Distribution Rules and Its Genesis of Low-resistivity Pay Zones in Gaotaizi Reservoir of Honggang Oilfield

Some of horizons in Gaotaizi Reservoir of Honggang Oilfield were obvious low permeability pay zones.To clarify their genesis and distribution rules was one of the important tasks.Through analyzing its distribution rules,lithology,lithic facies and fluid properties,its distribution rules and genesis were identified.The analysis shows that vertically the low-resistivity reservoirs are mainly distributed in 21,22,25 subzones with fine lithology and high shale content,they are mainly grown in front delta sediments.Horizontally the low-resistivity reservoirs are mainly distributed in thin sands of front delta sediments.The main causes of their formation are rocks with fine particles,reservoirs with low amplitude,high shale content and oil saturation,same of pay zones in the area present low resistivity because of the unique action or co-action of these factors.