METHOD OF ISOLATING AN ABSORPTION ZONE IN A CONSTRUCTED WELL AND A DEVICE FOR CARRYING OUT INSULATION Russian patent published in 2020 - IPC E21B33/138 E21B27/02 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to drilling of wells, namely to methods and devices for isolation of drilling fluid absorption zones in a well under construction. In particular, disclosed is a method of isolating an absorption zone in a well being constructed, comprising determining an absorption interval, a volume of the grouting mixture, assembly of device for insulation of absorption zone, filling with grouting mixture, device lowering to well to tamponing zone, well borehole shutoff above plugged interval, displacement of grouting mixture into absorption zone. At the well head, a device for insulation of the absorption zone from below upwards is assembled, which includes a guide shoe with flushing holes, closed with plastic conical plugs and a destructible diaphragm installed on it, tubular housing with centralizers in form of drilled pipe. Then the grouting mixture is poured into the tubular housing of the device; the upper branch pipe is connected to the self-packing packer and the centraliser installed on it and the bushing installed in the tubular case. After that, the upper branch is connected to the electromagnetic disconnector and the device is lowered into the well on the geophysical cable to the bottomhole, the speed and depth of descent are controlled. At that, the absorption zone of the device is shut off, and the self-sealing packer is placed at the level of the roof of the absorption zone, overlapping the annular space of the well. Device is disconnected from the electromagnetic disconnector and the electromagnetic disconnector is removed from the well on the geophysical cable. Assembly of the bottom of the drill string is assembled and lowered to the well on drill pipes to the level of liquid in the well; the entire interval of the well above the device for insulation of the absorption zone is filled with the drilling fluid by the drilling fluid. Self-sealing packer and the bung tube inside the device operate synchronously and isolate the absorption zone from the rest of the well. Assembly of the bottom of the drill string is lifted above the shoe of the conductor and the preventer of the well is closed. Cementing unit is connected to the pump manifold of the drilling rig and the flushing fluid is pumped into the well through the drilling pipes. Device diaphragm is broken, grooving mixture is to be forged from device in interval of absorption zone to obtain "stop" pressure. At that, the backfill mixture is squeezed into the formation, the preventer is opened, the well is left for process exposure for the time of waiting for hardening of cement. Then the hardened cement is drilled together with the device for insulation of the absorption zone using the guide shaft produced inside the tubular body of the device at the grouting mixture marketing, and deepening wells in standard mode is continued.

EFFECT: high success of isolating absorption zones in a drilled well and reducing time and costs for carrying out said operations.

3 cl, 1 dwg