IRTG-StRATEGy - Basin Modeling

163-G 3.4

Anonymous — Fri, 25 Sep 2015 10:15:35 +0000

10|2018 – 09|2021

Testing long-term controls of sedimentary basin architecture in the broken foreland II

M.Sc. Michele VallatiUniversity of Potsdam Prof. Dr. Maria MuttiPotsdam University

Disparate and diachronous basin stratigraphies control petroleum prospects for both conventional and unconventional resources.. The spatial variability of the strata and associated depositional geometries exert a fundamental control on the migration of fluids and determine if hydrocarbons are trapped close to the area where they were generated.

In the first phase of this project, our team has focused on understanding basin-scale controls over the complex spatial distribution of depositional facies in the postrift basin in NW Argentina. The multi-scale stratigraphic architecture reflects the interplay of extrinsic and intrinsic processes, ranging from inherited topography, tectonics, climate and sediment supply and resulted in the superposition at different temporal scales of clastics and carbonates sedimentary facies.

We now plan to focus on quantitative outcrop studies over two comparative basins to better constrain the rules determining the interplay of clastic and carbonate sedimentation. Which roles play the different controls on the basin stratigraphic evolution? How do clastics and carbonates reflect climatic processes? The diverse depositional realms provide archives of the dominant climate dynamics. Carbonate deposition is the product of biogechemical processes induced by increased alkalinity and salinity in the shallow water setting. Do the characterisation and quantification of sedimentary 3D facies distribution in outcrops provide reliable analogues for exploration, at both reservoir and regional scales?

10|2015 – 09|2018

Testing long-term controls of sedimentary basin architecture in the broken foreland

The spatial architecture of sedimentary facies in a basin exert a fundamental control over the patterns of fluid flow and determines the regional distribution of possible reservoirs and seal units. The distribution of sedimentary facies can be predicted to some extent by sequence stratigraphic theories. These models offer a conceptual framework to extrapolate facies distribution at a regional scale in 2D, ranging from continental to basinal. However, as soon the scale of observation increases, these models are not able to represent the geological complexity and facies variability in a realistic way. Furthermore, these concepts are rarely applied in 3D. Field studies reveal much more complex facies mosaics and patterns than predicted by 2D-models. Here, we will characterize the 3D facies distribution and sedimentary architecture evolution of a post-rift basin at different temporal and spatial scales prior to its evolution as a foreland basin. More specifically, the goal is to model the above mentioned parameters by coupling integrative seismic data, petrographic investigations of well logs, and outcropping sedimentary successions. Specific attention will be given to sedimentary discontinuities that often point to noteworthy events or record significant modifications of the environmental conditions, but also have the potential to affect fluid flow behavior and to compartmentalize reservoirs. Petrographic and geochemical analyses will be used to identify environmental parameters and assess diagenetic overprint in various limestone intervals. The outstanding quality of the sedimentary successions of several subbasins of the Salta Group (Yacoraite Formation) in NE Argentina offers a fantastic natural laboratory to study spatial facies variability in a postrift basin. The integration of facies analysis and stratigraphic units together with petrographic and geochemical studies on their bounding unconformities will provide data to test the role of extrinsic and autocyclic controls (tectonic, climate and sediment supply, inherited topography) on the stratigraphic successions. Constrained by stratigraphic and sedimentological information from field, well-log, and seismic data, numerical forward modeling will provide a valuable tool for testing stratigraphic correlations and the geological hypotheses controlling their occurrence. We will employ numerical modeling (DIONISOS, Petrel) to explore hypotheses concerning their occurrence and spatial distribution. This project will thus contribute to characterizing and quantifying sedimentary 3D facies distribution in outcrops (analogs for subsurface exploration) at basin and reservoir scales and to evaluate controls over their vertical and lateral stratigraphic architecture.

