Showing papers by "Abu Dhabi Company for Onshore Oil Operations published in 2012"

Evaluation of Naturally Occurring Radioactive Materials (NORMs) in Inorganic and Organic Oilfield Scales from the Middle East

Abstract: The distribution of natural nuclide gamma-ray activities and their respective annual effective dose rates, produced by potassium-40 (40K), uranium-238 (238U), thorium-232 (232Th), and radium-226 (226Ra), were determined for 14 oilfield scale samples from the Middle East. Accumulated radioactive materials concentrate in tubing and surface equipment, and workers at equipment-cleaning facilities and naturally occurring radioactive materials (NORMs) disposal facilities are the population most at risk for exposure to NORM radiation. Gamma-spectra analysis indicated that photo-gamma lines represent the parents of 10 radioactive nuclides: 234Th, plutonium-239, actinium-228, 226Ra, lead-212 (212Pb), 214Pb, thallium-238 (208Tl), bismuth-212 (212Bi), 214Bi, and 40K. These nuclides represent the daughters of the natural radioactive series 238U and 232Th with 40K as well. The mean activity concentration of 238U, 232Th, and 40K were found to be 25.8 ± 11.6, 18.3 ± 8.1, and 4487.2 ± 2.5% Bq kg−1 (average values for 14 samples), respectively. The annual effective dose rates and the absorbed doses in air, both indoor and outdoor, for the samples were obtained as well. The results can be used to assess the respective hazard on workers in the field and represent a basis for revisiting current engineering practices.

Conceptual Structural Model of an Onshore Carbonate Hydrocarbon Field in Abu Dhabi: Constraints and Implications

Abstract: A carbonate field in Onshore Abu Dhabi is characterized by its complicated structural setting, which involves basement tectonics. A new seismic attributes analysis has been conducted to reveal the structural style, and to identify significant lineaments representing possible major and minor faults. Based on this analysis, a conceptual model is presented, which reveals the development mechanism of the major structure and associated faults.Structural constraints such as lineaments length, faults throw and displacements are strongly related to the seismic resolution constraint. Whereas timing of the structural development events represents a challenge and needs to be linked to sedimentation and sequence stratigraphic framework and thus needs further study.In total, six fracture sets have been identified including the N75W, N45W, NS, EW, NE-SW and N70E. The Conceptual structural model shows that the contractional structure has been modified as a giant positive flower structure-like associated with a basement strike slip fault. At least two major longitudinal faults bound the structure parallel to its fold axis (NE-SW), which pose sigmoidal map geometry. There are numerous transverse faults linking and/or cross cutting those longitudinal faults creating andulations that may define new minor plays.Significant implications of this study include better understanding of the regional structural geology of Abu Dhabi, and define new plays within the studied structure. In addition, the new identified fracture system provides essential information for the ongoing and future development plans for this field and for other fields in the region with similar structural settings.

Photochemical and thermal spiropyran (SP)-merocyanine (MC) interconversion: a dichotomy in dependence on viscosity.

Abstract: The current study extends our work with spiropyran-merocyanines (SP-MC) as molecular photoswitches by delving into the effects of viscosity. This has led to the interesting finding of a dichotomy in viscosity dependence. Solutions of SP [6′-nitro-1,3,3-trimethylspiro(indolino-2,2′-benzopyran)] in a wide range of ethylene glycol–methanol (EG–MeOH) media (3.59 to 17.9 M in EG) were irradiated 90 s (365 nm). The absorbance at 90 s of MC (532 nm) formed photolytically varied with solvent. The least viscous medium yielded the highest concentration of MC and yields declined with increasing viscosity. Once irradiation ceased each system achieved thermal equilibrium. Molecular dynamics studies of typical thermal reactions governed by electronic and steric factors show that the transition state is achieved primarily after solvent reorganization has occurred to accommodate the new structure. It follows that in such thermal reactions viscosity may not cause any hindrance to the motion of atoms in molecules because solvent has already rearranged. In contrast, photochemical excitations occur at much higher rates (10−15 s) than solvent reorganization, i.e. dielectric relaxation (10−10 to 10−12 s). The viscosity dependence of photochemical MC formation suggests that a major geometrical change is required for excited SP to be converted to MC. The dichotomy in dependence on viscosity is confirmed by the thermal equilibration of SP and MC. The equilibrium constant for the process increases three-fold (from 0.0535 to 0.158) as the EG content of the medium increases. However, the forward rate constant (SP → MC) is almost invariant with EG content or viscosity. The process is viscosity independent. The increase in the equilibrium constant with EG concentration is a result of a decline in the reverse rate constant for MC cyclisation to SP. This is attributed to special stabilisation of the MC that increases with increasing EG concentration. The present study, to our knowledge, is the first to dissect viscosity from solvent stabilisation factors in SP-MC systems. Further, the study highlights the fundamental difference between photolytic and thermal processes, providing another avenue of control for these SP-MC photoswitches.

Security & Privacy Architecture as a service for Small and Medium Enterprises

Abstract: This paper focuses on Security and Privacy for Small and Medium Enterprises pertaining to their dependency on small clouds to carry out their business activities. They lack the knowledge pertaining to the security to be applied to safeguard their data and services due to lack of in-house expert technical resources, security architects or less budgets to carry out the vulnerability study for them and to safeguard their data. Customers can rely on the services offered by the SMEs only if the hired services are secured. SMEs should have a proper understanding of the threats pertaining to the security aspect of the Software as a Service which they undertake. They should be able to investigate and asses the risk involved in showcasing their services on a cloud via the internet. The aim of this paper is to design a framework that brings out a Security & Privacy Architecture as a service for SMEs (SPAaaS) pertaining to Web Applications which can be offered by various security vendors. SPAaaS will assist the SMEs to evaluate the security requirements pertaining to host their data and services on cloud.