The Blockage Theory For Polymer Flooding Injector And Research Reservoir Effective Retrievement Technolug

After entering into the industrialized development stage of large scale of polymer flooding in Daqing oil field, that the longer time of polymer injection, the higher injection pressure occurred, has become a prominent problem day alter day Therefore, directly affects the development period of polymer Hooding and total economy profits.Base on the research of increment of injection pressure, a point that the major reason for increased injection pressure is an attribution to the blockage of polymer deposition is presented in this paper The injection pressure increment, which caused by well bore pollution is obviously bigger than that by deposition of polymer in well bore. The injection pressure increasing by deposition of polymer in well bore is a relatively slow process, but the trend of injection pressure increasing is continues with the total amount of accumulative polymer injection, and it's a kind of unavoidable tread, therefore, polymer deposition causing the increment of injection pressure is an inevitable result for polymer flooding to increase EOR.The major radius of polymer deposition in well bore is described using Numberical Modeling, the degree of injection pressure increment becomes smaller with the longer well distance, and the larger the pressure gradient changing area, namely, polymer mainly absorbing, deposition and gathering in this area, within 40m to the injector, contributing to the increment of polymer injection pressure.MD membrane is developed and selected in lab, as a tiny positive ion polymer melecule deposition MD membrane, it's a kind Nami level membrane, which is created, by the interaction of static electricity between organic (inorganic) positive ion and negative ion, having the features of intensive force, heat stability, long period stability, economy, intoxication, no pollution, independence of membrane without restriction of shape and the area of the rocks. Experiment indicates that MD membrane is well adaptive to the reservoir, and compatible to water in place polymer and crude oil in Daqing oil field. It's proved by static and dynamic absorption test that MD membrane has perfect absorption feature to the rock, the biggest amounts of MD membrane absorption in the surface of crude oil and sand is as high as 0.4mg/g.The feasibility of injection enhancing technology by MD membrane and the resolution to high injection pressure problem is approached through physical modeling driving MD membrane, the higher molecule weight it has, the lower effect on injection enhancing is, by comparison to water driving the draw down doesn't decrease distinctively, it has a ideal effect.So can say, the length of molecule chain has certain adaptivity with the size of porosity, when decreasing the concentration of MD membrane from 400mg/l to 200mg/l, the effect has a little change, because unless the certain amounts of MD membrane absorption achieved, it can have the functioning to decrease the draw down, the low concentration of MD membrane is helpless for absorption. For verities rocks, just because for higher permeability formation, the amounts of MD membrane gathering there is relatively less than that of lower permeability formation, and increment of pressure in higher permeability formation by MD membraneAccording to the analysis of MD membrane "self loading", dispersing into membrane, the theory for EOR increasing, the process for MD molecule membrane to because MD membrane is the attraction of by the functional distance of static electricity action is becoming even longer, the force is proportional to square distance, and due to the repel of itself, it's impossible for them to absorb in two layers, but only one, spreading along the direction of higher electricity attraction in the surface of crude oil and sand until reaching the bottom of oil drop. The above process dispersing to membrane is called "self loading". Obviously," self loading", process can change the moisture of formation to increase EOR, therefore, this technology will not have the disadvantageous effect to the EOR wh...