A Conceptual Study of Dual Lift Design in Ultradeep Wells

Abstract

Abstract For many years rod pumping has been a desirable artificial lift method for on-shore oil wells. Today, in addition to rod pumps, other artificial lift methods such as gas lift and electrical submersible pumps (ESP) are also available for assisting well production. While rod pumps have been proven to be one of the simplest and most economical choices, when it is not sufficient for high-rate wells, harsh-fluid production, or deep wells, operators turn to other lift methods to produce hydrocarbons to the surface. The selection of appropriate artificial lift methods revolves around many factors, including economics. This paper presents a conceptual and feasibility study of combination of two methods of lifting for production of moderate volumes of oil from deep or ultra-deep onshore wells. It proposes to use an ESP and a sucker rod pumping unit simultaneously to lift fluids. The argument is that to lift from a deep well, with only ESP the cost and housing limitation of the wellbore may become a vital problem. Lifting the hydrocarbons to a certain depth by an ESP system, and then using the rod pump to transport the fluid to the surface may be a solution for deep and ultra deep wells. One of the critical issues in this concept is that rod pump lift is an intermittent lift, but ESP is a continuous lift. This issue has been address with the design of a chamber in between the two systems to accommodate the two lift devices and ensure continuity. This paper presents an example with detailed calculations to provide the technical support to the idea. Even though this approach has not been applied in the field, once proven feasible, the dual lift method can bring a solution with economic value to artificial lift for ultra-deep onshore oil wells.