Abstract:

There is great deal of oil and water existing in the same bed because of lower closure and poorer oil and water separation in P pay zone，G area，and there are similar physical and electrical properties between the bed containing both water and oil and the pay zone，the common method calculating water saturation by resistivity and porosity is ineffective，and also，in the process of development in the area，multibed testing is applied，the beds that liquid production is both oil and water are fewer，the samples that can be used to set up the model for the saturation o oil and water existing in the same bed are fewer，too，which makes correct calculation of the saturation of oil and water existing in the same bed more difficult in present resource amount.In this paper，it is presented that some pressure tight coring wells are taken as examples，the relationship between water productivity and water saturation is established by using phase permeability data，then the result is popularized to conventional coring wells to obtain supplement samples of water saturation，furthermore，by means of such modeling parameters as optimal porosity and resistivity ratio etc.，the new model calculating the saturation of oil and water existing in the same bed and being suitable for the area is set up，the mean relative error is 3.59%，which meets the need of the precision of resource calculation.

Key words: oil and water in the same bed, phase permeability curve, saturation model, pressure tight coring, water productivity