This paper focuses on the experience gained during the development and use of the novel aspects of the integration and installation of the MARS TLP project. These include:- The use of a Specialized Lifting Device [SLD] to place the MARS TLP topsides on the hull at lngleside, Texas. The design, construction and operation of the SLD are described. The scope and timing of the integration work are presented, and the interfaces with other aspects of the project discussed. The MARS foundation consists of 12 driven piles, one for each of the 12 tendons, which connect direct to the tendon with no foundation templates. A driveable connector was developed and tested, these were built into each pile. Soilcyclic behaviour, relevant to tension pile design, was investigated in an extended series of laboratory tests. The piles were placed in 2940' waterdepth using acoustic positioning and driven to grade using a hydraulic hammer with an underwater power-pack. Detailed installation engineering and preparations included model tests of the TLP and Balder while moored together and simulation of critical aspects of their positioning, including failure of mooring lines and positioning tugs. The tendons were barged to location in 750 ton packages containing 12 segments, nominally 240 feet long each, which were lifted and secured to the deck of the SSCV Balder. Theindividual segments were stalked together in assembly towers over either side of the SSCV using pressure actuated mechanical connectors. After all 12 tendons were assembled and hung off on both sides of the vessel, the TLP was moored to the stem of the Balder using a combination of surface lines and an array of tugs for positioning control. Fully assembled tendons were sequentially passed over slacked mooring lines and hung off on the TLP. Using special chain jacks, tendons were stabbed into their foundation pile receptacles with the assistance of ROV's, latched and tensioned to a balanced condition using a combination of chain jack stroke and ballasting. Introduction The MARS TLP configuration is described in the preceeding papers of this session [Refs I to 5]. The MARS TLP hull and deck modules were integrated at lngleside, Texas beginning in September 1995. A shore based Specialised Lifting Device [SLD] was used to place the modules on the hull. Hook-up and commissioning of the structure and suystems was brought to a high level of completion prior to sailaway. The TLP sailed away from lngleside on April 24th, 1996. Manufacture of the tendons and piles began in 1994, final fabrication being performed at Aransas Pass, Texas. Installation of foundation and TLP was planned to take place in a single operation to minimise mobilisations of the SSCV Balder. The TLP was moored to the SSCV during tendon transfer and stabbing. Pile installation began on March 29, 1996, the TLP arrived on site on April 29th, 1996, and installation was completed on May 19th 1996. First Oil began to flow on July 8th, 1996. A bar chart indicating the main activities is shown In Figure 1.

This paper presents a mathematical model of casing strings subjected to thermal loads in steam injection wells. The model includes the effects of temperature on material properties and the effects of wellbore curvature and pre-stress during the heating cycle. Several counter-intuitive aspects of the casing stress state during cooling/unloading are examined. Example calculations are used throughout to illustrate key insights. Introduction The design and development of steam injection fields is a mature subject. Since the tubulars in these wells invariably experience inelastic loading, issues such as the effects of temperature on the static and cyclic (fatigue) material properties become important. The original papers that address steam injection casing design issues date back to the 1960s. These studies include temperature prediction1, casing stress analysis2 and development of design guidelines3. Though these works acknowledge the role of temperature on the static and cyclic material properties, data on the cyclic thermal properties of OCTG steels rarely appears in oil field literature4,5. This paper presents a mathematical model of casing strings subjected to thermal loads in steam injection wells. The model includes the effects of temperature on material properties and the effects of wellbore curvature and pre-stress during the heating cycle. Several counter-intuitive aspects of the casing stress state during cooling/unloading are examined. Further, the general equations are shown, with appropriate simplifications, to reproduce the earlier work cited above2,3. Example calculations are used throughout to illustrate key insights. Governing Equations for Steam Stimulation Consider a deformation for which the strains are small enough to be characterized as infinitesimal. Then we may write the total strain rate as Equation (1) In developing a multi-dimensional, thermomechanical constitutive relation, we honor available experimental evidence that suggests that both the viscoelastic and plastic components of the deformation depend exclusively on the deviatoric tensors, with hydrostatic behavior being purely elastic, i.e. the mean components of the viscoelastic and plastic strains (and strain rates) are zero. In this regard, we introduce the deviator strain and stress tensors Equation (2) Equation (3) where for and for , and Equation (4) Equation (5) where a repeated subscript index indicates summation over the range 1 to 3. Similar definitions for deviatoric and mean elastic, viscoelastic and plastic strain rate components can also be written. The mean elastic strain rate is related to the mean stress rate by Equation (6) and from our previously stated assumption Equation (7) The mechanical constitutive relations for the deviatoric components are as follows.

Introduction The design and development of steam-injection fields is a mature subject. Because the tubulars in these wells invariably experience inelastic loading, issues such as the effects of temperature on the static and cyclic (fatigue) material properties become important. The original papers that address steam-injection casing-design issues date back to the 1960s. These studies include temperature prediction (Leutwyler and Bigelow 1965), casing-stress analysis (Willhite and Dietrich 1967), and development of design guidelines (Holliday 1969). Though these works acknowledge the role of temperature on the static and cyclic material properties, data on the cyclic thermal properties of oil-country tubular-goods steels rarely appear in oilfield literature (Placido et al. 1997; Maruyama et al. 1990). This paper presents a mathematical model of casing strings subjected to thermal loads in steam-injection wells. The model includes the effects of temperature on material properties and the effects of wellbore curvature and prestress during the heating cycle. Several counterintuitive aspects of the casing-stress state during cooling/unloading are examined. Further, the general equations are shown, with appropriate simplifications, to reproduce the earlier work (Willhite and Dietrich 1967; Holliday 1969). Example calculations are used throughout to illustrate key insights.