Study On Methods Of Paraffin Removal And Control For Deep Imbedded And High Pressure Oil Wells

At present,paraffin removal and control technologies which can be used in HTHP oil wells always receive much concern.In this paper,several methods had been studied to solve the problem.In order to obtain character of wax precipitation,the physical property and components analysis of oil and wax had been done.Equipment had been self-designed to evaluate the result of tungsten alloy coating tubing wax control method based on its property of corrosion resistance and heat-resistant,which could be used to simulate wax precipitation in vertical wells at different conditions.Chemical paraffin method was researched.Wax dissolve rate was determined by the static method of wax dissolution,and wax control rate was got through “cup-inversion method”.Electrical heating paraffin method had been studied,and parameters of it were got.Researches show that,the wax content and wax precipitation point of SM2 oil are high,while water content,colloid and asphaltene content are low.Its wax precipitation condition is good.The microcrystalline wax content and the peak value of carbon number of SM2 sample are higher than that of BZ1 sample.With more branch and long carbon chain,the wax will have characteristics of high viscosity and hardness,which causes difficulty for wax removal and control.As temperature and flow rate will affect wax precipitation,it has been found that the wax precipitation amount will increase and then decrease as the temperature increases,and an wax precipitation peak point exists;wax precipitation amount will drop when the flow rate increases.Meanwhile,the differential pressure of tungsten alloy coating tubing is lower than that of normal tubing,which indicate that the tungsten alloy coating tubing is effective.According to experiments,the wax control rate is about 30%.Wax dissolve rate of paraffin remover will increase for the increasing of temperature,but the sensibility of paraffin remover to temperature is various.The construction of wax sample also affects wax dissolve rate,which presents that the simpler it is,the faster it dissolves.Type of paraffin remover is related to dissolve rate.For samples in experiments,the dissolve rate of oil-based paraffin remover is the fastest,and the emulsion paraffin removal ranks the second,and water-based paraffin remover's rate is slowest.For paraffin inhibitor,the wax control rate increases with the increasing of concentration.The wax control rate of water-based paraffin inhibitor,oil-based paraffin inhibitor and emulsion paraffin inhibitor decreases successively.The distribution of temperature in wellbore have been given,and the position of electrical heating was determined.Energy conservation equation has been established,then the heating power can be calculated.