Application of High Density-saturated organic salt drilling fluidin Well Yangtake 5

The problem of borehole instability in Lower tertiary of Yangtake region has been kept as a major difficulty in the exploration and development.The key of successful drilling of complex lithological formation was to use drilling fluid with appropriate density.This paper analyzed and researched the labile factor of Yangtake region Lower tertiary complex formation and the difficulties to the implementation of drilling fluid technology,improved the compatibility of the drilling fluid and optimized High Density-saturated organic salt drilling fluid system as the appropriate drilling fluid.The drilling fluid system has good rheological,building capacity,oiliness and rejection capability.Application result shows that the drilling fluid is useful to the easy drilling,underground safety and hydrocarbon reservoir protection.