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Vienna, Austria

Rohöl-Aufsuchungs Aktiengesellschaft is an oil and gas company with headquarters in Vienna, Austria. The operations center responsible for drilling and production is situated in Gampern, Upper Austria. Together with Wingas and Gazprom Export it owns the Haidach gas storage. Wikipedia.

Masalimova L.U.,Stanford University | Lowe D.R.,Stanford University | Mchargue T.,Stanford University | Derksen R.,Rohol Aufsuchungs
Sedimentology | Year: 2015

Deep-water sediments in the Molasse Basin, Austria, were deposited in a narrow foreland basin dominated by a large channel belt located between the steep Alpine fold and thrust belt to the south and the gentler northern slope off the Bohemian Massif. Several gas fields occur outside the channel belt, along the outer bend of a large meander. Accumulation of these overbank sediments reflects a complicated interplay between slope accommodation and debris-flow and turbidity-flow interaction within the channel. The tectonically oversteepened northern slope of the basin (ca 2 to 3°) developed a regionally important erosional surface, the Northern Slope Unconformity, which can be traced seismically for >100 km in an east-west direction and >20 km from the channel to the north. The slope preserves numerous gullies sourced from the north that eroded into the channel belt. These gullies were ca 20 km long, <1 km wide and ca 200 m deep. As the channel aggraded, largely inactive and empty gullies served as entry points into the overbank area for turbidity currents within the axial channel. Subsequently, debris-flow mounds, 7 km wide and >15 km long, plugged and forced the main channel to step abruptly ca 7 km to the south. This resulted in development of an abrupt turn in the channel pathway that propagated to the east and probably played a role in forming a sinuous channel later. As debris-flow topography was healed, flows spread out onto narrow area between the main channel and northern slope forming a broad fine-grained apron that serves as the main gas reservoir in this area. This model of the overbank splay formation and the resulting stratigraphic architecture within the confined basin could be applied in modern and ancient systems or for subsurface hydrocarbon reservoirs where three-dimensional seismic-reflection data is limited. This study elucidates the geomorphology of the oversteepened slope of the under-riding plate and its effects on the sedimentation. © 2015 International Association of Sedimentologists.

Pichler M.P.,Rohol Aufsuchungs
Sustainable Earth Sciences, SES 2013: Technologies for Sustainable Use of the Deep Sub-Surface | Year: 2013

Renewables suffer from fluctuating energy generation, which means that they generate energy overspills during beneficial weather conditions which, due to lack of large scale storage options, cannot be used at a later point but is wasted. A viable option would be to convert the energy into hydrogen and to store it in existing porous subsurface formations. To assess the influence of hydrogen rock interaction during underground storage of natural gas hydrogen mixtures in porous subsurface formations, a geochemical gibbs free energy simulation was done. The simulation was conducted for the mineral assembly of two existing porous subsurface formations. The model showed that hydrogen increases the pH, and therefore changes the mineral composition of the reservoir rock by dissolving dolomite and precipitating calcite and talc. Additional investigations included crystalline minerals which were not affected and clay minerals which could not be assessed as reliable data for these minerals is not yet available. Finally the stability of sulphides was assessed to rule out the possible generation of H2S. It was found that under subsurface conditions, sulphides will stay stable.

Bechtel A.,University of Leoben | Gratzer R.,University of Leoben | Linzer H.-G.,Rohol Aufsuchungs | Sachsenhofer R.F.,University of Leoben
Organic Geochemistry | Year: 2013

The Austrian part of the Alpine Foreland Basin has been studied previously by organic geochemical methods to establish oil-oil and oil-source rock correlations. The lateral distance of oil fields to the position of mature source rocks (Lower Oligocene Schöneck and Eggerding formations) beneath the Alpine nappes in the south suggests long distance migration up to 50km. Minor compositional trends in W-E direction were obtained reflecting differences in depositional environment (facies) and maturity of potential source rocks. Therefore, the oil and source rock samples are thought to provide valuable insights into carbazole distributions in relation to migration distance, maturity and facies. Compound specific carbon isotope analyses on n-alkanes and isoprenoids reflect the W-E trend, already seen within the total hydrocarbon fractions. The observed trend toward lighter δ13C values of alkanes from oil fields in a W-E direction are consistent with lower δ13C values of organic matter in unit c and similar differences obtained from sediments of the Schöneck Formation at wells Oberhofen 1 (W) and Molln 1 (E). The δ13C patterns of n-alkanes and isoprenoids are in agreement with data obtained from the potential marine source rocks (Schöneck Formation) of the oils. The hydrogen isotopic composition of short chain n-alkanes (C15-19) of most oil samples are lower than the data obtained from the extracts of the marine Permian Kupferschiefer of the Polish Zechstein Basin at similar maturation stages. Only the oils from the western oil fields yield δD values of n-alkanes comparable to those obtained from marine source rocks. The data imply brackish water conditions during deposition of 'unit c' of the Schöneck Formation. Differences in the position of δD of isoprenoids in relation to the respective maturation trend line are most probably related to calibration errors. Alkylated carbazoles and benzocarbazoles are only present in sufficient amounts for quantification in oils sampled from the eastern fields. Rock extracts of the Schöneck Formation from drill cores Molln 1 (5200m depth, 0.92% Rr) and from the marginally mature (ca. 0.6% Rr) samples from well Oberhofen 1 (4300m depth) obtained sufficient amounts of carbazoles. The significantly different concentrations of benzocarbazoles in the extracts (around 10μg/g at Oberhofen 1; > 50μg/g at Molln 1) are related to maturity differences, whereas the predominance of 1-methylcarbazole in the Oberhofen samples is inferred to reflect differences in source rock facies. In the oils from the eastern deposits, neither the concentration ratios of methylcarbazoles, nor the benzocarbazole ratio show indications for the influence of facies differences. Maturity of oil expulsion is estimated on the basis of MPI 1 (Rc=0.76-0.88%), confirmed by sterane isomerization parameters. The results argue for a minor influence of maturity differences on the benzocarbazole ratios of the oil samples. The obtained ratios and the reservoir source fractionation parameters, calculated from the data of Molln 1 source rocks and the respective oils, show a systematic decrease with the estimated migration distance. The results argue for the applicability of benzocarbazoles for the assessment of relative differences in migration distances in oil plays characterized by minor differences in source rock facies and maturity during oil expulsion. © 2013 Elsevier Ltd.

