Evalution Of Paleogene Reservior Characteristics And Stratigraphic-lithologic Traps In Western Tanhai Sag, Liaohe Oilfield

Paleogene Reserviors in the western beach area of Liaohe Basin have a great petroleum geologic potential. It is an important successive area for the further exploration and development in Liaohe Oil Field. Because of the limit of exploration data, the previous research of this area is relatively inadequate and lacks systematic comprehensive understanding. Therefore, it is important to study reservior characteristics and stratigraphic-lithologic trapsGuided with sedimentology, reservoir geology, high-resolution sequence stratigraphy, together with the technical methods of the observation and description of cores and specimen, well and logging data analysis, 3D seismic data volume tracking, reservoir's seismic reproduction, this research focuses on reservoir characteristics and stratigraphic-lithologic traps in West Tanhai Sag, Liaohe Oilfield.The main lithological types are feldspathic lithic sandstone, lithic feldspar sandstone, lithic sandstone and greywacke. The clastics were composed of quartz (16-48%, with an average of 31%), feldspar (16-56%, with an average of 28.3%) and debris (17-63%, with an average of 40.4%).The pore types are primary pores, secondary pores and composite ones.The porosity and permeability alter regularly with the burial depth and the abnormal high porosity and permeability appear at the depth of 1400 through 2600 meters and 2800 through 3400 meters. The research shows that the diagenetic stage of the reservoirs are from B substage of Early Diagenesis to A substage of Late Diagenesis and the diagenesis include mechanic compaction, cementation, dissolution and replacement.Making use of high-resolution sequence stratigraphy, change of base-level cycles controls vertical sediment mode, horizontal spread area and porosity-permeability of sandstone. Sequence frame controls different types of stratigraphic-lithologic traps, LST (low system tract) slope fan and sublacustrine fan, TST (transgressive systems tract) pinch-out upward sandstones, HST (high system tract) slump fan and deltas?Through analysis of 3D seismic data, in the research area, the stratigraphic- lithologic traps can be divided into four categories: sandstone lenses, pinch-out upward reservoir, turbidite, and buried highs.Jason inversion results show that eastern slope of Hulu island and core of Sag develop three sandstone lenses traps in E2d3, the sandstone lens trap on eastern slope of Hulu island is better stratigraphic-lithologic traps than others in E2s2, lithologic-tectonic traps distribute east slope of Bijialing in E2s2, and their sands are wide and continuing.