DOWNHOLE PRODUCTION CASING STRING Russian patent published in 2019 - IPC E21B17/08 E21B7/20 

FIELD: soil or rock drilling; mining.

SUBSTANCE: invention relates to a downhole production casing string for insertion in a borehole in a reservoir. Downhole production casing string has a first and a second end, and comprises at least one opening which allows hydrocarbon-containing fluid to flow from the reservoir into the downhole production casing string during production, a plurality of casing parts having end sections and a base section between the end sections, the base section having outer diameter (D_o), and at least one annular projecting element having an outer surface and at least one helical groove arranged in or on the outer surface and having an overall outer diameter (D_∞) which is larger than the outer diameter of the base section. Downhole production casing string further comprises at least one annular barrier, the annular projecting element being located between the two annular barriers or the annular projecting element being part of the annular barrier.

EFFECT: technical result is improvement of the casing string.

16 cl, 11 dwg