METHOD FOR CONTROL OF ASPHALT-RESIN-PARAFFIN DEPOSITS FORMATION IN LIFT PIPES DURING GASLIFT OPERATION OF WELLS Russian patent published in 2021 - IPC E21B37/06 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry. In the method for preventing the formation of ARPD in lift pipes during gas-lift operation of oil wells, initial data are obtained on the component compositions of the formation fluid and associated petroleum gas APG, which is used as a working agent, then it is purified from hydrogen sulfide and carbon dioxide, then the purified associated gas is injected oil gas without changing its hydrocarbon composition and determine the temperature T₁ of oil saturation with paraffin and the depth of its formation in the well, taking into account the change in the composition of oil when injecting associated petroleum gas. The ratio of light and heavy fractions of the injected associated petroleum gas is changed and the temperature T₂ of oil saturation with paraffin and the depth of its formation for a given ratio of light and heavy fractions are determined. If T₂ > T₁, the ratio of light and heavy fractions of the injected working agent is changed again and the determination of the temperature T₂ of oil saturation with paraffin and the depth of its formation is repeated. If T₂ < T₁, the resulting temperature is taken as a new initial version. The condition of the possibility of ensuring the required ratio of fractions based on the component composition of APG is checked, if it is confirmed, then this procedure is repeated for another variant of the ratio of light and heavy fractions, if not confirmed, the optimal variant of the required amount of flow rate of the working agent is selected at the lowest temperature of oil saturation with paraffin. Hot APG is injected into the annulus of the well between the tubing string and the production string, while the optimal flow rate of hot APG is preliminarily determined based on the volume of the injected working agent and the smallest value of its injection depth. The interval for running the process string with a heat-insulating coating with an optimal thickness of 20-35 mm is set below the depth of hot APG injection into the well by no more than 30 m. The heat-insulating coating of the technological column is made of polyurethane. The injected APG is preheated to 90-105°C, the mode of hot APG injection into the well is determined by predicting the rate of formation of organic deposits in the tubing string to reduce the well flow rate and increase the thickness of the deposits over time - the area of the intersection of the dependences of the change in the flow rate of the well and the thickness of the deposits corresponds to the optimal value of the intertreatment period of the well operation, then hot APG is continuously injected into the gas-lift well until the planned value of the current flow rate of the well is restored, after which the constant pressure valve is closed.

EFFECT: increasing the efficiency of gas-lift wells, complicated by the intensive formation of asphalt-resin-paraffin deposits of ARPD in lift pipes during the production of highly paraffinic oil, increasing the overhaul period of the well.

1 cl, 10 dwg, 2 tbl, 4 ex