Research On Accurate Calculation Method Of Cement Flow Friction And Field Application

Cementing engineering as a vital part of the drilling engineering, is directly related to oil and gas well production and life, and cementing is a top priority in the whole cementing engineering. Cement is a one-time project, as well as we can’t see the concealed work, once appear problem, it is difficult to remedy, not only the economic loss is immeasurable.In the process of cementing slurry flow friction is influenced by flow pattern, the size of annular clearance, temperature and local resistance, so that the calculation result error is bigger, when error is too big, it will affect the cementing quality of well cementation. Therefore, this paper in order to improve the cement slurry flow friction calculation accuracy, for the purpose of the rheological model of flow pattern identification method, temperature, the local resistance influence several aspects to study; And write the cementing flow friction calculation software.Flow pattern discriminant analysis method, this paper found that the commonly used criterion Reynolds number of Newtonian fluid, the relatively accurate judging criterion of plastic and pseudoplastic fluid has a larger error. The Z value criterion is based on the hierarchical identification method to calculate the Reynolds number, it can be calculated for each layer fluid, even can also be applied in eccentric annulus.By calculating the rheological parameters of different temperatures, and put forward according to the method of cyclic temperature section, established a calculation model of the annulus considering rheological property under different temperature. Analysis of annulus size different influence on flow friction calculation, found that annulus size affects the critical flow velocity, different parameters such as slurry rheological property, friction coefficient, put forward the small gap flow pattern discriminant criteria and calculation formula of modified Reynolds number.Paper considers the nipple to produce local resistance to the influence of the cement flow friction, found that when the deeper the well casing joints of local resistance impact will be greater, hus established in view of the divergent type reducing outburst at the sudden enlargement and shrinkage calculation model of two kinds of casing joints to produce local resistance.Finally, according to the theory of model, the paper established the cement flow friction calculation software, applications for different parts of the site construction. hrough various well the size of the data to calculate the error, and to determine the accuracy of the calculation method in this paper. Making the cementing cement design more reasonable, the construction is more secure.