The Research Of Pore Structure Characteristics Of Second-class Reservoirs In Daqing Placantieline

Though the conventional mercury penetration experiment, the rate controlled mercurypenetration experiment, the X-ray CT scanning technology and the principle of the fractalgeometry, the pore structure characteristics of the second-class reservoirs were studied inDaqing Placantieline. By using the conventional mercury penetration experiment date of398second-class reservoirs and major reservoirs cores and the rate controlled mercury penetrationexperiment data of10second-class reservoirs cores, the pore structure characteristicsparameters were obtained, the pore volume, permeability contribution and pseudo pore-throatratio distribution of different pore radius interval in second-class reservoirs and majorreservoirs were analyzed, the distribution characteristic of pore radius, throat radius andpore-throat ratio of second-class reservoirs were researched, the differences of pore structurebetween second-class reservoirs and major reservoirs were given. By using the X-ray CTscanning technology, the coordination numbers of cores were given. According to theprinciple of the fractal geometry, by use of the conventional mercury penetration experimentdata, the pore structure fractal dimension and other fractal parameters were calculated.The results showed that more than60%of the second-class reservoirs pore volumedistributed in the pore radius interval from0.1m to5m, the range of pseudo pore-throatratio was1.5~89.5. More than50%of the major reservoirs pore volume distributed in thepore radius interval from5m to20m, the range of pseudo pore-throat ratio was1.04~3.2.Therefore the reservoir space range of second-class reservoirs was from0.1m to5m andthe major reservoirs were from5m to20m. The rate controlled mercury penetrationexperiment results showed that, the range of second-class reservoirs pore-throat ratio was20~120and the range of major reservoirs pore-throat ratio was15~45. The pore-throat ratiowas much higher than the pseudo pore-throat ratio. Though the X-ray CT scanning technology,the range of cores coordination number was5~15, but mainly concentrated in the7~11. Thepore structures of cores have fractal property, the fractal dimensions of second-class reservoirsand major reservoirs were between2and3. The fractal dimension of second-class reservoirswas more than that of the major reservoirs. The mean and the median values of pore radiusand the relative sorting coefficient calculated by means of the fractal dimension accorded withthe results of the conventional mercury penetration experiment.