>Magister Scientiae - MSc / The Bredasdorp Basin is one of the largest hydrocarbon producing blocks within Southern Africa. The E-M field is situated approximate 50 km west from the FA platform and was brought into commission due to the potential hydrocarbons it may hold. If this field is brought up to full producing capability it will extend the lifespan of the refining station in Mosselbay, situated on the south coast of South Africa, by approximately 8-10 years. This study is focused in block 9 off shore western part of the Bredasdorp Basin in the main Outeniqua Basin South Africa. Cretaceous Sandstone reservoirs are commonly heterogeneous consequently they may require special methods and techniques for description and evaluation. Reservoir characterization is the study of the reservoir rocks, their petrophysical properties, the fluids they contain or the manner in which they influence the movement of fluids in the subsurface. The main goal of the research is to assess the potentials of hydrocarbons in Cretaceous sediments in the Bredasdorp Basin through the integration and comparison of results from core analysis, production data and petrography studies for the evaluation and correction of key petrophysical parameters from wireline logs which could be used to generate an effective reservoir model for wells (E-BB1, E-BD2, EA01) in the Bredasdorp Basin. Porosity and permeability relationships, wire-line log data have been examined and analysed to determine how the porosity and permeability influence reservoir quality which further influences the potential of hydrocarbon accumulation in the reservoirs. The reservoir sandstone is composed mainly of fine to medium grained Sandstones with intercalation of finger stringers of Siltstone and Shale. In carrying out this research the samples are used to characterize reservoir zones through core observation, description and analyses and compare the findings with electronic data obtained from Petroleum Agency of South Africa (PASA). Secondary data obtained from (PASA) was analysed using softwares such as Interactive Petrophysics (IP), Ms Word, Ms excel and Surfer. Wireline logs of selected wells (E-BB1, E-BD2, E-A01) were generated, analysed and correlated. Surfer software also used to digitize maps of project area, porosity and permeability plotted using IP. Formation of the Bredasdorp Basin and it surrounding basins during the Gondwana breakup. The Bredasdorp Basin consists mainly of tilting half graben structures that formed through rifting with the break-up of Gondwanaland. The model also revealed that these faults segregate the reservoir which explains the pressure loss within the block. The production well was drilled, confining pressure relieved and pressure dropped hence production decreases. The age, transportation, deposition and thermal history of sediment in the basin, all plays a vital role in the type of hydrocarbon formation. Structural features such as faults, pore spaces determines the presence of a hydrocarbon in the reservoir. Traps could be stratigraphic or structural which helps prevent the migration of hydrocarbons from the source rock to reservoir rock or from reservoir rock to the surface over a period of time. The textural aspects included the identification of grain sizes, sorting and grain shapes. The diagenetic history, constructed from the results of the reservoir quality study revealed that there were several stages involved in the diagenetic process. It illustrated several phases of cementation with quartz, carbonate and dolomite with dissolution of feldspar. A potentially good reservoir interval was identified from the data and was characterized by several heterogeneous zones. Identifying reservoir zones was highly beneficial during devising recovery techniques for production of hydrocarbons. Secondary recovery methods have thus been devised to enhance well performance. As recommendation, additional wells are required to appraise the E-M structure and determine to what extent the cement present in the basin has affected fluid flow as well as the degree of sedimentation that could impede fluid flow. There are areas still containing untapped resources thus the recommendation for extra wells. This research may well be reviewed with more data input from PetroSA (wells, seismic and production data) for additional studies, predominantly with respect to reservoir modelling and flow simulation. Based on the findings of this research, summary of calculated Net Pay shows that in well E-BB1, reservoir (1) is at depth 2841.5m – 2874.9m has a Gross Thickness of 33.40m, Net Pay of 29.72 and Pay Summary of 29.57 and reservoir (2) has depth of 2888.1m – 2910.5m, Gross Thickness of 22.40m, Net Pay of 19.92m and Pay summary of 1.48m. Well E-AO1 has depth from 2669.5m – 2684.5m and Gross Thickness of 15.00m and has Net Pay of 10.37m and Pay Summary of 10.37m. Based on the values obtained from the data analysed the above two wells displays high potential of hydrocarbon present in the reservoirs. Meanwhile well E-BD2 has depth from 2576.2m – 2602.5m and has Gross Thickness of 350.00m, Net Pay of 28.96m and Pay Summary of 4.57 hence from data analysis this reservoir displays poor values which is an indication of poor hydrocarbon potentials.

