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 continental depositional settings predominantly made of shoreface deposits with few channel sands. The depositional model of the area shows that the deposition went down the axis of fluvial depositional system, which transports sediments through channels down to the shelf into the base of the slope down the basin. The seismic reflection patterns in this field are parallel to divergent reflections, high-continuity and high-amplitude facies, low-amplitude facies, low-continuity and variable-amplitude reflections, chaotic reflections and wavy reflection patterns. The seismic stratigraphic analysis of this field revealed the presence of low stand system tract (LST), high stand system tract (HST) and transgressive system tract (TST). Sands 1 and 2 were delineated within high stand systems tract (HST) while sand 3 was within low stand systems tract (LST). The results of this study show that the Nandy Field was of high hydrocarbon potentials and highlight the importance of using seismic reflection parameters (reflection configuration, amplitude, frequency and continuity) in the division and classification of seismic facies.
In this paper, the time-history responses of a square plan two-story reinforced concrete prototype building, considering the elastic and inelastic behavior of the materials, were studied numerically. ABAQUS software was used in three-dimensional (3D) nonlinear dynamic analysis to predict the inelastic response of the buildings. Concrete Damage Plasticity Model (CDPM) has been used to model the inelastic behavior of the reinforced concrete building under seismic excitation. The input data included geometric information, material properties, and the ground motion. The building structure was designed only for gravity load according to ACI 318 with
... Show MoreIn engineering, the ground in seismically active places may be subjected to static and seismic stresses. To avoid bearing capacity collapse, increasing the system's dynamic rigidity, and/or reducing dynamic fluctuations, it may be required to employ deep foundations instead of shallow ones. The axial aptitude and pipe pile distribution of load under static conditions have been well reported, but more study is needed to understand the dynamic axial response. Therefore, this research discusses the outputs of the 3D finite element models on the soil-pile behavior under different acceleration intensities and soil states by using MIDAS GTS NX. The pipe pile was represented as a simple elastic, and a modified Mohr-Coulomb mode
... Show MoreThis study includes structural and stratigraphic interpretation of 3D seismic reflection data for Zubair Formation (L. Cretaceous) within Al-Akhadeir area, southwestern Iraq (Karbala Governorate). Depending on the 3D seismic reflection interpretation process, and based on the synthetic seismogram and well logs data, two horizons were identified and selected (top and base Zubair reflectors). These horizons were followed up over the entire area in order to obtain structural and stratigraphic settings. TWT, depth, and velocity maps for the base and top Zubair Formation were constructed. From the interpretation of these maps and based on the seismic section, the study concluded that there are some enclosures that represent anticl
... Show MoreFive subsurface sections and a large number of thin sections of the Hartha Formation (age Late Campanian – Early Maastrichtian) were studied to unravel the depositional facies and environments. The Hartha Formation is important as an oil reservoir in Iraq.
Petrographic and microfacies analysis of selected wells from Balad and East Baghdad oil fields in Central Iraq, enable the recognition of three main Sedimentary paleoenvironments. These are restricted marine, the shallow open marine environment within the inner ramp, deep outer ramp.
The studied Formation represents by two asymmetrical cycles bounded below by sequence boundary (SB1) the contact between Hartha and Saadi Formations. The deep outer ramp facies of
... Show MoreThe current study deals with microfacies and the depositional environment of the Lower Cretaceous Sarmord Formation at selected sections in Sulaimani and Erbil Governorates, northern Iraq. The Sarmord Formation alternates rhythmically between yellowish grey marly limestones and grey black marls. These lithologies are observed in all studied sections of Sarmord Formation in northern Iraq. Petrographic investigation of this study based on 240 thin sections demonstrated that the carbonate constituents are mainly composed of skeletal and non-skeletal grains. The skeletal grains include a variety of foraminiferas (planktonic and benthonic), bioclasts, calcispheres, ostracods, radiolaria, echinoderms, sponge spicules, ammonoids and be
... Show MoreThis study deals with interpretation of stratigraphic and structural of Khlesia area north-west Iraq in Nineveh province, near the Iraq- Syria border, by using 2D seismic data. Synthetic trace are prepared by using available data of the well (Kh-1) using Geoframe program to define and picking the reflectors on seismic section. These reflectors are: (Within Fatha and Kurra Chine reflectors) representing Middle Miocene and Late Triassic ages respectively. A listric growth normal fault is affecting the stratigraphic succession, and normal fault as a result of collision of Arabian plate with Eurasian plate. In addition, minor normal faults (Dendritic and Tension) are developed on the listric normal growth fault
... Show MoreThis study deals with the seismic reflection interpretation of lower Cretaceous Formations in Dhufria area, including structural and stratigraphic techniques. In the interpretation process, the 3-D seismic data volume and well logs have been used. Based on well logs and synthetic traces two horizons were identified and picked which are the top and bottom of Zubair Formation. These horizons were followed over all the area in order to obtain structural setting as well as studying Kirkuk group Formation of Tertiary age which represents highstand progradational seismic facies.
A comparison was conducted between two wells, Kt-1and Kt-2, in Kumait and two wells, Du-1and Du-2, in Dujaila oil fields that belong to Mishrif formation, southern Iraq. Seismic inversion method was employed to detect oil and water reservoirs. The comparison included the behavior of acoustic impedance (AI) of fluids and the lithology with related petrophysical properties. The values of water saturation, Shale volume (Vsh), and effective porosity were compared between the AI, two fluid reservoirs. It was found that the AI value for the oil reservoir unit is relatively low to medium, whereas it was relatively medium for the water reservoir. Effective porosity value showed, in general, an increase in the oil reservoir and
... Show MoreThe Shiranish Formation is cropped out in several areas in northern Iraq. A stratigraphic and facies study was conducted within the Duhok region to determine the sedimentary environment. Three microfacies, reflecting the various subenvironments within different shelf parts of the deep sea, have been identified within the Shiranish Formation. Four depositional environments are identified: slope, the toe of slope, deep shelf, and deep-sea or cratonic deep basin. The Shiranish Formation in the Duhok region, Northern Iraq, was deposited in an open shelf carbonate platform. The Shiranish Formation sequence is divided into six third-order cycles in the study area. These asymmetrical cycles reflect an imbalance between the relative level of the
... Show MoreThree seismic instantaneous attributes (phase, frequency, and variance) were utilized on 3D-seismic poststack migrated data, covering 617.31 km2, integrated with data of two wells (Du-1 and Du-2) in Dujaila oil field, southeast of Iraq. They gave good results in detecting reef buildups and confirmed the existence of the stratigraphic hydrocarbon trap that was not obvious in the conventional seismic amplitude sections. They display several seismic criteria in attribute sections for recognizing reef buildups and hydrocarbon accumulation, such as phase reversal, low frequency, and high amplitude variance. The seismic attributes emphasized that the stratigraphic trap of reef rudist buildups with hydrocarbon content is con
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