TECHNIQUE TO DRIVE HOLES IN HIGHLY PENETRABLE CRUMBLING GAS- SATURATED COLLECTORS Russian patent published in 2002 - IPC

FIELD: drilling technology. SUBSTANCE: invention refers to technology of drilling of oil and gas wells, vertical and inclined, in highly penetrable crumbling gas-saturated collectors with gradient of seam or pore pressure of 0.002-0.009 MPa/m. Invention can be employed first of all in driving of wells in intricate geological conditions characterized by full absorption of drilling fluid which causes gas manifestation that can not be liquidated in standard manner. According to technique rock is broken with direct washing with drilling fluid along drill pipe string. Drilled out rock is removed to day surface. After achievement of absorbing crumbling gas-saturated seam which is judged by fall of pressure and lack of circulation, washing agent is replaced with drilling fluid with low content of solid phase and drilled out rock is removed into absorption zone. Waterlock is formed in hole clearance in the form of column floating above absorption layer. Column of stable three-phase foam obtained by way of aeration and mixing produced immediately before pumping foam-forming liquid and air with density of foam and height of column sufficient to bring system "well-seam" in balance into hole clearance of well is used as floating column. When upper boundary of floating column of three-phase foam achieves well-head aeration by air supply is stopped and portions of foam-forming liquid is pumped above column of three-phase foam to press foam. EFFECT: increased efficiency of wells construction thanks to reduction of construction time and decreased usage of materials to liquidate complications. 6 cl