Browsing by Author "Eladj, Said"

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Aeromagnetic data analysis using the 2D directional continuous wavelet transform (DCWT)
(Springer, 2013) Ouadfeul, Sid-Ali; Hamoudi, Mohamed; Aliouane, Leila; Eladj, Said
AVO Seismic data inversion using global simultaneous technique
(2012) Eladj, Said; Ouadfeul, Sid-Ali; Aliouane, Leila; Djarfour, N.
Geological Description and Modeling of Djebel Kerdada in Saharan Atlas–Bou Saada, Algeria
(Springer Nature, 2023) Belahcene, Brahim; Doghmane, Mohamed Zinelabidine; Eladj, Said
This paper presents stratigraphic and structural descriptions of Djebel Kerdada in the studied areas of Bou Saada in Algeria. The choice of Djebel Kerdada is due to its geological complexity that can provide more detailed information about the regional geology of the area located at the northern limit of the African plate. This region belongs, geologically, to the Saharan Atlas, which is limited by flexures caused by slow dislocations, transgression, alternations, and regressions. The marginal basin in western Mediterranean Sea was generated by an N-NW subduction of the African and Adriatic plates under the European plate. The geological structures created by the subduction are near the city of Bou Saada, which is located 234 km South-East of Algiers. Based on the results of field investigation internship, it has been confirmed that, due to the compressive tectonic phenomenon caused by the sliding of the African plate under the Euro-Asian plate, many geological structures have a N-E/ S-W direction. Thus, this field study allowed us to limit the different litho-stratigraphic series that appeared in the form of outcrops, fossils, measurement of dips, and all structural faults. Moreover, a static modeling of the geological structure, namely Djebel Kerdada, was established based on the isopath maps of the region and data obtained from the internship. In addition to the limits of the litho-stratigraphic series, the results demonstrated the paths of the hydro-geodynamic forces toward the river of Bou Saada.
Petrophysical Parameters Curves’ Calculation for Non-conventional Reservoirs’ Modeling and Characterization
(Springer Nature, 2024) Doghmane, Mohamed Zinelabidine; Ouabed, Noureddine; Eladj, Said
The quantitative petroleum reservoir analyses’ topic is one of the biggest challenges facing geo-modelers. The difficulty lies in the fact that the constructed model depends on many empirical Archie’s law parameters such as tortuosity factor (a), cementation exponent (m), and saturation exponent (n). The most used methodology of choosing the appropriate set values of (a, m, n) is the trial/error technique. The parameters values’ sets are calculated empirically based on core data taken from different wells. The main drawback of this method is that these petrophysical parameters are not constant all over the reservoir section and are very variant in non-conventional reservoirs. The objective of this study is to provide curves of the petrophysical parameters (a, m, n) from petrophysical logs based on new equations. The new equations are based on relating tortuosity as a function of the sonic log and other basic logging curves (Gamma Ray, Neutron-density). Then, the calculated curves are used in constructing a more accurate non-conventional reservoir model. The obtained results have been compared to the conventional interpretation where a, m, and n are taken constants for all reservoir sections. Moreover, the obtained results are validated through core data and MDT tests in Algerian Southern non-conventional reservoirs.
A Practical Seismic Attributes’ Workflow for Natural Fractures’ Characterization of Tight Reservoirs in Algeria
(Springer Nature, 2024) Bacetti, Abdelmoumen; Doghmane, Mohamed Zinelabidine; Eladj, Said
In this paper, a new workflow of geometrical seismic attributes for a structural geological study has been proposed. The small faults with low throw were detected, and the natural fractures’ model has been obtained for tight reservoirs. The fractures model has been correlated with imagery data taken from exploration wells in the studied field. The proposed attributes allowed us to map major faults with a throw less than the seismic resolution, and the curvatures have also been used to map subtler folds and flexures and overlying other formations. The geometrical seismic attributes used are: Curvature, Variance, Chaos, Structural smoothing, Edge enhancement, and Ant tracking. Moreover, the effectiveness of the proposed methodology has been demonstrated through the case study of Ain Amenas tight reservoir. The obtained results have been compared to conventional seismic interpretation results, for which it was demonstrated the existence of small faults that cannot be seen by the old methodology. Therefore, the constructed fracture model has been correlated and matched to the results of imagery interpretation of data taken from wells in the field. Finally, a relationship between fracture density and the attributes has been proposed in order to be considered for reservoir model construction in the production phase. This workflow can be useful in the optimization strategy of exploration costs of hydrocarbon resources of oil and gas national companies. The main novelty of this study is that it provides a practical workflow tool for continuous fracture modeling (CFM) and its successful application to several projects.
