TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractRecently, various companies published sophisticated design methodologies to engineer the 'cement' sheath in a oil/gas well completion such that the zonal isolation would remain intact (i.e. pressure tight) during its projected lifetime. Loading within a prescribed design envelope (e.g. pressure and/or thermal cycling or mechanical compaction processes) are the main considerations. Improved performance of a candidate zonal isolation material is achieved by adjusting its material properties, especially the Young's modulus and the compressibility. These earlier studies indicated that apart from a proper mechanical characterisation of the 'cement sheath' (preferably described by non-linear material models), the in-situ stresses in the 'cement' play a prominent role as well. The latter are influenced by the volumetric behaviour of the slurry during setting and the thermal expansion coefficient of the set 'cement'. However, often these parameters are not known for 'real life' well construction materials. Therefore, Shell International E & P B.V., the Netherlands, decided to design and construct dedicated laboratory equipment to determine those parameters for commercial 'cement' formulations at conditions encountered in typical well completions. A first feature of this unique system (which can operate at pressures up to 1500 Bar and temperatures up to 300 o C) is to monitor i) the progress of the 'setting' reaction of Oil Well Cements and or thermosetting resins, ii) their reaction behaviour (from the onset of gelling to the 'final set') and iii) the softening or swelling phenomena encountered in thermoplastic and thermoset materials.