Applications of Zwitterionic Polymer HRH Drilling Fluid in Linpan Oilfield

PAM drilling fluid has been commonly used in Linpan Oilfield in recent years,but this drilling fluid has shortcomings such as poor inhibition,short stable time,limited anti-sloughing property and higher cost,etc.In order to solve these problems,the advanced zwitterionic polymer HRH has been introduced based on the advanced techniques at home and abroad.The formula of the drilling fluid was optimized through solubility,flocculation,inhibition and compatibility test on HRH.The laboratory tests showed that the drilling fluid had good rheological property,with the ratio of yield value to plastic viscosity at around 0.5,temperature resistance of above 150 ℃,better inhibition than PAM drilling fluid,and the core permeability recovery rate of over 90%.When it was combined with lubricant,the mud cake adhesion coefficient could be lowered to less than 0.1.The HRH drilling fluid has been used in 295 wells in Linpan Oilfield,the results showed that the rheological property,filtration,lubrication and inhibition of the HRH drilling fluid were all better than that of PAM drilling fluid.After using the HRH drilling fluid,the average hole diameter enlargement ratio was kept under 10%,the downhole complex accidents was reduced from 2.57% to 1.64%,the penetration rate increased from 20.58 m/h to 23.02 m/h,which together resulted in good economic benefits.Thus it could be seen this drilling fluid which could solve all the problems of PAM drilling fluid,should be popularized in Linpan Oilfield.