologic models based on the connections among diagenesis, depositional facies, and sequencestratigraphic surfaces and intervals may not only contribute to optimized production through the design of appropriate simulation models for improved or enhanced oil recovery strategies, as well as for CO2 geologic sequestration, but also support more effective hydrocarbon exploration through reservoir quality prediction.
S. Morad, Khalid Al-Ramadan, J. M. Ketzer, and L. F. De Ros. 2010
AAPG Annual Convention and Exhibition 2010
Paper presented at the AAPG Anual Convention and Exhibition 2010, New Orleans, LA.
Abstract
Fluvial and estuarine sandstones of the Aptian Mucuri Formation are major reservoirs in the onshore Espírito Santo Basin, eastern Brazil. They are temporally equivalent to the huge offshore pre-salt reservoirs under exploration. The quality of the Mucuri reservoirs is strongly impacted by intense diagenetic processes. The sandstones are dominantly medium to coarse-grained, and very rich in detrital feldspars, biotite, garnets and other heavy minerals. The main diagenetic process involved the authigenesis of rims, coatings and microcrystalline aggregates of smectitic clays, as intergranular cement and replacing grains of feldspars, biotite and unstable heavy minerals, in places also dissolved and replaced by kaolinite. Cementation by coarse calcite was very heterogeneous, and concentrated in the sandstones with less smectite. Coarse pyrite replaced biotite, mud intraclasts, and previous diagenetic constituents. Minor diagenetic constituents include dolomite, K-feldspar overgrowths and Ti minerals. Porosity is mostly primary, dominantly reduced by cementation, although secondary intragranular and moldic pores from grain dissolution are locally significant. Diagenesis promoted the development of very heterogeneous, complex and irregularly-connected pore systems, what strongly impacts oil recovery from the reservoirs. The intense and complex diagenetic processes are interpreted as product of the interaction between the unstable primary composition and reactive pore fluids. Meteoric fluids related to the alluvial setting promoted grain dissolution and kaolinite authigenesis. The voluminous authigenesis of smectite and calcite was caused by reactions between the feldspars, heavy minerals and micas, and brines derived from the adjacent saline environments and from overlying Aptian evaporites. The precipitation of replacive pyrite was related to fluids charged in H2S derived from thermal sulfate reduction. The characterization of the types, amounts, and time and space distribution of the major diagenetic processes responsible for porosity modification in the Mucuri sandstones is of paramount importance for increasing oil recovery from producing reservoirs, as well as for the reduction of exploration risks through the development of quality-predictive models. Furthermore, the understanding of eodiagenetic conditions taking place in pre-salt marginal settings should shed light on the origin and evolution of the voluminous offshore reservoirs.
Luiz F. De Ros¹, Karin Goldberg¹, Norberto Dani¹, Garibaldi Armelenti¹, Awilsa S. G. Carvalho¹, Eveline E. Zambonato²
1 Geosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
2 PETROBRAS UN-ES/EXP/SE, Vitória, ES, Brazil
Integrated Petrographic, Stratigraphic and Statistical Analysis of Complex Albian Reservoirs in the Espírito Santo Basin, Eastern Brazil
AAPG International Conference and Exhibition 2009
Paper presented at the AAPG International Conference and Exhibition 2009, Rio de Janeiro, Brazil.
Abstract
In the northern onshore portion of the Espírito Santo Basin, E Brazil, fluvial and platform sandstones and shales of the Albian São Mateus Formation grade northward and towards offshore into shallow-marine carbonates of the Regência Formation. Three stratigraphic sequences were identified in these units, comprising six depositional cycles characterized by increase and decrease of fluvial channel amalgamation. Carbonate rocks display in general low porosities due to fine texture and to intense recrystallization. In the southern, dominantly clastic area, reservoir quality and heterogeneity of the medium to very coarse, feldspathic fluvial sandstones was strongly impacted by diagenetic processes, involving mostly cementation and grain replacement by kaolinite, smectite, calcite, pyrite and sulfates, limited mechanical compaction and feldspar grains dissolution. Early calcite cementation was the most voluminous diagenetic product, especially at the base of the succession, where cemented levels constitute barriers to fluid flow. Smectitic clays coatings, rims and microcrystalline, intergranular and grain-replacive aggregates also reduced intensely the permeability. Fifteen reservoir petrofacies were recognized and related to five calibrated wireline log facies (evaporitic, carbonatic, smectitic, calcitic and paleosol), what allowed mapping reservoir quality across the area. Statistical correlation analysis of the major petrographic parameters was carried out to unravel the patterns of major diagenetic processes and reservoir quality and heterogeneity distribution. The weak correlation between intergranular volume and porosity is due to the early, pre-compactional (even displacive) character of smectite and mostly calcite cementation. Calcite and smectite show complementary distribution, as calcite precipitation was inhibited in sandstones with more smectite, which retained some porosity. The less permeable, basal interval is dominated by the calcitic log facies, while the more porous, upper interval is characterized by the smectitic log facies. There is a clear correlation between the distribution of kaolinite and micas, concentrated at finer-grained cycle tops, as well as with macroporosity, suggesting a preferential circulation of meteoric fluids. The characterization of these patterns and their spatial and stratigraphic distribution contribute to decrease the exploration risks and to optimize the production of these reservoirs.
