Logging Interpretation Re-Evaluation of Upper Tertiary Reservoir in Huabei Oilfield

The nine Nm-Ng high-porosity and high-permeability reservoirs in the middle and upper Tertiary of Huabei Oilfield are distributed along the oil source faults in a string of beads. The structure is dominated by reverse traction anticline or fault nose trap, with low oil content, small scale but enrichment. The resistivity boundary of shallow oil and water layers in the Upper Tertiary is not clear, and fluid identification is difficult. Affected by factors such as low salinity of formation water, low oil saturation and rapid change of lithology thickness, there is a high-resistivity water layer, and the electrical characteristics of oil and water layers are not obvious. The coincidence rate of conventional logging single factor chart is low, and a large number of class II layers have not been effectively used, which has the prospect of re-excavating potential and increasing oil. In this paper, aiming at the characteristics of the upper Tertiary shallow reservoir and the difficulty of logging evaluation, the effective logging information is deeply dug, and two oil and water layer identification methods, conventional fitting multi-parameter chart identification method and post-casing saturation logging oil-bearing evaluation method, are formed. The success rate of oil increase measures in old wells has been improved, and the ’ zero footage ’ has been realized.