Three Pond Lake Basin To Cow Circle Lake Piece Of Xishan Kiln Reservoir Characteristics Research

The Santanghu oilfield Niujuanhu block Xishanyao group reservoir is a low porosity and permeability reservoir, owing to not have a clear understanding of its water flooding mechanism and controlling factors, injection and recovery have quick responses demonstrated in the production process, obvious contradiction between the plan and section plan, most of the wells after fracturing put into production, the high moisture content, the characteristics of the low-yielding liquid, poor water flooding, low production per well. In order to enhance the effects of reservoir development and further improve the oil recovery ratio of the study area, in this paper, the following experimental methods include casting thin sections, scanning electron microscopy, authentic sandstone microcosmic water flooding, the conventional high-pressure mercury intrusion, constant pressure mercury, nuclear magnetic resonance, etc. have been used on the study area, to conduct an in-depth research of the sandstone reservoir rock pore structure and microscopic flow characteristics. After study we can see Niujuanhu oilfield Xishanyao group reservoir is a low porosity and permeability reservoir, the microscopic pore structure of sandstone reservoirs is complex and have strong heterogeneity, and the waterflood development of water displacing oil efficiency is poor in production. Through a variety of experimental methods to analyze the study area, the oil displacement efficiency of the waterflood development in addition to the size of the reservoir porosity and permeability impact, but also impacted by the heterogeneity of the reservoir, and reservoir heterogeneity is an important affecting factor to the oil displacement efficiency.Obtained through this study, Xishanyao reservoir is fan delta front subfacies. Pore types are mainly tuffaceous dissolved pores, intergranular pores and feldspar dissolution porosity, the main types of pore combination is intercrystal pore-dissolution pore type and intergranular pore-dissolution pore type, the type of throat mainly is point-like throat, flaked or curved sheet throat, pore throat overall connectivity is poor, coordination number is relatively low.According to casting thin sections and scanning electron microscopy observe we found that Niujuanhu reservoir bed experienced the types of diagenesis including compaction, cementation, dissolution, and a small amount of metasomatism and recrystallization. compaction makes the original pore space of sandstone reservoirs become less; cementation is not only destroy part of the primary porosity and further damage to the secondary dissolved pores, in addition, authigenic minerals filling and cementation lead to deterioration of reservoir permeability is one of the important reasons. Because of the dissolution and the formation of secondary dissolved pores, the reservoir space has increased. The diagenesis stages of Xishanyao group reservoirs are early diagenetic B-late diagenetic A. After research, the study area diagenesis type is more, and the causes is complicated, which further enhanced the reservoir heterogeneity.Through authentic sandstone micro-pore model water flooding experiment, the observed displacement types are well-distributed displacement type, the fingerlike displacement type and mesh displacement type, and the model type of residual oil mainly are pellicle residual oil, flow around the residual oil and water channeling the residual oil. After analysis of the physical properties of reservoir rock, injection pressure, injection multiples, and microscopic pore structure as well as heterogeneity which are varying degrees of impact on oil displacement efficiency, and the most prominent impact of the reservoir is the heterogeneity.