Conventional oil or gas well design involves multiple casing strings because of alternation of zones in the cross-section characterized by various reservoirs properties and, consequently having different geological settings and geomechanical conditions. To drill a well deeper into formation such zones are generally isolated by intermediate casing strings run from wellhead to drilled depth, drilling is continued with a smaller-diameter bit. This results in higher material consumption (cement, casing strings) and increases cost of well casing.
Available expandable tubular technologies offer a viable solution to these challenges enabling selective isolation of trouble zones without loss of wellbore diameter. Total weight of casing strings in wells of up to 3500 m TD may be reduced by 100-300 tons. Oil-well cement requirements are cut down respectively.
Production wells at Tatneft’s oil fields are not provided with intermediate casing strings. To date, expandable profile liners for local casing have been successfully installed in more than 1,700 wells. Equipment for local well casing expandable profile liners are available in eight sizes intended for five various applications. Considerable work is underway in Tatneft to improve the expandable tubular technology for adjusting it to complex geological conditions encountered in oil production regions outside the Republic of Tatarstan.
References
1. Abdrakhmanov G.S., Kreplenie skvazhin ekspandiruemymi trubami (Well casing by expandable pipes), Moscow: Publ. of VNIIOENG, 2014, 267 p.
2. Patent no. 2483190 RF, MPK E 21 B 33/10, E 21 V 43/10, Method and device for isolation of troublesome zones when drilling wells with shaped shutter with cylindrical sections, Inventors: Abdrakhmanov G.S., Khamit'yanov N.Kh., Kirshin A.V., Yagafarov A.S., Filippov V.P.
3. Patent no. 2521241 RF, MPK E 21 B 29/10, Hydraulic jack for installation of shutter in well, Inventors: Abdrakhmanov G.S., Zalyatov M.M., Khamit'yanov N.Kh., Starov V.A., Timkin N.Ya., Vil'danov N.N., Bagnyuk S.L.
4. Patent no. 2516119 RF, MPK E 21 B 23/04, Anchor for fixation of downhole equipment, Inventors: Abdrakhmanov G.S., Khamit'yanov N.Kh., Kirshin A.V., Yagafarov A.S., Pronin V.E.
