Abstract: The present invention is a method of monitoring recovery site hydrocarbons (HC) using an unconventional method which permits quantifying the HC present in zones above the exploration and development zone. The method according to the invention is based on the adjustment of a model describing the gas concentration as a function of time, using in-situ geochemical analyzes of rare gases and, when appropriate, of injected gas used for fracturing, contained in fluid phases of subsoil samples. By use of rare gas analysis, the method according to the invention allows anticipation of hydrocarbon leakage above the exploration/development site.

Abstract: A method of selecting the positions of wells to be drilled for the development of a petroleum reservoir from a set of reservoir images. Well configurations are optimized by calculating a first quality criterion using a flow simulator applied to a limited number of reservoir images. Previously obtained configuration simulation results previously obtained are used for configurations physically close to the configuration to be assessed. A second reservoir development quality criterion is calculated for the optimized configurations using a flow simulator applied to each image of the reservoir. Finally, the well location corresponding to the optimized configuration having the best second quality criterion is selected.