The geological history of the Rio Del Rey sedimentary basin has been known since the 1980s, and the majority of the large oil fields discovered more than 20 years ago are already tending to be depleted. According to the latest report declared by the national hydrocarbon company, production in Cameroon would have gone from 26.8 million barrels for an average daily production of 73,094 barrels in 2009 to 21.4 million barrels in 2011 for 63,211 barrels per day, a decline of 13.08% compared to 2008. The purpose of this work will therefore be to show that in this basin, there are still hydrocarbon reserves that could probably be exploited and that could make up for the deficit observed during the previous years, particularly from 2008 to 2011. Thus, it will be based on the evaluation of a block located in the southwest of the Rio Del Rey from 3D seismic data and wells. This study will consist of determining the type of trap, the place of accumulation of hydrocarbons, the extension of a reservoir and the estimation in volume of its content by designing a 3D model that is as close to reality as possible.