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Litho 2: Enabling the power of mobile devices and cloud computing for creating comprehensive sedimentary logs from outcrop, core and mud logging
Abstract
Since the beginning of modern Geology, representation of core and outcrop data in on-scale sedimentary columns became a fundamental tool for sedimentological and stratigraphic analysis of ancient sedimentary successions. Initially, sedimentary logs were sketched in the field or core facilities, and then redrawn in the lab, often requiring long time of processing with the associated risk of data lost. Later, personal computers provided new resources with applications that facilitate the column drawing, but the problem of data acquisition in the field was still unsolved. In recent years, two new technologies irrupted allowing new possibilities to solve this problem. In first place, smartphones became powerful devices allowing the user to interact with data using multi-touch screens. The other game-changer technology is cloud computing. Litho is an application that allows the creation of sedimentary logs in a complete new way. The user literally interacts with the sedimentary column using the device screen. Additionally, the data is transparently synchronized across multiple platforms. Litho was initially launched as an Android application and it is currently available as a free tool at the Google Play Store. Typical applications of this software are the description of stratigraphic columns from outcrops, cores, and mud logging. In this work we introduce the version 2.0 of this free software. The new release enables the benefits of the latest disruptive technologies making the creation of sedimentary logs a complete new experience.
Read More: http://library.seg.org/doi/abs/10.1190/ice2016-6349079.1
... The sections were sedimentologically logged, measured with a Jacob's staff, and positioned by GPS. The data were digitally acquired and stored using the free LithoHero software, which provides a real-time visualization of the stratigraphic column that is being described (Iparraguirre et al., 2016). The description was performed bed by bed, and relevant sedimentological features recognizable in the outcrops (lithology, texture, bed geometry and bounding surfaces, primary and secondary sedimentary structures, fossil content, and bioturbation degree) were noted. ...
This study introduces a new sequence stratigraphic framework for the Middle-Late Triassic Yanchang Formation based on the sedimentological analysis of a ~ 850-m-thick composed stratigraphic column constructed after the integration of 21 partial field sections and 17 high-resolution photomosaics showing overviews of the stratigraphy and stacking of the sequences in the field. The hierarchy of bounding surfaces and internal cyclicity suggests the existence of at least four orders of sequences. The lowest-order sequence consists of a large transgression/regression cycle encompassing the entire Yanchang Formation (Yanchang Supersequence). It can be subdivided into three megasequences (Lower, Middle, and Upper Megasequences), which comprise at least seven depositional sequences and 20 elementary sequences (3rd- and 4th-order sequences). Facies analysis and stacking-pattern trends suggest that the Lower Megasequence accumulated in an underfilled lake, whereas the Middle and Upper Megasequences represent balanced-fill and overfilled lake conditions. The results emerged from this study suggest that the origin of source rocks and sandstone reservoirs was controlled by a complex interaction between basin physiography, subsidence, climate, and sediment/water supply.
... El registro de los datos se efectuó en forma digital mediante el uso del software LithoHero®, diseñado específicamente para levantamiento de columnas estratigráficas (Iparraguirre et al., 2016). LithoHero® permite obtener una visualización en tiempo real de la columna estratigráfica que se está describiendo a medida que se van creando diferentes registros con base y techo definidos (Fig. 2.1A). ...
The Vaca Muerta Formation is a fine-grained marine stratigraphic unit accumulated during the Late Jurassic-Early Cretaceous in the Neuquén Basin, Argentina. This contribution presents a sedimentological and stratigraphic analysis of Vaca Muerta´s shales emerged from the integration of regional and detailed outcrop research and subsurface data gathered from the study of different well cores.
The fieldwork comprised, on the one hand, the description of 7 stratigraphic sections of the Early Tithonian-Early Valanginian interval widely distributed across the western region of the Neuquén province and southern Mendoza province. The sedimentological and sequence-stratigraphic analysis of the different stratigraphic sections allowed integrating them into a regional N-S oriented correlation panel covering an area of 340 km. Five composite depositional sequences were recognized (GS1-GS5). They represent the evolution of a complex mixed shelf/ramp depositional system comprising from basinal/slope facies (central area) to ramp (northern area) and mixed-shelf to continental deposits (southern area). Depositional sequences are represented by thin, organic-rich (up to 10 % TOC), mudstone dominated transgressive cycles, whereas regressive cycles are commonly thicker and mainly composed of organic-lean, carbonate and mixed (carbonate/siliciclastic) facies.
