Study On A Wellbore Wax Deposition Experiment And Prediction Model In Bohai Oilfield

Based on the actual production situation of J and B oil and gas wells in Bohai Oilfield,this paper simulated the cold-finger experiment of wellbore wax deposition in the laboratory,and explored the deposition process of J and B wells under different temperatures,yields and time(deposition quality,carbon number distribution).).The experiment found that the J well deposit contains wax deposition and gelation and siltation,so that the wall temperature of the J well is higher than that of the wax deposition point.The deposition of well B is a typical wax deposition process,but there are two peaks of wax deposition in the wax-out characteristic curve of B oil.The deposition quality of different yields and well depths should be combined with the wax-out characteristic curve.Subsequently,combined with experimental data,the J,B wellbore wax deposition prediction model was constructed by molecular diffusion + gelation / molecular diffusion + shear stripping calculation principle,and the importance of the location,thickness and pigging cycle of the wellbore deposition in different wells was clarified.The parameters and the calculation results of the model are verified based on the on-site production data,which provides an important theoretical basis for field operations.Finally,combined with the research progress of gelation and deposition of oil and water two-phase wax in J well,the interface activity of colloid and asphaltene was studied,and the effect of wax crystal interface adsorption on wax deposition was explored.The difference between the deposition quality of liquid and single-phase waxy oil,the difference of water content and carbon number distribution,it is obtained that the adsorption of wax crystal interface promotes the diffusion and deposition of some wax molecules,and initiates the water droplets in the emulsion system to enter the wax deposition layer.