WELL COMPLETION METHOD Russian patent published in 2015 - IPC E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: well completion method includes the injection of an acid solution by circulation with the wellhead by means of a jet nozzle placed at the end of a flexible flush-joint pipe, simultaneously with the acid solution circulation lifting of the flexible flush-joint pipe with a rate that does not exceed the rate of the borehole filling with the acid solution, upon filling of a horizontal borehole with the acid solution flushing of the acid solution to the formation with the staged pressure increase and the process withhold at each stage for the purpose of acid reaction with rock, injection of inert gas, recording of the level recovery curve, well killing and well development. A tubing string with starting clutches and with a funnel on the end is lowered into the well preliminarily at the interval of the shoe of the production casing. The flexible flush-joint pipe with the jet nozzle is lowered inside the tubing. Before the acid is flushed to the formation, the horizontal shaft of the well at an open annular space is filled through the flexible flush-joint pipe with a water solution of a surface active substance (SAS). At the closed annular space the water solution of the surface active substance is flushed to the formation, the process is withheld till oil flowing to the well. Then through the annular space the acid solution is flushed, the process is withheld for the purpose of the acid reaction with the rock, the borehole is washed, the flexible flush-joint pipe with the jet nozzle is lifted from the well. Inert gas injection is made through the annular space with the fluid sampling in the tubing string. Upon development of the well a geophysical survey is made for the horizontal borehole at the flexible pipe by thermometry and measurement by a flowmeter. Upon receipt of the survey results non-operated intervals are identified and by comparing geophysical data with final logging data non-operated intervals are identified in the horizontal borehole having high permeability and porosity. By running the flexible flush-joint pipe in, the jet nozzle is set in these intervals of the horizontal borehole, the jet nozzle end is thrusted to the horizontal borehole wall and the acid solution is circulated through the flexible flush-joint pipe, jet nozzle and tubing string until depression (channel) is formed in the rock and the surface area of the impact interval is increased. Then through the annular space the acid solution is flushed, the process is withheld for the purpose of the acid reaction with the rock, the borehole is washed, the flexible flush-joint pipe with the jet nozzle is lifted from the well. Inert gas injection is made through the annular space with the fluid sampling in the tubing string.

EFFECT: improving the acid treatment efficiency.

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