Crude Oil in Water Drilling Fluid Properties and Application in Horizontal Wellbore Drilling

Oil in water drilling fluid is a suitable water based drilling fluid for horizontal well, because of good lubricity, liquidity and borehole stability.Optimized and matching emulsifiers, in the2:8 ratio of oil to water, the emulsifiers OP-10+SP-80 ratio of 3:2 is the best effect of emulsion stability, the formation of oil in water drilling fluid system have low filter loss, strong stability, low lubricating coefficient properties , which can meet the needs of drilling horizontal well design.The crude oil in Water drilling fluid application in Xin Sha21-1H,Xin Sha23-1H and XinSha 21-3H well shows that, the oil in water drilling fluid system has good rheological properties and lubricating property.The average single well diameter expanding rate of 12.23%, lower than 16.75% with other well.Utilization drilling rate increased from 35.82% to 54.67%, which increase 52.6% significantly reduced the horizontal well drilling cycle.