No abstract

Throughout well lifetime, formation damage can occur during the activities of drilling, completion, injection, or well stimulation treatments. Typically, remedial treatments to restore the well performance involve injection of reactive fluids capable of removing such damage. Therefore, understanding damage mechanism and type is critical for fluid selection and effective treatment design. Without this knowledge, the conducted stimulation treatment could cause a more severe form of formation damage. This report discusses the improper use of mud acid at (9 wt% HCl/1 wt% HF) in restoring the injectivity of N-510. The subject well was stimulated with two acid stimulation treatments as an attempt to improve the poor results of a previous clean-out job, conducted to remove mud filter cake. These treatments were designed to remove the damage that has been limiting the well injectivity. However, it was found that these acidizing treatments created a new formation damage which resulted in severe decline in the well injectivity. Integration of chemical analysis techniques of return fluids and core-flood experiments was used to assess the effectiveness of all conducted treatments. This report demonstrates the techniques used to identify the source and type of formation damage mechanism that occurred during each treatment. Based on these studies, it was found that the poor results of clean-out job were due to precipitation of calcium sulfate. This precipitation was a result of the mixing between spent cleanout acid, having a high amount of calcium, and the high-content sulfate water. Most of this precipitation occurred in the well-bore vicinity during the last stages of the well flow-back. Calcium sulfate precipitation had a negative impact on the performance of the conducted acid stimulation treatments. In the presence of this precipitation, the two successive mud acid stimulation treatments created another form of damage, i.e. in-situ fluoride-based scale. Initially, the fresh injected mud acid dissolved most of the calcium sulfate scale and as a result it contained high amount of dissolved calcium ions. However, upon the spending of injected mud acid in the formation, calcium fluoride precipitated as a result of the increase of solution pH value. The interactions between different acid systems and the constituent of down-hole environment, resulting in the precipitation of calcium sulfate and calcium fluoride, are discussed. In addition, this report provides recommended modifications to future stimulation treatments, conducted under similar conditions so as to prevent the formation of these scales.

In vitro anti-malarial activity of petroleum ether extracts of Ficus sycomorus leaves was investigated using Candle Jar method. The extractions were carried out through activity guided fractionation. Petroleum ether extract has the highest activity, at the concentration of 1mg and 0.5mg with percentage growth inhibition of (33.12 and 31.9%) respectively. These results suggest that the leaves of Ficus sycomorus plant have significant antimalarial activity and that the antiplasmodial agents might be as a result of the extract fractionated using the petroleum.

Aim:The aim of this study was to demonstrate the amount of endogenous bone morphogenic protein 2 released under the effect of EDTA exposure for different time intervals. Material and methods:The dentin scaffold was randomly assigned to the groups (n = 4). Group 1 received 17 % EDTA for 5 minutes, while Group 2 received 17 % EDTA for 10 minutes. For 15 minutes, Group 3 received 17 % EDTA. Distilled water was used as a control in Group 4. After each treatment, a PBS wash step was performed, Quantikine TM ELISA was used to quantify the amount of BMP2 liberated from the dentin scaffold after pretreatment with EDTA for 5, 10, and 15 minutes, the scaffolds were analyzed under SEM to investigate the cell attachment, morphology, the opening of dentinal tubules, and smear layer removal.Results: Dentin scaffold conditioned with 17% EDTA for 10 and 15 min showed the maximum degrees of enlargement in dentinal tubules and smear layer removal and revealed higher DPSCs viability than the control group (p < 0.001), Moreover, dentin treated with 17% EDTA for 10 min manifested higher concentration of BMP2 release than the unconditioned dentin (p < 0.05). Using scanning electron microscopy Dentin scaffold treated with EDTA for 10 min presented the highest degrees of enlargement in dentinal tubules and smear layer removal than the dentin treated with EDTA for 5 or15 min. Conclusion:Maximum endogenous bone morphogenic protein 2 release was obtained when dentin scaffold treated with 17% EDTA for a period of 10 minutes.

Coupling of deformation and magmatism has been reported in several old orogenic belts, particularly along thrust faults and shear zones. The syn-kinematic plutons in exhumed shear zones offer the best opportunity to understand the complex relationship between magmatism and regional deformation. The present paper investigates the geometry and internal structure of granite plutons emplaced in thrust faults and shear zones, and structural control on their emplacement mechanism. Abu Ziran pluton is an example of the intrusions emplaced in active brittle-ductile zones in the Nubian shield, and documents clear evidence on the interaction between magmatism and regional deformation during melt ascent and emplacement. Results from detailed geological mapping, remote sensing, and structural analysis of the pluton and associated highly strained rocks permitted the constraining of the pluton's geometry, emplacement mechanism, and spatio-temporal evolution. Structural analysis of the study area indicates that pluton emplacement was syn- to-late-tectonic. The brittle-ductile fabrics in the wall rock are consistent with a sub-horizontal thrust shear zone with a top-to-NW shear sense. The activity of the shear zone was accompanied by an episode of a calc-alkaline magmatic pulse. Granitic magma ascended upward via non-exposed feeder dykes, or through ramps and flats in the thrust system and emplaced laterally along the shear zone, forming complex sub-horizontal sheet-shaped intrusion. The geometry and extent of pluton emphasize that inherited heterogeneities and regional stress states played important role in the emplacement processes. In addition, localization of pluton along or near the contact between ophiolitic nappes and mylonitic metasediments suggests that the rheological boundaries act as barriers that impedes the rise of ascending magma, causing magma arrest, and triggers lateral spreading and emplacement. The outcomes of this study allowed the reconstruction of the geometry and internal structure of Abu Ziran pluton and an understanding of its evolution in space and time.