Luiz Fernando De Ros, Karin Goldberg, Claiton Scherer, Juliano Kuchle, Eduardo Castro, Mara Abel. 2009
K-Annotations, an Approach for Conceptual Knowledge Implementation using Metadata Annotations
International Conference on Enterprise Information Systems 2009
Paper presented at the International Conference on Enterprise Information Systems 2009, Milan, Italy.
Abstract
A number of Knowledge Engineering methodologies have been proposed during the last decades. These methodologies use different languages for knowledge modelling. As most of these languages are based on logic, knowledge models defined using theses languages cannot be easily converted to the Object-Oriented (OO) paradigm. This brings a relevant problem to the development phase of KS projects: several complex knowledge systems are developed using OO languages. So, even if the conceptual model can be modelled using the logical paradigm, it is important to provide a standard knowledge representation with the OO paradigm. This paper introduces the k-annotations, an approach for conceptual knowledge implementation using metadata annotations and the aspect oriented paradigm. The proposed approach allows the development of the conceptual model using the OO paradigm and it establishes a standard path to implement this model. The main goal of the approach is to provide ways to reuse both the knowledge design and related programming code of the model based on a single model representation.
Castro, ESE; Price, RT; Abel, M. 2009
AAPG Annual Convention and Exhibition 2009
Paper presented at the 2009 AAPG Annual Convention & Exhibition. Denver, CO.
Abstract
The Parecis Basin is a large intracratonic basin in western Brazil, with more than 6 km os sediments. The petrologic study of the Paleozoic Pimenta Bueno Formation in the PB-01-RO drill core revealed the occurrence of sabkha deposits, in which playa lake evaporites are interbedded with fluvial sandstones. The diagenetic processes observed in these rocks are largely facies-controlled. The evaporites show early silicification of originally microbial, micritic mud, followed by extensive replacement by dolomite and coarse anhydrite. Gypsum and silica replaced dolomite and anhydrite under eodiagenetic and telodiagenetic conditions. In the fluvial sandstones, diagenetic products and processes are numerous. During eodiagenesis, hematite and clay coatings covered the grains, followed by multiple phases of quartz (and locally K-feldspar) overgrowths. Mechanical compaction of mud intraclasts led to the formation of pseudomatrix, which was commonly replaced by dolomite during mesodiagenesis. The main mesodiagenetic process was the precipitation of sulfates (anhydrite and barite) and carbonates (calcite, dolomite and Mn-Fe-rich dolomite). Telodiagenetic processes include the formation of pore-filling hematite, gypsum nodules and veins, and kaolin, and during a second mesodiagenetic stage illite and anhydrite were formed. Fluvial sandstones in the studied core show relatively good porosity and occurrences of residual bitumen. Such evidence suggests a good potential for hydrocarbon exploration in the Parecis Basin.
AAPG Annual Convention and Exhibition 2009
Paper presented at the 2009 AAPG Annual Convention & Exhibition. Denver, CO.
