PROCESS OF BOTTOM-HOLE TREATMENT Russian patent published in 2004 - IPC

FIELD: oil and gas production, drilling, operation and overhaul of wells. SUBSTANCE: process can be widely employed in gas and gas condensate fields with cluster position of wells, for bottomhole treatment of wells with underground equipment with open and shut circulation valve and in packer-free wells with low values of formation pressure. Given process ensures increased permeability of formation thanks to shortened presence of reagent in well shaft above perforation interval and prevention of contact of chaser with reagent and formation-collector when effect of pressure of hydrostatic column of chaser on bottom hole is excluded. Process includes injection of reagent into tubing string with shut-off hole clearance, delivery of reagent to bottom by energy of compressed air of hole clearance, injection of chaser, driving of chaser into formation after stabilization of pressure in pipe clearance and hole clearance of well and removal of reaction products from formation. According to process first of all bottom hole is cleared from fluid, water, condensate and contamination. On closing-in of well instrument-densimeter is sunk into bottom hole to record changes of fluid density at bottom hole with its setting at level of upper holes of perforation interval. After it reagent is injected. Then high-viscosity buffer is injected into tubing string and into hole clearance. Thereafter natural gas with rise of pressure across well head to static is injected into hole clearance and pipe clearance. Later service water with surface active substance and stabilizer is pumped. Pressure across well-head is decreased to 1.0-3.0 MPa. Thereupon gas is injected into well to level of static pressure and then portion of water again. Process is repeated several times till reagent is driven into formation. EFFECT: increased permeability of formation. 1 dwg