Vaca Muerta Formation

"Penecontemporaneous decimetre-scale soft-sediment deformation structures are reported from the basal part of the Upper Jurassic–Lower Cretaceous Vaca Muerta Formation, in the Malargüe–Las Leñas area of the back-arc Neuquén Basin (Mendoza Province, Central Andes). The deformed interval (Amarillas bed) is only 0.3 to 0.9 m thick but occurs in a wide area, larger than 1500 km2. Its age, determined by ammonite
biostratigraphy, is Early Tithonian.
The soft-sediment deformation structures were generated in finely laminated, partially consolidated, organicrich, carbonate microbialites that were deposited in open-marine, poorly oxygenated settings, apparently devoid of any significant slope. Those structures include boudins of different sizes and complexity, a variety of folds, normal (listric) dm-scale faults, sub-horizontal detachment surfaces and other features, which are part of several larger-scale, complex slump structures. Deformation was dominantly plastic but near to the
ductile–brittle field transition.
On the basis of the observed soft-deformation structures, their geographic distribution, their lateral homogeneity, and the geodynamic framework of the basin in which it was generated, the Amarillas bed can be tentatively attributed to a large, intermediate-depth earthquake that occurred within the plate that subducted beneath the Andean continental margin and the Neuquén back-arc basin."

Microseismic mapping during hydraulic fracturing processes in Vaca Muerta (VM) Shale in Argentina shows a group of microseismic events happening at shallower depth and at later injection time, and they clearly deviate from the growing planar hydraulic fracture. This spatial and temporal behavior of these shallow microseismic events incurs some questions regarding the nature of these events and their connectivity to the hydraulic fracture. To answer these questions, in this paper, we investigate these phenomena using a true 3D fracture propagation modeling tool along with statistical analysis on the properties of microseismic events. First, we propose a novel technique in Abaqus incorporating fracture intersections in true 3D hydraulic fracture propagation simulations based on pore-pressure Cohesive Zone Model (CZM). The simulations fully couple slit flow in fracture with poro-elasticity in matrix and continuum-based leak-off on the fracture walls, and honor the fracture tip effects in quasi-brittle shale. Using this model, we quantify vertical natural fracture activation depending on reservoir depth, fracturing fluid viscosity, mechanical properties of the natural fracture cohesive layer, natural fracture conductivity, and horizontal stress contrast. The modeling results demonstrate this natural fracture activation in coincidence with the hydraulic fracture growth complexities at the intersection such as height throttling, sharp aperture reduction after the intersection, and multi-branching at various heights and directions. Finally, we investigate the hydraulic fracture intersection with a natural fracture in the multi-layer VM Shale. We infer the natural fracture location and orientation from the microseismic events map and Formation MicroImager log in a nearby vertical well, respectively. We integrate the other field information such as mechanical, geological, and operational data to provide a realistic hydraulic fracturing simulation in the presence of a natural fracture. Our 3D fracturing simulations equipped by the new fracture intersection model rigorously simulate the growth of a realistic hydraulic connection path toward the natural fracture at shallower depths, which was in agreement with our microseismic observations.

The genus Steinmanella Crickmay is recorded in several Lower Cretaceous marine units of the Neuquén Basin. It is particularly abundant at the transition between the Vaca Muerta and Mulichinco formations. This paper presents a taxonomic revision of this fauna, discusses the stratigraphic range of each species, and describes and interprets the associated lithofacies based on detailed field sections, newly collected specimens and revision of previous fossil collections. Four sections were measured in northern Neuquén comprising the upper beds of the Vaca Muerta Formation and the lower ones of the Mulichinco Formation. The Steinmanella fauna was dated accurately on the basis of a precise ammonoid zonation. The species were found in the Neocomites wichmanni and Lissonia riveroi zones of early Valanginian age. Specimens were collected in situ from dark grey shales, alternating siltstones, wackestones and mudstones, and rudstones. Three species were identified: Steinmanella curacoensis (Weaver), S. quintucoensis (Weaver), and S. subquadrata sp. nov. Steinmanella curacoensis has an oval outline, poor demarcation of carinae, flank and corselet ribs partially intercalated at the median part of the valve, and oval escutcheon. Steinmanella quintucoensis has a furrow below the marginal carina, subrectangular outline, robustly tuberculated flank ribs, and lanceolate escutcheon. Steinmanella subquadrata sp. nov. has a subquadrate outline, well-marked carinae, and oval escutcheon ornamented with thin ribs and small elongated tubercles.

