Thesis (PhD (Geology))--University of Stellenbosch, 1997. / 1123 leaves printed on single pages, preliminary pages and numbered pages 1-286. Includes bibliography, list of figures and tables and explanation of abbreviations used. / Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner. / ENGLISH ABSTRACT: This first comprehensive study of the petroleum geochemistry of the Bredasdorp Basin, and the adjacent Southern Outeniqua Basin, documents the characteristic large number of hydrocarbon shows and the four regionally distinctive marine source rocks. Detailed correlation of reservoired hydrocarbons with source rock bitumens shows that two source rocks have expelled oil in commercial quantities and two others have expelled commercial quantities of wet gas/condensate. In contrast with earlier studies which indicated that thermal 'gradualism' prevailed, this study indicates that the post-rift thermal history of the basin is very complex. Post-rift cool-down is punctuated by periods of rapidly increasing heat flow resulting in much of the maturation being localised in time. These periods of increased heating coincide with regional plate tectonism. The associated thermal uplift and downwarp effects govern the periods of trap formation and control the hydrocarbon migration direction. Migration distances of these hydrocarbons are described and show inter alia that oil migrates no more than -7-10 km but gas migrates regionally. Two regional episodes of meteoric water flushing reduce sandstone cementation in palaeo-highs forming potential reservoirs at specific times. The unusually low salinity of remnants of this water in some sandstones help characterise these two main migration conduits. A highly detailed hydrocarbon correlation scheme derived from gas, light oil and biomarker data has been established which differentiates products of the four active source rocks and helps characterise the oil-oil, oil-source and source-source pairs. It is evident from these correlations that two periods of migration and reservoiring occurred at 50-60 Ma and 0-10 Ma. As a result, source-reservoir plays which characterise certain areas of the basin as predominantly oil or gas prone can be described. These correlations also highlight areas where mixtures of hydrocarbons are common and where some of the early reservoired oil has been displaced to new locations, constituting potential new exploration plays. Source rocks for some of the analysed hydrocarbons have yet to be found and may not even have been drilled to date. One such source rock appears to be located in the Southern Outeniqua Basin, making that area a potential target for further exploration. This study resolved the common heritage of the source rocks and reservoir sandstones which form part of the Outeniqua petroleum system. The hydrocarbon volumes available to this system show that by world standards it is indeed significant. / AFRIKAANSE OPSOMMING: Die groot aantal koolwaterstof voorkomste asook vier streekskenmerkende mariene brongesteentes word in hierdie eerste omvattende studie van die petroleumgeochemie van die Bredasdorp-kom en die aangrensende Suidelike Outeniqua-kom saamgevat. Gedetaileerde korrelasies van die opgegaarde koolwaterstowwe met brongesteente bitumen, dui daarop dat twee van die vier geidentifiseerde brongesteentes olie in kommersiele hoeveelhede uitgeset het. Die ander twee het kommersiele hoeveelhede nat gas-kondensaat uitgeset. In teenstelling met vroeer studies wat daarop gedui het dat termale 'gradualisme' voorgekom het, dui hierdie studie daarop dat die na-riftermale geskiedenis van die kom baie meer kompleks is. Verskeie periodes van versnelde toename in hittevloei het voorgekom in die na-rifse verkoeling. Dit het daartoe gelei dat veroudering plaaslik binne 'n beperkte tydsverloop plaasvind. Hierdie periodes van hittetoename stem ooreen met die regionale plaattektoniek. Die geassosieerde termiese opheffing en afwaartse vervormingseffek, beheer die totstandkoming van opvanggebiede en die migrasierigting van die koolwaterstowwe. Migrasie-afstande van die koolwaterstowwe word bespreek en wys inter alia daarop dat olie nie verder as -7-10 km beweeg nie, maar gasmigrasie vind regionaal plaas. Twee kort episodes van meteoriese wateruitsetting, het sandsteensementasie in palaeohoogsliggende gebiede verminder wat potensiele reservoirs gevorm het op spesifieke tye. Die ongewone lae soutvlakte van oorblyfsels van die water in sekere sandstene help om die twee vernaamste migrasieroetes te kenmerk. 'n Hoogs omvattende koolwaterstof-korrelasieskema wat van gas, ligte olie en biomerkerdata verkry is, is opgestel. Die skema het onderskei tussen produkte van die vier aktiewe brongesteentes en help om die olie-olie, olie-bron en bron-bron pare te karakteriseer. Dit is duidelik van die korrelasies dat twee periodes van migrasie en opgaring plaasgevind het ongeveer teen -50-60 Ma en 0-10 Ma. Gevolglik kan bronreservoir omskrywings wat sekere dele van die kom karakteriseer as grotendeels olie of gas-ontvanklik beskryf word. Hierdie korrelasies beklemtoon ook areas waar mengsels van koolwaterstowwe algemeen voorkom en waar sekere van die vroeer opgegaarde olie verplaas is na nuwe lokaliteite, wat nuwe eksplorasieteikens daarstel. Brongesteentes vir sekere van die ge-analiseerde koolwaterstowwe, moet nog gevind word en is tot op hede nog nie raakgeboor nie. Een so 'n brongesteente kom voor in die Suidelike Outeniqua-kom, wat daardie area 'n potenslele teiken vir verdere eksplorasie maak. Die studie het die gesamentlike oorsprong van die brongesteente en reservoirsandsteen, wat deel is van die Outeniqua Petroleumsisteem, geidentifseer. Die koolwaterstofvolumes wat beskikbaar is vir die sisteem wys dat, gemeet teen wêreldstandaarde, dit wel beduidend is.

