Study and Application of KCl-polymer"Light Mud"

With low density,low viscosity,low clay and low gel strength,the so-called "light mud" plays an important role in increasing ROP and making full use of advantages of different drilling technology.Triaxial stress test apparatus was applied to research the mechanical property and strength of formation rock that met some different drilling fluids,and get the conclusion of the decreased value of ECD caused by the caving pressure.This paper introduces the KClpolymer "light mud",developed through optimization of high temperature and shale inhibitor,modification of shut off capability rheology inhibition and reduction of formation collapse pressures,showing good application in well TZ721-5 that increased the ROP by more than 20%.