Anomalous fluid distribution at Mulichinco Formation and its relation with the Chihuido High - Aguada Pichana block - Neuquén Basin Aguada Pichana is a gas field producing from Valanginian Mulichinco formation within Neuquen basin. The main field, AP Central, located at the foot of Chihuido High, is in production under Total Austral lease concession since 1996 and, searching for new reserves, field development has progressed towards the north (AP Norte) and west (Las Cárceles & Chihuidos). Vertical wells had to be replaced by high offset ones due to topographic complexity. Two different domains are recognized: oriental and occidental. The first corresponds to AP Central, which is topographically low, with the best facies, the greatest lateral and vertical connection and the lowest water saturation. The occidental domain coincides with the Chihuido High. It also has good reservoirs but they are separated by very low permeability tight facies so lateral connectivity is poor. This domain is characterized by higher water saturation and lower pressures than normal trend in the East. It coincides with the most intensely structured area (Chihuido & Las Cárceles). The highest water saturation at top of the structure and water bearing intervals above gas bearing ones suggest an anomalous fluid distribution interpreted as the result of dynamic disequilibrium. The aim of this work is to review various data (fluid distribution, pressure, reservoir types, structure, charge timing, paleo fluid contacts, depocenter evolution, etc) to place them into the geological evolution context and allowing to a better understanding of the complex fluid distribution in Aguada Pichana field.