Facies association of the tithonian-berriasian Vaca Muerta Formation from the Loncoche creek section, Neuquén Basin, west central Argentina allow the distinction and definition of 12 lithofacies and 8 microfacies, wich are dominated by molluscs, echinoderms, foraminifera, brachiopods, serpulids and radiolarians. The Vaca Muerta Formation consist in a rhythmical alternation of black shales, grey shales, marls and siltstones, with bioclastic mudstones, wackestones, packstones, floatstones and rudstones. Facies associations corresponding to 4 types of depositional settings were distinguished: a) basin, b) outer ramp (distal and proximal), and c) middle ramp. The nassellarian/spumellarian ratio was used for bathymetrical interpretation that allows estimating minor as 200 m depth. The strata pattern and vertical facies distribution of three depositional sequences distinguished allow recognizing a tithonian homoclinal ramp system, and a berriasian greatest gradient homoclinal ramp system. A depositional sequence 1 consists of basin and distal outer ramp facies and it is characterized by a retrogradational pattern. It reaches 124 m in thickness, and may be assigned to the Virgatosphinctes mendozanus zone up to the base of Corongoceras alternans zone. Depositional sequences 2 and 3 consist of outer ramp and middle ramp facies. They are characterized by agradational and progradational patterns. The thickness of sequences 2 is 66 m and is assigned to Corongoceras alternans zone, meanwhile sequence 3 reachs 78 m and corresponds to Substeueroceras koeneni and Spiticeras damesi zones.

Se menciona y describe por primera vez la presencia de microcoprolitos de crustaceos de Argentina. Palaxius decaochetarios Palik representa el primer hallazgo de este tipo de estructuras en la Cuenca Neuquina y representa la primera mención del ichnogénero para el Jurásico-Cretácico de sudamérica.

The Vaca Muerta Formation in the Cerro Domuyo area shows an interesting intercalation of facies with opposite paleocurrents. The unit is represented by outer ramp to basinal facies with a westward direction of progradation. However, in its middle section, slope deposits correlatable with the Huncal Member, intercalate with slumped strata verging northeast. This interval is composed of carbonate facies and it is probably associated with the development of a slope related to a carbonate platform or a distally steepened carbonate ramp. Based on the ammonoid fauna, the age of the Vaca Muerta Formation ranges from the early Tithonian to the late Berriasian, but it could also reach the early Valanginian. The Huncal Member yields representatives of the Substeueroceras koeneni Biozone (Upper Tithonian), hence its age is older than that proposed in its type locality allowing its correlation with units exposed in the Chilean territory.

Se presenta una síntesis de los megainvertebrados fósiles cretácicos organizados en un esquema estratigráfico por pisos, actualizando la información brindada en 1978 en el Primer Relatorio de la Geología del Neuquén. Dada la actual incertidumbre sobre la ubicación del límite Jurásico-Cretácico en términos bioestratigráficos, se provee inicialmente de una breve discusión sobre el tema. Se describe la presencia y distribución de diversos grupos de invertebrados tanto en ambientes marinos como continentales. Entre ellos moluscos tales como amonoideos, nautiloideos, bivalvos y gastrópodos asi como crinoideos y equinoideos, corales, briozoos, anélidos poliquetos, esponjas y crustáceos decápodos. En el Cretácico más temprano (Berriasiano-Hauteriviano) las faunas de invertebrados fósiles son dominantemente marinas, y abundan formas nectónicas y bentónicas asociadas a la transgresión del Océano Pacífico. En el Barremiano la diversidad y abundancia decrecen dramáticamente y se registran unas pocas especies marinas y continentales. Durante el Aptiano-Albiano las faunas de invertebrados se reducen a unos pocos moluscos de agua dulce. En el lapso Cenomaniano-Campaniano Temprano persisten los ambientes continentales y las faunas de invertebrados están restringidas a escasos bivalvos dulceacuícolas. Finalmente en el Campaniano Tardío-Maastrichtiano las sedimentitas marinas asociadas a la transgresión atlántica portan abundantes faunas bentónicas de moluscos y otros invertebrados y escasos elementos nectónicos.

