The Application of a Fiberglass Liner in Well Tubing as Cost Effective Material Option in High Velocity Production Wells

Abstract

Abstract The composite liner is made of a Glassfibre Reinforced Epoxy (GRE) resin, inserted in Carbon Steel tubing and it can be used in both production and water injection wells. Different laboratory tests performed either by manufacturers and by operators, have been carried out in order to confirm and verify the material characteristics and reliability. In particular, Eni in 2009 tested GRE in sour environment with CO2 and H2S to investigate the capability and service limits of the resin liner at different temperatures. According to the positive results of the tests, Eni has firstly applied GRE in 2005 in Tunisia where it was successful in reducing onshore workover costs and extending the life of Carbon Steel tubing in oil producer wells with high CO2 and water cut. The latest application was in Norway where it has been installed on water injector offshore wells, where, due to high corrosiveness of the injection fluid (raw seawater with antifouling chlorination), the liner was selected as cost effective alternative to high alloyed materials. More recently, Eni was involved in particularly challenging deepwater development projects with highly productive gas wells in sour and harsh environment. Typically, these applications require high grade Corrosion Resistant Alloys (CRA) production tubing with an important impact on the completion costs and operative run in hole issues. Following the positive experiences gained in the last 15 years in the application of glassfibre liner, it was evaluated the possibility to deploy the material as a corrosion barrier in well production tubings under more critical conditions. Eni decided to perform some additional laboratory tests in collaboration with Milan Polytechnic. Direct impact test and straight pipe test were performed in order to characterize the erosion behaviour of GRE composite material, supplied by two different manufacturers, and simulating the case of wells with high erosion rate risk. The results demonstrated GRE to have a good resistance to the solid particles erosion in comparison to very similar tests on Inconel Nickel Alloy material and confirmed the potential use of GRE as a corrosion resistance material when combined with Carbon Steel tubulars as an alternative to the usual high CRA materials in producer wells. This paper will present the characteristics of the technology, the laboratory tests performed with their results and the acceptable range of field conditions. Additionally, the paper will provide Eni field experiences, including feedback, lessons learned and economic evaluations.