Sedimentary microfacies and remaining oil distribution of the Eocene Guaduas formation in Velasquez Oilfield, Columbia

To get a proper knowledge of remaining oil distribution and improving oil recovery rate in Velasquez oilfield, the core observation, depositional structure, lithologic, granularity and seismic response characteristics were analyzed. The sedimentary condition, sedimentary micro-facies and their features were studied, and the model of proper reservoir was built. The predict sandbodies' thickness was predicted using the root-mean-square amplitude, and through it the micro-facies distribution was discussed. The relationship between microfacies and remaining oil distribution was discussed. The results show that the depositional environment of the Guaduas formation in 48-45 fault block belongs to braid delta deposit. The depositional facies include two subfacies (braided river delta plain and braided river delta front) and six micro-facies (braided channel, flood plain, subaqueous distributary channel, mouth bar, sheet sand and interdistributory bay). The lake level has rise-fall-rise during Guaduas formation sedimentary period. Reservoir water flooding degree and remaining oil distribution are controlled by micro-facies. And the remanent oil is relatively concentrated in the top of braided channel and subaqueous distributary channel, the side of mouth bar and sheet sand, which are the major targets of next development adjustment and remaining oil potential tapping.