"Resumen
La presencia de crinoideos saccocómidos en la Cuenca Neuquina es uns hallazgo relevante, ya que constiruye el resgistro más temprano del orden Roveacrinida en el Hemisferio Sur y el primer registro de Saccocoma fuera de la región del Tethys. El material fue estudiado a partir de laminas delgadas provenientes de la Formación Vaca Muerta y pueden ser asignadas a los géneros Saccocoma Agassiz y Crassicoma Sieverts-Doreck y Hess. Las placas radiales aparecen en el sector de la rampa externa proximal, mientras que lo elementos de los brazos aparecen tanto en la rampa externa proximal como distal. Los restos fueron encontrados formando dos tipos de depósitos: elementos dispersos en wackestones bioclásticos, típicos del HST, y como concentraciones sedimentarias (microfacies de Saccocoma) asociadas mayormente al TST.

Abstract
Presence of saccocomid crinoids in the Neuquén Basin is an important finding since it is the earliest record of Roveacrinida in the Southern Hemisphere and the first record of Saccocoma outside the Tethys. The material was studied in thin sections from the Vaca Muerta Formation and it can be assigned to the genera Saccocoma Agassiz and Crassicoma Sieverts-Doreck and Hess. Radial plates appear on the proximal ramp, while elements of the arms appear in the proximal and distal outer ramp. Dispersed Saccocoma elements are typical of HST, while Saccocoma sedimentary concentrations are associated with the TST."

Even though oil continues leading energy discussions worldwide the share of natural gas in total energy is expected to equal that of oil by 2030. The United States (US) has played a key role in that transition: in the last two decades a qualitative technological leap forward has driven this country to an energy revival through the exploration and production of unconventional gas and oil.

Since its independence Latin America has been considered theUnited States‘ backyard with notorious emphasis in Central American andCaribbeancountries. However, the increasing energy potential that others Latin American countries like Argentina and Brazil have turned to posses in the unconventional hydrocarbons industry have led to a renewed interest in the region beyond its traditional partners.

The aim of this paper is to explore what could be the interest for theUSin shale developments inSouth America; which are the countries with more potential in developing shale gas industries based on their reserves and above ground factors; and which is the current state of the foreseen South American shale revolution.

Keywords: Shale gas; energy; South America; energy security.

Este artículo analiza las políticas diseñadas e implementadas en Argentina, entre 2012 y 2015, con el propósito de promover la obtención de hidrocarburos de reservorios “no convencionales”. En 2012, la Ley “de Soberanía Hidrocarburífera” dispuso la recuperación del control estatal de Yacimientos Petrolíferos Fiscales (YPF) y convirtió a aquellos recursos en objetivos estratégicos de la política energética. Ello implicó la posterior adopción de un amplio abanico de medidas destinadas a atraer inversores extranjeros. Desde la perspectiva de la internacionalización del capital y del Estado, se muestra a ese conjunto como “políticas de posicionamiento” que deben enfrentar distintos límites y contradicciones asociadas a la volatilidad del mercado mundial, la dinámica local de la acumulación y la producción de consenso. A tal fin, se empleó una estrategia metodológica mixta, basada en la triangulación de métodos y técnicas de recolección de información y análisis de datos.
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This  article  analyzes  the  policies  designed  and  implemented  in  Argentina,  between  2012  and  2015,  with  the  purpose  of  promoting  the  obtaining  of  hydrocarbons  from  “unconventional”  reservoirs.  In  2012,  the  “Hydrocarbon Sovereignty” Law provided for the recovery of state control of Yacimientos Petrolíferos Fiscales (YPF) and turned those resources into strategic objectives of the energy policy. This implied the subsequent adoption  of  a  wide  range  of  measures  aimed  at  attracting  foreign  investors.  From  the  perspective  of  the  internationalization  of  capital  and  the  State,  this  set  of  measures  is  shown  as  “positioning  policies”  that  must  face  different  limits  and  contradictions  associated  with  the  volatility  of  the  world  market,  the  local  dynamics of accumulation and the production of consensus. To this end, a mixed methodological strategy was  employed,  based  on  the  triangulation  of  methods  and  techniques  of  information  collection  and  data  analysis.

