Study On The Transporting Capability Of The Sandstone And Unconformity In The Shallow Strata Of Dongpu Sag

There were two main types of pathway system in shallow strata of Dongpu sag.The two types of pathway system were sandstone and unconformity.The deep hydrocarbon that was migrated along faults from deep strata to shallow strata,mainly lateral or vertical migration happened in the two types of pathway system.They were the communication channels between the hydrocarbon source faults and the traps of shallow strata.It was very important to forecast shallow strata hydrocarbon reservoir that studied the distribution of them.On the basis of sedimentary facies,integrated macro-distribution and micro-pore texture of the sandstone,the distribution range and micro-transporting capability of the sandstone were investigated.And then,On the basis of diagenesis,in combination with the characteristics of the today's porosity and permeability of the sandstone pathway system,the porosity and permeability in the critical period were reconstructed through seizing the main factors that changed the porosity and permeability and using the image analysis and the measured results of pore diameter in scanning electron microscope.On the basis of the statistics of log data and the detailed explanation of seismic data,integrated the micro-lithology texture,macro-tectonic style and their configuration,the existent type and distribution of the unconformity of the Dongying Formation in Dongpu sag were analyzed and summarized.On the basis of the study of the transporting medium,integrated hydrodynamics and fluctuation of the unconformity in critical period,introducied storage coefficient and flowage coefficient,the distribution range of the sandstone and unconformity efficacy pathway system in the critical period was sketched,and the shallow strata sandstone and unconformity transporting model in the critical period was summarized.It is shown that that the distribution of the shallow sandstone of transporting strata was controled by sedimentary facies,the sandstone shown as leaflike in the first member of the Shahejie Formation was distributed in the edge of sag;the sandstone of the Dongying Formation was distributed in the south,the center and the northeast region;the Guantao Formation almost entirely was composed of coarse-grained sediment;the sandstone in the lower segment of the Minghuazhen Formation was distributed almost throughout the region.The micro-pore structure of sandstone shown that the width of throat and the ratio of pore and throat diameter was the main factors that affected the transporting capability of the sandstone.The diagenetic history shown that the main diagenesis that changed the porosity and permeability of the first member of the Shahejie Formation and the Dongying Formation sandstone was the denudation and the packing action of dissolution product,the porosity and permeability of the Guantao Formation and the Minghuazhen Formation sandstone was changed weakerly by diagenesis from the critical period.There were four types with the unconformity of the Dongying Formation.They were lateral transportation, vertical transportation,trap and non-transportation.In these four types,the lateral and vertical transportation was the role of transporting.The lateral transportation was mainly distributed in the west slope and the vertical transportation was mainly distributed the central uplift.The lateral and vertical transportation had the help(?)for the hydrocarbon accumulation of the Dongying Formation and the Minghuazhen Formation separately.The sandstone efficacy pathway system in the first member of the Shahejie Formation was distributed in the east,the west and the north region;it was distributed in the north of Qianliyuan region,the sorth of Guancheng region, Huzhuangji region and Qingzuji region in Dongying Formation;it is distributed broadly,in addition to the north and the local area of the west,other areas were its distribution areas in the lower segment of Minghuazhen Formation.