This thesis deals with genesis of the Cretaceous thermal waters in the Ústí nad Labem. These thermal waters are interesting in that are very different from other Cretaceous thermal waters, which also appear in Benešov-Ústí aquifer system of the Bohemian Cretaceous Basin in Děčín. Thermal waters in the Ústí nad Labem area more than chalk waters resemble the thermal waters in Teplice, which are associated with body of Teplice rhyolite. Many authors studied thermal waters in the Ústí nad Labem, but isotope analysis and inverse geochemical modeling were not used for their study. Results based on water chemistry, water D and 18 O, 87 Sr/86 Sr ratios, and dissolved sulfate 34 S and 18 O values, indicate mixing of ground water from aquifers of the Bohemian Cretaceous Basin with ground water derived from crystalline rocks of the Erzgebirge Mts. Unlike thermal waters in Děčín are Ca-HCO3 type (160 mg/L), in Ústí nad Labem there are two types of thermal waters, Na-HCO3 type with higher TDS values (over 1 g/L) and Na-(Ca)-HCO3-SO4 type with lower TDS values (approximately 600 mg/L). Carbon isotope data and speciation and inverse geochemical modeling suggest a significant input of endogenous CO2 at Ústí nad Labem. Besides CO2 input, both silicate dissolution and cation exchange coupled with dissolution of...

This diploma thesis is focused on morphological studies and taxonomic analyses of small regular and irregular echinoids found at the Nebužely locality; at this locality clastic sediments of Teplice Formation of Bohemian Cretaceous Basin are exposed. Presence of the belemnite Praeaxtinocamax bohemicus makes possible to assign the outcrop to late Turonian. Detailed morphological study of more than one hundred specimens enabled to distinguish four echinoids species (Echinogalerus, Glyphocyphus, Nucleolites, Phymosoma), less favourably preserved and/or very limited material is classified as belonging to two orders (Cidaroida, Holectypoida) and one family (Phymosomatidae), respectively. The next part of the thesis contains a possible palaeoecological reconstruction of the environment at the studied locality. Based on bathymetrically indicative molluscs, a shallow−water palaeoenvironment is suspected for this locality. Key words: echinoid, Bohemian Cretaceous Basin, Turonian

Title: Sytematics, palaeoecology and trophical structure of bivalve associations within the OAE2 in the Bohemian Cretaceous Basin (Upper Cenomanian): Pecínov quarry Author: Bc. Lucie Kunstmüllerová Department: Institute of geology and palaeontology Supervisor: doc. RNDr. Martin Košťák, Ph.D. Abstract: This master thesis provides an updated taxonomic inventory of the bivalve fauna of the Pecínov locality, places the fauna in its palaeobiogeographic setting, and addresses its palaeoecological significance. In the literature research part of the thesis the basic geology of the locality and an overview of the Bohemian Cretaceous Basin are presented. Processes connected to the ocean anoxic events, specifically to the OAE 2 are also discussed. The research part of the thesis describes the systematics of the bivalve assemblage (with the exception of Inoceramidae) and its statistical evaluation with the emphasis on the environment interpretations of the locality. In total, over 350 specimens have been considered and assigned to 20 genera within 15 families and 9 orders. Bivalve functional morphology and guilds are described to interpret palaeoecology. Guilds are based on life habit and feeding category. Four main guilds are recognized: epifaunal suspension-feeders, semi-infaunal suspension-feeders, infaunal...

The present study of the Abu Roash and Bahariya formations in well GPTSW-7 refines our understanding of the subsurface Cretaceous of the north Western Desert of Egypt. Our investigations are based on the palynological analyses of 71 cuttings samples, of which 24 have also been analyzed for geochemistry, in addition to 3 sidewall cores analyzed for vitrinite reflectance (Ro). Four palynological zones and three subzones in addition to a poorly fossiliferous interval ranging in age from Coniacian-Santonian to early Cenomanian are proposed. These include a poorly fossiliferous interval (Coniacian-Santonian), Dinogymnium vozzhennikovae Interval Zone (late to middle Turonian), Ephedripites ambiguus-Ephedripites multicostatus-Foveotricolpites giganteus-Foveotricolpites gigantoreticultus Assemblage Zone (early Turonian), Classopollis brasiliensis Interval Zone (late to middle Cenomanian), and Afropollis jardinus Interval Zone (early Cenomanian). The succeeding subzones are; Afropollis kahramanensis Interval Subzone, Elaterosporites klaszii Interval Subzone and Cretacaeiporites densimurus Interval Subzone, all of early Cenomanian age. Total organic carbon (TOC) and Rock-Eval pyrolysis and palynofacies analyses indicate that the Bahariya Formation and the Abu Roash G Member are primarily of kerogen III type and hence gas prone, suggesting a strong influence of hydrogen-enriched organic matter. The Abu Roash A, C-E Members may also be gas prone (type III kerogen) and appear to contain highly oxidized terrestrial organic matter. In contrast, the Abu Roash F Member has very high TOC and HI values and contains a very high proportion of amorphous organic matter (AOM) indicating a highly oil-prone facies. While this finding is not unexpected for anoxic black shale, it contrasts with earlier studies that suggest a gas prone nature. Ro measurements show that the Bahariya Formation represents an immature-early genesis dry gas phase. This is also true for all investigated samples from the Abu Roash and Bahariya formations, based on their low thermal alteration index (TAI). Quantitative and qualitative analyses of both the palynoflora and palynofacies show that the Abu Roash A and C Members (B is missing), both of Coniacian-Santonian age, represent oxic proximal and distal shelf environment. The Abu Roash D and E Members, dated as Turonian, represent oxic (proximal) shelf, whereas the Cenomanian Abu Roash F Member was deposited in a distal suboxic-anoxic basin. The Cenomanian Abu Roash G Member and the Bahariya Formation were deposited in a shallow marine and shallow marine to fluvio-deltaic setting, respectively. The Senonian Palmae Province is recognized in the palynoflora by the presence of Proteacidites, Auriculiidites reticulatus, Ariadnaesporites, Gabonisporis vigourouxii. On the other hand the Albian-Cenomanian Elaterates Province is characterized by the presence of Steevesipollenites, Gnetaceaepollenites, Elaterocolpites, Elaterosporites, Elateroplicites, Senegalosporites, Sofrepites, Afropollis and Cretacaeiporites.

