Study Of Protection Technology In Hydrocarbon-Bearing Formation Of Horizontal Well In Jianghan Oilfield

Due to its longer soak time and larger drainage area, the horizontal well is susceptible tosevere pollution during the drilling compared with the vertical well. Once thehydrocarbon-bearing formation is polluted during the drilling and oil testing, the unpluggingmeasures will be greatly affected. A temporary plugging and shielding technology is thereforeutilized to properly protect the formation for the purpose of reducing the occurrence of accidencein the course of follow-up drilling and oil testing, decreasing production cost and increasing thesuccess rate. The technical conditions facing the existing drilling technology in Jianghan Oilfield includethe irremovable solid particles in the slurry and inevitable positive pressure difference on theformation. There exists the plugging of the formation due to the damage by the solid and liquid.Therefore, a damage-prevention area is formed against the wellbore wall rapidly and effectivelywhen drilling the formation. The damage-prevention area can prevent the slurry from damagingthe formation, eliminating the effect of soak time and removing the slurry damage by certainstrength. For the perforated well, the damage-prevention area can be removed by perforationsince it is very thin.