Abstract
The first electrical submersible pumps (ESPs) were installed nearly 100 years ago by simply running an ESP on tubing in a cased hole. Since then, ESP completion architectures have evolved to cater for a wide range of needs such as dual barriers for offshore operations, reservoir monitoring, flow assurance, backup gas lift, back-allocation for multilayered reservoirs, and dual ESPs for enhanced run life to name a few. These solutions have been made possible by new completion tools which continue to be developed. However, the biggest driver behind the proliferation of completion architecture arrangements has been the creativity of field engineers to meet production and operational needs. Key to justifying additional complexity in a completion is to demonstrate the value, and, to this end, an exhaustive list of functional production and operational requirements was developed and reviewed to serve as a check list for evaluation of artificial lift completion architectures. Establishing the requirements are often overlooked as architectures are often adopted based on what is known or legacy practices (i.e., "This is how we have always run our ESPs.") To illustrate how the functional requirements can be achieved, a wide range of completion architectures were compared and evaluated against the "functional check list" and the review contains references of where these completions have been successfully installed. One of the findings was that, all too often, the completion architecture does not provide a method for circulating the well without losses to the reservoir, which is an important consideration for maintaining flow assurance. Of course, the perfect ESP completion architecture does not exist. However, this review of requirements and completion architectures provides the practicing completion engineer with a methodology for developing the inevitable engineering compromise between cost, complexity, and value based on documented functionality.
