溶液の粘弾性を考慮したポリマー攻法の解析 その２．一次元ポリマー攻法の室内実験

Abstract

To study how the viscoelastic flow behavior of polymer solution described in Part. 1 (ref. 1) had an effect on oil-recovery performance, 1 D flood experiments were carried out with glass-bead packed cores. Two white mineral oils of viscosity about 25mPa•s and 50mPa•s were used as displaced fluids. In each experiment, water and polymer floods were done with the same core at a relatively-high flooding velocity above 16μm/s. In polymer floods, polymer concentration of effluents was measured by the spectrophotometric method of M.W. SCOGGINS and J.W. MILLER.In polymer floods, oil was recovered faster as flooding velocity became faster. In high flooding velocity, interstitial velocity of polymer solution in the core becomes high and shear rate for flow becomes larger, too. The viscoelastic flow behavior of polymer solution that increased its viscosity with increasing shear rate was thought to improve mobility ratio and make oil recovery faster. By analysis of polymer-concentration histories of effluents, water bank was observed to be produced from the core before breakthrough of injected polymer solution. This water bank was thought to originate from mobile water which was initially present in the core before the flood. The histories of pressure of oil and water phase at the center of cores during flood experiments were measured separately with semi-permeable filters made of teflon and ceramics. Oil pressure could be measured well, but the method to measure water pressure was remained to be a problem.These data obtained in this study will be compared with calculated results by the simulater in the next paper.