Abstract
A low-cost method is proposed for evaluating the degree of compaction in reservoir rocks by using automatic inference methods on optical photomicrographs. In order to reproduce the visual interpretation performed during petrographic analysis, a hybridmethod was developed combining image processing algorithms with knowledge representation and reasoning models. The method proposed was inspired on visual attention, the mechanism used by the human brain for dealing with visual information. This mechanism allows the brain to filter the huge amount of information that comesthrough the eyes, selecting the relevant elements to be further analysed by the highly abstract level of reasoning. The process involves the decomposition of scenes, and the competition among their different aspects in order to isolate and select the relevantareas. In other words, the eyes of petrographers initially examine a thin-section by capturing and isolating the grains borders (outlines), and then focus on the grains. The outlines are essential to separate each grain from other grains and their interstices, because petrographic analysis is performed in the two-dimensional universe of thinsections. The knowledge at this level is modelled in terms of Sections (grains), Outlines (borders of grains), and Interstices, which may be Pores (empty) or NonPores (e.g. cement, matrix). The shapes of the outlines (mainly concave or convex), complemented by the detection of the impregnation blue resin, indicates if they contain Pores, NonPores or Sections. The types of contacts between grains are then used to define the degree of compaction of the rocks. The system provides a preliminary identification of the objects that can be interactively refined by the user when the grain outlines are unclear in the images. The evaluation of compaction degree provided by this method is far more sensitive and precise than those based on the intergranular volume or number of intergranular contacts. This formalized interpretation method shows better results for the complex tasks of reservoir quality characterization and prediction.
AAPG Annual Convention and Exhibition 2009
Paper presented at the 2009 AAPG Annual Convention & Exhibition. Denver, CO.
Abstract
Despite the spectacular advances in seismic and log acquisition and interpretation, and in 3D and 4D modeling, the risks involved in the exploration of new, deeper, depositional, tectonic or diagenetically-complex prospects remain large. This, essentially because these sophisticated methods simply lack information on an essential part of petroleum systems: the reservoir. Most new prospects represent clastic or carbonate rocks with strong diagenesis. For these, the conventional, indirect evidence of texture and composition provided by logs and conventional, simplified petrographic descriptions is simply not enough. There is an emerging trend for the integration of systematic petrographic analysis, aided by petrologic and geochemical analyses, with log analysis, petrophysics, and seismics, to tackle the challenges represented by such reservoirs. Petroledge®, an intelligent database system combining resources from relational databases and knowledge-based expert systems, was created to support systematic analysis, storage and processing of detailed petrographic information on primary structures, textures and constituents, and mostly on the habits, location and paragenetic relations of diagenetic constituents and pore types. Such systematically-organized petrographic information can be effectively retrieved and integrated into 3D reservoir models and flow simulation softwares. Systematic petrographic characterization can be used to calibrate log and seismic attributes through reservoir petrofacies, defined by the combination of key petrographic parameters. Log and seismic facies and seismic reflectors calibrated by such reservoir petrofacies allow the realistic 2D and 3D representation of reservoir quality and heterogeneity, leading to enhanced static and flow simulations during development and production, and increasing the precision and efficiency of seismic interpretation in deep, new or unconventional settings. The appropriation of systematic petrographic characterization into realistic reservoir quality models will allow a better assessment of exploration risks and optimized production procedures. The challenges involved in the exploration and production of complex reservoirs will be surpassed with the intelligent integration of petrography into the operational E&P workflow.
Ontology Research Seminar - Brazil - 2008
Paper published in Ontology Research Seminar, Brazil, 2008.
Abstract
Domain ontologies have shown a powerful approach for capturing strategic knowledge and is being studied in the Petroleum Geology domain. Geologists apply multiple types of knowledge for problem solving, the visual knowledge being the most important for interpretation task even being hard of representing by ontological primitives. We have proposed the definition of representational primitives of visual knowledge in three levels of abstraction, keeping the symbolic anchor between levels. We have also introduced primitives for temporal ontologies to support the identification of sequences of non-time labeled events. The results of this project were implemented in a petrographic system to support the description and interpretation of reservoir rocks.
AAPG 2008 Annual Convention and Exhibition
Paper presented at the 2008 AAPG Annual Convention and Exhibition, V. 17, Abstracts Volume, p. 68.
Abstract
The Echinocyamus Formation comprises complex fluvial and deltaicreservoirs deposited during the Lower Eocene in the fore-arc Talara Basin (NW Peru). Detailed petrographic analysis performed with the Petroledge® system yielded crucial information on the main controls on the quality and heterogeneity of these reservoirs.
