15 research outputs found
Investigating controls on Carboniferous high-relief carbonate platform margin (Cantabrian Mountains, N Spain) using a forward stratigraphic modeling program (Carbonate 3D)
No full textRecord of sea-level fall in tropical carbonates
No full textStratigraphic forward modeling and comparison with published case studies have been used to determine the controls and stability domains of two conceptual models concerning relative sea-level fall in carbonate sequence stratigraphy. In the standard model, deposition occurs principally during rise and stillstands of relative sea level; a continuous erosional unconformity develops during sea-level fall. The falling-stage systems tract model (FST) postulates significant deposition during sea-level fall. Sedimentological principles, numerical models and published case studies of tropical carbonate sequences indicate that presence or absence of FST is not simply a function of the rate of sea-level fall but depends on the balance of the rates of erosion, sea-level fall and carbonate production, whereby the FST is favoured by high production, slow erosion and slow sea-level fall. Case studies plotted in the parameter space spanned by these variables support the modeling results. The ranges of rates required for the FST in the modeling runs are common in the geologic record. Consequently, the FST can be expected to be more common in tropical carbonate rocks than published records, particularly seismic data, currently indicate. © 2009 The Authors Journal compilation © 2009 Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
Acquiring Remaining Gas Saturations in a Pilot Hole Drilled from a very Extended Reach Drilling Well in a Mature Field
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New Vision of the Shuaiba at a Regional Scale
No full textThis reference is for an abstract only. A full paper was not submittedfor this conference.AbstractThe regional integration of well data, seismic observations and publishedinformation from the southern part of the Arabian Peninsula has led to abreakthrough in understanding the stratigraphy and depositional history of theShuaiba and in extracting implications regarding hydrocarbon prospectivity.The Shuaiba Formation is composed of system tracts from two supersequences,and the following subdivision is proposed: The Lower Shuaiba contains a TST andHST of a supersequence (Early Aptian, earliest late Aptian), while the UpperShuaiba is a LST prograding package of the next supersequence (late Aptian).The TST of the older supersequence is distributed more or less equally over theentire Shuaiba province and the HST of the same supersequence is characterizedby the development of the Bab Basin with a well-marked differentiation betweenbasin and margins. An unconformity separates this supersequence from the LST ofthe next Supersequence during which new carbonate facies prograded into the BabBasin. On the basis of this subdivision, we propose a new, unifiedstratigraphic nomenclature for the Shuaiba.Depositional facies associated with the 3 supersequence systems tracts aremarkedly different. Monotonous, widespread carbonate facies dominated the oldersupersequence. During the HST, organic-rich fine carbonates accumulated in theBab Basin while rudist-rich facies lined and vertically enhanced the southernand western basin margin or developed as relatively large isolated platforms onthe eastern slope of the Bab Basin. In the LST of the younger supersequence,new platforms prograded into the Bab Basin in a series of sub-linear, regularclinoforms that grew either parallel to the pre-existing southern and westernmargins of the Bab Basin or in a series of concentric rings, away frompre-existing isolated platforms.Extracting the detailed sequence stratigraphy of the clinoforms andunderstanding reservoir quality, presence of intraformational seals and trapconfiguration has allowed us to identify and predict areas of higher HCprospectivity in the southern part of the Arabian Peninsula
Overcoming Scale Effects in Characterisation of Vuggy Carbonates by Core, Logs and Geology Integration
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Associations between preschool attendance and developmental impairments in pre-school children in a six-year retrospective survey
No full textBACKGROUND: Many school-aged children suffer physical and mental impairments which can adversely affect their development and result in significant morbidity. A high proportion of children in western countries attend pre-school, and it is likely that the preschool environment influences the prevalence and severity of these impairments. Currently there is insufficient data available on the prevalence of these impairments and their causal associations. The influence that location of a pre-school and the duration of preschool attendance have on the prevalence of these impairments is not known. METHODS: In a retrospective survey spanning six years (1997–2002) we reviewed the records of 6,230 preschool children who had undergone routine school entry assessments. These children had been assessed utilising a modified manual of the "Bavarian Model" for school entry examinations. This model outlines specific criteria for impairments of motor, cognitive, behavioural and psychosocial functioning. Prevalence rates for physical and behavioural impairments were based on the results of these assessments. The relationship between the prevalence of impairments and the duration of preschool attendance and the location of the preschool attended was estimated utilizing logistic regression models. RESULTS: We found that 20.7% of children met the criteria for at least one type of impairment. Highest prevalence rates (11.5%) were seen for speech impairments and lowest (3.5%) for arithmetic impairments. Boys were disproportionately over represented, with 25.5% meeting the criteria for impairment, compared to 13.0% for girls. Children who had attended preschool for less than one year demonstrated higher rates of impairment (up to 19.1% for difficulties with memory, concentration or perseverance) compared to those who had attended for a longer duration (up to 11.6% for difficulties with pronouncation). Children attending preschool in an urban location had slightly elevated rates of impairment (up to 12.7%), compared to their rural counterparts (up to 11.1%). CONCLUSION: Our results demonstrate that there are high prevalence rates for physical and mental impairments among preschool children. Furthermore, children without preschool experience are a risk group for struggling with educational successes. The associations between the duration of preschool attendance and location of preschool attended and rates of impairment need replication and further exploration. Larger prospective studies are needed to examine if these relationships are causal and may therefore lend themselves to specific intervention strategies.Heribert L. Stich, Bernhard T. Baune, Riccardo N. Caniato and Alexander Kräme
