Study On The Sedimentary Characteristics And Its Effectiveness Of Sand-conglomerate Bodies In The Paleogene Of Northern Chezhen Depression

In this paper, on the basis of seismic, logging, core and other analysis data, using of sedimentology, reservoir geology and other research methods, conducts a study of sedimentary characteristics, distribution rules and controlling factors, characteristics and effectiveness of reservoir of the Glutenite of the steep slope of Chezhen depression during Paleogene. The result and conclusion are obtained as follow:It mainly developed alluvial fan, inshore subwater fan, fan delta and sublacustrine fan that four kind of genetic types of the fan body in the steep slope of Chezhen depression during Paleogene. And it mainly developed alluvial fan in Es4x; fan delta and small-scale sublacustrine fan in Es4s; inshore subwater fan and sublacustrine fan in Es3x; inshore subwater fan and slumping turbidite fan in Es3z; fan delta and inshore subwater fan in Es3s; fan delta in Es2-Ed.Glutenite fanbody in the north steep slope of Chezhen depression with the characteristics about Fan—groove corresponded, distribute like skirts, in the plane, and multistage superposition, inheritance development in vertical direction. The distribution characteristics of glutenite fanbody are complicated, such as the forceful source control, the fault control groove, bottom boundary control the shape, evolution control layer etc. All of these characteristic means that the activity of chengnan boundary fault control the source of glutenite fanbody, the fault control the distribution of all groove in depression, the combination of fault surface and bottom shape control sedimentary types and assemblage characters. Sequence evolution control of the distribution of glutenite layers .The main kinds of reservoir space are primary porosity, secondary porosity and cracks in the steep slope of Chezhen depression during Paleogene. The foremost reservoir space of shallow is primary porosity and in deep is secondary porosity. The diagenesis types are various. Overall the pore throat structure is poor, and reservoir properties deteriorate with the increase of depth.The porosity lower limit and log depth are linear relationship, and the lower permeability limit and depth are exponential relationship in Es3 in the north steep slope of Chezhen depression, and the lower property limit of reservoir properties have a descent trend with depth increase. The lower limit of effective physical properties of reservoirs in Es3 in Chexi area and Dawangbei, Guojuzi area were got separately. The lower limit of physical property of Es3 in Chexi area is lower than that of Dawangbei and Guojuzi area in that this formations in Chexi area have lower density and viscosity of crude oil and more developed overpressure in formation than those of Dawangbei and Guojuzi area. Regarding the porosity and permeability difference as comparison parameters, the controlling actions of which sedimentation, formation pressure and diagenesis played on the Es3 effective reservoir were researched. And the main controlling factor was discussed. It is thought that deposition is the most important factor affecting the reservoir, which is followed by diagenesis and the least is pressure.