OREANDA-NEWS. March 16, 2012. TATNEFT continue implementing the program of introducing long-stroke balancer-free chain drives (CD) in sucker rod pumping installations which significantly reduce maintenance costs of oil production, reported the press-centre of TATNEFT.

The active Company's well stock, equipped with chain drives amounted to 1,383 units as of the beginning of 2012. Of this amount 1,069 wells were equipped with CD 60 with the stroke length of 3 m, and CD 80 drives with the stroke length of 6 meters were installed in 314 wells.

The change-over of TATNEFT to mass introduction of chain drives has primarily been due to the proven technological and economic efficiency of their application.

Practical experience of operating CD 60 and CD 80 drives shows that their most efficient application is in the wells complicated by extra-viscous oil, formation of oil-water emulsion (OWE), deposits of salts and asphaltene/resin/paraffin compounds on the downhole equipment working in the periodic pumping mode, as well as in small diameter wells (114 mm).

CD 60 drives are recommended for implementation in the wells with extra viscous production, as well as in the marginal periodically operated wells stock and the wells, which operation is complicated with deposits of salts and asphaltene/resin/paraffin compounds. The wells equipped with 3 m stroke length chain drives provide for saving specific energy costs of the liquid lifting on average by 15 percent compared with conventional sucker rod pumping units. Application of these drives also reduces dynamic loads, specific content of metal, transportation, installation and maintenance costs. The number of workovers due to formation of the emulsion is reduced by 3.9 times, and the ones resulting from rod breaking and parting by 2.4 times.

The advantage of CD 60 drives (with 3 m stroke length) comparing with balancer drives is the possibility of operating the periodic low-productivity wells in a continuous mode and receiving an additional increment of output at the same time.

CD 80 drives (with 6 m stroke length) have significant advantages over the analogous balancer units and electric submersible centrifugal pumps (ESP). These chain drives should be used in high production rate wells, including the ones producing extra-viscous oil, wells complicated by the sand and solids production, as well as in the wells of small diameter with additional production casings and cyclic injection. Chain drives with the stroke length of 6 meters allow for reduction of specific energy costs for lifting the liquid in comparison with the ESP on average by 57 percent.

The downhole pump chain drive CD80-6-1/4 developed by the specialists of BMZ and manufactured at the Bugulma Mechanical Plant of TATNEFT is the winner of the contest "100 best goods of Russia". Currently there are 11 different versions of the chain drive for the sucker-rod pump. BMZ is also developing technical documentation for prototyping chain drives to operate in regions of the Far North and in areas of hot climate.