Development Of Hydroxyethyl Cellulose Acrylamide Modified Bentonite Drilling Fluid

Bentonite is the most commonly used material in oil and gas field drilling operations.However,the properties of natural bentonite cannot meet the requirements of bentonite for drilling.The rheology and filtration loss of bentonite will greatly affect the properties of drilling mud,and then affect the efficiency of drilling tools and the cycle of drilling operations.Therefore,researchers pay much attention to the modification of bentonite.Modification of bentonite by using modifiers such as surfactants,polymers,inorganic salts can improve the basic properties of bentonite(such as rheology,filtration loss,dynamic plastic ratio,etc.).The research of using polymer modified bentonite is still in the early stage of research.Therefore,this article will use homemade polymers to modify the bentonite in order to improve the basic properties of bentonite.In this paper,a hydroxyethyl cellulose-acrylamide(HEC-AM)graft polymer was synthesized using microwave-assisted solution polymerization and hydroxyethyl cellulose and acrylamide as raw materials.The natural sodium-based bentonite intercalation was modified by ball milling to superfine polymer by polymer solution intercalation with strong mechanical stirring.Finally,the preparation conditions(p H,HEC / AM ratio,initiator concentration,temperature,time,and monomer concentration of reactants)of the bentonite nanocomposite were optimized by single-factor experiments.The composites were chemically characterized according to Fourier far-infrared(FT-IR)test,X-ray diffraction(XRD)test and electron scanning electron microscope(SEM);Finally,the formulation of the drilling fluid prepared by the bentonite complex is optimized,and the apparent viscosity,plastic viscosity,dynamic shear force,dynamic plastic ratio,and high temperature and high pressure filtration loss of the bentonite complex and the bentonite complex drilling fluid are tested respectively.And the optimal formula is obtained and evaluated and summarized.As for the drilling mud formulation prepared by the HEC-AM / Bt composite,the fluid loss reducing agent SPNH,the viscosity increasing agent FA367,and the anti-sagging agent FT-1 are preferred.The formula was finally determined as: 4%HEC-AM / Bt complex + 1.5%SPNH + 0.2%FA367+2%FT-1;This water-based drilling mud has good rheological properties in laboratory tests and has the ability to carry rock cuttings;both API filtration loss and high temperature and high pressure filtration loss are superior to drilling mud prepared from untreated bentonite.In the shale rolling recovery rate experiment,the drilling mud prepared by the HEC-AM / Bt complex has a high rate of cuttings recovery,has a good effect on inhibiting the shale hydration,swelling and dispersion,and has a strong ability to stabilize the borehole wall.