High-wax Condensate Gas Well Wax Deposition Experiment And Prediction Study

Wax deposition is a serious problem in the oil industry, in the process of oil and gas production, with the decrease of temperature and pressure, the wax dissolved in the fluid will precipitate and deposit onto the wall, and it will cause wellbore blockage, lead to a decline in oil and gas production, or even shut down the well.Wax deposition problem is a very serious problem of Jiuqu condensate gas reservoir, due to lack of methods in calculating wax deposition position, wax deposition thickness and other parameters, making it impossible to develop a effective way to solve the wax deposition problem, seriously affecting the production of gas well. Based on the studies of wax deposition mechanism and experiments, the dynamic wax deposition prediction model of multiphase flow was established, and it can provide technical support for making wax removal plans. The following understanding:(1) The fulid from the well bottom to head, the process of wax deposition can be describe d with solution theory, crystallization theory, molecular diffusion and phase equilibrium theory, the wellbore wax deposition is a result of multiple mechanisms of interaction. The composition, temperature and pressure conditions of the fulid is the main factors affecting wax deposition.(2) Through the analysis of composition and IR of Jiuqu samples, the results shows that the heavy component content of gas condensate is high, the wax content of the oil samples is high; Through the melting point test and simulated distillation experiment, the results shows that wax sample contains about 65% crude crystalline wax and 35% microcrystalline wax.(3) By measuring the wax precipitation point and the amount of wax precipitation at different temperature and pressure, the results indicate that the wax precipitation point of Jiuqu degassed oil is high, at atmospheric pressure, the wax precipitation point between 32.1? to 47.2?, and it will increase while the pressure increase; As the pressure increases, the wax precipitation point of live oil first decreases then increases; Under the same pressure, the amount of wax precipitation increases with decreasing temperature; Under the same wax precipitation temperature, wax precipitation amount is different under different pressures.(4) According to the wax deposition is a static and dynamic process that deposit after generating, the dynamic wax deposition prediction model of multiphase flow was established, so that the static equilibrium model of wax deposition and the current prediction model has been unified, the solution results match with field data well, and proved the reliability of the model;(5) By using the wax deposition prediction model of multiphase flow, combined the actual production of Jiuqu condensate gas well, established the forecast charts, predicted the depth and period of wax inhibit and removal of each well. Such as YJ2X well, the period is about 17 days, and the reasonable depth is 0-360 meters, it is not necessary to remove wax to 2000-2300 meters, it can reduce the cost of removing wax.