Master of Science / Department of Geology / Sambhudas Chaudhuri / The exploration and development of unconventional shale plays provide an opportunity to study the hydrocarbon generation process. These unconventional plays allow one to investigate the interactions between the fluid, mineral, and organic material that occur in a hydrocarbon-generating source bed, before any changes in composition that may occur during secondary migration or post migration processes. Previous studies have determined the chemical constituents of formation waters collected from conventional reservoirs after secondary migration has occurred. This investigation targets formation waters collected from the Woodford shale that acts as both source and reservoir, therefore samples have yet to experience any changes in composition that occur during secondary migration. This investigation focuses on the major element and trace element chemistry of the formation water (Cl, Br, Na, K, Rb, Mg, Ca, Sr, and Rare Earth Elements), which has been compared to chemical constituents of the associated crude oil and kerogens. Analytical data for this investigation were determined by the following methods; Ion Chromatography, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The information is used to assess the presence of different sources of water that constitute the formation water, and also to investigate interaction between different minerals and formation waters within the source beds. The formation water data also yields new insights into compartmentalization of oil-gas rich zones within the source beds.

Call number: LD2668 .T4 1956 K66 / Master of Science

The presence of gas and oil in some sand formations decreases the seismic velocity and density to such an extent that anomalously large reflections coefficients are encountered at fluid contacts. Geerstma and Gassmann's theories are equivalent and provide a good way to study the physical properties that affect the elastic behavior of the porous rock. The fluid-contact reflectivity (gas-water, oil-water) can be well estimated based on the brine saturated velocity alone. A comparison between the estimated and observed fluid-contact reflectivities on seismic and well log data from an Offshore prospect showed a remarkable agreement. / text

No description available.

Master of Science / Department of Geology / Matthew Totten / There are some who hold the view that liquid hydrocarbons in the upper Paleozoic formations in Kansas are being locally derived. It has been the long held belief that the liquid hydrocarbons found in Kansas have come from distant sources in Oklahoma. To shed further light on this issue about the origin of hydrocarbons in the upper Paleozoic formations in Kansas, a study was conducted to analyze the geochemical characteristics of REE in Lansing-Kansas City oils that were collected from several locations in a small area within Rooks County, Kansas. The total REE contents in these oils ranges from about 3.1 ng (or 10-12 gram) per Liter of oil to about 131 ng per Liter of oil. The pattern of relative distribution of the REEs for each oil sample has been constructed from values that were obtained by dividing the individual REE concentrations of a given oil sample by the respective concentrations of the REEs in a standard or a reference sample (such as PAAS, a representation of average argillaceous sediments in the crust that is commonly used for the analyses of a variety of crust originated sedimentary products). A standard- normalized relative distribution pattern of an oil sample can reveal an important history of chemical evolution of the oil of interest. The PAAS-normalized patterns of relative distribution of the REEs in the Lansing-Kansas City oils from Rooks County, Kansas are significantly diverse. Although nearly all oil samples investigated in this study have varied degrees of light REE-enrichment across the REE series from La to Sm, they differed in their relative Ce abundances. Some samples have positive Ce anomalies; some have negative Ce anomalies, and some others with the absence of any Ce anomaly. The oils also differed in their PAAS-normalized relative distribution of the middle rare earth elements (MREEs), ranging from Sm to Tb. All oil samples were relatively enriched in the MREEs, but with varied degrees of enrichment from a prominent one to almost a barely noticeable one. The oils differed in their relative distributions of Eu, as some were with a positive Eu anomaly, some with a negative Eu anomaly, and some with the absence of any Eu anomaly. The trends of the heavy rare earth elements (HREEs) from Tb to Lu among the oils ranged from nearly flat for the most oils to a progressive depletion across the series for few samples. Furthermore, the oils were varied in having prominently anomalous relative distributions, in some cases with a positive anomaly and in others with negative anomaly, for such elements as Tb, Ho, and Tm (MM-JS-04, MM-MC-3A, and MM-MC-01). The anomalies for Tb, Ho, Tm are reflections of enzyme activity of source material during its primary (growth) environment. The metals are known to be preferentially located at the active sites of the enzymes. The oils not only differed significantly in their REE-geochemical characteristics, they also had a wide range of K/Rb weight ratios from about 877 to about 2000. These high values are typically the ones that can be assigned to organic materials, well exceeding the range of values that are associated with common silicate minerals and rocks, having an average value of 250-350ppm. Different zones in the Lansing-Kansas City formations also show distinct REE distribution patterns. There are four broadly classified distribution patterns. MREE enrichment can be observed in samples with production from the middle Lansing-Kansas City zones (G-I). In samples with comingling Lansing-Kansas City zones, amplification of anomalies from differing source materials can be observed. The diversity in the REE distribution patterns and K/Rb ratios in oils collected from central Kansas makes a strong argument against long distance transportation from a distant source in Oklahoma

