Solid-free Thermal Insulation Water Base Packer Fluid Technology for Deep Water Operation

Solid-free thermal insulation water base packer fluid is a water base fluid used in the annulus of oil and gas wells to minimize the heat loss in oil and gas pipes and thus inhibit waxing and formation of gas hydrate therein.Heat loss in oil and gas pipes can be achieved by reducing the coefficient of heat conductivity of the fluid flowing in the pipes,and by controlling the free convection taking place in the pipes.In laboratory studies,a polybasic alcohol,C4,is selected as a reagent to reduce the coefficient of heat conductivity.A biopolymer,MT,is chosen as a rheology modifier;it reduces the viscosity of the flowing fluid at high shearing rate,thus satisfying the needs for pumping the fluid.On the other hand,MT increases the viscosity the fluid at low shearing rate,thus minimizing the heat loss caused by free convection in the annulus.Using soluble salts,the density of the fluid flowing in the pipes can be adjusted between 0.9 g/cm³ and 1.2 g/cm³,thus satisfying the needs of reservoirs with different pressure coefficients.The studies reveal that the new solid-free thermal insulation water base packer fluid has low coefficient of heat conductivity,good thermal insulation performance,wide density range,and good stability over long period.Compared with oil base packer fluid and alcohol base packer fluid,this new packer fluid has better heat insulation performance and low preparation cost,and it is free of solids precipitation and poses no pollution to the environment.