Gratzer R.,University of Leoben | Bechtel A.,University of Leoben | Sachsenhofer R.F.,University of Leoben | Linzer H.-G.,Rohol Aufsuchungs | And 2 more authors.
Marine and Petroleum Geology | Year: 2011

The Alpine Foreland Basin is a minor oil and moderate gas province in central Europe. In the Austrian part of the Alpine Foreland Basin, oil and minor thermal gas are thought to be predominantly sourced from Lower Oligocene horizons (Schöneck and Eggerding formations). The source rocks are immature where the oil fields are located and enter the oil window at ca. 4 km depth beneath the Alpine nappes indicating long-distance lateral migration. Most important reservoirs are Upper Cretaceous and Eocene basal sandstones.Stable carbon isotope and biomarker ratios of oils from different reservoirs indicate compositional trends in W-E direction which reflect differences in source, depositional environment (facies), and maturity of potential source rocks. Thermal maturity parameters from oils of different fields are only in the western part consistent with northward displacement of immature oils by subsequently generated oils. In the eastern part of the basin different migration pathways must be assumed. The trend in S/(S + R) isomerisation of ααα-C29 steranes versus the αββ (20R)/ααα (20R) C29 steranes ratio from oil samples can be explained by differences in thermal maturation without involving long-distance migration. The results argue for hydrocarbon migration through highly permeable carrier beds or open faults rather than relatively short migration distances from the source. The lateral distance of oil fields to the position of mature source rocks beneath the Alpine nappes in the south suggests minimum migration distances between less than 20 km and more than 50 km.Biomarker compositions of the oils suggest Oligocene shaly to marly successions (i.e. Schoeneck, Dynow, and Eggerding formations) as potential source rocks, taking into account their immature character. Best matches are obtained between the oils and units a/b (marly shale) and c (black shale) of the " normal" Schöneck Formation, as well as with the so-called " Oberhofen Facies" Results from open system pyrolysis-gas chromatography of potential source rocks indicate slightly higher sulphur content of the resulting pyrolysate from unit b. The enhanced dibenzothiophene/phenanthrene ratios of oils from the western part of the basin would be consistent with a higher contribution of unit b to hydrocarbon expulsion in this area. Differences in the relative contribution of sedimentary units to oil generation are inherited from thickness variations of respective units in the overthrusted sediments. The observed trend towards lighter δ13C values of hydrocarbon fractions from oil fields in a W-E direction are consistent with lower δ13C values of organic matter in unit c. © 2011 Elsevier Ltd.

Grunert P.,University of Graz | Hinsch R.,Rohol Aufsuchungs | Sachsenhofer R.F.,University of Leoben | Bechtel A.,University of Leoben | And 4 more authors.
Marine and Petroleum Geology | Year: 2013

To improve the prediction of gas and oil in strata along the tectonically imbricated southern margin of the Puchkirchen Trough (North Alpine Foreland Basin, Central Paratethys), a better understanding of facies distribution and stratigraphic control of the basin is essential. The present study provides bio- and chemofacies analyses and a biostratigraphic evaluation for the pelitic Hall Formation from the borehole Hochburg 1 in the central part of the Puchkirchen Trough. A statistical evaluation of benthic foraminiferal assemblages together with geochemical proxy records (TOC, sulphur, hydrogen index, δ13CTOC, δ15NTN) reveals a succession of early Burdigalian depositional environments.Following a major subaqueous erosional hiatus, conglomeratic sands at the base of the section, which contain reworked Chattian and Aquitanian foraminiferal assemblages, record the reactivation of a basin-axial channel system. During the early Burdigalian eustatic sea-level rise, the channel was cut off from its sediment sources on the shelf and a deepening bathyal environment was established. Agglutinated foraminiferal assemblages with abundant Bathysiphon filiformis developed that were adapted to an unstable environment with frequent deposition of turbidites. The middle part of the Hall Formation is characterized by prograding high-relief clinoforms, which are fed by the Wachtberg Delta of the Paleo-Inn river. High sedimentation rates are interpreted and increased input of terrestrial-derived organic matter is documented with a strong correlation of TOC and TOC/S and low HI values, as well as frequent occurrences of Ammodiscus spp. and other opportunistic agglutinating foraminifers. A renewed transgression reestablished a eutrophic and suboxic bathyal environment, followed by the development of an oxygenated outer-middle neritic shelf environment heralding the ultimate infill of the deep-water basin.Based on a comparison of the revealed development to existing sequence stratigraphic models for the Puchkirchen Trough, three sequences and their corresponding systems tracts can be identified for the lower, middle and upper Hall Formation. Biostratigraphic evidence from benthic foraminifers and calcareous nannoplankton indicates that they correspond to the regional substages of the middle and upper Eggenburgian and lower Ottnangian, and to global 3rd-order sequences Bur 1-3. The observations suggest a primary control of eustatic sea-level on the Puchkirchen Trough rather than Alpine tectonics during the Burdigalian. © 2012 Elsevier Ltd.

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