| Yuan284oilfield is one of the important oil producing area In theHuaqing area of Ordos Basin, and chang63of Triassic Yanchang formation is the main oil-bearing in the field. Due to the long-term water flooding development,the study area currently has been in high water cut exploitation phase,reservoir properties, the water flooding regular pattern and percolation characteristics are very different with before in this phase, the reservoir heterogeneity strongly, and not enough understanding on microscopic flow characteristics of low permeability sandstone reservoir, the description is not enough meticulous, tapping the potential difficulty of remaining oil in the study area is also growing. Therefore, it is necessary to recognize study area chang63oil-bearing formation reservoir in high water cut period, it is more reasonable and more refined to reservoir flow unit division, and further understand the characteristics of the reservoir at this stage; and get to in-depth study about the microscopic flow characteristics of different flow units, to find out at this stage reservoir flow unit property characteristics,waterflood oil flow characteristics, influence factors and the shape and formation mechanism of remaining oil and distribution regular pattern, for the exploitation of the late deployment of oilfield providing a scientific basis, the corresponding measures for the further adjustment of oil zone has important guiding significance.The study on reservoir geology, the development of geology,combining previous research results, based on the analysis of a lot of well logging, mud logging, experiment data and the microscopic percolation water flooding experiment method and means, to study petrologic feature, microscopic pore structure characteristics and microscopic percolation characteristics on chang63petrology characteristics of reservoir flow unit.Research chang63reservoir in the ordos basin west leans against the background of monoclinic, form4-5nose-like structure, mainly for the delta front sedimentary subfacies, including underwater distributary channel and distributary bay; chang63reservoir flow units can be divided into three categories, including I class flow unit storage and permeability is best; II class flow unit times;III worst type of flow unit;And different rock types of flow unit, clastic composition, filler type, pore type, throat type and pore structure is different..Through the research of flooding experiments about Chang63reservoir microscopic sandstone models shows:displacement type of oil flooding water and water flooding oil in study area is mainly non-homogeneous type, Includes a mesh displacement, the fingers and the net displacement of finger drive for three types, displacement modes of water flooding oil have piston and non-piston, shape of residual oil reservoir diversity, Including flakes, small clusters, oil film,card off type oil droplets and solitary point residual oil; iMPact factors mainly of oil displacement efficiency in study area have reservoir properties, microscopic pore structure, interstitial content, micro-heterogeneity, displacement pressure and injection multiple.Through the flow unit division and percolation characteristics of Chang63reservoir study, As can be seen:different flow units corresponding to percolation characteristics are different, Mainly in the oil-driven water features, water displacing oil, displacement mode, displacement efficiency and the residual oil types are different. Through these studies can be found, the remaining oil is mainly distributed in Ⅱ and Ⅲ types flow unit in study area. |
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