Research On The Calculation Of Wellbore Temperature Distribution And The Prevention And Control Of Steam Channeling In Steam Drive Production Wells

Block Jin 45 is the largest heavy oil driven by steam in LiaoHe oil field, the Jin 45 steam flooding pilot test have driven more than 2 years, the production condition conforms to the production rule of steam flooding. At present, it is in the second stage of the steam flooding develop, namely steam effectively displace exploitation. But the anisotropy of pilot area well group is more serious, imbalance are shown by the effect on vertical and plane, parts of the oil layers were heated unevenly, the predominant pathways were formed by steam that the sweep efficiency was decreases force the steam assemble into near bottom-hole area. The temperature of part of production wells head have more than 90℃.As the steam flooding ceaseless development that temperature of bottom hole further rising, the production process was influenced by flash vaporization phenomenon. Such as the efficiency of pump is reduced, the fluid volume can not be recovered etc.Flashing is a new problem in the production process of heavy oil steam flooding production Wells, and it may cause pump air lock, tubing and pump damage, the amount of fluid production drop and other problem. So, the urgent problem must be solved without hesitation in oil production. In accordance with the principle of fluid-dynamics, and the key factors temperature and pressure, establish wellbore temperature distribution model and stress distribution model for computed and simulated the downhole status. Based on the heat transfer and two-phase flow theory, takes energy conservation as basis, owing to the impact of the temperature and pressure on thermophysical parameters, emphasize the effect on the geothermal gradient changed by the steam driver response layer, deduce out the wellbore temperature distribution of the non-homogeneous differential equation, established a Wellbore two-dimensional mathematical model of temperature field. Fluid of different flow rate flow through the fixed valve and swimming valve from the bottom to up of pump was conducted by the experiment, combined the basic principles of fluid mechanics, the fluid in the annular space between the tube and casing is divided into three sections due to the gravity difference: gas segment, oil segment containing gas, the oil-water mixture segment containing gas, the stress distribution model was established. So, according to the fluid, moisture content, temperature and other production and wellbore structure parameters on the bottom and flashing situation inside pump achieves real-time monitoring. Then Based on the principle of polybasic vapor-liquid balance, the oil-water mixture correction of saturated steam critical temperature- pressure curve was revised, so that the judging critical curve of flashing for heavy oil production wells flooded by steam is obtained. By analyzing the factors of flashing, the two control measures was proposed, one of the measures was changed the production parameters, the other was injected the protective liquid from casing tubing annulus.Test was carried out by Jin 45-22- K281 Wells, for example, through the comparative analysis of calculation results and the measured result, prove flashing prediction model can accurately forecast for bottom fluid. At the same time, the control measures were performed for the flashing were occurred well groups,the results show that the control measures can be weakened the flashing influence in production.