Micro-properties and influence factors of deep turbidite fan reservoirs in the eastern Dongying subbasin, Shandong

Abstract：Most of turbidite sandstones are fluxoturbidite in the delta front in the deep zone of the eastern part of the Dongying subbasin. The turbidite sandbody reservoir of the deep zone consists predominantly of feldspathic fine sandstone, lithic fine sandstone and siltstone with low compositional maturity and textural maturity. The micro-properties of the reservoir show that the reservoir space types include primary pores, micro-pores in clay mineral matrix, intergranular dissolution pores, intragranular dissolution pores and micro-fissures, and the pore textures are mainly of low-permeability, fine-throat type, and that the reservoir has medium- and low porosity and low permeability and so poor physical properties. Study of the influence factors of the reservoir physical properties indicates that the rock fabric, sedimentary micro-facies, diagenesis and the generation and distribution of abnormally high pressures are the main factors for influencing the physical properties of the turbidite sandbody reservoir in the study area, of which diagenesis has obviously modified the physical properties of the turbidite sandbody and compaction and cementation are the main factors which caused the porosity and permeability of turbidite sandstones become poor. On the other hand, dissolution and diagenetic shrinking improved the porosity and permeability of the reservoir. The existence of the abnormal high pressures, high geothermal field and early hydrocarbon injection play a good role in conserving and improving the physical properties of the reservoir.