铝离子-聚合物凝胶调驱体系配方室内优选研究

Laboratory study of formula optimization on aluminum ion-polymer gel profile control system

铝离子-聚合物凝胶调驱技术是一种较为成熟的CDG调驱技术。从开展的调驱试验看,均取得了较好的增油效果,在相同的条件下,注剂成本低于单纯的聚合物驱油。由于A区水源矿化度高、钙镁二价离子含量高,导致注入液粘度低,注入浓度1350mg.L-1左右时,注入液粘度才达到45mPa.s,而萨南外试验区注入水配制的1200mg.L-1的聚合物溶液粘度则可达到66.0mPa.s以上。为此开展了室内研究工作,研究不同浓度铝离子-聚合物凝胶与不同水质的配伍性,研究表明配制水的矿化度越高,越难形成铝离子-聚合物凝胶;聚合物的分子量增大、溶液浓度增加、聚铝比降低,体系的粘度和转变压力增大,铝离子-聚合物凝胶越易于形成。随着体系中聚合物浓度的增加,采收率提高幅度增大,考虑到经济效益等问题,研究认为中分聚合物清水体系450mg.L-1、聚铝比30∶1为铝离子-聚合物凝胶体系可选配方,该数据为开展现场试验提供了理论依据。

Aluminum ion-polymer gel profile control technology is a kind of more mature CDG profile control technology. Transferred from the profile control test has been carried out, we can see it has obtained a good effect of oil increase. In the same conditions, the cost of injection agent is less than the pure polymer flooding. Because of high salinity water and high levels of calcium and magnesium ions, it has resulted in low viscosity fluid injected into A-oilfield. When the eoncentration of injected fluid reaches about 1350mg·L^-1, the viscosity just reaches 45mPa.s; But in Sanan test area the viscosity of 1200mg·L^-1 polymer solution prepared with injection water can reach above 66.0mPa·s. We earry out the laboratory study and work on the compatibility of different concentrations of Aluminum ion-polymer gel with different water qualities. The study has shown that the higher the salinity of water preparation, the more difficult it is to form the Aluminum ion -polymer gel; As the polymer molecular weight increases, the solution concentration increases and the poly-aluminum ratio decreases, the viscosity and trans- formed pressure of the system increase, so it will be easier to form the Aluminum ion-polymer gel. With the in- crease of polymer concentration in the system, the recovery degree increases in a large range. Taking into account the economic benefits, the study suggests that the aluminum ion -polymer gel system of 450mg·L^-1 polymer water system and 30：1 poly-aluminum ratio in the refining process is an optional formula to provide technical support for the next step to carry out field trials.