Modeling, Calculation And Realization In Steam Huff-puff Production Well

The method of exploiting oil with injecting steam is widely used in many heavy oil field of our country. At present the first phase, steam huff-puff, still stays. When steam is poured from top of oil well, Heat loss from tubing to earth layer should decrease as well as possibly in order to make dry degree of steam at the end of well high. On the other hand, Input heat must assure that casing temperature is not more than limited safe one, so heat stress will not destruct case, and super high temperature will not degenerate cement sheath surrounded by earth layer. The procedure that hot water and steam, as heat carriers, are poured and heat oil layer between earth layers is synthetically including physical, chemic and kinetic change. When heavy oil is exploiting, electric cables are usually used to heat produced liquid because of loss of well bore heat transmission. If time, temperature and range of heating are correctly confirmed, exploitation cost will reduce, and benefit will increase. In this paper, firstly, mechanism of well bore heat transmission is analyzed. It is introduced how to calculate heat exchange coefficient. Physical properties of water, steam and oil are showed. A program of solving physical properties of water, steam and oil is finished. Viscosity and density of crude oil are gotten by experimentations. At the same time the way to calculation of them is concluded. An iterative algorithm of distributes of temperature and pressure during injection is designed. In the dynamic process that hot water and steam heat oil layer, changes following time about heat area of hot water and steam in oil layer, heat loss and heat efficiency of heating oil layer, distributes of temperature in oil layer and speed of driving oil are described. On these bases the corresponding algorithms are built, and the dynamic state of the well bottoms in three periods, which are phases of stewing wells, puffing water and producing oil, is studied. In the period of exploiting oil two mathematics models, which are well bore radial heat transmission mode and liquid radial heat transmission model, are established. They both are adaptive to heating produced oil or not.Consequently, A database about huff-puff production wells is established according to practical characteristics in the oil field .It includes seven tables about tubing, casing, heat insulation sheath, cement sheath, earth layer and oil layer. Corresponding procedures for querying, inserting, updating, deleting records in the database are designed, and a corresponding algorithm is given.Finally, The software, which calculated temperature and pressure in injection and production wells, was developed with defined algorithms and established database. Practical production can be guided effectively according to using it.