Tag Archives: начальные и граничные условия
Parameters of unsteady movement of injected fluid in tubing string during operation of pulsing devices
During the operation of pulsing devices on the well face there are short-term overlappings of a through bore for liquid pass as a result of which water hammers appear in the column of injected liquid, the parameters of which depending on the difference of elasticity of liquid and the tubing are transferred to the last one. In this regard there is a need to define the analytical dependences characterizing the values of pressure and speed of movement of liquid in any arbitrary cross section of a liquid column inside the tubing. To study these processes a problem of distribution of a water hammer of viscous liquid in the tubing from operation of pulsing devices on the well face on the basis of N.E. Zhukovsky’s classical equation about a water hammer was solved. Linearized equations of unsteady liquid movement represent a linear hyperbolic system and are a special case of telegraph equations. The problem was solved by the variable separation method which consists in finding particular solutions of the considered system meeting the set conditions. Entry and boundary conditions taking into account the unit at the bottom end of the tubing of reformative pulsing devices are set, and the column is isolated by a packer. The common decision of non-uniform system, according to the known formulas, is decomposed in Fourier series. As a result, we obtained expressions for speed of propagation and pressure amplitudes of hydroblows of injected liquid from operation of pulsing devices in the tubing on the well face. The received expressions were analyzed resulting in regularity of determination of amplitude of hydroblow pressure change in any cross section of the tubing being revealed. It will allow to predict in advance the most dangerous sites from the point of view of long-life reliability of a column of pipes during cyclic liquid injection in the system of reservoir pressure maintenance.
Structural modeling and analysis of dynamic processes in semi-main pipelines with known law discharge
By combination of the system and structural analysis and a discrete method the structural analysis, for the purpose of identification and management of difficult systems with the distributed parameters on the example of the main oil pipeline is provided. Investigating physical sense of operator transfer functions and their originals of separate links of structural architectural models, it is possible to solve problems of identification, the analysis and synthesis of difficult systems with the distributed parameters. Structural architectural models as model of physical process are one of convenient ways of the description and the analysis of the interconnected processes. On the basis of structural architectural models it is possible to write the equations of a link or group of links that allows to establish connection between coefficients and variables of the equations. The structural architectural models made thus allow visualization of interaction and pressure and expense transformation, are informative mathematical model of dynamic processes in the pipeline petrowire systems. As a whole structural architectural models display continuous information on a condition of object. If necessary having passed to area of originals time can receive approximate or exact information at the moment. Having studied methods of creation of structural architectural models, their transformation it is possible to increase informational content of structural architectural models, formulations and the solution of tasks. Investigating physical sense of operator transfer functions and originals of separate links of structural architectural models, it is possible to solve problems of identification, the analysis and synthesis of difficult systems with the distributed parameters. Combination of a discrete and system and structural method allows to unify tasks in difficult systems with the distributed parameters for the purpose of development of uniform schemes of the analysis and calculation of parameters of a stream. This problem is reduced to adaptation of mathematical models to real conditions by means of identification of parameters of system for the purpose of a choice of the correct decisions, and also to the solution of a number of the return and pseudo-return tasks on the basis of the settlement architectural models of management developed by us.