Abstract
Electric Submersible Pumps (ESPs) are complex, high power electromechanical systems that operate in extreme environments under very tight geometric constraints. Despite the efforts of suppliers and operators ESPs will eventually fail, requiring replacement. In addition, it is sometimes necessary to intervene in a well to optimize or remediate production – a process not possible, or limited, with an ESP restricting access to the reservoir or lower completion.
The process of installing or removing an ESP has changed little since their introduction almost 90 years ago. Removing (or installing) a conventional ESP requires pulling the tubing string, replacing the ESP and reinstalling the tubing string with the use of a rig or pulling unit (a "heavy workover" or HWO). This expensive, time consuming process creates significant logistical challenges and QHSE risks along with significant lost production.
Increasing use of ESPs, along with today's difficult economic environment has brought a renewed interest in the potential of alternatively deployed ("rigless") ESP systems to improve project economics by reducing the cost of interventions while simultaneously increasing the oil produced per well.
Evaluation of the economics associated with alternative deployed systems is not straightforward, with many nuances which are not obvious. This paper seeks to develop a framework which can be used to compare the economics of wireline retrievable ESP systems (WRESP) to conventional, tubing deployed ESP systems, taking into account the uncertainties surrounding the reliability of the various system components (both conventional ESP and WRESP) through the use of Monte Carlo simulation.
This framework will be used to compare the likely economic outcomes in six ‘typical’ operating environments: West Africa Offshore, Middle East Land (high rate and moderate rate), Asia Offshore, Alaska, and US Land (lower 48) using (to the greatest extent possible) actual reliability data and operating parameters in these environments. The production and economic outcomes of both conventional ESP and WRESP deployments will be compared and presented along with the sensitivity of these outcomes to typical uncertainties in each of these environments.