On the other hand, aiming at studying the transport and accumulation processes of Vaca Muerta´s organic-rich shales, hand specimen samples of early-diagenetic carbonate concretions were collected from the organic-rich basal condensed section deposited in basinal settings. Concretion samples were thoroughly examined (mm- μm scale) integrating the observation of macroscopic polished samples, thin sections and scanning-electron microscope analyses. The evidence found inside concretions suggest an origin related to muddy underflows, possibly triggered by slope failures on the western margin of the basin. The bedload and suspended-load transport of mud within these muddy underflows would have resulted in the accumulation of graded event mudstone beds exhibiting ripple lamination. Petrographic analysis demonstrates that muddy underflows would have been important mechanisms for reworking the seafloor and redistributing mud in basinal settings. Furthermore, muddy underflows would have been effective processes for organic matter concentration in organic-rich mudstone strata (up to ≈ 6 % TOC).
The subsurface studies comprised the sedimentological analysis of seven well cores of the Vaca Muerta Formation, representing a total core data of 387 m. The descriptive facies analysis at centimeter scale allowed the recognition of a distally steepened mixed ramp system. Sediment delivery to basinal settings was mainly controlled by muddy underflows triggered by different mechanisms. Deposition from muddy underflows would have interacted with fallout processes from buoyant plumes and marine snow from the water column. The stacking pattern of the studied core deposits shows ≈ 0.5 to 3 m-thick parasequences building up prograding/retrograding parasequence sets of high-order depositional cycles (10-20 m thick).
... Las secciones estratigráficas fueron medidas con báculo de Jacob, capa a capa, de base a techo, y se describieron detalladamente todos aquellos rasgos sedimentológicos reconocibles en las unidades de roca. El registro de los datos se efectuó en forma digital mediante el uso del programa LithoHero, diseñado específicamente para levantamiento de columnas estratigráficas (Iparraguirre et al., 2016(Iparraguirre et al., , 2018 ). El relevamiento estratigráfico de las columnas fue complementado con medidas de rayos gamma (RG) con una densidad de 3 medidas/báculo mediante el empleo de un scintilómetro portátil (Exploranium GR-113) a fin de posibilitar la construcción de un registro de RG. ...
The conventional sedimentological model suggests that the accumulation of organic-rich fine-grained sedimentary rocks (<62.5 μm) is uniquely associated with fallout processes in low energy depositional environments. This contribution analyzes organic-rich mudstones belonging to the lower section of the Vaca Muerta Formation at central areas of the Neuquén Basin (Arroyo Mulichinco, Tres Chorros and Río Neuquén localities). The studied interval is characterized by the highest organic matter content of the Vaca Muerta Formation (up to 8% TOC). The associated mudstone deposits are usually highly compacted, thus obscuring the recognition of the original fabric and the analysis of mudstone depositional processes. Nevertheless, the common occurrence of carbonate concretions within these highly compacted intervals provides an exceptional preservation of mudstone primary fabric. After macroscopic study of polished slabs and thin sections of these cemented beds, a series of facies genetically linked to muddy underflows were recognized. The origin of these deposits is related to long-lived muddy hyperpycnal flows (quasi-steady mud flows) triggered by extreme river discharges during rainfall humid periods. During their travel basinward, hyperpycnal flows, originally composed of detrital mud, would be able to go through very low gradient reliefs, incorporating the available intrabasinal components (including organic matter) to their extrabasinal sedimentary load. The rapid basinward transfer of organic-rich mud would have provided a fast deposition and efficient burial of organic matter, avoiding its potential degradation at seafloor. Muddy underflows constitute a rational mechanism to explain the common occurrence of bituminous mudstones at central areas of the Neuquén Basin.
... Se considera una leve bioturbación cuando las rocas muestran una baja densidad de trazas fósiles, moderada bioturbación cuando la densidad de trazas llega a destruir parte de las estructuras primarias de la roca y bioturbación fuerte cuando se observa una alta densidad de trazas fósiles obliterando completamente las estructuras sedimentarias primarias. Con dicha información, se confeccionaron las columnas estratigráficas mediante la utilización del Software LithoHero ® (Iparraguirre et al. 2016). El fotografiado de los testigos corona se efectuó con una cámara réflex digital Cannon EOS 500 y un soporte con iluminación, a los fines de obtener un registro con la menor distorsión posible. ...
