Seismic facies analysis constrained with well log information have been used to predict lithofacies distribution across the Okam Field of Niger Delta. Density and gamma ray logs were cross-plotted and the seismic section was subdivided vertically into different seismic facies. The delineated lithologies, from well logs were correlated with seismic facies signatures using lines of intersection across the wells. Gamma ray and resistivity logs were used to identify the interfaces between the lithofacies and correlated across the field. Structural interpretation was carried out. Time slices were generated and examined at different intervals within the identified reservoirs. Stratigraphic related attribute and envelope were extracted on these time slices. Three seismic facies type (facies A, B and C) were identified based on reflection amplitude, reflection patterns and continuity. Seismic facies A represents the undisturbed sediments in the Uppermost Benin Formation (parallel continuous, moderate to high reflections). Seismic facies B corresponds to the sand-shale pairs of the Agbada Formation which is diagnostic of moderate to high amplitude subparallel-parallel discontinuous reflections. The chaotic seismic facies signature (facies C) beneath this represents the overpressured mobile deformed Akata shales. The time slices show lateral variation in amplitude from high amplitude continuous reflections to low amplitude chaotic reflections from the southwest to northeast direction of the field. The extracted stratigraphic related attribute and envelope show lateral changes in amplitude from the northeast direction depicting increase in shaliness towards the northeast direction. The lateral variation in lithofacies across the field suggest varied and spatial changes in key reservoir parameters such as porosity and permeability that suggest changes in reservoir qualities across the field.
An integrated seismic sequence stratigraphy and facies analysis has been carried out with a view to understanding the depositional environment and stratal stacking pattern of Nandy Field of Niger Delta. Well logs and biostratigraphic information were used to identify the lithologies, stratal stacking patterns, stratigraphic surfaces, system tracts and reservoir potentials of the field. Seismic sequence stratigraphy and seismic reflection patterns were used to identify the seismic facies. Facies-related attributes were employed to identify the continuity and amplitude of seismic events. Three seismic facies packages and three reservoir sands were identified. The environments of deposition of the area consist of marginal marine to continen
... Show MoreWell log rock physics and seismic facies analysis was carried out with a view to enhancing reservoir sand characterization of Mafe Field of Niger Delta. Lithofacies were identified using suites of well logs and correlated across the block. Rock properties were estimated from wireline logs using empirical methods. Vp-porosity crossplot was used to characterize the delineated sandstone reservoirs by comparing observed clusters and trends with various rock physics models. Seismic attribute analysis was employed to detect lateral changes in lithology across the field. Reservoir A is a relatively clean sand, with low average volume of shale of 0.4, average thickness of 55m, good average porosity of 0.
... Show MoreThis study assessed the quality of hand-dug drinking water sources in Eku and its environs at Eku I, Samagidi, Eku 2, and Okuechi, using the weighted arithmetic water quality index method. Water samples collected from hand-dug wells at these locations returned values for analyzed parameters. Temperature 26 – 30(⁰C), dissolved Oxygen (D.O) 5.2-8mg/l, biological oxygen demand (BOD) 5.2-8(mg/l), Electrical Conductivity (EC) 77-119(µS/cm), Total suspended solids were (TSS) 20000-120000(mg/l), pH 5.31-7.09, Phosphates 2-9.2(mg/l), Alkalinity 28-160(mg/l), Turbidity, 0.02 -0.19(NTU) Total coliform 2 -48 (cfu/ml) and fungal count 1-502. Variations in the values of these parameters were only significant for phosphate, alkalinity, and turb
... Show MoreThis study was carried out to estimate the effect of shaliness on water saturation from TN field of Niger Delta. The conventional Archie and the Shaly-sand water saturation models was used in the evaluation of wells. Two sand bodies (Sand 01 and 02) were mapped with thicknesses range from 76.8ft to 119.3ft across the three wells for Sand 01 and 187.5 to 339.9ft across wells TN_1 and TN_4 for Sand 02. The cross plot of the effective porosity (φe) versus volume of shale (Vsh) show a decrease in the effective porosity with an increase in shale volume. This reveals a laminated shale pattern across the reservoir sands. The estimations from the conventional method and the Shaly-sand models of Simandoux and Indonesia show a clear disparity due
