ABSTRACT
Serious lost circulation often occurs with relatively fast lost circulation velocity during drilling construction in Yingtai Area, Daqing oilfield. The maximum lost circulation velocity may reach 100–120 m3/h. The lost circulation volume is large, and the highest lost circulation volume may reach 1100 m3/well. The main cause of the lost circulation in this area lies in the relatively developed natural fracture in the Yingtai Area due to its geological structure. As to the characteristics of the lost circulation in the Yingtai Area, a test on plugging materials was carried out in the laboratory to evaluate six plugging materials of low-density rubber particles, dander plugging material, 801 plugging material, complex plugging material, liquid casing plugging material and shielding temporary plugging material. Through analysis of the effect of six plugging materials for fracture plugging of simulated formation, the plugging material suitable for the Yingtai Area, Daqing oilfield was found, based on which a field application was conducted, obtaining a good effect and effectively resolving the lost circulation problem during well exploration and drilling in this area.
