Influence of Natural Fractures on Oil Production of Unconventional Reservoirs

In recent years, awareness of the role of fractures on the production and recovery of hydrocarbons has become increasingly strong in the oil community.To shed light on this question, this paper examines the fractures characterization and their effects on production and enhanced oil recovery; also, it deals with characterization of specific features of fractured reservoirs, using different tools as cores analysis and 3D imagery.The effect of fractures on well productivity is explained and in this point, we have taken the data of wells production from a single reservoir to put these wells at the same overburden conditions. We have selected as example “El Gassi” field to follow the evolution of gas/oil ratio (GOR) according to wells daily production.To analyze the effect of the injection on the daily production of the field, we have compared the evolution of the production of three tanks, two fractured reservoirs and a third non-fractured (consolidated). We took the “El Gassi” and “Rhourde El Bagel” fields as fractured reservoirs, and “Hassi Berkin” field as consolidated one. Then we have treated the impact of fractures on assisted oil recovery; we have studied the response of production at “Rhoud El Bagel” field after gas injection.Data analysis of the production of these three Algerian fields shows that there is no direct apparent relationship between the intensity of fractures and average production. A change in the recovery mode is required by the orientation to water injection or water alternating gas “WAG” process.