The Adaptability Study Of Polymer Flooding For Niuxintuo Oilfield

The Niuxintuo Oilfied what is low-permeability fractured reservoir. At present, it'scomposite water rate is above 70 percent through about twenty years of water-blooding, it hasgotten into middle-high composite water period when its composite water rises quickly andoil yield declines by a wide range. Harder and harder stabilizing yield is. polymer flooding isan effective technology of stabilizing yield during middle and later period of water- floodingexploitation of the oilfield. But little work has been done for the study and application of highpour point heavy crude reservoir with low split characteristic. For the feasibility study ofpolymer flooding in Niuxintuo oilfield was undertaken to estimate the feasibility of polymerflooding in Niuxintuo oilfield and to get optimal flooding plan. By the studies of flowingexperiments and judging surface tension, the molecular weight and consistence of thepolymer which is suited to Niuxintuo oilfield, the surfactant have been ascertained. On thisbasis, we have compiled displacing oil experiment plan, determined the viscoelasticity ofdisplacing oil system and carried out indoor physics simulation tests in which the three kindsof plans of polymer flooding, active water flooding and binary-compounds flooding arecombined with adjusting section through the artificial anisotropic syenite cores with differentsplit length and different coefficient of variation. Form them, we have picked out two betterkinds of displacing-oil systems, and researched the law in which how the split length andcoefficient of variation affect the effect of displacing-oil. In the end, we have checked theeffects of displacing oil of the two kinds displacing oil systems through the natural cores.Otherwise, we have also implemented numerical simulation of displacing oil effects ofdisplacing systems on the conditions of various pore volume and polymer consistency.The tests showed the ragularities that with the addition of split length the recovery ratioincreased accordingly, that with the addition of coefficient of variation chemical floodingrecovery ratio increased and overall recovery efficiency declined, that with the addition ofpore volume and polymer consistency the recovery ratio increased. Synthesizing the results of physical simulation and numerical simulation can give the plans of field application andoffer theoretical bases to field application, and they can have definite the significance ofguidance to field application.