Cores recovered from PANG0001 and PANG0003 wells provide an exceptional record of the upper Paleozoic of the Ventania/Claromecó Basin. These wells are located at 90 km at the northeast of Sierra de la Ventana locality, reaching a depth of 958.30 and 901.66 meters, respectively. Two continuous sections of more than 700 m each were described. These cores show a succession of fine-grained sandstone interbedded with black claystone, carbonatic claystone, coal and fine tuff. The analyzed succession is included to the Tunas Formation based on lithology, age, thickness and stratigraphic position. Sixteen sedimentary facies and four facies sequences were recognized and interpreted as shelfal to prodelta shales, shelfal sandstone lobes, shelfal to mouth bars and fluvial to distributary channels, interdistributary swamps to alluvial plains. The sequence stratigraphic analysis allows to identify 8 main third-order depositional sequences (T1 to T8), which are in turn grouped into two megacycles or transgressive-regressive megasequences. Taking into account its lithological characteristics, internal arrangement, and ichnological content, a river-dominated deltaic environment is interpreted. Within this context, a dominantly sandy sequence would have been accumulated in delta plain to delta front areas, while heterolithic levels would represent prodelta and shelfal deposits. Coal levels appear associated with the lower sequences (T1 and T2) and correspond to floodplain to interdistributary swamp deposits related to fluvial systems.
... A total core data of 412 m from 8 wells property of Pampa Energía S.A. and Vista Oil & Gas were carefully examined (Fig. 2).Primary rock attributes (e.g. texture, bedding, composition, physical sedimentary structures, bioturbation degree) were captured using a specific software designed for stratigraphic column description (LithoHero®, Iparraguirre et al. 2016). Nevertheless, the purpose of this study was to describe and illustrate different event beds within the Vaca Muerta mixed-system, trying to establish a genetic linkage between outcrop and subsurface fluid mud flow deposits (FMFd). ...
RESUMEN El rol de los flujos fluidos de fango en la acumulación de fangolitas bituminosas. Formación Vaca Muerta (Tithoniano temprano-Valanginiano temprano), Cuenca Neuquina, Argentina. Durante los últimos años, el avance de técnicas no convencionales de explotación de hidrocarburos puso especial interés en obtener una mejor comprensión de los procesos sedimentarios que controlan la acumulación de materiales finos con abundante contenido orgánico. Bajo este escenario, en Argentina el principal foco de estudio ha sido puesto en la Formación Vaca Muerta, dadas las excelentes propiedades que presenta esta unidad como reservorio no convencional de hidrocarburos. En esta contribución se presenta un estudio integrado de afloramiento y subsuelo orientado al análisis sedimentológico de la Formación Vaca Muerta. El estudio de afloramiento se focalizó en el análisis de procesos de sedimentación de materiales finos en cortes pulidos de concreciones carbonáticas. Por otro lado, el estudio de subsuelo permitió abordar un análisis sedimentológico de alta resolución en testigos corona provenientes de ocho pozos exploratorios de la Formación Vaca Muerta. Las evidencias encontradas en los intervalos analizados permitieron reconocer una gran variedad de depósitos asociados a flujos fluidos de fango. Su origen se relaciona a dos procesos principales: flujos hiperpícnicos fangosos de larga duración (origen extracuencal) y flujos de fango intracuencales asociados a procesos de resedimentación. Los flujos de fango intracuencales serían más frecuentes en sectores próximos al quiebre de la plataforma, generando depósitos con bajo contenido orgánico. Por otro lado, los flujos hiperpícnicos fangosos de origen extracuencal habrían actuado como excelentes medios de transferencia de sedimentos finos y materia orgánica desde áreas emergidas hasta zonas internas de la cuenca, atravesando relieves de muy baja pendiente. En su trayectoria cuenca adentro, habrían incorporado material intracuencal previamente depositado creando depósitos de origen mixto. La rápida transferencia de fango rico en materia orgánica (tipo II y III) hacia sectores internos de la cuenca habría permitido alcanzar un soterramiento rápido y eficiente, evitando su exposición en el fondo marino. Este proceso habría favorecido la preservación de fangos bituminosos en sectores internos de la Cuenca Neuquina.
Palabras clave: flujos fluidos de fango (extracuencales, intracuencales), preservación de la materia orgánica, fangolitas bituminosas
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