Study On Scaling Mechanism And Solution Of Inorganic Scale In Bozi-Dabei Gas Area

Keshen gas field is located in the South Tianshan Kuqashan qianbozi-Dabei area of Xinjiang,the area of high-yield natural gas wells generally cracked,the overall permeability of the reservoir due to the cracks caused by structural compression has been improved,which is of great significance to natural gas exploitation.Residual water is the residual water caused by the non-development of local reservoir cracks,the process of retained water from the pore in the rock to the wellbore until it is extracted to the surface,and the interaction between the fluid and the rock matrix and the wellbore steel blocks the flow channel of the fluid This has had an extremely adverse impact on the stable production and increase of the Keshen gas field.Therefore,it is of great significance to study the problem of reservoir fractures and wellbore blockage for the development of Keshen gas field.Through the physical simulation of high temperature and high pressure and microscopic visualization model,it is revealed that the trapped water in the reservoir matrix first blocks small cracks and then blocks large cracks.The Toughreact simulation results revealed that the original crystal nuclei in the trapped water were generated by temperature drop and pressure drop from the throttling of the trapped water through the rock pores.The simulation results also show that compared with the matrix core,the presence of cracks increases the amount of fouling in the reservoir and the amount of fouling in the large fractures is larger than that of the small cracks,and the near well fractures are larger than the far well fractures,which increases with the increase of mineral deposition in the CO₂ partial pressure in natural gas.Scalechem prediction results indicate that when the well depth is 6000-6800m,the wellbore fouling is serious,and the wellbore fouling amount reaches 1.97kg/d;when the well depth is 2000-6000m,it is 2000-6000m Strontium carbonate,strontium sulfate and barium carbonate precipitate will not be generated in the wellbore;at a depth of 1000-2000m,most of them are calcium sulfate,sodium chloride,barium sulfate mixed scale;0-There is almost no fouling in the wellbore of 1000m;corrsion Analyser results illustrate the wellbore corrosion rate at a depth of 3400m Reached the highest value,6.37mm/yr.The results of the scale inhibitor screening experiment showed that in the simulated water of the gramshen 221 well,the grease resistance efficiency of GUL-PASP at 90mg/L was 1 00%,the best anti-scaling effect.