Ways to Decrease Production Costs for Sucker-rod Pumping

Mainly due to its long history, sucker-rod pumping is a very popular means of artificial lift all over the world, roughly two-thirds of the producing oil wells are on this type of lift. To maximize profits from these wells in the ever-changing economic situation with rising costs of electric power, installation designs must ensure optimum conditions. In the paper, basic considerations on ensuring profitable rod pumping operations are given. The key topics of installation design (pumping mode selection, optimum counterbalance, rod string design) are addressed and their role in the improvement of sucker-rod pumping operations and the reduction of lifting costs is discussed. After a review of the surface and downhole energy losses in sucker-rod pumped wells, some key considerations on the ways to improve system efficiency are given. The most important task is the proper selection of the pumping mode, i.e. the combination of plunger size, pumping speed, stroke length, and rod taper design for lifting the prescribed amount of liquid to the surface. The best pumping mode maximizes the lifting efficiency and, at the same time, reduces prime mover power requirements and electrical costs. The operational efficiency of the surface equipment is improved by using an optimum counterbalancing of the pumping unit. To achieve an ideal sucker-rod pumping system the mechanical design of the tapered rod string must be properly made. The paper gives aspects and details of installation design improvements along with practical examples.