The correct study of the reservoir leads us to develop drilling programs suitable for producing stratum. In addition, this makes us do successful operations to achieve the best recover factor ,within the convenient time and at the lowest appropriate cost. This study will help us to avoid or solve many of the problems associated with the production processes and the most important problem of rehydration .In this research I did a geological and reservoir study of the Jido Field which is one of the fields of the Euphrates Company and it is located within the area of graben Euphrates in Deir Azure to the east of Syria, where recoverable reserves which are estimated in this field is about 83 million barrels. The objective of the study was to know the specifications and behavior of the reservoir and fluid inside and the possibility of a Hydrodynamic connection between blocks ,where this information is taken into account when calculating recoverable reserves and the assign of technological indicators for investment.