METHOD OF TREATMENT OF WELL BOTTOMHOLE ZONE Russian patent published in 2009 - IPC E21B43/25 

FIELD: mining.

SUBSTANCE: invention can be implemented for development and build up of production rate of producing wells when flow rate has been reduced due to mudding of bottomhole zone with asphalt-resin-paraffin formations and mechanical impurities. The method of treatment of well bottomhole zone consists in generating depressive pressure difference between the bottomhole zone and a borehole cavity. Then in the bottomhole zone there are produced periodic pressure pulses in form of a wave motion in the cavity; the said wave is created by means of periodic opening of a pump-compressor pipe (PCP) at a head for draining well fluid under pressure and by means of closing PCP with valves. One of the valves is the valve of fluid draining; it connects PCP with a drained capacity, while the other valve is the valve of fluid refilling which connects PCP with a source of fluid under pressure. Opening and closing of the well cavity at the well head for draining well fluid under pressure is performed by the fluid draining valve. By means of opening the fluid refilling valve and connecting PCP with the fluid source pressure is periodically built up in the well. Via the valve PCP is connected with a receiver filled with gas. Then the second refilling valve is installed which connects the source of fluid under pressure with an annular space. At the first stage the valve connecting PCP with the receiver is shut. The bottomhole zone is subject to periodic pressure pulses. At the second stage the valve connecting PCP with the receiver is opened. By means of circulation a working agent is pumped into the bottomhole zone. The bottomhole zone is treated by stepping-up well fluid mass due to opening the fluid drain valve with frequency providing mass motion in a resonance mode. If necessary, pressure in the borehole cavity is built up by means of opening the first valve of fluid refilling. At the third stage when the valve connecting PCP with the receiver is opened there is performed treatment of the bottomhole zone by stepping-up mass of well fluid due to opening the fluid drain valve and the second valve of fluid refill with frequency providing its mass motion in the resonance mode and providing its circulation for reverse well flushing out.

EFFECT: applying different by shape and power periodic pressure pulses in formation bottomhole zone for each alternating stages of well treatment.