STIMULATION OF RESERVOIR INFLOW BY REDUCING LEVEL OF WELL FLUID IN NEW AND REPAIRED OIL BLOWING WELLS WITH SUCCESSIVE MAINTAINING OF STATIC LEVEL Russian patent published in 2009 - IPC E21B43/18 

FIELD: oil and gas production.

SUBSTANCE: invention refers to oil and gas industry, particularly to methods of stimulation of inflow of reservoir fluid from new and repaired producing oil, gas and gas condensate wells; invention can be implemented at completion and stimulation of inflow of oil, gas and gas-condensate wells by means of reducing level of fluid in annular space of flow string and by successive maintaining this level at specified mark. The essence of the invention is like follows: the method consists in creating depression at bottomhole zone of reservoir in a bored and cased well with a flow string; depression is formed by reducing level of well fluid due to replacing it with a gaseous medium pumped into annular space of the flow string. Also as gas medium mixture of nitrogen with carbon dioxide, mixture of helium with carbon dioxide, mixture of argon with carbon dioxide, carbon dioxide or tetra-fluorine-ethane are pumped into annular space of the flow string of the well filled with fluid. Pumped gas effects filling fluid of annular space of the well flow string at pressure 150-600 kgf/ cm² and productivity of feed of neutral gas 100-1200 m³/hour with successive replacement of well fluid with pumped gas in the line of gas supply to a shoe of lifting pipes, with reduction of density of gas-fluid mixture and simultaneous rising of level of well fluid to the well head and with outburst of part of well fluid. Then priming pressure of pumped gas is lowered. Further pressure of pumped gas is steadily built up to the value of priming pressure during process of drawdown of level of well fluid in the line of pumped gas supply to the shoe of the lifting pipes and in the process of rising of level of gas-liquid mixture in the lifting pipes to the well head. Primary pressure of pumped gas and its maximum pressure is calculated from formulas. Notably, the highest primary pressure of pumped gas in the well exceeds working pressure of pumping of gas in the process of normal operation of the well.

EFFECT: increased efficiency of method of stimulation and maintaining stable gas influence onto producing reservoir at simultaneous raised level of fire safety of operations performed at well.

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