LOG CURVE NORMALIZATION OF C-6 OIL-BEARING FORMATION IN HAIZITA AREA, ORDOS BASIN

The Yanchang Formation is derived from continental delta facies in Ordos Basin with C-6 oil-bearing formation as the main reservoir. During the normalization of log curves, the log responses of non-permeable layer are quite different due to the influence of sedimentary environment and organic content in mudstone, which eventually leads to the lack of marker layer with stable log responses. Under this situation, on the basis of the construction of virtual marker bed by means of curves like gamma ray, caliper logging, acoustic logging and induction logging, the ΔlgR method is used to remove the impact of organic matter in non-permeable layers, and then to select a "virtual marker bed" unaffected by borehole conditions, lithology, physical properties and oil-gas potential. Finally, the histogram translation is applied in normalization of logging curves followed by test with the porosity-calculated model. The results show that the ΔlgR method is an effective way to eliminate the effect of organic content in non-permeable layer and to improve the construction quality of the"virtual marker bed" in continental strata, which also lays foundation for later determination of reservoir parameters.