关键词: 储集层, 孔喉网络场, 演化规律, 渗流场, 三角洲储层, 剩余油分布模式

Abstract: Water-flooding is the main method for oilfield development in the eastern China.The reservoirs for a long-term water-flooding development can be lixiviated and scoured continually by the injected fluid.The clay,seepage,pore throat and rock framework of reservoirs will be changed dynamically after a long-term water flooding,which may cause the complex pattern of remaining oil distribution.Taking the data of a delta reservoir in the third layer of eighth group of second member of Shahejie Formation in Shengtuo oilfield,the pore-throat-net evolvement law and mechanism of the reservoir lixiviated and scoured by developed fluid over a long period were investigated.The relationship between variety of microscope reservoir and micro remaining oil distribution was also analyzed.The results show that the pore-throat-net evolvement was caused by dynamical geological process of developed fluid in the reservoir and also took place dynamically and continually.The general laws of evolvement show the following features:①The point and line contacts of grains decreased;②The communication degree of pore with throat increased.The grading of pore and throat got meliorative;③The total content of clay was reduced;④The wettability of rock trended to hydrophile.The distribution of remaining oil in reservoir was controlled and affected by the pore-throat-net evolvement.Four types of distribution modes for micro remaining oil in the development stage of reservoir with supper high water-cut were built up.

Key words: reservoir, pore throat net, evolvement, seepage field, delta reservoir, remaining oil distribution mode