Schedule
24 septembre 2018
14h30 - Geophysics applied to Brazilian Pre-salt Reservoir | by Carlos Jesus
16h30 - 3D modeling of Carbonate Rock Types - why & how | by Maria Olho Azul e Pricilla Souza
25 septembre 2018
14h30 - General characterization of pre-salt carbonates along Petrogal concession areas | by Michelle Mepen
16h30 - The importance of siliciclastic reservoirs in Petrogal portfolio | by Patricia Takayama
26 septembre 2018
14h30 - Geophysics applied to Brazilian Pre-salt Reservoir | by Carlos Jesus
16h30 - 3D modeling of Carbonate Rock Types - why & how | by Maria Olho Azul e Pricilla Souza
27 septembre 2018
14h30 - General characterization of pre-salt carbonates along Petrogal concession areas | by Michelle Mepen
16h30 - The importance of siliciclastic reservoirs in Petrogal portfolio | by Patricia Takayama
The importance of siliciclastic reservoirs in Petrogal portfolio
Por Patricia Takayama
For many years the siliciclastic deposits, especially the turbidites of the Campos Basin, represented the main oil producing reservoirs of Brazil. With the discovery of the pre-salt this scenario has changed, and the pre-salt production currently corresponds to 53.2% * of the total produced in Brazil.
However, Galp estimates that there is still potential for oil discovery in the siliciclastics deposits of the Brazilian basins and has invested in the evaluation of the onshore and offshore basins, such as Potiguar, Barreirinhas, Pernambuco-Paraíba and Parnaíba. The diversity of depositional environments, discoveries and challenges will be presented in this presentation.
* ANP Oil and Natural Gas Production Bulletin - July / 2018
General characterization of pre-salt carbonates along Petrogal concession areas
Por Michelle Mepen
This presentation aims to show a general overview regarding the carbonate deposition in Santos pre-salt Basin, in areas where Petrogal/GALP is part on a consortium;
Pre-Salt carbonates comprise Lacustrine environment with tectonic origin showing fast subsidence and thick sedimentation. Rift lakes present great variety of carbonates, corresponding sub-air and subaqueous depositional settings. Regarding its origin, it can characterize biogenic (ex.,microbiolites) and abiotic origins (ex.,travertine), depending on the conditioning that drives the carbonate development. All these information, illustrate how carbonate depostition can be complex on reservoir characterization.
The carbonate environment deposition is represented by several seismofacies types; the lake gradation is related to shallowing upwards and some sub-air exposition could occurs resulted from the water lake level oscillation. In this sense, truncations, downlaps, onlaps, and chaotic facies (especially found in buildups and mounds) are observed in seismic sessions representing these fluctuations;
In this context, some seismic sessions are presented, showing seismofacies that could infer on several depositional environment characteristics, and thus provide some information regarding the reservoir quality prediction.
Geophysics applied to Brazilian Pre-salt Reservoir
Por Carlos Jesus
A workflow proposal on how to combine geometrical attributes and hybrid spectral decomposition (HSD), to efficiently identify good reservoir quality carbonate mounds within the complex environment of the Brazilian pre-salt zone.
Carbonate mounds, as described in this work, often present seismic characteristics such as high density and low amplitude which can be easily oversampled and blurred with other rock features in simple geobody extraction processes.
For a better identification of these geobodies within the seismic volume our methodology for characterizing specifically carbonate mounds is divided into four stages: Seismic data acquisition and processing overview, preconditioning of seismic data using structural-oriented filtering,calculation of seismic attributes; and classification of seismic facies.
While coherence and curvature attributes are used to identify fault and fracture zones with high densities, which represent one of the most important features of carbonate mounds, HSD employment is necessary to discriminate good reservoir quality low amplitude carbonate mounds from low amplitude shale zones (non-reservoir). Finally, a multi-attribute facies classification is used to generate a geologically significant outcome and to educate a final geobody extraction that is calibrated by well data and that can be used as spatial indication of good reservoir quality distribution for static modeling.
3D modeling of Carbonate Rock Types - why & how
Por Maria Olho Azul e Pricilla Souza
Predicting reservoir quality distribution is a key aspect since early stages of any project for establishing an optimal field development plan and later for production enhancement through the project life cycle.
3D static models focus on field scale variations of reservoir quality and its flow characteristics and should be able to capture heterogeneity down to the level where it may have impact on production.
However, the levels of uncertainty at each project stage and available data for model calibration greatly determine the approach used to characterize reservoirs from a 3D perspective.
Very often in the carbonate domain, purely depositional models are a non-unique solution to describe present day reservoir quality, as these rocks tend to be highly affected by diagenetic processes and prone to extensive alteration of its primary reservoir characteristics.
Geomodelers often need to move back and forth from purely depositional models to more petrophysical rock type models which can be used as proxy to present day reservoir quality.
This is a key component in the pre-salt carbonate modeling workflows that Galp is applying at this moment for its assets in the Santos Basin (offshore Brazil).