... Show MoreDisequilibrium compaction, sometimes referred to as under compaction, has been identified as a major mechanism of abnormal pore pressure buildup in sedimentary basins. This is attributed to the interplay between the rate at which sediments are deposited and the rate at which fluids associated with the sediments are expelled with respect to burial depth. The purpose of this research is to analyze the mechanisms associated with abnormal pore pressure regime in the sedimentary formation. The study area “Jay field†is an offshore Niger Delta susceptible to abnormal pore pressure regime in the Agbada –Akata formations of the basin. Well log analysis and cross plots were applied to determine the unde
... Show MoreEmpirical and statistical methodologies have been established to acquire accurate permeability identification and reservoir characterization, based on the rock type and reservoir performance. The identification of rock facies is usually done by either using core analysis to visually interpret lithofacies or indirectly based on well-log data. The use of well-log data for traditional facies prediction is characterized by uncertainties and can be time-consuming, particularly when working with large datasets. Thus, Machine Learning can be used to predict patterns more efficiently when applied to large data. Taking into account the electrofacies distribution, this work was conducted to predict permeability for the four wells, FH1, FH2, F
... Show MoreTime-domain spectral matching commonly used to define seismic inputs to dynamic analysis in terms of acceleration time history compatible with a specific target response spectrum is used in this study to investigate the second-order geometric effect of P-delta on the seismic response of base-isolated high-rise buildings. A synthetic time series is generated by adjusting reference time series that consist of available readings from a past earthquake of the 1940 El Centro earthquake adopted as an initial time series. The superstructure of a 20-story base isolated building is represented by a 3-D finite element model using ETABS software. The results of the base isolated building show that base isolation technique significantly reduces inter-s
... Show MoreThe study is an attempt to predict reservoir characterization by improving the estimation of petro-physical properties (porosity), through integration of wells information and 3D seismic data in early cretaceous carbonate reservoir Yamama Formation of (Abu-Amoud) field in southern part of Iraq. Seismic inversion (MBI) was used on post- stack 3 dimensions seismic data to estimate the values of P-acoustic impedance of which the distribution of porosity values was estimated through Yamama Formation in the study area. EMERGE module on the Hampson Russel software was applied to create a relationship between inverted seismic data and well data at well location to construct a perception about the distribution of porosity on the level of all uni
... Show MoreThe current study summarized the construction of a three-dimensional geological model of the Aquitanian sediments age, which represented by the Euphrates and Serikagni formation in Ajeel Oil Field, where Ajeel Oil Field has structural closure towards northwest - southeast. Sedimentary of the current study consist of limestone, dolomitic limestone, dolomite (compose of skeletal grains, non-skeletal grains and cement) and the appearance of some anhydrite rocks.
The petrographic study of the Euphrates Formation were prepared using a thin section of wells (Aj-1, Aj-4, Aj-5, Aj-6 and Aj-7), Previous studies and geological reports, as well as use well logs data in the statistical analysis by Petrel softwa
... Show MoreThe Zubair Formation is the most significant sandstone reservoir in Iraq which deposited during the Barremian. The study area is located in the central part of Iraq at the Kifl oil field, in the northern part of the Mesopotamian Zone.
The petrographic study showed that quartz mineral is the main component of the sandstone in Zubair Formation with very low percentage of feldspar and rare rock fragments to classified as quartz arenite sandtone. There are five lithologic changes (lithofacies) that have characterized the studied succession: - well sorted quartz arenite, poorly sorted quartz arenite, poorly sorted graywacke, sandy shale, and shale. These lithofacieses were deposited in the deltaic environments as three associate
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