Research and application of plugging technology for fractured formation in Yihuang block

Drilling & Production Engineering Technology Institute, CNPC Chuanqing Drilling Engineering Company Ltd., Xi’an, Shaanxi, 710018, China

Abstract

The formation drilling in Yihuang block is prone to loss and difficult to plug. Through field practice and mechanism analysis, it is concluded that the leakage in this block is mainly caused by the propagation of micro-fractures and the connection of natural fractures. In view of the leakage characteristics of the block, the indoor study is carried out, and all the plugging materials in the plugging zone are cemented and solidified with gel materials, forming a plugging working liquid called Dust-1. The working fluid works at well temperature of 50~60°C, curing strength of 24 hours is 28MPa, good fluidity, strong pressure bearing capacity and can be cured. In the field test of 7 Wells in Yihuang block, the drilling cost is reduced by 15%, and the pressure bearing capacity of leakage layer is increased from 1.19g/cm3 to 1.25g/cm3, indicating that this technology can meet the plugging needs of differential pressure induced fracture loss in Yihuang block.