CASING CEMENTING JOB IN SLANTED-DIRECTIONAL WELLS Russian patent published in 2003 - IPC

FIELD: well drilling, casing cementing job in slanted-directional and horizontal wells. SUBSTANCE: invention increases cementing quality and prevents emergencies while executing this job by prevention of break of column of cement slurry under action of hydrostatic pressure in process of injection of cement slurry into casing string based on mathematical description of physical process of overflow of cement slurry into hole clearance under action of pressure difference and qualitative evaluation of intensity of overflow which in its turn determines required value of volumetric flow rate of injection of cement slurry during segmentation. Casing cementing job includes sinking of casing string, injection of cement slurry into casing string, break of separating plug, pumping of flushing fluid and forcing of cement slurry into hole clearance. In correspondence with invention minimal value of volumetric flow rate of injection of cement slurry into casing string with due account of curvature of well shaft is found by analytical expression prior to injection and efficiency of injection of cement slurry is to be chosen above this value. EFFECT: increased cementing quality and prevention of emergencies while executing casing cementing job. 4 dwg, 1 tbl