Tag Archives: моделирование
In geophysics, one of the most important areas isgeothermy – science about the study of the thermal field of the Earth. One of the main problems of geothermy is to determine the undisturbed temperature of rocks. The geothermal field parameters (natural rock temperature, geothermal gradient, heat flux) can be used as search attributes of oil and gas deposits. Knowing the natural temperature of rocks is also necessary for wellbore thermal data interpretation. In borehole thermometry, the geothermal distribution as the unperturbed natural rock temperature is the background in the detection and analysis of temperature anomalies associated with productive layers and casing integrity damage. Today, there are no generally accepted methods for determining the unperturbed temperature of rocks. The methods used in practice have a number of problems and allow only to estimate approximately the natural temperature of the rocks. When drilling, the temperature field in the surrounding rocks varies and it takes a considerable time to restore it. This process can continue from a few days to several months-in the case of deep wells, so the natural temperature of the rocks can be measured directly only in a small amount of long time of idle wells.
The known methods for determining equilibrium temperature of rocks are analyzed in the article. A new method based on recording the non-stationary temperature in the well after stopping drilling and determining the equilibrium temperature of rocks based on the use of a simulator of non-stationary temperature in drilled wells is proposed. The mathematical model of the simulator, the formulation of inverse problems and algorithms of their solutions are discussed.
The article deals with the construction of the borehole cable’s electric model using a serial connection of two-in chain-substitution pattern.
Modeling is necessary in the study of the current measurement systems errors, when the sensor and a measuring device are at a considerable distance from each other and are electrically connected to the borehole cable located down hole. Since the conditions in which there are portions of the cable, are different, the parameters of chain equivalent circuits are unstable, i.e. chained scheme is non-uniform.
In constant current mode it’s proposed an algorithm for calculating the voltage and current at the beginning and end of the borehole cable (so called chain-substitution scheme) based on the recurrence relations obtained on the basis of mixed parameters quadrupole. As a result of the calculation the borehole cable model in the form of a single quadrupole with lumped parameters is obtained.
In non-stationary electric mode the borehole cable is also modeling by chain-modeled equivalent circuit. In this case longitudinal branches of quadrupoles haven’t inductances and in cross branches – active conductions. This is because the energy stored in the distributed capacitance of the cable is much greater than the energy stored in the distributed inductance of the cable, in therefore the latter will not have a noticeable effect on the transition process. Distributed leak active conductions also will not have much impact on the transition process as in case of AC they are much smaller than reactive conductivities due to the distributed capacitance of the cable.
A special feature of the solution is that the vector of initial conditions, is determined independently of the state and the entire load of chain equivalent circuits, and based only on idling and load connection at the output of the first. The solution for the last four-pole equivalent circuit is obtained from the matrix difference equation that describes the chain-substitution pattern.
The most common method of gas purification from acidic impurities is cleaning with amines-natural organic compounds that are derivative of ammonia. Amine purification is a regenerative process. Absorption of acidic pollutants occurs approximately ambient temperature Wednesday, and Amina regeneration occurs at boiling point in stripping column. The disadvantage of the process natural and technological gases from acidic impurities is the large amount of heat required to desorption. The most common and effective method for purification of gas currently cleaning using alkanolaminov. This process differs with the opportunity to achieve a high degree of purification at relatively low cost. Gas purification schemes to reduce heat flow supplied to the bottom of the stripping column, were simulated in the package Unisim Design: standard process flows, Division steam, their combination of recompression. Also offers purification scheme when using a mixture of amines (DEA + MDEA). Method of combining schemes and Division of flow helps reduce the heat load compared with the method of replacing monoethanolamine on 23%, but the method of steam recompression has a lower heat load compared with replacement of monoethanolamine-on 30%.Other options for change process flow diagrams are associated with large capital costs. Thus, the proposed scheme with steam recompression will reduce the heat load with relatively small capital cost.
Underground main oil pipelines are very extended objects which pass not only through stable areas with steady soil, but also areas with active manifestations of soil changes, including through bogs, the rivers, seismic breaks, is long-term – frozen soil, sites with karst manifestations, slopes and ravines. At long operation of pipelines on such sites it is necessary to watch the happening changes and to take anticipatory measures for safety of pipelines.
In article research of dependences of interaction of the pipeline with soil in a landslide zone from various factors is considered. The problem is solved by method of physical and mathematical modeling. The model of interaction of the pipeline with soil in a landslide zone represents a valuable contribution to the solution of the actual scientific and technical problem connected with safety of pipeline systems.
As a result of work the state equation in the form of the differential equation is received. Methods and features of the decision in some simple cases when reaction of soil is expressed by analytical expressions are investigated. At determination of tension from external forces difficult correctly and precisely to describe regularities of interaction of a pipe with soil which besides change at soil changes. Other complexity that in many cases boundary conditions for the considered pipeline site are in advance unknown; they are defined only during the solution of a task. Therefore in article decision methods in real cases when reaction of soil can’t be described by means of simple analytical expressions are considered. For these cases the algorithm based on numerical methods with consecutive approximations is made.
Electronic training complexes play an important part understanding of new studying material. They help to understand the complicated processes that are often hidden from view. Various operations connected with the calculations, drawings and visual representation of the object cause difficulties. There are several types of electronic training complexes, their aim is to systematize educational material, mathematical calculations and modeling of mechanical and technological processes.
Owing to the three-dimensional modeling electronic training complexes give information, allow to observe the mechanical processes, to examine technical device of machines and apparatus.
For solving the problem of mechanical gears visualization the variant of training complex is suggested. It is a collection of the main types reducers’ dismantling video demonstrations.
In the work the main stages of computer program are analyzed development.
The gear models were created in program “Compass 3D” with the help of three-dimensional computer modeling. Their usage helps to demonstrate mechanism dismantling. An interface of the complex, allows a user to select the desired gearbox for visualization.
An application of training complex will help to solve the problem of the mechanisms’ spatial representation and to optimize the studying process of the subject “Machine parts and bases of designing”.