Study On Performance Evaluation Method Of Asphaltene Removers In Tahe Oilfield Wellbores

With the development of major oil fields in recent years,oil quality is getting worse,many oil fields are facing high viscosity,high asphaltene quantity and other serious production problems.In the Tahe Oilfield,for example,some production wells have been facing the problem of asphaltene blockage for several years,even off production.While,there is a lack of uniform evaluation standard for asphaltene removers by now.Aiming at the issue of wellbore blockage in Tahe Oilfield,many instruments such as SEM and Rod-like thin layer chromatograph have been used,analyzing the compositions and properties of wellbore blockages.According to the Tahe crude oil of different properties,the author of this paper investigates the disassemble and containment performance of different asphaltene removers in multiple ways,compares the advantages and disadvantages of different evaluation methods,and makes a set of asphaltene remover evaluation standard and construction plan for Tahe Oilfield.The researches show that: the wellbore blockages in Tahe Oilfield belong to the asphalt-type.The most suitable method for evaluating the dispersion solubility of removers is the dissolution rate method,the higher the temperature of the system,the higher the dissolution rate.And for the blocking performance is the multiple light scattering method,which can reflect the dynamic process of asphaltene deposition,regardless crude oil color.The volume ratio of n-heptane to crude oil is 30:1 in thin oil system,and 15:1 in heavy oil system,the TSI is used as the evaluation index.Moreover,in the early stages of blocking,removers can be squeezed the into flowing well with pump,and poured into pumping well through casing annulus or pumping rods.Otherwise,the removers should be injected through coiled tubing and flowback when it is completely blocked.