introduction lead-based shields are the most widely used attenuators in x-ray and gamma ray fields. the heavy weight, toxicity and corrosion of lead have led researchers towards the development of non-lead shields. materials and methods the purpose of this study was to design multi-layered shields for protection against x-rays and gamma rays in diagnostic radiology and nuclear medicine. in this...

generally, alluvial basins of arid and semiarid zones are the places with excessive groundwater withdrawal, and also they have a high potential for land subsidence. excessive groundwater withdrawals have caused severe land subsidence in tehran, iran. at present, the maximum land subsidence rate is 36 cm/year, covering an area of nearly 530 km2. in the 2000s, as a result of economic and populati...

In thin-layered reservoirs, drilling engineers face tough challenges—planning their drilling programs to follow the most productive reservoir layers while avoiding nearby water, gas or high-pressure zones. The rewards for a successful drilling strategy are clear—increased oil production and reduced water cut. In an oil field in the Persian Gulf, for example, oil production was increased four- t...

Proper determination of bed boundaries in layered reservoirs is vital ‎for accurate petrophysical interpretation of conventional logs. In the ‎wellbore, logs continuously measure physical properties of reservoir ‎while the properties change stepwise. This continuous representation ‎of logs may lead to ignorance of some high potential reservoir zones. ‎The main reasons for continuous nature of l...

In matrix acidizing operations, the main goal is increasing permeability. For production engineers, it is desirable that acid could be injected into whole [M.N.1] [amehri.gh2] pay zone. Sometimes, this pay zone has a long height and various sub-layers which have different permeability values. To prevent acid from going completely into the most permeable sub-layer, one of the useful techniques i...

This study is a numerical simulation of different stratigraphic development schemes for three encrypted well networks based on historical fitting by establishing fine geological model Block II Area A. The relationship between reservoir physical parameters and recovery rates combinations obtained applying multiple linearity regression methods to guide the delineation sections in multi-layered no...