Optimization Of Injection Parameters For Pre-Slug Of ASP Flooding For Major Reservoir In Nanyixixi Block

On the basis of the original well pattern, oil and water wells were encrypted and then fully went into production in September 2006 in major reservoir of Nanyixixi Block of Sazhong development area, which are currently at the blank water flooding stage of ASP flooding. Due to the serious heterogeneity of major reservoir of the block, the single-well personalized injection of pre-slug can be adopted for plane and profile adjustments before ASP flooding to enable ASP flooding technology adapt to a different reservoir and ultra-low interfacial tension flooding within the whole reservoir thickness.In the paper, the geological deposition feature, reservoir heterogeneity, flooding conditions and degree of reservoir use of major reservoir of Nanyixixi block were analyzed. Through physical simulation experiments, the formula of ASP flooding injection system was optimized which was suitable for major reservoir and the compatibility of pre-slug and the formula was studied. The fine geological model of Pâ… 1-4 oil layers was established in the 3# injection plant of Nanyixixi block of Sazhong development area, and based on the water flooding history matching, the numerical simulation research was completed with regard to optimization of injection parameters for pre-slug of ASP flooding. The results showed that the best ASP formula was 1.2% NaOH +0.3% surfactant + 2300mg/L, 25 million, 0.3PV polymer solution, the combination system of the formula and polymer pre-slug may ensure that the displacement efficiency of chemical flooding was increased by 20% than water flooding. The best injection parameters of pre-slug of combination flooding were 38 million, 2300mg/L, 0.05PV polymer slug, and the value of enhanced oil recovery rate of the combination system which was composed of pre-slug,ASP main slug and follow-up polymer protection slug can be up to 19.58%.In the paper, injection parameters of pre-slug of ASP flooding in major reservoir of 3# injection plant of Nanyixixi block were optimized which improved the tapping effect of major reservoir, and the outcomes of this paper provided the practical experience and theoretical reference for high and stable yield in Daqing oil field.