A contribuição deste trabalho é um framework conceitual para a inserção de dados diretos de rocha em modelos de grid de reservatório, através da calibragem de logs de poço. Este tipo de dado é frequentemente ignorado ou processado manualmente nas modelagens atuais, seja por custos elevados para sua obtenção, seja pelo alto grau de complexidade para a modelagem, interpretação e extrapolação dos dados. O framework busca definir os requisitos para um projeto de software que inclua os componentes necessários para o processamento automático ou supervisionado dos dados de rocha desde sua geração até sua utilização final, em modelos de simulação de fluxo, suportando a interoperabilidade dos dados e o rastreamento da informação de rochas. A proposta é embasada na combinação de ontologias de domínio para a petrografia, o conceito geológico de petrofácies de reservatório, um algoritmo de reconhecimento de padrões em logs de poço que podem corresponder a camadas homogêneas na rocha e um algoritmo para extrapolação de padrões baseado em algoritmos de alinhamento de sequências de DNA. A combinação das abordagens utilizadas neste trabalho é inédita e fornece suporte para o uso de petrofácies de reservatório durante a modelagem de reservatório. O levantamento de informações foi realizado em forma de aquisição de conhecimento, através de entrevistas com cinco profissionais de Geologia, Geofísica e Geoquímica, com diferentes formações na indústria do petróleo, além de extensa revisão da literatura. Esta aquisição nos possibilitou mapear as grandes atividades durante o processo de exploração, bem como os dados resultantes de cada etapa. Um modelo conceitual ontologicamente bem fundamentado permite mapear e integrar os dados de rocha nas diferentes etapas de processamento desde sua aquisição, como descrições de amostras de poços, descrições microscópicas e logs geofísicos até a identificação e inserção das propriedades relevantes em grids 3D utilizando padrões de trocas de dados da indústria. / A Conceptual Framework to insert direct rock data into reservoir models trough well logs calibration is the contribution of this work. This kind of data is often ignored or manually processed in the current modeling process, due to its high costs or due to the complexity for the modeling, interpretation and extrapolation of the data. The framework aims to define a software project requirements that includes the necessary components for automated or supervised process of the rock data from its generation until its final use in the flow simulation models, supporting the interoperability of the data and the tracking of the rock information. The proposal is based in the combination of domain ontology for petrography, the geological concept of reservoir petrofacies, a pattern recognition algorithm on well logs that can correspond to homogeneous rock layers and an algorithm to extrapolate patterns based on algorithms for the alignment of DNA sequences. The combination of the approaches used in this work is novel and provides support for the use of reservoir petrofacies during reservoir modeling. Five different professionals from the Geology, Geophysics and Geochemistry fields, with different backgrounds in the oil industry, were interviewed in order to acquire the necessary knowledge, and an extensive review of the literature. This acquisition enabled us to map the major activities during the process of exploration, as well as the data resulting from each step. A ontological well-grounded conceptual model allows mapping and integrating rock data in the different processing steps from its acquisition, such as descriptions of sample wells, microscopic descriptions and geophysical logs, to the identification and insertion of the relevant properties on 3D grids using standards of industry data exchange.