Pre-stack Seismic Inversion for Potential Reservoirs’ Characterization in Oued Mya Basin, Algeria
(Springer Nature, 2024) Eladj, Said; Benabid, MounaKeltoum; Doghmane, Mohamed Zinelabidine
The main objective of this study is to characterize the potential reservoirs situated in Oued Mya basin in Algeria by using pre-stack seismic inversion data. In fact, rock physics has been used to estimate shear waves and their densities from the compressional wave velocities at six wells, and then, cross-plots were exploited to establish a mathematical relation between the petrophysical and acoustic parameters of the rocks. After that, the lithological classification has been iteratively generalized for the whole seismic volume. The final model, obtained with a correlation ratio of 75%, allowed the classification of the dominant facies in the reservoir. Furthermore, the Petrophysical volumes obtained using these mathematical relations provided the horizontal distribution of the different existing reservoirs with a focus on the potential ones. The obtained results in this case study have highlighted the crucial role played by the seismic inversion in the characterization of the oil reservoirs in the Oued Mya Basin. It also permitted to provide lateral variations of petrophysical parameters of the reservoir; thus, it eliminates the problem of punctuality of the information provided by logging data. This characterization step is very important for determining the positions of new exploration drillings in order to optimize exploration strategy with minimal uncertainties; therefore, exploration costs can be optimized. The main novelty of this paper is that the obtained model was very reliable and its correlations with six wells in the basin were high; hence, it has been used to characterize the reservoirs and to identify new areas with hydrocarbons potentials where highly probable discoveries were identified.
Random seismic noise attenuation using the wavelet transform
(2012) Aliouane, Leila; Ouadfeul, Sid-Ali; Boudella, Amar; Eladj, Said
Recent Euler pole parameters and relative velocities of the Nubia–Eurasia and Nubia–South America plates estimated using GPS technique
(Springer, 2023) Allal, Saddam Housseyn; Eladj, Said; Dekkiche, Hicham; Hasni, Kamel; Betchim, Younes Ahmed
The convergence of the Nubian plate toward Eurasia and the spreading rate between the Nubian and South American plates are currently subjects of scientific debates. In this paper, we improve the estimation of Euler pole parameters and the recent relative velocities of the Nubian plate using Global Positioning System (GPS) velocities. These estimates are based on mathematical models and statistical tests for plate tectonic motion represented on a spherical surface. First, we derive the angular velocity and the precise coordinates of the Euler pole to describe the Nubian plate absolute motion expressed in the ITRF2014 geodetic system. This derivation is obtained by inverting the horizontal velocities of 202 GPS stations well distributed across the Nubian plate. Then, we use the same data to obtain the current relative velocities and parameters of the Euler pole characterizing the Nubia–Eurasia and Nubia–South America relative plate motion. A number of 21 and 29 GPS stations located on tectonically stable domains are used to fix the Eurasian and the South American plates, respectively. The results show Nubia–Eurasia relative velocities ranging from 1 to 7 mm/yr, with a direction of NW to WNW for the northern Nubian plate. The velocity in the southern part of this plate reveals a NNE to N direction. The inversion of these velocities allows the determination of the Euler pole parameters: the coordinates PNub-Eu(λNub-Eu=-23.17∘±0.92892;φNub-Eu=-5.62∘±0.72322) and the angular velocity ΩNub-Eu=0.053∘/Myr±0.00101. On the other hand, the estimated relative velocity of Nubia–South America is varying in the range of 15–30 mm/yr, with a NE to ENE direction and rotating around the pole PNub-SA(λNub-SA=-44.5263∘±0.57624,φNub-SA=66.7484∘±0.16524) with an angular velocity (Ω Nub - SA= 0. 26689 ∘/ Myr ± 0.0007). The obtained research results demonstrate an improved precision compared to the existing studies. Furthermore, the use of the Algerian GPS velocities played a key role in the enhancement of the estimates’ precision, which allows us to better understand and monitor the crustal deformations at the limit of the plates