Study Of Water-base Drilling Fluid For Horizontal Well In Daqing Oilfield

The technic of the horizontal well is one of the most importanttechnic in prospection and exploitation of petroleum resources at thepresent age. The technic of drilling fluid for horizontal well ,one of theimportant part of the technic of the horizontal well,has gaineddevelopment,too. The proportion of using Oil-base drilling fluid onhorizontal well has descended evident after 1990.In 135 horizontal wellof domestic from 1991 to 1997, the water-base drilling fluid account for77 percent,but oil-base drilling fluid only account for 7.4 percent.Themost advantage of oil-base drilling fluid is the strong cuttings inhibitionand low resistance of friction,but it is not as good as the water-basedrilling fluid in the cuttings capacity,and it is high cost and pollutecircumstance. The weakness of the water-base drilling fluid has beenovercome along with the development of the new additive for drillingfluid,which can satisfy basically the need of the common horizontalwell.It is the main reason of the decreasing of the applying of theoil-base drilling fluid.Methylglucoside(MEG) is a monomeric ramification ofpolysaccharide.It is annulus monomer.It can be used as additive fordrilling fluid,which have excellent character of restrainability andlubrication. The monomeric ramification of MEG has not the matter ofthe fracture on daisy chain.So MEG has higher thermal stability.According to the report, MEG can form a bed of semipermeablemembranes,which can cortrol the movement of water by adjusting theactivity of drilling fluid as same as the mechanism of oil-base drillingfluid.MEG drilling fluid is a new-style drilling fluid,the performances ofwhich excel evidently the others. The drilling fluid can form a bed ofsemipermeable membranes,restrain the hydration and expanse of theclay,possess preferable lubricity,and it is innocuous and degradable.The drilling fluid have a good effect of protect storage of petroleum.Theresumptive value of permeability of the middle or low osmotic rock canreach 80 percent,and it can reach over 90 percent for the high one. Thedrilling fluid can solve the toxicity,lubricity,stability of the boreholewall,and protection of the storage of petroleum.According to the principle of choosing drilling fluid and request ofperformance of the drilling fluid of the horizontal well ,this paper studythe MEG drilling fluid for horizontal well in iaqing oilfield by analyzing theapplication of domestic and foreign water-base drilling fluid.Wedeveloped MEG drilling fluid in laboratory ,and confirmed the standardformula,and evaluated the restrainability,lubrication,floatability, higherthermal stabilityc and protection of the storage of petroleum.MEG drilling fluid has good characteristic of rheological andfiltration.It's density can adjust from 1.02 to 1.55.The filter loss is lessthan 5 milliliter after aging 16 hours under 90℃and the filter cake isthin and compact.The coefficient of lubrication is 0.08.Plastic viscosity...