El presente texto reflexiona sobre el megaproyecto Vaca Muerta, una formación geológica rica en hidrocarburos no convencionales, que advino como una esperanza pública en la Argentina tanto en el segundo gobierno de Cristina Fernández de Kirchner, como en el gobierno de Mauricio Macri, en un contexto geopolítico y en una fase particular del modo de acumulación capitalista caracterizada por la producción de energía extrema. A partir de una investigación de orientación cualitativa y de un enfoque socio político, este trabajo se propone analizar las siguientes dimensiones: 1) la importancia de Vaca Muerta en la agenda de gobierno y la expectativa pública por su desarrollo 2) los cuestionamientos en torno de la técnica privilegiada para su explotación, el fracking 3) los interrogantes existentes respecto de la viabilidad económica y productiva del megaproyecto, así como respecto de sus efectos ambientales y territoriales, 4) las resistencias sociales que se gestaron en torno a esta actividad. El escrito aporta a una reflexión crítica sobre las distintas dimensiones, niveles y actores que, en un entramado asimétrico de poder, disputan, valoran y adoptan posiciones contrapuestas en torno de un recurso de relevancia sustantiva en el presente: la energía

Resumen. El artículo se propone reflexionar sobre la extracción de hidrocarburos no convencionales en el megaproyecto Vaca Muerta, que abarca principalmente a las provincias de Neuquén, Río Negro y Mendoza, en una etapa societal en la que se produce energía extrema. Esta actividad involucra distintos niveles de gobierno, y permite advertir un conjunto de resistencias y críticas de actores sociales en relación con la dinámica y los efectos que tiene sobre el territorio y el ambiente. Las diversas posiciones que adoptan los actores, en un entramado de relaciones asimétricas de poder, implica el surgimiento de controversias vinculadas con los impactos de este megaproyecto sobre los recursos naturales y las condiciones de vida de los sectores que habitan en el territorio. En esta dirección, algunas inquietudes serán trabajadas en el presente texto: ¿Cómo visualizan los actores que promueven la actividad los efectos ambientales de la producción de energía extrema? ¿Cómo problematizan esta cuestión aquellos grupos críticos al avance de la producción de hidrocarburos no convencionales? ¿Cómo se redefinen y actualizan las controversias en torno a la técnica del fracking, y con respecto al megaproyecto de Vaca Muerta? La orientación que ha guiado este estudio es de carácter sociopolítico, y se han privilegiado técnicas de investigación cualitativa para construir los datos y los argumentos que se presentan en el escrito. De esta forma el artículo aportará a la sistematización y la intelección de controversias, consensos, disensos, tensiones y conflictos que se registran en torno de Vaca Muerta. Abstract. This article intends to reflect on the extraction of unconventional hydrocarbons in the Vaca Muerta megaproject, which mainly covers the provinces of Neuquén, Río Negro and Mendoza, in a societal stage in which extreme energy is produced. This process involves different levels of government, and allows us to notice a set of resistance and criticism of social actors in relation to the dynamics and the effects it has on the territory and the environment. The diverse positions that the actors adopt, in a network of asymmetric power relations, imply the generation of controversies in relation to the impacts of this megaproject on the natural resources and the living conditions of the sectors that inhabit the territory. In this direction, some concerns will be worked on in this text: How do the actors promoting the activity visualize the environmental effects of extreme energy production? How do these groups problematicize those groups critical to the advance of the production of unconventional hydrocarbons? How are controversies around the fracking technique redefined and updated, and regarding the formation and megaproject of Vaca Muerta? 1 UNGS/CONICET (Argentina)

El objetivo de este artículo es investigar el desempeño de la empresa tecpetrol, subsidiaria del Grupo Techint en el área petrolera, durante el período 2016-2018. La hipótesis de trabajo es que la empresa fue beneficiada por la conformación de un ámbito privilegiado de acumulación de capital en torno a la explotación de la formación Vaca Muerta. Mediante la Resolución 46-E/2017 del ex Ministerio de Energía y Minería de la Nación se creó un Programa de Estímulo a la Producción de gas no convencional, al cual Tecpetrol se adhirió con su proyecto de producción de shale gas en el yacimiento Fortín de Piedra. El programa facilitó un salto productivo y la obtención de ganancias extraordinarias por parte de Tecpetrol con escaso riesgo empresario. La estrategia  metodológica articula el análisis macro, para determinar la conformación de un ámbito privilegiado de acumulación (APA), y el análisis micro, por medio del estudio de caso de Tecpetrol. se utilizan distintas técnicas que van desde el análisis bibliográfico y documental hasta el análisis económico-financiero, y distintas fuentes, tales como la bibliografía específica sobre el tema, series estadísticas oficiales y los estados contables de la empresa.

