| When the reservoir began displacement, the larger the production pressure difference, the greater the oil well production. however, when the reservoir develops to a certain degree, the formation pressure is less than the saturation pressure, the displacement mode becomes dissolved gas drive, As the bottom hole flowing pressure sharply reduced, production pressure differential continues to increase, crude oil will be serious degassed near the bottom of a well, oil well production and pump efficiency began to reduce, and gases produced escapes through the casing annulus and causes environmental pollution and resource waste. This article selects oil and gas Wells in changqing oilfield production 3 factory as the research object, analyzing the feasibility of casing pressure-out to recycle casing gas(associated gas). Theoretical analysis: when casing pressure-out, reasonable casing pressure value can not only recycle associated gas in the premise of without affecting the pump efficiency, but also may improve flowing pressure of the bottom hole, to increase oil production.When pressure-out production, the whole production system is divided into two parts by bottom hole for the node(the flow In the formation and the flow of the shoe to the separator), Through percolation mechanism and wellbore multiphase flow set up mathematical model of bottom hole flowing pressure and formation pressure, bottom hole flowing pressure and casing pressure, to determine the reasonable range of casing pressure values, and through software programming completes the calculation; In addition, through the curve fits out the relationship between the pump efficiency and the submergence depth, determine the reasonable submergence depth of study blocks. This paper selected 11 test Wells to verify this model, the experimental data show that the casing pressure is too low or too high, oil production will be reduced in the process of pressure-out, Only when the casing pressure value changes in a reasonable scope, casing pressure does not affect the oil well production and the pump efficiency; And proper adjusting the pump setting depth can make well average daily oil production increased by about 15%. |
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