Scaling Risk Analysis And Anti-scaling Measures In Wellbore Of Deepwater Gas Field

Wellbore scaling is a common flow guarantee problem in oil and gas field production.For deepwater oil and gas fields,conventional anti-scaling and descaling measures in onshore oil fields face problems such as high construction difficulty and high cost.Therefore,it is of great significance to accurately predict the risk of wellbore scaling in deepwater oil and gas fields and optimize anti-scaling measures.Based on the working conditions of the LS17-2 deep-water gas field in the South China Sea,this paper uses literature research,theoretical analysis,laboratory experiments and model prediction to carry out the risk analysis and anti-scaling measures of the wellbore in the development of deepwater gas reservoirs.Based on the wellbore flow characteristics of deep-water aquifers,the wellbore scaling simulation experiment was carried out to reveal the scaling mechanism and influencing factors of the wellbore,and the wellbore scaling dynamics prediction model was established to analyze the dynamic deposition and plugging evolution mechanism of the wellbore scaling particles,and the wellbore scaling and The risk of clogging is evaluated;considering the construction conditions of the deep-water field,a technically feasible anti-scaling method is proposed.The results show that the scale and scale of the wellbore in the water-bearing gas well are mainly affected by the scale ion content,gas production and water production in the well type and formation water.Na HCO₃ type formation water mainly produces calcium carbonate scale,which is greatly affected by wellbore pressure and temperature.The higher the temperature and the lower the pressure,the greater the scaling tendency.Under the same gas and water production,the horizontal well has a greater risk of scaling than the vertical well;in the process of gas-liquid flow,a part of the scale generated in the wellbore will adhere to the pipe wall,which is the main cause of blockage.When the scaling tendency is large,the proportion of the adhesion scale is small,but the amount of adhesion scale is increased;when the scaling tendency is small,the proportion of the adhesion scale is relatively large.The scaling process in the wellbore is related to hydrodynamic conditions.For horizontal wells,the adhesion scale is mainly formed in the horizontal section and the inclined section,that is,the position where the pressure drop is large and the temperature is small.As the hydrodynamic conditions in the wellbore increase,the scale adheres to the upper part of the wellbore.The scaling risk of the target gas field wellbore mainly occurs in the vicinity of the vertical well gas layer and the middle and lower horizontal wellbore,and the proportion of adhesion scale is in the range of 0-0.21.The risk analysis of scaling blockage shows that if the anti-scaling measures are not taken,the wells with a large scaling tendency will have a scale of 0.18in the wellbore scale during the development cycle(30 years),and the shrinkage rate will reach9.29%,which will be the later stage of the gas field.Production has a greater impact.Therefore,it is proposed to use the underground anti-scaling agent to prevent scale,and to optimize the formulation and dosage of polymer anti-scaling agent(HPMA and MA/AA compound anti-scaling agent),effective anti-scaling in laboratory experiments.The rate is over 90%;the compatibility of the scale inhibitor with the hydrate thermodynamic inhibitor is verified by experiments,and the method of putting the scale inhibitor solution through the downhole chemical pipeline is proposed.