HTHP In-Situ Mechanical Test Rig and Test Method for High-Temperature Polymers and Composites

Abstract

Abstract High-temperature polymers and their composites have been used extensively in critical industrial applications, including composite drill pipes, tubing and casing, logging tools, and various drillable tools for oilfield downhole operations. However, when a wet condition is combined with high temperature, most high-temperature polymers and their composites behave very differently from their original dry state because of severe hygrothermal or hydrolytic degradation. In many cases, oilfield service tools are required to perform in a hot-wet fluid condition at temperatures above 204oC and pressures above 70 MPa. These conditions present significant challenges to applications of polymers and composites downhole. Properly characterizing and fully understanding the HTHP hot-wet thermomechanical properties of various high-temperature polymers and composites based on an accurate, environmentally simulated HTHP mechanical test method is extremely important for successful applications. This paper will present a newly developed HTHP in-situ mechanical test rig and the associated test method for high temperature polymers and composites. The in-situ mechanical test rig has been performed successfully in a fluid and gas environment up to 204oC and 34.5 MPa. For the first time, true HTHP hot-wet tensile and compressive strengths of a high temperature epoxy neat resin and selected high-temperature polymer composites have been determined in a real HTHP hotwet environment in the HTHP in-situ test rig immediately after a period of the HTHP hot-wet exposure. These results are found to be very different from those determined by conventional environmental-mechanical test methods. The authors will briefly review the conventional environmental-mechanical test methods for polymers and composites based on current literature and test standards and will discuss how the new HTHP in-situ mechanical test methods can eliminate the problems with the conventional test methods and procedures. 1. Introduction Oilfield downhole operations, including drilling, logging, completion, production and workover, require the service tools to perform in an extremely harsh environment in a deep well involving high-temperature, high-pressure (HTHP) and various corrosive fluids and gases. This requires the materials for downhole equipment to possess high strength with heat- and corrosion-resistant capabilities. Recently developed new technologies in oil and gas exploration and production, involving offshore deepwater extended-reach drilling and completion, further require materials for downhole tubular components and equipment to be lightweight and fatigue-resistant. Advanced fiber-reinforced high-temperature polymer composites enable work at elevated temperatures in deep wells while offering the required advantages such as being lightweight, corrosion resistance, long fatigue life and easy removal. Furthermore, the non-conductive and non-magnetic high-temperature polymer composites are considered to be ideal materials for construction of resistivity and induction logging tools for oil and gas exploration (Y. Yuan and J. Goodson, 2001, 2004, 2007).