This paper aim is to propose a radio transmission analysing method for the site survey of telemetry systems (e.g., SCADA: Supervisory Control And Data Acquisition), these systems are usually used to supervise remote process installations in large oil and gas fields. This method is presented over a software design and development which includes all radio propagation data and calculations, needed during the technical site survey phase of a telemetry system project execution. The approach is applied for the acquisition, control and online modeling of an oil collection pipeline network using a SCADA system.

The designed software we named "SCADA Radio Transmission," is to perform the radio propagation analysis. By introducing data (topographic coordinates, obstacles heights and characteristics data of the transmission equipment) it allows calculation of towers heights that ensure good radio clearance (Fresnel Zone), plot of the radio transmission link and to visulize results of the radio link budget. Complete calculations equations of this software are provided with detailed radio propagation analysis sample results of the studied oil collection pipeline network, to permit more comprehension for readers. The designed software role is to:

 

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  determine the correct height of the towers by inserting the topographical data of the field, thus providing a radio clearance of the Fresnel first ellipsoid;

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  Draw up, for the established link, a link budget including the received signal power as well as the margin against the reception threshold;

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  In addition, this software allows the adjustment of the pylons heights in order to rectify any diffraction, due to bad visibility hop.

 

A case study application of this software is presented for the data acquisition, control and online modeling of an oil collection pipeline network at Hassi Messaoud oilfield.

This study aims to estimating annual soil erosion rate and its spatial distribution in the Bou Namoussa water-shed located in the North-East of Algeria by applying the revised universal soil loss equation (RUSLE) within a Geographical Information System environment (GIS). The application of the RUSLE model in different natural environments and on every scale takes into account five key factors namely: the rainfall erosivity, the soil erodi-bility, the steepness and length of slopes, the vegetation cover and the conservation support practices. Each of these factors was generated in GIS as a raster layer, their combination, resulted in the development of a soil loss map indicating an average erosion rate of 7.8 tꞏha–1ꞏy–1. The obtained soil loss map was classified into four ero-sion severity classes; low, moderate, high and very high severity representing respectively 40, 30.48, 22.59 and 6.89% of the total surface. The areas, showing moderate, high and very high erosion rates which represent more than half of the basin area were found generally located in regions having high erodibility soils, steep slopes and low vegetation cover. These areas should be considered as priorities in future erosion control programs in order to decrease the siltation rate in the Cheffia reservoir.