THE EFFECT OF FLUID LOSS AND SUCTION WITH INVERTED SEQUENCE ON CEMENTING QUALITY OF RESERVOIR IN ADJUSTMENT WELL AND ITS PREVENTION

Generally the cementing of adjustment well is of bad quality because longterm water injection made the formation pressure, temperature and heat absorption environment of cement slurry change. The characteristics of cementing technology determined that the highest point of temperature of cement slurry that returned to the annulus was in the certain distance away from the bottomhole instead of bottomhole reservoirs. The cement slurry with higher temperature had priorlty to enter the initial setting period and began to loss weight after returning to the annulus. Thls made the lower cement slurry without being solidified absorbed into fluid from higher pressure formation and began to discharge into the lower pressure formation,, it was defined as "fluid loss and suction with inverted sequence"for cement slurry. So the cementing of slurry is always from bad quality. This paper analyzed the reason for "fluid loss and suction with inverted sequence" and gave precautions.With the field test of some wells, the optimlzation of types and dosages of filtrate loss reduction additive for cement slurry is beneficial for improving cementing quality.