New insights on subsurface energy resources in the Southern North Sea Basin area

The Southern North Sea Basin area, stretching from the UK to the Netherlands, has a rich hydrocarbon exploration and production history. The past, present and expected future hydrocarbon and geothermal exploration trends in this area are discussed for eight key lithostratigraphic intervals, ranging from the Lower Carboniferous to Cenozoic. In the period between 2007 and 2017, a total of 95 new hydrocarbon fields were discovered, particularly in Upper Carboniferous, Rotliegend and Triassic reservoirs. Nineteen geothermal systems were discovered in the Netherlands onshore, mainly targeting aquifers in the Rotliegend and Upper Jurassic/Lower Cretaceous formations. Although the Southern North Sea Basin area is mature in terms of hydrocarbon exploration, it is shown that with existing and new geological insights, additional energy resources are still being proven in new plays such as the basal Upper Rotliegend (Ruby discovery) for natural gas and a new Chalk play for oil. It is predicted that hydrocarbon exploration in the Southern North Sea Basin area will probably experience a slight growth in the coming decade before slowing down, as the energy transition further matures. Geothermal exploration is expected to continue growing in the Netherlands onshore as well as gain more momentum in the UK

The role of salt tectonics and overburden in the generation of overpressure in the Dutch North Sea area

In this paper we study the effects of timing of salt movement and mechanical compaction on the generation of overpressures in Mesozoic rocks. To that end we apply 2D basin modelling on two N-S trending cross sections in the Dutch Central Graben and Terschelling Basin, respectively. Several overpressuring scenarios were calculated by modifying the mechanical compaction of the sealing layer, the rate of sedimentation, and the timing of salt movement. Pressure and porosity measurements from several wells along the cross sections were used as calibration data. The results show that rapid sedimentation and early compaction of Pliocene to Quaternary mudstones explain most of the overpressures in the Cretaceous and Jurassic rocks. The modifications of the mechanical compaction of the Upper Cretaceous Chalk Group performed in this study could not explain the overpressure anomalies in the southern part of the Dutch Central Graben. Processes such as chemical compaction are probably more important in this respect. Overpressures in the Triassic are mainly controlled by the timing of salt movement and the closure of lateral seals. This study has lead to a better understanding of the processes that generate overpressures and those that are involved in their lateral distribution. The integration of modelling scenarios and information on the timing of seal formation enables to define new play concepts and is important for the assessment of possible drilling hazards as well

Focus on Shallow Gas Systems

Recent exploration activities in two of the largest deltas in the world, the still active Nile delta and the Cenozoic Southern North Sea (SNS) deltas, proved the potential of shallow gas resources. However, shallow gas production is still limited due to a lack of understanding of this gas system. For both the Nile and the SNS delta, there is an on-going debate about the origin of the gas. For both settings, the origin of shallow gas may be deep subsurface thermogenic sources, microbial sources in shallower strata, or a mixture of both. The origin of shallow gas was studied in the Dutch SNS delta as part of a comprehensive multidisciplinary workflow developed and applied to enhance the quantitative knowledge and understanding of the shallow gas play in the delta (Ten Veen et al., 2014). Timing and quantification of microbial gas generation in the SNS delta was studied using a combination of different modeling approaches, and included new detailed basal and surface thermal boundary conditions. Modeling results indicate that intra SNS delta deposits are an important source of microbial gas that are able to fill most of the available traps in the Dutch SNS delta

Tectonic heat flow modelling for basin maturation - Implications for frontier areas in the mediterranean

Basement heat flow is one of the most influential parameters on basin maturity. Although rapid progress has been made in the development of tectonic models capable of modelling the thermal consequences of basin formation, these models are hardly used in basin modelling. To better predict heat flows we have developed a multi-1D probabilistic tectonic heat-flow model, incorporating a variety of tectonic scenarios (including rifting, underplating and mantle upwelling). The model has been applied for a range of basin settings, and predicted temporal and spatial heat flow variations are well in accordance with observations on heat flow for specific tectonic settings. In the Mediterranean observed heat flow is markedly heterogenous, ranging from values from as low as 30mW m-2 up to 150 mW m-2, having major implications for basin temperature and maturation levels. Tectonic models for heat allow to asses geodynamic causes for these varations and aid considerably in constrining spatial and temporal variations in heat flow. In particular modelling results indicated that the interplay of rifting, underplating, back-arc extension, has resulted in much stronger temporal and spatial tectonic heat-flow variations than hitherto assumed