The sandstones are feldspathic litharenites, rich in andesitic volcanic rock fragments, low-grade meta-sedimentary and meta-volcanic rocks. Common diagenetic constituents include smectite, calcite, albite, quartz overgrowths, mud pseudomatrix, pyrite and titanium minerals. Zeolite and siderite occur only in fluvial sandstones.
Twelve reservoir petrofacies were defined by the combination of depositional structures, textures and primary composition with dominant diagenetic processes and products: Rims-Porous, Intraclastic, Conglomeratic, Overgrowths, Rims-Compacted, Zeolite-Calcite, Fine-Porous, Post-Comp-Calcite, Pre-Comp-Calcite, Smectite-Filled, Fine-Unsorted, and Fine-Compacted. These petrofacies are associated in different proportions in the fluvial and deltaic depositional domains.
Packing is normal to tight, and deformation of ductile grains into pseudomatrix is common. Intergranular porosity averages 7.5% in the fluvial and 4.6% in the deltaic sandstones. Grain dissolution porosity attains up to 8% in the fluvial and 10.3% in the deltaic. Intergranular cements reduce porosity and decrease permeability both in deltaic and fluvial intervals, especially in the petrofacies Rims-Compacted, Fine-Porous, and Smectite-Filled. This effect is stronger in the fluvial interval, where smectite is the main cement controlling permeability. Fluvial reservoirs always display higher porosity and permeability than deltaic reservoirs and, within the latter, delta-plain deposits are relatively better than delta-front. Objectively-defined reservoir petrofacies were a significant and operational tool for understanding the heterogeneous distribution of quality within the extremely complex Echinocyamus reservoirs.
Theoretical/Advances and Applications of Fuzzy Logic and Soft Computing 2007
Paper published in Theoretical /Advances and Applications of Fuzzy Logic and Soft Computing.: Springer-Verlag, 2007.
Abstract
Depositional and post-depositional (diagenetic) processes control the distribution of porosity and permeability within petroleum reservoir rocks. The understanding of these controls is essential for the construction of models for the systematic characterization and prediction of the quality (porosity, permeability) of petroleum reservoirs during their exploration and production. The description and documentation of key petrographic features is an important tool for the evaluation of reservoir quality that try to minimize the uncertainty associated to visual recognition of the features. This paper describes the role of visual controls on the petrographic analysis of reservoir rocks, and presents a knowledge-based tool that supports a workflow for the collection and documentation of visual information. This tool allows the spatial referencing of significant features in thin sections of reservoir rocks and the association of these features to a complete ontology of description. The whole process allows the preservation of original information that would support reservoir evaluation and guarantees further analysis even when the original rock sample is not available.
AAPG Annual Convention and Exhibition 2007
Paper published at AAPG, in Long Beach, USA (April, 2007).
Abstract
The precise and comprehensive description of the textural and compositional features of reservoir rocks is crucial in petroleum exploration. However, in order to substantially contribute to decrease exploration risks and increase hydrocarbon production efficiency, petrographic reservoir characterization must include not only information on the volumes of detrital and diagenetic constituents and pore types, but also a detailed record of their habits, locations, modifications and paragenetic inter-relations, which strongly control porosity and permeability, as well as log and seismic signatures. The Petroledge® system is an intelligent database application created to support the detailed petrographic analysis and interpretation of reservoirs, combining resources from relational databases and knowledge-based expert systems. Systematic description is facilitated by the use of flexible menus with standardized nomenclature and parameters, what radically reduces description time and errors. An integrated electromechanical microscope stage allows an optimized modal quantification through point-counting, as well as the generation of a virtual map of the thin section, storing the spatial position of each petrographic feature and associated information. A relational database system guarantees safe data storage, distribution, integrity and recovery. The system provides compositional classifications, interpretations of tectonic provenance modes and diagenetic environments using Artificial Intelligence methods, along with multidimensional online consultation, statistical and graphic processing of petrographic data, which are essential for the design of reservoir, optimized recovery and quality prediction models.
AAPG Annual Convention and Exhibition 2007
Paper published at AAPG, in Long Beach, USA (April, 2007).