Working Package:

WP3 - Basin Modeling

Temporal Process:

Long Term

M.Sc. Wera SchmidtPotsdam University Prof. Dr. Maria MuttiPotsdam University Prof. Dr. Claudia GalliJujuy National University (ARG)

163-G 3.3

Anonymous — Fri, 25 Sep 2015 10:14:50 +0000

10|2018 – 09|2021

Lithospheric-scale 3D configuration of the Central Andes and adjacent forelands: constraints on along- and across-strike variations of density, temperature and strength

Lic. Constanza Rodriguez PicedaGFZ Potsdam Dr. Judith Bott (née Sippel)GFZ Potsdam Prof. Dr. Magdalena Scheck-WenderothGFZ Potsdam Prof. Dr. Claudia PrezziBuenos Aires University

There is a great variability in observed crustal deformation style and intensity from the subduction trench across the highest Andes to the foreland lows as well as from the Northern to the Southern Central Andes. Beside the subducting plate that exerts important controls on deformation through its (spatially and temporally) varying dynamics, it is the intrinsic physical properties of the overriding plate that govern the formation of zones of crustal strength and weakness. With this project we want to explore the present-day compositional, thermal and rheological configuration of the Central Andes and adjacent forelands on a lithospheric scale by means of data-driven 3D numerical models. While in the first project phase of StRATEGy this work package focused on the Northern Central Andes, this follow-up project will investigate lithological and related physical heterogeneities of the sediments, the crystalline crust, and the mantle of the Southern Central Andes. For this purpose, geological and geophysical observations such as seismic, seismological, gravity and thermal data will be integrated into consistent 3D models. These static models will be useful to constrain numerical thermo-mechanical experiments (such as planned in project G 3.2) that explore the stress-and-strain relationships across the entire subduction system.

10|2015 – 09|2018

3D lithosphere-scale density and thermal structure of the Central Andean foreland basins

Since the late Oligocene, the intracontinental Chaco-Paraná basin system evolved contemporaneously with the adjacent Andean fold-and-thrust belt. Consequently, four characteristic foreland depozones with different sediment thickness have developed, including (from west to east) wedge-top, foredeep, forebulge, and backbulge depositional environments. In places, very young sedimentary sequences directly overlie basement rocks in the E, while toward the orogen, they cover several kilometres of Paleozoic and Mesozoic sediments. Geophysical data provides local information on the depth to the Moho and the lithosphere-asthenosphere-boundary (LAB); accordingly, the crust and lithosphere thin from ~43 km and ~120 km in the north-eastern parts of the Chaco-Paraná basin to ~35 km and ~80 km, respectively, in the central parts. Towards the Andean orogen in the west, crustal thicknesses increase to more than 60 km and the LAB deepens to more than 150 km. Despite the abundance of geological and geophysical data, there is currently no regionally consistent 3-dimensional representation of the entire lithosphere in the region. Such a model depicting the main compositional heterogeneities of the sediments, the crystalline basement, and the lithospheric mantle has recently been developed for the Central Andes and will be critical for unraveling the long-term evolution of the foreland basin. Based on geological maps, well-logs, and seismic data made available to StRATEGy from industry and our Argentine partner E. Rossello, regional thickness variations of main tectonostratigraphic units will be integrated in a 3D structural model in the framework of PhD project. Subsidence rates and spatiotemporal shifts of depocentres will be cast in terms of phases of increased Andean tectonic loading. The models developed in this project will provide boundary conditions for petroleum-potential assessment in project [G 3.1] and a regional tectonic framework for project [G 3.4]. Furthermore, these models will allow rheological heterogeneities to be distinguished, particularly crustal zones of mechanical weakness, representing important constraints for large-scale numerical thermo-mechanical models developed in projects [G 3.2].

Working Package:

WP3 - Basin Modeling

Temporal Process:

Long Term

Intermediate

Dr. Christian MeeßenGFZ Potsdam Dr. Judith Bott (née Sippel)GFZ Potsdam Prof. Dr. Magdalena Scheck-WenderothGFZ Potsdam Prof. Dr. Claudia PrezziBuenos Aires University

163-G 3.1

Anonymous — Fri, 25 Sep 2015 10:13:20 +0000

10|2018 – 09|2021

Quantification of Central Andes growth and erosion in relation to sedimentation in the Neuquén and Colorado basins - a source-to-sink approach

Lic. Román FealGFZ Potsdam Dr. Robert OndrakGFZ Potsdam Prof. Dr. Matias GhiglioneBuenos Aires University (ARG)Prof. Dr. Laura GiambiagiCuyo National University (ARG)Prof. Manfred Strecker, Ph.D.Potsdam University

