Key technologies for the fluvial reservoir characterization of marginal oil fields

Fluvial reservoirs of the lower member of the Neogene Minghuazhen Formation in Q33-1 Oilfield, Bohai Bay Basin, are studied as examples to determine the distribution and characteristics of marginal reservoirs and develop offshore marginal oilfields effectively. Based on seismic, geological and logging data, three key technologies for the fluvial reservoir characterization of marginal reservoirs are proposed. The geometry and heterogeneity of fluvial sandbodies were studied through well-seismic calibration, 3D seismic interpretation and boundaries characterization. The geological knowledge database of fluvial reservoirs was established by the methods of width prediction outside wells and variogram analysis based on the high resolution 3D seismic data. Three types of well correlation modes of vertical facies changes, stacking sandbodies, incised channels, were constructed by integrating the analogous data from the oilfield with dense well pattern. According to the above three techniques of reservoir characterization, the most likely mode of reservoir distribution was established, based on which the oil field development plan was made and economic benefits have been gained.