Study On Provenance System And Reservoir Characteristics Of Upper Es₄ In The Western Area Of Guangli

The western area of Guangli is located in the east slope of Niuzhuang Sag in Dongying Depression,and the deposition of the Upper Es4 mainly developed sandstone, siltstone, shale and other kinds of sedimentary strata. By the comprehensiveutilization of drilling core data, logging data, seismic data and other related test and analysis data,and based on the fundamental principles of sequence stratigraphy ,sedimentology and reservoir geology, the framework of sequence stratigraphy ,the provenance system ,genetic types and distribution of sandbody, the reservoir characteristics and evaluation of effective reservoirs were systematically studiedThe Upper Es4 is divided into two third-order sequences , respectively corresponded to chunshang and chunxia deposition.The chunxia sequence is divided into low stand system tract,lake transgressive system tract and highstand system tract.The chunshang sequence is divided into lake transgressive system tract and lake regression system tract,and it is divided into nine quasi sequence groups furtherly.There are south and north two provenance systems in formation period for the upper Es4,the south provenance area is the west shandong rise and sediments of south provenance system is characterized by high mature degree and fine size. The northeastprovenance area is qingtuozi salient and sediments of the provenance system is characterized by low mature degree and rough granularity.The south provenancesystem was developed in early sedimentary stage of the upper Es4 and it controls the early deposition system of meandering river delta, sand bar of shallow-shore lacustrineand other sedimentary systems. The northeast provenance system was developed in late sedimentary stage of the upper Es4 and it mainly controls the sedimentary system of braided delta and fan delta. The middle sedimentary stage of the upper Es4 when the fifth quasi sequence groups of chunshang deposition formed was under the control oftwo major provenance systems and the sedimentary types are sand bar of shallow-shore lacustrine and channel gravity flow deposition.The reservoir of the upper Es4 has a relatively good quality and the reservoir spaces invole primary pore,secondary pores and. small amount of fractures.Based onoil production test data,the lower limit of petrophysical parameters of effective reservoirs is calculated systematically. Reservoir effectiveness is controlled by sedimentation,formation pressure and diagenesis synthetically,and sedimentation is key factor to form effective reservoirs.On the base of analysis of main controlling factors of effective reservoirs,the reservoirs are classified into eight categories.