This project follows a source to sink approach relating Central Andes growth with sedimentation in Neuquén and Colorado basins. The working hypothesis is that tectonic mountain growth produces large volumes of eroded rocks and subsidence in the foreland basins that catches those sediments. While contractional tectonics accelerates subsidence rates of foreland basins, periods of neutral tectonics produce low to no accommodation space in the retroarc. On those cases, large portion of sediments will bypass the continent toward the offshore basins, therefore controlling overburden and petroleum generation. The idea is to compare the Central Andes (34°-42°SL) changing tectonics and exhumation rates - source region - with sedimentation rates and volumes of sediments in the Neuquén foreland basin to determine if there is an inverse correlation to the Colorado offshore basin - sink basins - for periods to be defined during data acquisition. In particular, we will test the hypothesis by calculating sedimentation rates in the Colorado offshore basin from available basin models. Sedimentation rates in the Neuquén basin and tectonic and exhumation in the Central Andes can be summarized from a plethora of publicly available data. We will study paradigmatic localities in the Neuquén basin to recognize the appearance of highly condensed stratigraphic sections representing periods of neutral tectonics. Lab analysis will be conducted in order to better constrain and characterize those periods of potential sediment bypass towards the offshore which is of significance for the evolution of the petroleum potential of the region. The project will also contribute to the partner projects [G 3.2] and [G 3.3] by providing data from the sedimentary cover of the region.

10|2015 – 09|2018

Tectono-stratigraphic evolution of the intermontane Salta basin and Chaco-Paraná foreland basin: characterization and evolution of petroleum potential

The evolution of the inter-mountain Salta basin is related to the evolution of the Central Andes. An intracontinental rift was formed by extensional processes and subsequently filled by up to 5500 m sediments from the Neocomian to the Paleogene intercalated by minor volumes of magmatic rocks. This complex constitutes the Salta group. Paleoenvironmental analysis reveals depositional history controlled by tectonic and climatic changes. Deformation of the basin began at the end of the Eocene and resulted in a rapid transition from a rift basin to a foreland basin filled by synorogenic continental deposits. The Chaco-Paraná Basin comprises the undeformed Chaco-Parana plain to the east, and the Subandes, Sierras Pampeanas, and the ranges of the Santa Barbara System to the west. The basin comprises >10 km of sediments spanning the Silurian to the Present. It is asymmetric, with a total stratigraphic thickness of Cenozoic rocks >7.5 km deposited at the western margin that thin eastward. Deformation of the Subandes and the Salta Basin developed since the Eo-Oligocene; and is characterized mainly by in-sequence, thin-skinned thrusting that includes ramp anticlines and passive roof duplexes separated by thrust faults and synclines, although Plio-Pleistocene out-offsequence thrusting has also been reported. The Subandes are home to several major gas discoveries during the last 20 years. The Chaco-Paraná foreland basin, as a frontier exploration area, has a high resource potential (some assessments attribute almost one third of Argentina’s total unconventional hydrocarbon potential to this basin), although exploration concepts are largely unproven. By combining 3D petroleum system modeling techniques with detailed source rock and petroleum-accumulation information, volumetric assessments of petroleum potential can be produced at different scales for basin wide assessments of the possible resource potential. We plan to investigate the evolution of the inter-mountain Salta basin and the Chaco-Parana Basin to deconvoluting its burial and thermal histories as well as source rock maturation, petroleum generation, migration, accumulation and leakage. A detailed basin modeling study is planned which integrates the tectono-stratigraphic evolution, timing of major unconformities, spatiotemporal migration of depocenters, source-rock occurrence and type to elucidate the hydrocarbon generation and migration history of this basin. Special focus will be put on the climatic and tectonic processes operating in the sediment source areas to determine the main variables and forcing conditions controlling the stratigraphic architecture and the distribution of source rocks. Within this context including all information available on the crustal evolution of the NW of Argentina is a pre-requisite. Especially the buildup of the Andes, and fault reactivation and thrusting along the basin margins are important factors in controlling both the burial as well as the maturation and petroleum migration histories. This project will provide an integrated and concise description of the evolution of Salta and Chaco-Parana basin petroleum systems. The project will cooperate closely with projects [G 3.3] and [G 3.4] to define boundary conditions for basin modeling and detailed description of the tectono-stratigraphic and sedimentary evolution of the basin.

Working Package:

WP3 - Basin Modeling

Temporal Process:

Long Term

Intermediate

Dr. Ricardo Ruiz MonroyGFZ Potsdam Dr. Robert OndrakGFZ Potsdam Prof. Dr. Magdalena Scheck-WenderothGFZ Potsdam Prof. Dr. Eduardo RosselloBuenos Aires University (ARG)Prof. Dr. Brian HorsfieldGFZ Potsdam