WELL COMPLETION METHOD Russian patent published in 2007 - IPC E21B33/13 

FIELD: methods or devices for cementing, for plugging holes, crevices, or the like for well construction and workover.

SUBSTANCE: method involves primary exposing productive reservoir; preparing casing pipe for lowering in well; lowering casing pipe provided with shoe, check valve and baffle plate in well; performing direct casing pipe cementing through the shoe along with following cement mix, baffle plug and two portions of displacement liquid injection so that density of the first displacement liquid portion exceeds that of the second one to obtain summary hydrostatic pressure of above two portions in casing pipe greater than productive bed pressure; waiting for cement mix hardening; performing pressure testing of casing pipe; secondary exposing productive reservoir with perforation operation; providing productive reservoir inflow. Casing pipe preparation includes covering of inner and sections of outer casing pipe surfaces arranged within perforation interval with heat-insulation material so that heat insulation layer extends at least from shoe to the first displacement liquid portion level. Before cement mix injection buffer liquid is additionally injected in well. Lubrication hydrophobic liquid in injected in well between cement mix and buffer plug injection. Amount of lubricating hydrophobic liquid is equal to casing pipe volume defined by baffle plate and check valve and summed with reserve volume corresponding to casing pipe section length spaced 1-3 m below check valve. The casing pipe is covered with several heat insulation layers. Maximal total heat insulation layer thickness is selected with taking into consideration of free cylindrical former passage through the casing pipe and possibility of casing pipe fishing from outside with elevator. Minimal heat insulation layer thickness is 0.5 mm. Cement mix is injected in two portions. The second portion is supplied in amount equal to hole annuity volume around casing pipe and inner casing pipe volume defined by baffle plate and shoe additionally has swelling additive.

EFFECT: extended time of water-free well operation, decreased quantity of well workover for water shutoff, prevention of asphalt-tar-paraffin deposit generation in bottomhole reservoir zone, improved bottomhole reservoir zone treatment, extended range of suitable compositions, including corrosive compositions, to be used.

3 cl, 1 ex, 2 tbl, 2 dwg