ANTI-SLOUGHING DRILLING FLUID TECHNIQUE IN LIUXI AREA

Aiming at the problem of unstable borehole wall which lead to long segment hole was pulled or sticking during drilling process in Liuxi area,to solve the problem,formation characteristic and it’s mineral group and pressure system were analyzed,the cause of sidewall unstable was found out,technique investigative ways were established.Based on indoor testing and formation characteristic of Liuxi area,KPAM-NPAN-SMP-BYL polymer anti-sloughing drilling fluid systems were optimized.The field testing of 6 wells showed that the drilling fluid technologies can satisfy Liuxi area drilling needs,reduce the rate of downhole complex accident as well,the average enlargement rate of hole diameter in easy collapse floor was lessed than 15%,drilling period was shorten by half,completion well success rate of electric logging was increased by 33%.This technique applied in Liuxi area can solve hole sloughing prevention problem,and has simple operate,convenient maintenance,low cost and wide application foreground.