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Three charts in pocket.

ABSTRACT The availability of useful information for research strongly depends on well structured relationships between consistently defined concepts (terms) in that domain. This can be achieved through ontologies. Ontologies are models of the knowledge of specific domain such as petroleum geology, in a computer understandable format. Knowledge is a collection of facts. Facts are represented by RDF triples (subject-predicate-object). A domain ontology is therefore a collection of many RDF triples, which represent facts of that domain. The SWEET ontologies are upper or top-level ontologies (foundation ontologies) consisting of thousands of very general concepts. These concepts are obtained from of Earth System science and include other related concepts. The work in this thesis deals with scientific knowledge representation in which the SWEET ontologies are extended to include wider, more specific and specialized concepts used in Petroleum Geology. Thus Petroleum Geology knowledge modeling is presented in this thesis.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references.

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No description available.

Meren field, located offshore Niger Delta, is one of the most prolific oil-producing fields in the Niger Delta. The upper Miocene D-07, D-08 and E-01 oil sands comprise a series of stacked hydrocarbon reservoirs in Block 2 of Meren field. These reservoir sandstones were deposited in offshore to upper shoreface environments. Seven depositional facies were identified in the studied interval, each with distinct lithology, sedimentary structures, trace fossils, and wire-line log character. The dominant lithofacies are (1) locally calcite-cemented highly-bioturbated, fine-grained sandstones, (middle to lower shoreface facies); (2) cross-bedded, fine- to medium-grained well-sorted sandstones (upper shoreface facies); (3) horizontal to sub-horizontal laminated, very-fine- to fine-grained sandstone (delta front facies); (4) massive very-fine- to fine-grained poorly-sorted sandstone (delta front facies); (5) muddy silt- to fine-grained wavy-bedded sandstone (lower shoreface facies); (6) very-fine- to fine-grained sandy mudstone (lower shoreface facies); and (7) massive, silty shales (offshore marine facies). Lithofacies have distinct mean petrophysical properties, although there is overlap in the range of values. The highest quality reservoir deposits are cross-bedded sands that were deposited in high-energy upper shoreface environments. Calcite cements in lower shoreface facies significantly reduce porosity and permeability. Integration of core and wire-line log data allowed porosity and permeability to be empirically determined from bulk density. The derived equation indicated that bulk density values could predict 80% of the variance in core porosity and permeability values. Three parasequence sets were interpreted, including one lower progradational and two upper retrogradational parasequence sets. The progradational parasequence set consists of upward-coarsening delta front to upper shoreface facies, whereas the upward-fining retrogradational parasequence sets are composed of middle to lower shoreface deposits overlain by offshore marine shales. The limited amount of core data and the relatively small area of investigation place serious constraints on stratigraphic interpretations. Two possible sequence stratigraphic interpretations are presented. The first interpretation suggests the deposits comprise a highstand systems tract overlain by a transgressive systems tract. A lowstand systems tract is restricted to an incised valley fill at the southeastern end of the study area. The alternate interpretation suggests the deposits comprise a falling stage systems tract overlain by transgressive systems tract.

The purpose of this investigation is to determine the effectiveness of projective well log analysis based upon data collected from Plummer Field located in Greene County, Indiana. Projective well log analysis consists of analyzing spontaneous potential (SP) logs from existing oil and gas wells in order to determine SP gradients that may be applied to locate other undiscovered hydrocarbon accumulations. Projective well log analysis was developed in 1963 by S.J. Pirson, however, the specific parameters employed in the Plummer Field investigation were developed in 1988 by Dr. R.H. Fluegeman in order to apply to the geologic conditions in southwestern Indiana.The results of this investigation indicate that SP gradients can be interpreted to determine hydrocarbon production potential in Plummer Field with a 62% to 73% certainty. Given the petroleum industry exploration success rate of 3% to 20%, it is believed that the SP gradients established in Plummer Field can be used to identify economical hydrocarbon accumulations in areas of similar geology such as other portions of the Illinois Basin and the Michigan Basin. / Department of Geology

The Karikari Plutonics are Early Miocene in age and consist of two plutonic bodies, with age relations delineated by cross- cutting relationships, and associated later stage dykes. The older pluton is a complex body exhibiting textural variability, cumulate-style crystallisation, varied enclaves (indicating complex magma chamber processes including convection and crystallisation along steeply-dipping northwest oriented fronts) and a multi-phase structural and dyke intrusion history. Modal analysis shows this body to be diorite to quartz monzodiorite, and geochemically calc-alkaline and medium-K in nature. In contrast the younger pluton is extremely homogeneous and intruded by a single, volumetrically sparse, dyke phase. Modally quartz monzonite to granite (adamellite), and high-K calc- alkaline, this body has higher Si, K-group + Na, REE group and HFSE group elements than the older pluton. Mineral differences are confined to An contents in plagioclase, En values in orthopyroxenes and a wider range of Al in younger pluton hornblendes. Igneous differentiation can be modelled within the older pluton and between the older and younger bodies, by fractional crystallisation dominated by plagioclase, with subordinate ortho- and clino- pyroxene and oxide phases. The dykes show a compositional range from basaltic andesite to dacite, with andesite volumetrically dominant. A temporal trend can be seen with younger dykes becoming more felsic and of greater volume, and changing orientation from northeast to northwest. Two subdivisions can be made based on the presence or absence of hornblende. Pyroxene only dykes are mostly medium-K and dominantly andesitic, whereas hornblende-bearing lithologies are both medium-K and high-K, are andesite and dacite, and appear to be more evolved chemically. The rock envelope into which the Karikari Plutonics was intruded consists of Cretaceousage basalts, rhyolites and sedimentary lithologies. Although a regular contact aureole is not exposed, the lowest grade of contact metamorphism is delineated by the first occurrence of biotite. Rocks equivalent to the hornblende hornfels facies are widespread and rare pyroxene hornfels are found adjacent to contacts. Alteration and veining, particularly prevalent in fault/shear zones, and the presence of a magmatic-hydrothermal type breccia are evidence for a hydrothermal system associated with the waning stages of Lower Miocene-age igneous activity on the Karikari Peninsula. Fluid inclusion and stable isotope data indicates the presence of fluids of both magmatic and meteoric origin. The Karikari Plutonics are correlated with the arc-type regional association of Northland and the Coromandel Peninsula. The source of these rocks is broadly M-type, hydrous and involving subduction zone, and modified mantle wedge components, but with some unspecified crustal involvement indicated by Sr isotopes. Specifically this source is modelled, for the Karikari Plutonics, as having LREE enriched 2x relative to HREE and partially melting (< 15% of the source) at the base of the crust (≥30 km). These melts gave rise to the arc-type association either erupting at the surface, or ponding in upper crustal (≤10 km) magma chambers.