Abstract: This article is based on the fact that our planet is facing an increasingly complex environmental situation, largely due to the prevailing energy pattern, based on the combustion of hydrocarbons. From this statement, we propose to investigate around what is the reality and the projections of the energy matrices of the two main countries of South America, Argentina and Brazil. In particular, we are interested in observing the perspectives that renewable energies have in them and reflecting on the transformations that we believe are necessary to obtain sustainable energy matrices. In all this development we do not stop paying attention to the place that the region occupies in the scheme of international economic and political relations, particularly taking into account the strategic interest that the People's Republic of China places on the South American natural resources.

Resumen: El presente artículo parte de la base de que nuestro planeta se encuentra de cara a una situación medioambiental crecientemente compleja, en gran parte debido al patrón energético imperante, sustentado en la combustión de hidrocarburos. Desde esa afirmación, nos proponemos indagar en torno a cuál es la realidad y las proyecciones de las matrices energéticas de los dos principales países de Sudamérica, Argentina y Brasil. En particular, nos interesa observar las perspectivas que en ellos tienen las energías renovables y reflexionar acerca de las transformaciones que entendemos necesarias para la obtención de matrices energéticas sustentables. En todo este desarrollo no dejamos de poner atención al lugar que ocupa la región en el entramado de las relaciones económicas y políticas internacionales, en particular teniendo en cuenta el interés estratégico que la República Popular China deposita sobre los recursos naturales sudamericanos.

Basin to mid-ramp cyclic facies of the Tithonian Vaca Muerta Formation are exposed in the Loncoche creek section of the Neuquén Basin, Mendoza province, Argentina. This unit is characterized by a decimetre-scale rhythmic alternation of marls/shales and limestones, and extends from the early Tithonian to late Berriasian. Cyclostratigraphic studies based on a detailed facies analysis allowed the identification of cyclic patterns with frequencies within the Milankovitch band. According to biostratigraphic data, the dominant cycle in the studied section has a period of 20 ky, which correlates with the Earth’s axis precession element. Spectral analysis based on series of compacted and decompacted cycle thickness identified a subordinate frequency of about 90-120 ky, which we interpret as the modulation of the precessional cycle caused by the Earth’s orbital eccentricity. The strength of the precession signal together with the absence of a well-defined cyclicity attributable to the obliquity orbital cycle (i.e. ~ 40 ky) is in agreement with previous data from the Northern Hemisphere.

Taphonomic and palaeocological studies of fossil assemblages from the transgressive and highstand succession of the Vaca Muerta Formation (lower Tithonian to upper Valanginian) in Loncoche Creek, Rahue Creek and Cuesta del Chihuido, Mendoza province was carried out. A range of paleoenvironments that include mid, outer and basin deposits of carbonate ramp has been determinated based on integrated studies of taphofacies, biofacies, lithofacies and microfacies. In the mid ramp zone were recognized the following taphofacies: autoparabiostromes types 1, and 2 as well as concentrations of bivalves, gastropods and serpulids. Meanwhile, biofacies included autobiostromes rich in grypheids and serpulids. In the outer ramp zone were recognized parabiostromes types 1 and 2, ammonite and aptychus pavements, bioclastic detritus, molluscs and brachiopods pavements, besides bioturbated nodular limestones and truncated ammonites. In the outer ramp zone, biofacies are characterized by a high diversity showing: Lingularia-Discinisca, infaunal bivalves, epistominid foraminifers, filament bivalves, besides of pectinidae, oysters and inoceramid bivalves, hardgrounds and microbial mats. Taphofacies and biofacies data allow to estimate relative sea level changes, sedimentation rates, substrate consistency, oxygenation, nutrient levels and productivity.