Drilling Fluid in Zhuang 129-1HF Extended Reach Well Drilling

Based on the analysis of technical difficulties of extreme friction,cuttings transport and bore hole stabilization in Zhuang 129-1HF extended reach well,aluminum-amine based polysulfonate drilling fluid was developed.It had optimized grade distribution and shale inhibitor through the experimental evaluation of the suspension and cuttings carrying ability for suspending agent CDXW.The fluid was also analyzed to determine its lubrication of lubricator BH-1 under both ambient temperature and HPHT conditions.API filtrate loss of the developed drilling fluid was less than 3 mL,HTHP filtrate loss of the developed drilling fluid was less than 10 mL,the yield point and plastic viscosity ratio is over 0.5 and the adhesion coefficient is less than 0.05.The results indicated that this drilling fluid can be characterized as having good resistance to high temperature,is excellent for cuttings carrying and lubricating.Field drilling application shows that borehole enlargement ratio was within 3.85%,drilling period shortened by 22.09 days,which demonstrates that the aluminum-amine based polysulfonate drilling fluid is excellent in rock carrying,lubricity and inhibition,and can effectively solve the problems of poor hole cleaning and great friction.