Sedimentary Characteristics and Reservoir Potential of Underwater Alluvial Fan

Using core analysis, thin slice identification, logging analysis and seismic interpretation, systemic study upon sedimentary types, sedimentary facies, physical and oil bearing properties of each sedimentary microfacies, etc presenting in underwater alluvial fan of Kerqin oilfield of Kailu basin in China, is performed. To identify sedimentary characteristics of underwater alluvial fan and determine its oil bearing property so as to develop this type of reservoir reasonably and effectively. Underwater alluvial fan comprises of 5 kinds sedimentary facies: clastic flow, high density flow, low density flow, overflow and river channel sedimentation. Further division includes three sub-facies, i. e. tail, body and front part of underwater alluvial fan, among which braided structure of body part features favorable accumulation and oil bearing properties. Underwater alluvial fan is formed from the double action mechanisms of gravitational flow and traction flow. Body microfacies are primary oil bearing play and braided channel is the main future development target.