Horizontal well drilling fluid technology at Mesozoic formation of Zhuangxi beach area

Abstract:

The whole well small circulation technology with zero-discharge of drilling fluid is implemented in Zhuangxi beach area, solid control is difficult at upper strata with rapid drilling; for there are serious block falling and collapse in mudstone of the Dongying formation and the oil mudstone of the Shahejie formation and high requirements in lubrication and collapse prevention for Mesozoic horizontal section, some targeted measures are taken respectively. The field test shows that by the use of calcium chloride high-inhibition drilling fluid system at upper formation, the dispersion of clay and cuttings is inhibited to meet the engineering requirements of the rapid drilling with small circulating and mud zero-discharge; low-activity and strong-inhibition drilling fluid system is used at lower formations, the drilling fluid activity is controlled below 0.96 and HTHP filtration loss is less than 12mL, which ensures the well stability of mudstone formation. The oil-base drilling fluid recycling technology is applied at the third horizontal section, the emulsification stability of the optimized drilling fluid performs well, demulsification voltage is greater than 460 v, which solves the problems such as big friction torque and collapse in horizontal well drilling in the Mesozoic formation.