>Magister Scientiae - MSc / Durban Basin located on the eastern coast of South Africa has been a focus of interest for Petroleum Exploration for the last few decades. Only four exploratory wells have been drilled in this offshore basin without success. During the initial stage of its creation, the basin suffered major tectonic disturbance as evident from the presence extensional faults followed by intense igneous activities. This was followed by marine sedimentation in the late Mesozoic (late Jurassic-early Cretaceous). An attempt has been made in this work to understand the distribution of the rock in space and time for the early Cretaceous sediments considered most prospective for hydrocarbon exploration in Southern Africa. Temporal distribution of planktonic foraminifera helps in identification of the three early Cretaceous (Barremian to Albian) stages within the drilled intervals. Foraminiferal biostratigraphic studies integrated with sedimentology, log motif analysis and seismic data analysis helps to predict paleodepth and depositional environment during early Cretaceous in this research. / 2022-04-30

No description available.

Evidence of the Cretaceous-Paleogene (K-Pg) extinction can be seen across the Mississippi Embayment, however research examining the K-Pg boundary in the state of Mississippi is lacking. The objective of this study addresses how macrofauna changed across the K-Pg boundary in Oktibbeha County, Mississippi and subsequent comparison to other Early Paleogene and Late Cretaceous benthic marine macrofaunal localities. Comparison included previously collected material as well as specimens collected during this study in order to reconstruct the biological community living on the seafloor in the earliest Paleocene Mississippi Embayment. The primary fauna present after the K-Pg extinction was mainly composed of small suspension and deposit feeding oysters and clams as well as carnivorous gastropods. New Paleocene fauna and survivor species exhibited drastically smaller body sizes than organisms in the Cretaceous; postulated to be due to a relative decrease in primary producers and environmental nutrients.

No description available.

<p> The Lower Cretaceous (Albian) Viking Formation at Harmattan East and Crossfield, Alberta, contains two regionally extensive erosion surfaces, VE3 and VE4, separating three allomembers, A-B, D and E. These erosion surfaces can be mapped over large areas of the Alberta basin allowing for the creation of a Viking allostratigraphy. </p> <p> The allostratigraphic base of the Viking alloformation in the study area is informally designated BV. The BV log marker is overlain by allomember A-B, which in turn is overlain by the regionally extensive ravinement surface VE3. The VE3 surface is sharply overlain by allomember D, a northeastward thinning clastic wedge composed of storm dominated facies and nonmarine deposits. Allomember D is in turn overlain by the regionally extensive ravinement surface VE4. Allomember E, which overlies this unconformity is a complex succession of coarse grained facies interbedded with dark mudstones. The upper . part of allomember E is composed of dark mudstones bounded at the top by a regionally extensive condensed section (Base of Fish Scales) that informally marks the allostratigraphic top of the Viking alloformation in the study area. </p> <p> Viking sedimentation began with the deposition of basinal and offshore transitional mudstones, siltstones and sandstones of allomember A-B. A major drop in sea level allowed valleys to incise into these sediments. Nonmarine and upper shoreface deposits of allomember A-B were eroded at Harmattan East during the ensuing transgression that produced the VE3 ravinement surface. A second relative sea level lowering resulted in northeastward progradation of allomember D. Renewed transgression modified the older subaerial erosion surface on top of allomember D, forming the marine ravinement surface VE4 and the overlying deposits of allomember E. Multiple stillstands or slow rates of transgression produced the "steplike" southwestward climbing morphology on the VE4 surface. Fluvial systems supplied coarse sediment to each shoreface incision ("step"). During minor sea level falls, storm and tidal currents reworked sediment at these shorefaces and also transported sediment basinward over older "stepped" shorelines forming onlap markers EO to E5. Continued transgression blanketed the coarse grained interbeds with offshore dark mudstones (Colorado Shale). A major pause in basin deposition led to the formation of a condensed section of fish skeletal remains (Base of Fish Scales). The base of this unit marks the end of Viking depostion in the study area. </p> <p> The Harmattan East Viking oil field is producing from the coarse grained transgressive lag that overlies VE4. It is separated from Caroline field (along depositional strike) by a rise in the VE4 surface. </p> / Thesis / Master of Science (MSc)