Drilling Fluid Technology of Horizontal Well Q5-1 in Qunkuqiake Area

The problem of borehole instability in Qunkuqiake Region was a major problem in oil exploration and development.Well Q5-1 was the first test well drilled for solving the problem of borehole instability.It analyzed and researched the labile factors in carboniferous complex formation and difficulties of implementing drilling fluid technology were analyzed in Qunkuqiake Region,the compatibility of drilling fluid was improved and the polymer drilling fluid and KCl /sulphonic polymer drilling fluid system were optimized as the appropriate drilling fluids.The drilling fluid system has good rheological,building capacity,lubricity and inhibition.Application result shows that the drilling fluid has good effect for well drilling,underground safety and hydrocarbon reservoir protection.