Decision Tree for Selection of Artificial Lift Method

Abstract

Abstract Recent changes, upgrades and development in artificial lift equipment have expanded the considerations for selection of pumping method. This paper covers sucker rod pumping, continuous gas-lift, intermittent gas-lift, electric submersible pumping, hydraulic reciprocating pumping, hydraulic jet systems, plunger lift, progressing cavity pumping, and additional miscellaneous pumping methods. Changes in well conditions and equipment capabilities demand timely reviews of the original lift method decision to determine if it is still the best choice. Often the selection of the lift method is based on operating personnel / decision maker equipment familiarity. Included in the decision tree should be a long term economic analysis. This paper will consider how new advances in individual methods have changed their cost effectiveness and provided solutions to unique problems. There is not a single lift system that is the most economic system for all wells. In order to access the practically and the economics of various methods of artificial lift, the first step is to generate an IPR (Inflow Performance Relationship) curve or a PI (Productivity Index). Then a profile of expected and desired production versus time should be determined. Figures 1 & 2. With the above information, potential artificial lift methods can be introduced, including expected run lives and cost considerations for the most obvious methods. Detailed cost estimates of the well operating cost are then reported and compared to the numbers used in the economic evaluation of the field. The economics of low rate wells and high rate wells need to be adjusted to account for the economics of the project. The economy of scale and simpler logistics of just using one lift system in most fields will probably not weigh up against the savings of using the most economic system on each well. Early in the life of the field the well may produce 100% oil with a moderate GOR. As the field declines and pressure maintenance begins GOR will increase and then rapidly decline while water production will increase. What range of BFPD is project, and what is the desired producing sand face pressure, Pwf. Areas of evaluation of lift methods include (1) lifetime cost, (2) operating cost, (3) energy efficiency, (4) initial capital cost.