Middle Pennsylvanian (Desmoinesian) strata of the Lower Desert Creek (LDC) sequence within the sub-surface Greater Aneth Field (GAF) reflect a hierarchy of 4th and 5th order carbonate-dominated cycles. The Lower Desert Creek sequence, along the studied transect are composed of eight carbonate facies deposited on an east-facing shelf. There is a lateral transition from open marine algal buildup from the southeast (cores R-19, Q-16, O-16, and J-15) to a more restricted lagoonal environment to the northwest (core K-430 and E-313). The Lower Desert Creek sequence within the GAF contains three main parasequence sets: a basal, relatively deep-water unit (LDC 1), a middle skeletal to algal unit (LDC 2-4), and a shallow, open-marine/restricted lagoon unit (LDC 5-7). The southeast cores (R-19, Q-16, O-16, and J-15) contain the dolomitized basal unit in parasequence LDC 1. The northwest cores (K-430 and E-313) also contain the dolomitized basal unit in LDC 1, but show a deeper facies succession through LDC 2-4. Parasequences LDC 2-4 are the heart of the algal buildup in the GAF particularly in the southern part of the transect. The upper few parasequences (LDC 5-7) are dominated by an open marine environment represented by robust fauna. The upper parasequences (LDC 5-7) show the same shallowing upward trends with algal facies in K-430 and restricted lagoon facies in E-313. Shoaling upward trends that characterize the Lower Desert Creek sequence terminate with an exposure surface at the 4th order (Lower Desert Creek-Upper Desert Creek) sequence boundary. Porosity and permeability is weakly correlated to facies. Diagenesis within the algal reservoir is the most important factor in porosity and permeability. Marine diagenesis is observed in the form of micritization of Ivanovia, a phylloid algae. Thin fibrous isopachous rims of cloudy cement also indicate early marine diagenesis. Ghost botryoidal cements are leached during meteoric diagenesis. Meteoric drusy dog tooth cements as well as sparry calcite fill most depositional porosity. Neomorphism of micrite and the isopachous rim cements reflect meteoric diagenesis. Burial diagenesis is represented by baroque dolomite cement, compaction, and mold-filling anhydrite cement.

Hydraulic connectivity for the Tiber field and 17 other Wilcox penetrations in Keathley Canyon (KC) and 5 fields in Walker Ridge (WR) protraction areas was assessed. All five chronostratigraphic Wilcox units are not in vertical communication across both protraction areas. Four of these units are in lateral communication across Tiber field except where faults isolate portions of the structure. Five “areas of connectivity,” where two or more fields are in communication, were found in KC. The fields in WR show no evidence of connectivity despite a relatively simpler structural environment than KC. I propose that the wells in WR are isolated due to a combination of diagenetic cementation and increased vertical effective stress acting to decrease permeability between structures. I also attempted to assess the possibility of hydrodynamic flow in the primary basin encompassing Tiber by geophysically identifying the field’s oil water contact and determining its orientation. This was unsuccessful.

We consider the structural and physical properties of complex model morphologies and microstructures obtained by Xray-CT imaging. The Minkowski functionals, a family of statistical measures based on the Euler-Poincar&eacute characteristic of n-dimensional space, are shown to be sensitive measures of the morphology of disordered structures. Analytic results for the Boolean model are given and used to devise a reconstruction scheme, which allows one to accurately reconstruct a complex Boolean structure given at any phase fraction for all other phase fractions. The percolation thresholds of either phase are obtained with good accuracy. From the reconstructions one can subsequently predict property curves for the material across all phase fractions from a single 3D image. We illustrate this for transport and mechanical properties of complex Boolean systems and for experimental sandstone samples. By extending the Minkowski functionals to parallel surfaces using operations from mathematical morphology, a powerful discrimination of structure is obtained. Further the sensitivity of the Minkowski functionals under experimental conditions is analysed. Accurate calculations of conductive and elastic properties directly from tomographic images are achieved by estimating and minimising several sources of numerical error. Simulations of electrical conductivity and linear elastic properties on microtomographic images of Fontainebleau sandstone are in excellent agreement with experimental measurements over a wide range of porosity. The results show the feasibility of combining digitised images with transport and elasticity calculations to accurately predict physical properties of individual material morphologies. We show that measurements of properties based on microtomographic images are more accurate than those based on conventional theories for disordered materials. We study the elastic behaviour of model clean and cemented sandstones. Results are in excellent agreement with available experimental data, and are compared to conventional theoretical and empirical laws. A new predictive empirical method is given for predicting the elastic moduli of sandstone morphologies. The method gives an excellent match to numerical and experimental data.