Mobil tests new flexible sucker-rod system in Hugoton field

For the past 3 y, Mobil Oil Corp. has been testing flexible sucker-rod systems for dewatering gas wells in the Hugoton field. The intent of the system is to provide the strength of conventional rods but to achieve superior corrosion resistance. The ''Flexirod'' system being tested is a joint development of Bethlehem Steel Co. and E. I. duPont de Nemours and Co. After determining that the Flexirod may, at least initially, perform much the same as standard rods, Mobil Co. cooperated with Lufkin Industries to develop a special pumping unit for the system. The unit is intended to be a self-contained machine capable of storing a Flexirod of 4000-ft length, lowering and seating a subsurface pump attached to the rod, stroking the pump to lift fluid, and then unseating the pump to raise to the surface for repair as needed. It should also (1) use the same prime mover for running and pulling the pump as is used to stroke the pump, (2) run and pull the pump with a crew of preferably 1 man and no more than 2 men, (3) compare in cost (in production quantities) to a conventional beam unit, and (4) be capable of lifting 40more » bbl/day of water from 3000 ft, operating with normal stress and strain. In Hugoton, the Flexirod system should save at least $250/pulling job. Other advantages are (1) being able to pull wells in bad weather or where roads are too muddy for pulling units, (2) not having to wait for or otherwise schedule a pulling unit, (3) permitting the use of pumps that may not last the longest but would be less expensive to repair, and (4) allowing more frequent pump inspection to maintain better pumping efficiency. Field applications to date have been generally successful, but additional use is necessary to establish long-range durability.« less