Sequence Stratigraphy Framework And Oil & Gas Reservoir Prediction In Xindong Areas, The Dongying Depression

Paleogene and neogene formations are researched in Xindong areas, Dongying depression. Through stratigraphy division, sedimentary facies analysis, reservoir evaluation, and reservoir characteristic & accumulation model analysis, oil-gas reservoirs are researched, and favorable exploration targets are predicted.Firstly division four second-order sequences and seven third-order sequences, isochronous stratigraphic framework for the forecasting of reservoir & trap. Rock types include sandstone, limestone, mudstone, and shale. Sand and mudstone are chiefly rock. By core observation, logging curve analysis, individual well sedimentary facies analysis, facies analysis and seismic facies in the profile, it is known that sedimentary environments include delta, shore-shallow lacustrine, deep and semi-deep lake facies, sub-lacustrine fan. Vertical evolution series are from turbidite fan to pro-delta, delta front, delta plain, fluvial facies, and shallow-lake facies. Sandstones comprise pebbled sandstone, moderate coarse sandstone, fine sandstone, and siltstone. Reservoir porosity type is mainly secondary porosity, because carbonate cements, feldspan and fractional cuttings dissolution, and clay minerals dehydration in 1600-2200m & 2600-3200m belts. Secondary porosity broadly distributes middle-fine sandstone which is controlled by fault activities and effective source rocks maturity. Permeability formations chiefly distribute Dongying member, Sha-2 member and Sha-3 upper segment.Hydrocarbon reservoir types contain fault, lithologic, fault-lithologic traps. Reservoirs are two period formations. The first is the primary hydrocarbon reservoir in oil source bed of Dongying period in Paleogene. The second is the formation from Neogene to Quaternary, and Minghuazhen period and Quaternary are mainly oil-gas migration-accumulation. The reservoir-formed dynamic system could be divided into lower self-source enclosed take, middle allo-source to self-source semi-full enclosed type and upper allo-source semi-open enclosed one.By integrating main controlling factors and oil-gas distribution, three favorable exploration targets are predicted. First is the turbidite of Sha-4 member and Sha-3 middle segment, and is lithologic trap in the flank of structure. Second is the sandstone of Sha-3 upper segment and Sha-2 member. It is porosity and permeability formation, and fault sealing controls hydrocarbon accumulation. Final is the shallow secondary hydrocarbon accumulations in the formation from Guantao member to Minghuazhen member, because oil & gas persistent migrating through fault and sand-body from flank to center, from deep to shallow in one structure.