Research And Optimization Of Viscosity Reduction Technology For Heavy Oil Wellbore In Halahatang Oilfield

Halahatang oil field is an Ordovician carbonate reservoir with well permeability.The heavy oil of Halahatang can flow into well successfully.But in the lifting process,with the gradual decreasion of temperature during liquid production,heavy oil can't flow smoothly out of the well.So it's necessary to take some methods to assure the outflow of heavy oi.Currently,there are many methods to improve heavy oil's fluidity in well,such as heating and dilution.Each viscosity-reducing measure has the according adaptability.How to choice the best measure is not just about the economy,but also about safety.In this article,I focus on the methods of viscosity-reducing,and rank the viscosity-reducing methods with a fuzzy method.Finally,the optimized method is recommended.In this article,the wellbore temperature field and pressure field's mathematical model viscosity reducing method is built to analyze viscosity-reducing-tech.Base on the actual well of Halahatang,this article analyzes the technological parameter of each viscosity-reducing-tech,and recommend 5 kinds of viscosity-reducing project based on a specific temperature of heavy oil.Then I build a well viscosity-reducing-tech assessment index system that includes 4 primary indexes(capacity,economy,engineering,HSE),and 10 specific indexes.There are two main ways to get the numerical value of each index.For quantitate indexes,this article provides specific mathematical ways to get the index value.For qualitative index,this article adopts the collected value statistic methods to get the index value.Next,this article valuates each assessment index's weighted value based on the method of analytic hierarchy process(AHP).Finally,an optimally selected model is built base on Vague similarity measure value to optimize well viscosity-reducing-tech.The higher similarity measure value,the better viscosity-reducing-tech.In addition,this article applies the optimally selected model in the Halahatang oil field,the analysis results indicate that dilution by light oil measure is the best way for Halahatang to reduce the viscosity of well fluid.The research results of this article are able to optimize well viscosity-reducing-tech for this specific oil field and well,and the best viscosity-reducing project of a well is recommended.