Abstract
The Bozi block of Tarim Oilfield is a typical tight sand condensate gas reservoir with serious wax plugging issue. It is necessary to study the phase behavior and the wax deposition pattern of well fluids in Bozi gas reservoir, which provides the phase enveloping diagram of the condensate gas and can help to control the paraffin deposition. In this study, the PVT tester and self-designed microscopic solid deposition tester are used to get the phase enveloping curve of the condensate gas, which is combined with software simulation results and production data of Bozi 104 well to analyze wax deposition from formation to wellbore, wellbore to ground and surface pipeline. The main conclusions and suggestions are as follows: with different temperature and pressure, condensate gas produces different phase regions such as gas phase, gas-liquid phase, gas-solid phase, gas-liquid-solid phase, etc. Above the dew point pressure, the WAT is less impacted from pressure while the WAT gradually decreases due to the dissolution effect below the dew point pressure. The experimental results are used to revise the software simulation results and then to obtain the phases of different temperature and pressure regions. The state envelope is used to predict the liquid separation and wax production situation at different production stages; the liquid condensation and waxing area of the Bozi 104 well lies in the surface pipeline behind the nozzle, where appropriate wax prevention measures are needed.
