Study On Drilling Fluid Of High Temperature And High Pressure Well In Tazhong Area,xinjiang

In recent years,major oil and gas discoveries have been made successively in shuntuo block,tazhong region,xinjiang.However,in the drilling engineering,the reservoir is currently faced with such complicated downhole problems as deep burial,high pressure,high formation temperature,natural fracture development,strong reservoir heterogeneity,poor physical properties,and easy occurrence of well leakage.Higher formation temperature and pressure require higher performance of drilling fluid.In this paper,the formation data of shuntuo block in tazhong region of xinjiang were collected,the formation fracture and fracture development status of the target block were clarified,the pore structure characteristics of the reservoir were analyzed,and the main causes and technical countermeasures of the complex formation well leakage in this block were analyzed.Through the selection experiment of slurry and anti-high temperature treating agent,the main treating agent of high temperature and high density drilling fluid was optimized,including filter loss reducing agent,viscosity increasing agent,viscosity decreasing agent,plugging agent,inhibitor,high temperature stabilizing agent,lubricant and weighting agent,etc.Through compatibility test,the formulation of high-temperature and high-density drilling fluid system was optimized,and its high-temperature stability,settlement stability,inhibition,plugging,lubrication and anti-pollution performance were comprehensively evaluated.The effects of temperature,clay content,polymer content and viscosity reducer content on the rheological properties of high-density drilling fluid were discussed.The experimental results show that the new developed resistance to high temperature drilling fluid system can resistance temperature of 220?,the subsidence stability is good,strong ability to resist pollution,also has better inhibition performance and lubricity.The anti-high temperature plugging agent was optimized,the formula of anti-high temperature plugging drilling fluid system and the plugging technology were given,and the field application test of high-temperature and high-density drilling fluid technology was successfully carried out.The field test shows that the newly developed high temperature and high density drilling fluid system and plugging formula can prevent and reduce well leakage and other complex situations,shorten drilling cycle and improve drilling and completion efficiency.