Capillary Interaction of Different Oleic and Aqueous Phases Between Matrix andFracture Under Ultrasonic Waves

摘要

Various mechanisms may be responsible for enhancing theflow of oil through porous media in the presence of anacoustic field. Major capillary related mechanisms areperistaltic transport due to mechanical deformation of the porewalls, reduction of capillary forces due to the destruction ofsurface films generated across pore boundaries, coalescence ofoil drops due to the Bjerknes forces, oscillation and excitationof capillary trapped oil drops, and sono-capillary effects. Thisstudy aims at analyzing the influence of high-intensityultrasonic radiation on spontaneous imbibition of surfactantand polymer solutions into porous media.A series of laboratory experiments were performed usingcylindrical Berea sandstone samples with all sides (co-currentimbibition) and only one side (counter-current imbibition)open to flow contacting with the aqueous phase. Emphasiswas given to the fluids of special interest to well stimulationand EOR applications. Anionic and nonionic surfactantsolutions above and below the CMC were chosen to evaluatethe effects of ultrasonic waves on the imbibition of lowinterfacial tension fluids and microemulsions. Xanthan gumsolutions were also used as an aqueous phase to examine theeffects of ultrasonic waves on the imbibition of viscoelasticfluids. The oil-saturated cores (crude and processed oil) wereplaced in an ultrasonic reaction chamber, and brought intocontact with the aqueous phase. The recovery rate due tocapillary imbibition was monitored against time.We compared the capillary imbibition recoveries with andwithout ultrasonic waves. A substantial increase in finalrecovery (up to 25% OOIP) and minor increase in recoveryrate was observed when ultrasonic waves were applied to thesurfactant solution. High intensity ultrasound was observed toenhance surfactant solubility and reduce adsorption onto therock matrix. A small increase in the ultimate recovery wasobserved at low polymer concentration. At higher polymer concentrations, however, the difference rose significantly (upto 12% OOIP).