Conference Agenda

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Session Overview
Poster session for Topic: 1.4
Tuesday, 21/Sept/2021:
6:00pm - 6:45pm


Influence of Quaternary glaciations on subsurface temperatures and pressures in NE onshore Netherlands

Sebastian Amberg1, Victoria Sachse1, Stefan Back2, Ralf Littke1

1Institute of Geology and Geochemistry of Petroleum and Coal, Energy and Mineral Resources (EMR), RWTH Aachen University, Lochnerstr. 4-20, 52054 Aachen, Germany; 2Geological Institute, Energy and Mineral Resources (EMR), RWTH Aachen University, Wüllnerstr. 2, 52052 Aachen, Germany

Several glacial ice advances shaped the present-day morphology of central Europe during the Quaternary. Two Pleistocene glaciations, the Elsterian and the Saalian stages, advanced as far as the north-eastern part of the onshore Netherlands. Remains of these glacial advances and retreats are deep erosional glacial valleys of the Elsterian glaciation and till sheets, glacio-tectonic ridges and glacial basins assigned to the Saalian complex.

In this study, we present the effects of sequential loading and unloading of ice sheets on the temperature distribution and rock properties of the subsurface using 3D basin and petroleum systems modelling in the northeast Netherlands. A 3D basin and petroleum systems model was set up, incorporating the Neogene to Quaternary Upper North Sea Group down to the Carboniferous Limestone Group, was used and extended to incorporate sequential loading and unloading of ice sheets in the Pleistocene.

Subsurface temperatures are decreased due to low ground and ice sheet base temperatures, with minimum temperatures observed at the beginning of a glacial stage. During an ice sheet coverage, the subsidence caused by loading leads to an increase in temperatures, therefore counteracting a low ice sheet base temperatures. Generally, a lower geothermal gradient is observed in the upper layers of the 3D model. Pore pressures build up during glacials caused by extra loading and then retreat to a pre-loading state with time, depending on the strength of ice loading, the depth of the layer, as well as the rock properties of the overburden.

Crustal structure and margin configuration of the La Baja Guajira basin, Colombia: regional 2D seismic reflection interpretation, gravimetric and thermal modelling

Leidy Castro-Vera1,2, Ralf Littke1, Stefan Back1, Rocío Bernal-Olaya3

1RWTH Aachen University, Germany; 2Grupo de investigación en Ciencias de la Tierra y Energía, Amonite SAS, Colombia; 3Universidad Industrial de Santander, Colombia

The La Baja Guajira Basin (LBGB) is the primary gas-producing region of Colombia and represents South America's northernmost prolongation. This study presents an analysis of regional 2D-seismic reflection data of LBGB integrated with borehole and gravity information. The deepest basement in the study area occurs in the northwestern offshore. This depocenter is oriented NW-SE. In the basin, four fault groups occur: 1) NW-SE-striking basement normal faults; 2) strike-slip faults; 3) inverted normal faults, and 4) local thrust faults. Prominent bottom simulating reflectors (BSRs) are present in the NW deep-water areas.

2D gravity modelling was used to comprehend the basin's geometry and basement type. It indicates that the crust under LBGB is best simulated with rocks of continental nature. 1D petroleum system modelling was applied to reconstruct and evaluate the basin's burial and thermal history. Modelling results show that the study area experienced two episodes of rapid tectonic subsidence (lower Middle Miocene, Late Miocene). During the Lower and Middle Miocene, sediment input into the LBGB was from east to west. In the Late Miocene, the Andean uplift provided an additional and significant sediments contribution from the south. A period of erosion due to uplift is evident in the northern area between the uppermost Middle and Upper Miocene. From the Pliocene to recent, relative tectonic quiescence is observed. Sediments in well Mero-1 (southern offshore) were subjected to high temperatures causing Middle Miocene source rocks to reach maturation indicated by 0.69 %VRr values; however, greater depths and temperatures are required for hydrocarbon generation.