Physical Properties Cutoff and Controlling Factors of Effective Reservoir of Middle-Lower Third Member of Shahejie Formation of the Yonganzhen Area in Dongying Depression, Bohaiwan Basin, China

Liu, Jie; Cao, Yingchang; Fan, Tailiang; Wang, Jian

Based on the oil production test, mercury injection data and physical properties, in Es3z-x of the Yonganzhen Area in Dongying depression, the physical properties cutoff and controlling factors of effective reservoir were analysed. Combined with distribution function curve method, oil production test method, testing method, minimum throat radius and irreducible water saturation method, the function of production Kcutoff was calculated in the form of Kcutoff=596.63e-0.002h, R=0.9429. On the basis of displacement pressure Pd, capillary median pressure Pc50, morphology of intrusive mercury curves and other parameters, four types of pore throat structure were recognized, with distinct value ranges of permeability K and permeability/porosity ratio K/Φ. And the functions about K and K/Φ ratio of the four types are respectively K/Φ=0.0508K0.9405, R=0.9894 (type I); K/Φ=0.1072K0.8252, R=0.9821 (type II); K/Φ=0.0983K0.8005, R=0.9870 (type III); K/Φ=0.0618K0.6506, R=0.9651 (type IV). Through the function of K and K/Φ ratio, the value of K/Φ ratio was calculated. Then the production Φcutoff has the function of Φcutoff=Kcutoff/K/Φ. In order to examine the reasonability of the calculated results, the oil production test data were checked out. Through comparing the average physical properties of one sandbody with production physical properties cutoff under the pore structure features, the accuracy rate of the comprehensive distinguishment was 82.35%. The data of the calculated production physical properties cutoff of the effective reservoir in Es3z-x was reliable. On the basis of calculated production physical properties cutoff, using the ways of quantization valuation, the physical properties cutoff and controlling factors of effective reservoir were analysed under a few conditions. Therefore sedimentation, diagenesis, formation pressure as the first order parameters, and lithology, sedimentary micro-facies, diagenetic stage, diagenetic facies and types of pressure as the second order parameters are processed with quantization valuation, in order to acquire the comprehensive scores, with the reservoir divided into five types (I, II1, II2, II3, III). Through the analysis, the score of the type I reservior with sedimentary micro-facies of underwater distributary channel, pebbled sandstone, normal pressure, and weak compaction diagenetic facies, is more than or equal to 0.9, as the best reservoir in Es3z-x of the Yonganzhen Area in Dongying depression, Bohaiwan Basin.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013