Research On Flow Process Calculation Of Cementing In Horizontal Well

The manual calculation can do the job like the traditional calculation of cementing design such as pump pressure,circulating pressure consumption,but involves U type pipe effect of complex calculation of dynamic,pure manual calculation workload is huge,the resulting in large calculation errors.Choosing a reasonable model accurately,using computer technology to research the flow process of cement injection,not only can get more accurate results,and can forecast and calculation of the whole process of cementing,and provide the basis for safe,efficient and controllable cementing construction.In the whole process of cementing flow calculation,it is an important part to choose reasonable cementing displacement efficiency calculation model and U tube effect calculation model.In cementing operation of horizontal well,improving cementing efficiency is the precondition of improving cementing quality.At present,the main methods for the displacement efficiency of horizontal wells are data statistics at the construction site and laboratory experiments,but the mathematical model of displacement efficiency of horizontal wells is not enough.In order to quantitatively study the influence factors of horizontal well cementing displacement efficiency,and provide guidance for indoor experiment and field cementing,cementing quality,reduce the cost of indoor experiment and cementing,according to the equilibrium condition of drilling fluid in the process of cement injection,the application of stress analysis of drilling fluid element,the paper established the eccentric annulus of horizontal wells drilling fluid layer thickness calculation model and efficiency model of cementing,at the same time,the effects of eccentricity,well angle,drilling fluid yield stress and rheological parameters of cement slurry on displacement efficiency of cementing in the horizontal well are analyzed respectively.The results show that when the eccentricity of the casing increases,the displacement efficiency at the narrow clearance of the annulus decreases rapidly,which seriously affects the cementing quality,when the static pressure of drilling fluid increases,the thickness of the drilling fluid remaining layer increases,and the thickness of the retained layer in the narrow annular gap increases obviously.Therefore,it is necessary to ensure the center of the casing as well as minimize the static shear force of the drilling fluid.In cementing operation,the parameters that are changed with the time of cement injection and the stability of downhole environment must be strictly controlled to obtain good cementing quality.The traditional cementing design,the calculation process of cement injection flow is simplified,involving only the ideal state of the annulus flow judgment,downhole pressure calculation,pump pressure calculation,ignoring the influence of fluid density in the well by the difference caused by the effect of U type tube.The present model of U type pipe effect for cementing is only applicable to the cementing process of vertical wells,and the study of horizontal wells is lacking.In this paper,the flow process of cementing in horizontal well is studied by using Euler differential equation.The model of U type pipe effect calculation for horizontal well is obtained.According to the flow process of horizontal well cementing calculation results show that the U type pipe effect occurs when cementing the horizontal well,which affects the velocity of annulus cementing,reduces the time of turbulent displacement of cement slurry to drilling fluid,and reduces the displacement efficiency of cementing.In this paper,according to the displacement efficiency calculation model of horizontal well and the model of U type pipe effect in horizontal well,in the Visual Studio 2013 development platform,based on SQL Server 2008 database and WPF framework,the flow calculation software of horizontal well cementing process is developed by using C#language.On the basis of conventional cementing design,this software focuses on cementing displacement efficiency of horizontal well and flow process of cementing well.The software runs stably and the calculation results of each model are reliable.It can calculate and predict the flow process of cementing wells in horizontal wells,and provide theoretical basis and reference for field construction and laboratory experiments.