Study On The Temporary Shielded Plugging Agent And The Process Parameters Optimization In Thermal Cleanout Well

Wei 2 fault block in jiangsu oilfield is a low permeable sandstone petroleum reservoir with high wax content in crude oil.Wax deposit in oil well is one of the important factors that affect the output of the block.The way of conventional hot washing to remove paraffin which is not only difficult to establish the well-flushing circulation but also easy to hurt near wellbore zone for serious leakage of working fluid into the formation through perforation.Therefore,decrease the damage of the washing liquid to the reservoir while removing the wax is the problem now to be solved.In this paper,the temporary shielded plugging technology is introduced into the thermal cleanout well for plugging perforation first and then washing well.This method can set up the well-flushing circulation quickly,reduce leakage of flushing fluid effectively,overcome the disadvantages of conventional thermal cleanout well and achieve the purpose of reservoir protection.Specific contents are as follows:(1)In this paper,considering the actual situation of reservoir,the basic properties of temporary plugging agent SA-1 and SW-13A have been studied by using experimental research.Moreover,this paper has compared the plugging capability and plugging removal technology of the two kinds of temporary plugging agent and selected suitable one for the purpose of simplifying the construction process and saving cost.(2)The process of perforation blocking by plugging agent has been researched and pointed out that combined effect of both inner filter cake and outer filter cake can reduce the filtration rate of flushing fluid in the perforation.The model of perforation blocking has been established to analyze how the particle concentration and injection pressure differential influence filter cake thickness,filtration rate of fluid and cumulative amount of filtration.(3)According to the results of laboratory test and simulation research,the process parameters of thermal cleanout well have been optimized.Results of on-site tests showed that the feasibility of the temporary plugging technology for thermal cleanout well.This measure has a significant effect on reservoir protect.The research contents and research results obtained in this paper have provided a strong technical support for solving the problems existing in the conventional paraffin removal operations of thermal cleanout well,and also have offered reference for technical train of thought for solving similar oilfield issues.