METHOD OF WHIPSTOCK-FREE DRILLING OF MULTIPLE WELL Russian patent published in 2003 - IPC

FIELD: technology of oil and gas drilling, particularly, whipstock-free multiple well drilling methods. SUBSTANCE: method consists in that main horizontal wellbore up to designated point of additional wellbore is drilled by downhole assembly having centralizers stabilizing its direction, then, by downhole assembly with bent sub from bottom formed in drilling of main horizontal wellbore used for drilling of additional wellbore with diameter equaling diameter of main horizontal wellbore and with its subsequent reaming by means of drilling bit with displaced center within interval of sidetracking of additional wellbore with formation of bottom behind said interval from which next part of main horizontal wellbore is drilled with previous diameter. Radius of spudding of main-horizontal wellbore equals radius of sidetracking of additional wellbore. EFFECT: increased oil recovery from tapped formations of multiple well due to increased surface of filtration of additional wellbores. 2 cl, 1 dwg