Showing papers by "Sonatrach published in 2007"

Corrosion-Electrochemical behavior of 13% chromium (Cr) martensitic stainless steel in hydrochloric acid (HCl) solutions

Abstract: Corrosion-Electrochemical behavior of a commercial API5CT grade L80 type 13Cr tubing enriched with microalloying elements is studied in 6, 7.5, 9, 12 and 15% HCl solutions by electrochemical methods. The objective is to contribute to the comprehension of corrosion phenomena caused by HCl of similar concentrations, generally used in acidizing job. The corrosion morphology is examined by scanning electron microscopy (SEM) coupled with EDAX. The soluble corrosion products are analyzed by atomic absorption spectroscopy and colorimetric methods. General, as well as localized, corrosion is present. The severest general corrosion with a maximum rate of 26 mm/year is obtained at 15% HCl. The localized corrosion which morphologically differs as function of HCl concentrations is revealed by SEM investigation. In all the above HCl solutions, the commercial 13% Cr martensitic stainless steel tubing shows no passive state. Above 6% HCl, the microalloying elements promote forming a discontinuous film of the corrosion products. The corrosion rate slightly decreases in 15% HCl compared to the published data on a conventional 13% Cr martensitic stainless steel tubing. This is due to both the chemical composition (silicon, manganese and vanadium) and microstructural properties. Copper seems to additionally accelerate the corrosion of the alloy.

Drilling Performance Management System

Abstract: Despite the capital intensive nature of drilling operations, drilling analysis is not routinely practiced as it should be. This is understandable since drilling engineers are principally rewarded for well planning and well construction. Therefore, the need to encourage best practices and continuous learning is a key to drilling improvement. Otherwise, the history will repeat itself “If you always do what you have always done, you will always get what you have always got”.

Neogene tectonic history of the sub‐bibanic and m'sila basins, northern algeria: implications for hydrocarbon potential

Abstract: The southern Bibans region in northern Algeria is located in the external zone of the Tell fold-and-thrust belt. Field observations in this area together with seismic data integrated with previous studies provide evidence for a number of Tertiary deformation phases. Late Eocene Atlassic deformation was followed by Oligocene (?)-Aquitanian-Burdigalian compression, which was associated with the development of a foreland basin in front of a southerly-propagating thrust system. Gravity-driven emplacement of the Tellian nappes over the basin margin probably occurred during the Langhian-Serravallian-Tortonian. The Hodna Mountains structural culmination developed during the Miocene-Pliocene. Analysis of brittle structures points to continued north-south shortening during the Neogene, consistent with convergence between the African and Eurasian Plates. The unconformably underlying Mesozoic-Cenozoic autochthonous sequence in this area contains two potential source rock intervals: Cenomanian-Turonian and Eocene. Reservoir rocks include Lower Cretaceous siliciclastics and Upper Cretaceous to Palaeogene carbonates. Structural style has controlled trap types. Thus traps in the Tell fold-and-thrust belt are associated with folds, whereas structural traps in the Hodna area are associated with reactivated normal faults. In the latter area, there is also some evidence for base-Miocene stratigraphic traps.

Crystallization behavior of PP/PP‐g‐MAH/GFR PA66 blends: Establishment of their continuous‐cooling‐transformation of relative crystallinity diagrams

Abstract: Polypropylene/polypropylene-grafted-maleic anhydride/glass fiber reinforced polyamide 66 (PP/PP-g-MAH/GFR PA 66) blends-composites with and without the addition of polypropylene-grafted-maleic anhydride (PP-g-MAH) were prepared in a twin screw extruder. The effect of the compatibilizer on the thermal properties and crystallization behavior was determined using differential scanning calorimetry analysis. The hold time was set to be equal to 5 min at 290°C. These conditions are necessary to eliminate the thermomechanical history in the molten state. The crystallization under nonisothermal conditions and the plot of Continuous-Cooling-Transformation of relative crystallinity diagrams of both PP and PA 66 components proves that PP is significantly affected by the presence of PP-g-MAH. From the results it is found that an abrupt change is observed at 2.5 wt % of PP-g-MAH as a compatibilizer and then levels off. In these blends, concurrent crystallization behavior was not observed for GFR PA66. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1620–1626, 2007

Group-Contribution Estimation of the Critical Properties of Hydrocarbons

Abstract: A groupcontribution method was developed to predict critical tempertaures, pressures and volumes of hydrocarbon compounds. The method was tested with satisfactory accuracy. The absolute average deviations obtained between experimental and calculated values are 0.36%, 4.6% and 1.7% respectively for critical temperature, critical pressure and critical volume.

Influence of breakouts on borehole sonic dispersions

Abstract: Borehole breakouts are commonly encountered during underbalance drilling in the presence of large tectonic stresses. The characteristics of borehole sonic data may be affected by strong departures from cylindrical geometry. A finite-difference time domain (FDTD) formulation with a perfectly-matched layer (PML) enables a study of the influence of breakouts on the borehole Stoneley, flexural and quadrupole dispersions. Breakout azimuths are oriented perpendicular to the maximum horizontal stress direction. The FDTD formulation yields synthetic waveforms at an array of receivers produced by a monopole, dipole or quadrupole source placed on the borehole axis. The borehole cross-section can be modified to simulate the breakout geometry. Synthetic waveforms are then processed by a modified matrix pencil algorithm to isolate both non-dispersive and dispersive arrivals in the wavetrain. While the axi-symmetric Stoneley dispersion is marginally affected by the presence of a breakout, there are discernible changes in both the flexural and quadrupole dispersions that can help in the analysis of such borehole failures. Computational results indicate that the presence of a symmetric breakout causes both the flexural and quadrupole wave splitting in the intermediate frequency band similar to the case of an elliptic hole. The two canonical dispersions approximately correspond to the largest and smallest diameters of the distorted borehole cross-section. These characteristic changes in the Stoneley, flexural and quadrupole dispersions can be used as indicators of the presence of breakouts and need to be accounted for in the sonic data inversion and interpretation.