MULTI ZONE OIL RESERVOIR AT LATE STAGE WITH UNSTABLE COVER FORMATION AND NON-HOMOGENEOUS COLLECTOR DEVELOPMENT METHOD Russian patent published in 2010 - IPC E21B43/16 E21B7/04 

FIELD: oil-and-gas industry.

SUBSTANCE: essence of the invention: according to the method execute at least of a one hole drilling in a multi zone reservoir at the late stage with unstable cover formation and non-homogeneous collector. Drill though the cover unstable formation under an angle, not greater than drilling without crushing limit angle. Case the borehole, overlapping the cover unstable formation until producing member. Pass through the producing member non-homogeneous formation total interval with a bit of smaller diametre and angle set up to 90° to the bottom. Execute research, select formation with the greatest residual reserve and depth. Enter the selected formation with the following angle set. Exit at 90°, go through the formation sub-horizontally and/or horizontally by the formation most permeable sub-layer, staying in it, execute control according to geo-process research. At clay bridges and/or watered sub-layers presents case the well with a tail, from the producing member roof until the selected formation with residue reserves after execution an oil saturation research. Open only oil saturated formations, each in two formation cross sections. Execute selected formation hole sub-horizontal or/and horizontal part production through an opened hole of a filter, descending tubing pipes tail till the well borehole bottom part.

EFFECT: field oil recovery increase.

2 ex, 3 dwg