The Sequence Framework And Reservoir Characteristics Of The Forth Member Of The Shahejie Formation In Binnan-Lijin Area

Binnan-Lijin area located in the west section of the north belt of Dongying depression.Abundant glutenite body developed at the thrown side in the 4th member of the shahejie formation.Based on the integrate studying on the cores ,the logging data and the seismic data,the sequence framework was established ,the origin of the glutenite and the reservoir characteristics were systematically studied by the method of sequence stratigraphy,sedimentology and reservoir geology.Using the sequence theory named"VC",the forth member of the shahejie formation was divided into four third-order sequences.The upper part of the forth member were divided into two third-order sequences and six forth-order sequences.And according to the fault activity characteristics and depositional characteristics in Binnan-Lijin area,the comparative mode of the forth-order sequence units (middle base-level cycles) were discussed.The mode of the middle base-level cycle was controlled by the accommodation space change caused by the fault episodic activity in Lijin area.While the mode of the middle base-level cycle was controlled by the accommodation space change caused by the river and lake energy change.There were two provenance systems in the 4th member of the shahejie formation in Binnan-Lijin area,included Lijin provenance system from Chenjiazhuang uplift and Binnan provenance system from Binxian uplift.The detrital grain was fine and the sand with high quartz and high metamorphic lithic content was the main clastic sedimentary,so controlled by them the fan delta,braid delta,channel gravity flows and beach bar were the main facies types in Binnan provenance system.The detrital grain was coars and the sand with low quartz and high sedimentary lithic content was the main clastic sedimentary,so controlled by them the nearshore subaqueous fan and turbidite fan were the main facies types in Lijin provenance system.There were different sedimentary system space distribution and vertical evolution inBinnan,Bindong and Lijin area because of the different paleogeomorphic and tectonic evolution characteristics.The braid delta and the shore-shallow lake beach bar were the main sedimentary types at the early stage ,and the fan delta,the shore-shallow lake beach bar were the main sedimentary types at the late stage in Binnan area.The braid delta was the main sedimentary type at the early stage ,and the channel gravity flows was the main sedimentary type at the late stage in Bindong area.There were always nearshore subaqueous fan and turbidite fan developed in Lijin area.The formation and distribution of the sandbody were controlled by the provenance systems, paleogeomorphic and ancient water depth and so on.In all ,the main channels of the detritus migration were controlled by the bedrock valley ,the main deposition position of the glutenite was controlled by the geomorphology,and the main developing position of the glutenite in vertical was controlled by the base-level cycle.The reservoir space dominated by primary pore and secondary dissolution pore in Binnan area.While in Lijin area the reservoir space dominated by secondary dissolution pore and secondary fractures.The sedimentary facies and formation pressure controlled the reservoir efficiency,the effect of diagenesis on the reservoir efficiency was weak.The reservoir was estimated by the method of several factors synthesis.The development area of the beneficial reservoir included the sandbody of the fan delta,braid delta, beach bar and channel gravity flows facies in Binnan and Bindong area ,and the reservoir efficiency of the sandbody of the nearshore subaqueous fan and turbidite fan closely related with the fracture development degree in Lijin area.