Abstract
The intrinsic quality of petroleum reservoirs (porosity, permeability) is controlled by depositional structures, textures and composition, by diagenetic processes and products (volume or intensity, habits and distribution), as well as by pore types and distribution. Reservoir petrofacies can be systematically defined by the combination of these attributes. The concept of reservoir petrofacies is useful and operational for the characterization of reservoirs and for the prediction of their quality during exploration. The determination of reservoir petrofacies is initiated by the recognition of preliminary petrofacies through a systematic description of the listed attributes in samples collected along a representative distribution, followed by recognition of the attributes with larger impact on porosity and permeability. The preliminary petrofacies are then checked against petrophysical and petrographic quantitative parameters by using statistical or neural network tools. Threshold values are defined for the influent textural and compositional attributes that constrain the significant reservoir petrofacies. Reservoir petrofacies defined by this methodology are consistent in terms of petrophysical porosity and permeability, seismic and log signatures. Consequently, they can be used for sensible calibrations and for tri-dimensional representations of the quality of reservoirs. Reservoir petrofacies can be linked to stratigraphic and structural framework parameters for the development of coherent models of reservoir quality prediction.
International Joint Conference on Artificial Intelligence 2005
Paper published in the in the IJCAI in Edinburgh, UK (August, 2005).
Abstract
A study about the inference of temporal information from visual-spatial characteristics. The study was applied to the Sedimentary Petrography domain.
Journal of Petroleum Science and Engineering 2005
Paper published in the JPSE.
Abstract
This paper presents a practical study of expertise in sedimentary petrography and its incorporation into a knowledge-based computing system, PetroGrapher.
Journal of the Brazilian Computer Society 2005
Paper published in the JBCS.
Abstract
Describes a knowledge-based model that helps users to make their image-interpreting knowledge explicit and apply in interpretation of oil-reservoir rock images.
Expert Systems With Applications 2004
Paper published in the ESWA magazine.
Abstract
Describes how to allow optimized management of relevant data using resources from both knowledge-based systems technology and database technology.
Brazilian Symposium on Artificial Intelligence 2004
Paper published in the WONTO-SBIA, in Manaus, Brazil.
Abstract
The authors propose different levels of image annotation, based on ontologies. The case study are sedimentary rock sample images.
Database and Expert Systems Applications 2004
Paper presented in the DEXA Conference, in Zaragoza, 2004.
Abstract
The work presents an study of the nature of expertise in geology. An experiment is performed about the differences of sedimentary rock images description made by geologists with distinct levels.
International Joint Conference on Artificial Intelligence 2003
Paper presented in the Workshop ICPI (IJCAI'03), in Acapulco, Mx.
AbstractIt presents an approach to model visual reasoning symbolically, and validates the model by interpreting oil-reservoir rocks in petrographic domain.
International Joint Conference on Artificial Intelligence 2003
Paper presented in the Workshop ICPI (IJCAI'03), in Acapulco, Mx.
Abstract
It presents the knowledge acquisition methodology employed to conduct the knowledge elicitation in the petrography domain, presenting a set of rules to be followed for development of expert systems in visual domains
2º Congresso Brasileiro de P&D em Petróleo e Gás 2003
Paper presented in the Brazilian Petroleum and Gas conference, in Rio de Janeiro, Brazil.
Abstract
It presents PetroGrapher, an intelligent database application to support and guide the petrographic analyst and the petrogenetic interpretation of oil reservoir rocks.
Estudo da perícia em petrografia sedimentar e sua importância para a engenharia de conhecimento. (Portuguese)
Author: Abel, M. PHD Thesis (2001). Advisors: John Arthur Campbell and José Mauro Volkmer Castilho. PPGC. Porto Alegre, Federal University of Rio Grande do Sul.
Compositional Controls on Sandstone Diagenesis.
Author: De Ros, L. F. PHD Thesis (1996). Advisor: JSadoon Morad. Uppsala Universitet, U.UPPSALA, Sweden.
Um modelo de conhecimento baseado em eventos para aquisição e representação de seqüências temporais em Petrografia Sedimentar. (Portuguese)
Author: Mastella, L. S. Master Thesis (2004). Advisors: Mara Abel and Luiz Fernando De Ros. PPGC. Porto Alegre, Federal University of Rio Grande do Sul.
Aplicando métodos de solução de problemas em tarefas de interpretação de rochas. (Portuguese)
Author: Silva, L. A. L. Master Thesis (2001). Advisor: Mara Abel. PPGC. Porto Alegre, Federal University of Rio Grande do Sul.
