CONSTRUCTION OF OIL PRODUCTION WELL Russian patent published in 2014 - IPC E21B43/00 E21B7/00 

FIELD: oil-and-gas industry.

SUBSTANCE: at construction of production well, vertical shaft is drilled through rocks, including unstable mud shale, with entry into productive seam, going-in of production string to productive seam, cementing of annular space and drilling the shaft from production string into productive seam. At exposure of horizon with unstable mud shale, mechanical drilling rate is set not over 6 m/h for drilling with increased flushing fluid flow rate of about of 30-40 l/s using drilling solutions with density of 1.12-1.40 g/cm³. After well shaft drilling, drilling assembly performs cleanup job over well shaft with working of the shaft by rotary machine at rotor rpm of 40-100 rpm. Drilling fluid mixed with fibres in amount of 6-15 m³ is forced through the shaft and drill assembly reciprocates over the length of drive pipe. For well shaft casing operation string is lowered section-by-section. First 400-1000 m long section is lowered to well bottom on drill tool and annular space if cemented in interval from bottom to first section head. Cement is cured to lower production string second section. Sections are coupled, annular space is cemented and cement is cured. Production string is sealed.

EFFECT: ruled out sticking of drill tool in drilling unstable mud shale.

2 cl, 3 ex