Michael Ndubuisi Oti

University of Port Harcourt · Department of Geology

This study was carried out to determine the rock mechanical properties relevant for hydrocarbon exploration and production by hydraulic fracturing of organic rich shale formations in Anambra basin. Shale samples and wireline logs were analysed to determine the petrophysical, elastic, strength and in-situ properties necessary for the design of a hyd...

The Niger Delta is one of the most prolific hydrocarbon provinces in the world, but information on basinal hydrogeology is scanty. Oilfield brines from nine producer wells in the Miocene reservoirs (2,472.25–3,532.48 m.b.s.l.), offshore Niger Delta, have been investigated along with two seawater samples to understand their hydrogeochemical characte...

Biogenic sulfide production in oilfield systems occurs due to the metabolic activities of sulfate-reducing prokaryotes. These activities of prokaryotes (bacteria and archaea) in production facilities in oilfields leads to unexpected increase in hydrogen sulfide (H2S) concentrations over time in produced fluids from petroleum reservoirs. This widesp...

Understanding the formation and distribution of reservoirs and seals is critical for continued field development and reservoir management. Compartmentalization of subsurface fluid can be predicted with good understanding of the sealing capacities and distribution of flow barriers. Therefore, sequence stratigraphic analysis and correlations of well...

This paper presents the study of the heterogeneity in lithofacies, porosity, permeability, mineral grain density, pore-throats sizes and hydraulic rock types and the intra sand-body compartmentalization in cored delta-front deposit of Greater Ughelli depobelt of Niger Delta. Sedimentological study of core samples results in the identification of ni...

Sedimentological and ichnological study of cored reservoir sands correlated with wireline logs between two wells, 0.8 km distance apart along dip direction, enabled vertical and cross sectional facies variability assessment aimed at determining intra sand-body continuity in longitudinal or down-dip direction; and sub-environments of deposition and...

A comparative study of seven wells from seven fields in both the Central Swamp and Coastal Swamp depobelts of the Niger Delta have been investigated for the variation in the abundance and diversity of ichnofossils, with the aim of assessing the intensity of bioturbation and their corresponding impact on reservoir quality. The work focused on the in...

Lateritisation and Origin of Ironstones & Bauxites embodies the results of in-depth studies of intense tropical weathering and their products. Five research papers are presented in five chapters. They span a broad range of studies which treat the very early or incipient stages of water/rock interaction; to mechanisms of breakdown of various princip...

Polydeformation has resulted in multidirectional orientations of planar and linear structures in basement rocks of southern Obudu plateau. Foliation with steep dips (60°-90°) in the N-S to NE-SW (0°-30°) direct on is the dominant structure, whereas subordinate orientations with low to moderate dips (20°-50°) are in the NW-SE, E-W and ENE-WSW direct...

Deltas are major depositional centres where processes and products often lead to the accumulation of organic matter-rich, thick clastic sedimentary wedges. Consequently, many ancient deltas contain large accumulations of oil and gas, coals and other economic deposits. Modern deltas, often forming large wetland areas with delicately balanced ecosyst...

This paper, largely a review of published and unpublished data, takes a cursory look at the geological framework and basinal characteristics of the distal delta, parameters which are essentially controlled by the lithological and structural attributes of the mobile overpressured marine Akata Shale Sequence. Dilution of terrestrial organic input, co...

Field and petrographic investigations of parts of the Oban Massif, which itself constitutes part of the southeastern margin of the mobile zone separating West Africa Shield, reveals that the metamorphic rocks which consist a thick succession of metapelites, semipelites and metabasic rocks have undergone progressive Dalradian type metamorphism recor...

This study focuses on the microfacies and diagenetic development of the mid-Cretaceous Mfamosing Limestone, a carbonate body which was deposited during marine incursions into the Calabar Flank in the eastern Niger delta hinge zone of the Lower Benue Trough. Microfacies and diagenetic criteria indicate that the carbonates are products of one Albian...

As is the case with their polycrystalline counterparts, the diagenetic stabilization of monocrystalline rock-forming carbonate skeletons which consist of the metastable calcium carbonate phase, Mg-calcite, is controlled by the process of dissolution and reprecipitation.In this study, the meteoric diagenesis of echinoderm skeletal parts — single cry...

Laterites of southeastern Nigeria developed on rocks of the crystalline Basement Complex and on sedimentary rocks of the lower Benue Trough were studied in order to characterize them geochemically and texturally. In the sedimentary basin, rocks of each major stratigraphic formation were analyzed.It is found that the laterites are mature with ratios...

Diagenetic transformation of Lithothamnion Mg-calcite to calcite is controlled by a dissolution-precipitation process and not by incongruent dissolution as hitherto believed. The process is structure-preserving at the micro-scale but not at the ultra-scale: the primary Mg-calcite prisms or rods which constitute the cell walls are replaced by equant...

In lateritic weathering systems, interstitial solutions laden with dissolved iron oxides dissolve quartz, during which time microcavities and microtunneis are created at points of crystal imperfections and dislocations. Goethite is then first precipitated in these pores as the initial phase in the form of globules and or/acicular needles with ortho...

Phacotus and Coccomonas, two carbonate-secreting, non-marine, planktonic chlorophyte genera, are important sediment contributors mainly in hard water lakes. The calcite loricae of these flagellate algae exhibit characteristic features easily recognizable under the microscope, making Phacotus and Coccomonas important facies fossils for the recogniti...

The results of scanning electron microscope studies on recent ooids from different environments are examined, and it is revealed that their microstructures are closely related to petrophysical parameters. Crystal size is the main factor that influences specific surface area and the pore size of intercrystalline pores, whereas crystal orientation pr...

Oolitic limestones and dolostones are among the most prominent reservoir rocks for oil and gas as well as for various other economic minerals occurring in sedimentary rocks. This paper is an attempt to relate the microstructure of ooids as revealed by stereoscan methods to certain petrophysical parameters: specific surface area, microporosity and p...