Numerical Simulation Method And Effect Factors About Temperature In Horizontal Wellbore

With the development of downhole monitoring technology,using the pressure and temperature data monitored by downhole gauges to analyze the dynamic variation of reservoir and production parameters has been an important part of smart well construction.Generally,pressure is used for data analysis as a traditional method,and because of the small variation and low accuracy,temperature data is ignored.However,the improvement of distributed temperature sensor and measurement accuracy make the analysis and application of temperature be refocused as a useful way for smart well research.In this study,heat conduction,convection,thermal expansion and viscous dissipation heating are considered for the flow in reservoir and wellbore.With the conservation equation of mass and momentum,the transient reservoir model and steady wellbore model which include thermal model and flow model are built,the coupled method for pressure and temperature distribution in reservoir and wellbore model is determined.And the finite difference method and Peaceman method are used to couple the reservoir and wellbore model.This study chooses a horizontal well located in a rectangle formation to analyze the response of different reservoir and operating system parameters for downhole temperature.The study shows that: the smaller the heat expansion coefficient of liquid phase is,the higher the wellbore temperature will be;the smaller the rock heat conductivity coefficient is,the lower the wellbore temperature will be.For the single flow in homogeneous reservoir,when it is operated by constant rate,with the increasing of permeability,from the toe to heel,the difference between inflow temperature and wellbore temperature becomes bigger.When it is operated by constant wellbore pressure,with the increasing of permeability,the inflow temperature decreases.For the single flow in heterogeneous reservoir,when it is operated by constant rate or wellbore pressure,there will be a concave for low permeability and a convex for high permeability on the inflow temperature profile.When gas or water entry occurs,the gas entry makes the inflow temperature lower and the water entry makes the inflow temperature higher in the entry point than that in other segments.There also has a knee point on the wellbore temperature profile for gas or water entry.The results of the study provides a technical way of using temperature data for real –time diagnosis of operation system,rate allocation of productive segments and estimation of parameters variation in reservoir.