Research On Enhanced Oil Recovery During Foam Profile Modification In High Water-cut Reservoir

According to the analysis of influencing factor of the sweep efficiency and displacement efficiency, firstly all sorts of new methods for enhanced oil recovery should synthetically consider two aspects as follows: one is to enhance the sweep efficiency through improving mobility,two is to enhance displacement efficiency through minishing interfacial tension or removing interfacial interaction between working agent and crude oil. Foam flooding is a kind of tertiary recovery that using foam as oil displacement medium, because it has high viscosity,strong ability of plugging and profile control, has selectivity for oil\water plugging ,and has the function of enhancing oil displacement efficiency, foam flooding is likely to effectively take over a kind of technique that improve development effect of water displacement or enhanced oil recovery after polymer displacement.The overseas mainly carries on several aspectes for foam flooding as follows:the mechanism for foam formation;the research for foam stability; the research for foam rheological property; the research for the function relation of foam material.The domestic also carries on a great deal of researches for the related contents. Also carried on experiments in the foam mine for many times at home and abroad, obtained a more results. Currently the primary problem of the research of numerical simulation for foam flooding is too many kinds of chemical parameter equation for foam, each has merit and shortcoming and hard tobuild up an uniform function relation model. On the other hand,these foam mechanism chemical equations still exist the following problems: without considering the wash oil function of surfactant and the problems of absorption and loss during displacement;about the research of enhanced oil recovery for foam flooding,people will pay more attention to its mechanism and phenomenon,but these mechanisms toward the degree of function for enhanced oil recovery,modeling mechanism and corresponding problem of reservoir engineering need an in-depth study;without considering or inadequately considering the influences of the pore structure to the formation rate,polymerization rate.based on the above causes,it is absolutely necessary to make an in-depth study to the theory and application of foam profile for nitrogen from four subjects of the physical model and mechanism study,building maths model,field application of foam profile for nitrogen,improve the interrelated theory and combine concrete field application to ulteriorly improve the application level of foam profile for nitrogen.The laboratory experiment of foam flooding system for nitrogen include:the static evaluation of foam system;the optimization of injection paramer for foam flooding of nitrogen;effect evaluation of foam flooding for nitrogen; according to the experiment to chose the agreeable foaming agent,chose appropriate injection-production parameters,the experiment showed that it is feasible to carry on the foam profile for nitrogen at commingled production block of high and low permeate layers.The research of numerical simulation in Block Xing212 reservoir fitted the development history for water displacement of the Xing212 block,the distribution of remaining oil for water displacement and potential analysis, on the basis of those carrying on the study of program and effect forecast for foam flooding of the Block Xing212 well group,and chose the Xing147 well group to implement the field experiment.The research result showed that the Block Xing212 enrich a number of remaining oil,the compatibility of the frother A of the foam profile system and the fluid of the Block Xing212 is better,when the concentration of the frother is 0.5%,make the water gas ratio to 1:1, inject 0.2pv nitrogen, improve recovery more than percent of fifteen for water displacement. the Xing147 well group were chosed to be the prior experimental well...