Abstract:

Based on the analysis of depositional settings, sandbody characteristics and core observations of wells drilled, the upper Shasan Member is a braided fluvial delta with a undeveloped delta plain. The braided fluvial delta front includes underwater distributary channel, mouth bar and sand sheet.The reservoir at the interval of 3200-4000m belongs to secondary pore type in the Liuxi region. The sandbodies of distributary channel and mouth bar buried less 4000m are all of exploratory targets with economic benefit. Structural landform low in the south and high in the north matchs with sandbodies  closed to westeast through going in the Liuxi region.So the conditions for pool-forming are created later. The structural reservoirs develop in the north and subtle reservoirs in the middle-south under the control of brush faulted system.

Key words: Liuxi region, braided fluvial delta, depositional characteristic, reservoir characteristic, subtle reservoir