BOTTOMHOLE ZONE TREATMENT METHOD FOR HORIZONTAL WELL Russian patent published in 2014 - IPC E21B43/25 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: at the wellhead a flush-joint pipe of coil tubing, which is used as a lower end of the pipe string, is equipped at first with a valve consisting of a saddle and case with openings covered hermetically by the saddle fixed by a shear pin in regard to the case and then with a liquid pulsator with a nozzle at the end. The pipe string is run in till the nozzle of the liquid pulsator rests at the bottomhole of a horizontal well, the pipe string is filled with acid solution and acid solution is injected in pulsed mode under pressure of 18 MPa at most with simultaneous movement of the pipe string from the bottomhole to the wellhead with the rate of 50 m per minute to the length of horizontal well screen. When the design distance is reached movement of the pipe string and injection of acid solution is stopped, the plug is placed to the pipe string at the wellhead, movement of the pipe string is renewed and the plug is flushed by process liquid. At that at the moment when the pulsator reaches the screen end interval close to the wellhead the plus is placed to the valve saddle and in result hydraulic pressure increases in the pipe string and the shear pin gets broken. Moreover the saddle moved downwards and openings in the valve case get open thus interconnecting inner space of the pipe string and tubular annulus of the horizontal well. The plug cuts off the liquid pulsator hermetically. Then the process is withhold during 1 hour, at that in process of this withhold the pipe string is run in until the liquid pulsator rests in the bottomhole of a horizontal well. Then, during three cycles in sequence, 0.5 m³ of process liquid is injected either to the pipe string or tubing-casing annulus in turn. When withhold time is over reaction products are washed out by return circulation in one and a halve volume of the well.

EFFECT: improving treatment efficiency of a bore-hole zone.

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