The present work intends to build up the knowledge on oil effect on carbon steel corrosion rates by evaluating the results of Rotating Cage and Submerged Impingement Jet immersion tests carried at moderate pressures 2.5 MPa, 25 to 50 oC, shear stress from 25 to 175 Pa, in brines containing CO2, H2S and CH4 with two levels of water cut: 20 and 60%. The results indicate temperature effect is stronger on BSW 60% and that shear stress had no influence on CR. On environments with 0.001 MPa of H2S Partial pressure at 50 oC the CR were below 0.05 mm/y whereas without H2S CR were 4x higher. No significant effect of H2S was observed at 25 oC. Although, without H2S, temperature and CO2 partial pressure had stronger influence on carbon steel CR. To water cut of 20% changes on temperature, pH, PH2S, PCO2 and acetic acid concentration, had minimum effect on carbon steel corrosion rate. A 40x smaller CR was observed to BSW 20% compared with 100% brine. The water content must be taken in account to improve corrosion prediction and also associated effects, such H2S contribution on CR decrease.