Making Non-Metallic Downhole Tubulars a Reality - Materials and Construction

Abstract

Abstract To combat the increasing corrosion costs and associated risks in well operations, one of the preventive strategies is to substitute metallic tubulars prone to corrosion with non-metallic (NM) alternatives for longer service life, elimination of corrosion-related hazards and lower total cost of ownership. The focus of this paper is to discuss the research and development for HPHT downhole application with the non-metallic materials and the pipe construction that have been utilized as pipeline tubulars successfully in surface and offshore applications. A detailed discussion on the commercially available non-metallics in terms of fibers, polymers, and composites is presented with focus on those utilized in oil and gas tubulars where high pressure and high temperature in subsurface are of utmost concern to material integrity, where specific material properties are to be considered during material selection. Consideration of how the pipe construction and design are impacted by the demanding restrictions of the well structure and conditions, as well as manufacturing limitations, are explained and indicate certain types of pipe construction are not viable to meet future demands as revealed from the gap analysis. This study identified the missing gaps where the stringent requirement of the downhole well conditions demand higher pressure rating and higher temperature resistance tubulars which are not readily available in the market. The selection of the materials in terms of the temperature and chemical resistance of the specific material properties are based on the application requirement, where technology and financial viability plays an important role too. These findings point to the disparity between a wide selection of non-metallic materials and yet limited commercial availability of these non-metallics materials for pipeline tubulars development. In that aspect, advancement of material development is paramount to improve the material properties that are suitable for use in downhole tubulars at HPHT condition. Besides material properties as a consideration for the selection of pipe construction and design, the stringent requirement of the well architecture, harsh conditions, and manufacturability limit the types of pipe construction and design to a great extent, which needs extensive effort to develop robust yet cost effective product. A lack of standardization in qualification and operational processes renders the deployment of non-metallic downhole tubulars a big challenge in the oil and gas industry. This publication provides a concise discussion of the material ranges that are currently available for use in pipeline tubulars and their relation to pipe construction and design. To advance downhole tubular development attention is directed to material development for a higher temperature and chemically resistance product to meet stringent downhole conditions. This leads to R&D efforts towards the part of the missing gaps that are essential to make non-metallic downhole tubular a reality.