Development of a Low-Risk Ultra-High Annular Flow-by Tubing Anchor Catcher


Jeff Saponja, Oilify 
Corbin Coyes, Q2 ALS 
Furqan Chaudhry, Ovintiv 

Sucker rod pumping commonly requires the tubing string assembly to be secured to the casing downhole near the pump to prevent tubing movement. Tubing movement can reduce downhole pump efficiency and result in premature failure of the tubing string due to mechanical wear. Downhole tubing anchors are used for this purpose, but they can bring about new risks that can increase operating expense and reduce production. Engineering application and operational use of a tubing anchor should consider the following risk controls: 1. it must be a catcher type (Tubing Anchor Catcher or TAC) to avoid the risk of a portion of a tubing string from falling uncontrollably down the wellbore in the event the tubing loses integrity (i.e., becomes parted), 2. it must have adequate tensile loading retainment capacity for all possible tubing movement scenarios to avoid the risk of compressional tubing loadings, 3. it must have adequate annular flow-by clearance or a large enough annular cross-sectional area with the wellbore casing to avoid the risk of excessive gas velocities limiting liquid fallback, and 4. it must possess low operational complexities and uncertainties for running (setting) and retrieving (unsetting), to avoid the risk of excessive workover costs or a loss of wellbore. An extensive and comprehensive review of existing TAC’s revealed that none address all four of the risk considerations collectively as described. A new TAC concept was hypothesized to address all four considerations. The new concept broke through a number of industry paradigms. It uses three dimensional slips and drag blocks for achieving more annular flow-by area than a 2-7/8” EUE coupling. It avoids the need to rotate the tubing for setting and unsetting. Simple low operational risk up and down motion sets, catches and unsets the TAC. A prototype was built, tested and field trialed. Case histories demonstrate this new TAC successfully lowers operational risk and improves production.