Thermoplastic Lined Tubing: A Cost-Effective and Uptime-Enhancing Solution to Prolong Well Run Life

Abstract

Abstract Production deferment and its associated costs are one of the key challenges in Well Reservoir Formation Management (WRFM) environment especially as wells are aging and frequently failing prior to their expected well life span. This could happen due to various reasons and one of them is the tubing erosion/corrosion in artificially lifted wells such as PCP and ESP. Therefore, the idea of installing thermoplastic lined tubing came up as an attempt to prolong the completion run life and thus reduce oil deferment along with CAPEX and OPEX. Fields in South of Oman operate at harsh reservoir conditions. Wells are producing relatively heavy oil at high BSW and high sand content. In 2020, hoist intervened 31 times in two fields (A and B) with a total of 70 active PCP wells only. 74% of failures were attributed to hole in tubing and 60% of these had less than one year run life. These alarming statistics necessitated out-of-the-box thinking. Thermoplastic lined tubing came into a picture as a mean of reducing failures by minimizing the friction between tubing and pump rods. This new method was first piloted in PDO in four wells in field A. Despite being installed for over two years, none of the wells in pilot have failed till to date. Completion run life has increased by double and nearly triple in some cases and wells are still continuously operating successfully. This is a great achievement when it comes to deferment and cost reduction. In field A & B, each hoist intervention cost $100-150k, and deferment might last for 20-40 days before well restoration take place. Preliminary results showed a saving of three interventions per well within two years and an increase of well uptime. The successful results extended the current plan to full deployment that will include other artificial lift well types. Furthermore, more than 30 thermoplastics lined tubing installations are currently expected per year in different fields for different clusters in PDO. Thermoplastic lined tubing has not only proven to increase completion run life but also improve workovers cost and has element of energy saving due to reducing friction loss between pump rods and the internal of the tubing. This means less pump torque and less power consumption to lift the fluid to surface with an estimated power saving of 7-10%.