Mechanical Behavior of Syntactic Foams for Deep Sea Thermally Insulated Pipeline

Abstract

Abstract.Ultra Deep offshore oil exploitation (down to 3000 meters depth) presents new challenges to offshore engineering and operating companies. Flow assurance and particularly the selection of insulation materials to be applied to pipe lines are of primary importance, and are the focus of much industry interest for deepwater applications. Polymeric and composite materials, particularly syntactic foams, are now widely used for this application, so the understanding of their behavior under extreme conditions is essential. These materials, applied as a thick coating (up to 10-15 cm), are subjected in service to:-high hydrostatic compression (up to 30 MPa) -severe thermal gradients (from 4°C at the outer surface to 150°C at the inner wall), and to high bending and shear stresses during installation. Damageable behavior of syntactic foam under service conditions has been observed previously [1] and may strongly affect the long term reliability of the system (loss of thermal properties).This study is a part of a larger project aiming to model the in-service behavior of these structures. For this purpose it is important to identify the constituent mechanical properties correctly [2,3]. A series of tests has been developed to address this point, which includes: -hydrostatic compression -shear loading using a modified Arcan fixture This paper will describe the different test methods and present results obtained for different types of syntactic foams.Introduction.

Analysis and numerical investigations on the temperature-dependent creep behavior of polypropylene matrix composite used for coating of offshore pipeline

“…trueS¯¯ is the elastic flexibility tensor put into the form proposed by ref. 19.G=E/2(1+ν) is the shear modulus and E and ν are the Young’s modulus and Poisson’s coefficient, respectively. The constitutive law of the spectral viscoelastic model indeed follows from the thermodynamic framework presented above where the total energy density being the sum of all constitutive energy densities and similarly the total dissipation potential the sum of all constitutive dissipation potentials.…”

“…The experimental methods were compared with each other to identify the elastic properties of syntactic foams. 19,20 The tests were carried out on epoxy and polyurethane matrix syntactic foams. In addition, a study by microscopic observation was allowed to highlight the effects of porosity defects generally present in syntactic foams with polymer matrix.…”

In situ observation of syntactic foams under hydrostatic pressure using X-ray tomography

“…The resulting slurry is then injected into a mold. Table 1 shows the formulation and reference of these three materials and their physical and mechanical properties measured by the hydrostatic compression test developed by Choqueuse et al in [11]. This method is based on the loss of buoyancy under hydrostatic compression which is directly linked with the filling of microspheres and gives access to an estimation of the maximum service pressure.…”

“…Syntactic foams, which are made of hollow glass microspheres embedded in a polymer matrix, are becoming more widely used for thermal insulation of offshore pipelines and bundles which convey oil and gas resources from extraction sites located in deep water [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11] and [12]. Insulation material durability contributes directly to the maintenance of reliable offshore production (flow assurance) over 20 years of service.…”

Effect of Porosity Gradient on Mechanical Properties of Cellular Nano-Composites

“…Syntactic foams are low-density materials with properties qualifying them for use in demanding non-structural applications from deep-sea exploration to aerospace [8,9]. Traditional syntactic foams consist of a compact polymer mixed with stiff and brittle hollow glass microspheres (HGM) [10][11][12][13][14]. With few reported exceptions, the elastic moduli, tensile and crush strengths, critical stress intensity factor, and the strain energy release rate of syntactic foams decrease monotonously with increasing relative porosity, e.g., with increasing the HGM content [15][16][17][18][19].…”