Caracterización y potencialidad de reservorios no convencionales tipo shale gas y tight gas sandstone asociados a gas de carbón, a partir del estudio de la estratigrafía mecánica, pozo Pangea 0003, Cuenca de Claromecó, Provincia de Buenos Aires
Choque, Giselle Caruso, Santiago Agustín Febbo, María Belén Fortunatti, Natalia Beatriz Cessareti, Nora Noemí
Caracterización y potencialidad de reservorios no convencionales tipo shale gas y tight gas sandstone asociados a gas de carbón, a partir del estudio de la estratigrafía mecánica, pozo Pangea 0003, Cuenca de Claromecó, Provincia de Buenos Aires - 2018 - 15 p. ; 19-34
Claromecó Basin, central-east Argentina, is defined as a frontier basin based on geological and geophysical data. In the 90 ś, exploration activity found 82 coal beds with thicknesses up to 8 meters in Pillahuincó Group, Upper Palaeozoic. PANG 0003 well, near Laprida city, drilled sandstones, tuffs, shales and sub-horizontal coal strata from Tunas Formation (Permian). Coal beds and seams recently became important as an energetic resource due to diagenetic methane gas produced in advanced coalification. In Tunas Formation, measured vitrinite reflectance values of 1.3-2.4% indicate catagenesis-metagenesis stage (wet gas to condensate and dry gas generation). The aim of this study is to identify and characterize geomechanical facies present in basal 200 meters section of PANG 0003 well cores, applying mechanical stratigraphy concept. Mechanical stratigraphy links a specific lithology with fractures development and constitutes a useful tool to identify possible migration paths for diagenetic fluids. The main lithological facies identified were sandstone and shale. Fractures analysis involves orientation, density and hierarchy. The fractures orientation is mostly represented by subvertical and subhorizontal discrete planes with subordinate conjugate joint systems, interpreted as result of compressive tectonic stresses. Fractures density is low for sandstone facies and high for shale facies. In the case of hierarchy, sandstone facies develop fracture thicknesses variation from high hierarchy (2-3 cm thick) to low hierarchy (1-2 mm thick) while shale facies displays only low hierarchies. Fractures are commonly cemented, with calcite as typical mineral and low quantities of quartz, sulfate and pyrite. Open fractures only occur locally for shale facies associated with coal beds. As result, three geomechanical facies were defined: sandstone geomechanical facies with absence of fractures; sandstone geomechanical facies with low density and variable hierarchy of fractures, always cemented and shale geomechanical facies with high density and low hierarchy of fractures, cemented or not. According to mechanical stratigraphy both previous sandstone geomechanical facies could work as unconventional tight-gas sandstone reservoir. Shale geomechanical facies displays an advantageous rheological behavior for fluid migration due to open fractures nearby coal beds. According to vitrinite reflectance data, unconventional reservoirs for Claromecó Basin could in the future be focused associated to coal beds and seams. This research represents the first subsurface fracture description for Claromecó Basin. Comprehension of fracture system and presence or absence of cements is necessary to characterize different stratigraphic levels in order to predict reservoir behavior towards eventual exploitation.
Formación Tunas
Testigos corona
Diagénesis
Geomecánica
Gas metano
068.82 553.28 C62 2018 0015657
Caracterización y potencialidad de reservorios no convencionales tipo shale gas y tight gas sandstone asociados a gas de carbón, a partir del estudio de la estratigrafía mecánica, pozo Pangea 0003, Cuenca de Claromecó, Provincia de Buenos Aires - 2018 - 15 p. ; 19-34
Claromecó Basin, central-east Argentina, is defined as a frontier basin based on geological and geophysical data. In the 90 ś, exploration activity found 82 coal beds with thicknesses up to 8 meters in Pillahuincó Group, Upper Palaeozoic. PANG 0003 well, near Laprida city, drilled sandstones, tuffs, shales and sub-horizontal coal strata from Tunas Formation (Permian). Coal beds and seams recently became important as an energetic resource due to diagenetic methane gas produced in advanced coalification. In Tunas Formation, measured vitrinite reflectance values of 1.3-2.4% indicate catagenesis-metagenesis stage (wet gas to condensate and dry gas generation). The aim of this study is to identify and characterize geomechanical facies present in basal 200 meters section of PANG 0003 well cores, applying mechanical stratigraphy concept. Mechanical stratigraphy links a specific lithology with fractures development and constitutes a useful tool to identify possible migration paths for diagenetic fluids. The main lithological facies identified were sandstone and shale. Fractures analysis involves orientation, density and hierarchy. The fractures orientation is mostly represented by subvertical and subhorizontal discrete planes with subordinate conjugate joint systems, interpreted as result of compressive tectonic stresses. Fractures density is low for sandstone facies and high for shale facies. In the case of hierarchy, sandstone facies develop fracture thicknesses variation from high hierarchy (2-3 cm thick) to low hierarchy (1-2 mm thick) while shale facies displays only low hierarchies. Fractures are commonly cemented, with calcite as typical mineral and low quantities of quartz, sulfate and pyrite. Open fractures only occur locally for shale facies associated with coal beds. As result, three geomechanical facies were defined: sandstone geomechanical facies with absence of fractures; sandstone geomechanical facies with low density and variable hierarchy of fractures, always cemented and shale geomechanical facies with high density and low hierarchy of fractures, cemented or not. According to mechanical stratigraphy both previous sandstone geomechanical facies could work as unconventional tight-gas sandstone reservoir. Shale geomechanical facies displays an advantageous rheological behavior for fluid migration due to open fractures nearby coal beds. According to vitrinite reflectance data, unconventional reservoirs for Claromecó Basin could in the future be focused associated to coal beds and seams. This research represents the first subsurface fracture description for Claromecó Basin. Comprehension of fracture system and presence or absence of cements is necessary to characterize different stratigraphic levels in order to predict reservoir behavior towards eventual exploitation.
Formación Tunas
Testigos corona
Diagénesis
Geomecánica
Gas metano
068.82 553.28 C62 2018 0015657