Физико-химические закономерности получения и применение литых стеклокристаллических материалов шпинелид-пироксенового состава из природного и техногенного сырья: диссертация на соискание ученой степени доктора технических наук: спец. 05.17.11

Sedimentary basins in The Netherlands contain significant amounts of hydrocarbon resources, which developed in response to temperature and pressure history during Mesozoic and Cenozoic times. Quantification and modelling of burial, maturity and temperature histories are the major goals of this study, allowing for a better understanding of the general geological evolution of the different basins as well as petroleum generation. All major basins in The Netherlands encountered at least one time of inversion and therefore moderate to high amounts of erosion. In order to determine the amount of inversion the basins have experienced, a 1D study was performed on 20 wells within three basins (West Netherlands, Central Netherlands and Lower Saxony Basins). New vitrinite reflectance values were obtained and existing data re-evaluated to gain a good data base. The burial histories of six wells, two for each studied basin, are presented here, to demonstrate the differences in basin evolution that led to their present shape and petroleum potential. The Permo-Triassic subsidence phase can be recognized in all three basins, but with varying intensity. In the Jurassic, the basins experienced different relative movements that culminated in the Cretaceous when the influence of the inversion caused erosion of up to 2,500 m. Most wells show deepest burial at present-day, whereas the timing of maximum temperature differs significantly. © Springer-Verlag 2007

An overview of basin modeling in The Netherlands: new results and applications

The subsurface of the onshore and offshore Netherlands has been studied extensively. In 2006 the first complete maps of the main stratigraphic horizons (down to the Permian) were published. Since then these maps were regularly updated and extended to include also the main reservoir horizons. This detailed stratigraphic information was used to quantitatively study the evolution of the Dutch subsurface by means of 3D basin modeling. At this time about 70% of the Dutch subsurface has been studied using basin modeling. Important results from these models include the heat flow evolution based on tectonic subsidence modelling, burial history, temperature evolution, maturity evolution and hydrocarbon generation of the main source-rocks as well as porosity evolution for the main reservoir horizons. These results can be used for conventional hydrocarbon exploration but also for more unconventional applications

European Unconventional Oil and Gas Assessment (EUOGA) - Development and application of a unified methodology

Over the last decade, various international and national assessments of shale gas and shale oil resources for most EU-countries have been published. Due to methodological differences and in fundamental assumptions related to the quality and quantity of underlying geological information, these results are not comparable and in some cases not reproducible. This presentation focusses on the development and definition of a uniform methodology for estimating (in-place) shale gas and shale oil resources at the pan-European level within the context of the EUOGA study (EU Unconventional Oil and Gas Assessment). The presented methodology is established to determine estimates of GIIP (Gas Initially In Place) and OIIP (Oil Initially In Place) including associated uncertainty bandwidths originating from the various geological input parameters. The method is applied to 81 onshore shale gas or oil formations from 33 thermogenic and two biogenic basins located within the participating European countries. The results of the assessment include a geological description of the basins together with a general chance of success, a ranking of the individual assessment units and the final calculation of GIIP or OIIP for the formations. Saudi Aramco; Shell; Tota

Thermal evolution and shale gas potential estimation of the Wealden and Posidonia Shale in NW-Germany and the Netherlands : a 3D basin modelling study

Sedimentary basins in NW-Germany and the Netherlands represent potential targets for shale gas exploration in Europe due to the presence of Cretaceous (Wealden) and Jurassic (Posidonia) marlstones/shales as well as various Carboniferous black shales. In order to assess the regional shale gas prospectivity of this area, a 3D high-resolution petroleum system model has been compiled and used to reconstruct the source-rock maturation based on calibrated burial and thermal histories. Different basal heat flow scenarios and accordingly, different high-resolution scenarios of erosional amount distribution were constructed, incorporating all major uplift events that affected the study area. The model delivers an independent 3D reappraisal of the tectonic and thermal history that controlled the differential geodynamic evolution and provides a high-resolution image of the maturity distribution and evolution throughout the study area and the different basins. Pressure, temperature and TOC-dependent gas storage capacity and gas contents of the Posidonia Shale and Wealden were calculated based on experimentally derived Langmuir sorption parameters and newly compiled source-rock thickness maps indicating shale gas potential of the Lower Saxony Basin, southern Gifhorn Trough and West Netherlands Basin