As an integral part of Exxon's Santa Ynez Unit (SYU) Expansion Project, the Harmony and Heritage platform jackets were loaded out from a fabrication yard in South Korea, transported across the Pacific Ocean, and installed offshore California in water depths of 1200 feet and 1075 feet, respectively (Figure 1). Overall this was a 9-1/2 month effort, beginning with the Harmony jacket load-out in April, 1989 and ending with the Heritage jacket post-installation inspection in February 1990. INTRODUCTION The loadout, transportation, and installation of the Harmony and Heritage jackets were nearly identical for each jacket. Consequently, this paper is structured to present the Harmony jacket, with reference to the Heritage jacket where procedures differed. A timetable of events for each jacket is provided in Figure 2. LOADOUT AND TIEDOWN After fabrication, each jacket was loaded onto an 853 foot long by 206 foot wide by 49 foot deep barge for separate transportation across the Pacific Ocean. This barge, which is the largest launch barge ever built, was capable of safely transporting and launching the Harmony and Heritage jackets. The Harmony jacket was the first to be loaded out. In preparation, bollards and winches were added to the barge to accommodate the loadout mooring arrangement. Further, considerable dredging and excavation was performed to accommodate the 32 foot maximum draft of the barge during loadout. The barge mooring system included six bow anchor lines attached to anchors and four lines at the stern attached to onshore bollards (Figure 3). For the Heritage loadout, only four bow lines were used due to the proximity of the adjacent quay wall. These four lines were tied back directly to the quay wall. The loadout plan was based on the use of the launch barge's 6000 ton jacking system. Once the mooring system was secured and proof-tested, a wire rope link system was installed to connect the barge hydraulic jacking units to pulling lugs on the jacket. In addition to the barge jacks, breakout was assisted by the use of auxiliary jacks mounted on the skidway. Breakout of the jackets required a pulling/pushing force of approximately 6500 tons for Harmony and 5000 tons for Heritage. In both cases this represented a 15% coefficient of static friction between the jacket launch timbers and the land-based skidways. After breakout, jacking forces steadily declined and stabilized at approximately 3300 tons for Harmony and 2000 tons for Heritage, indicating respectively a 7% and 6% coefficient of friction for the remainder of the loadout. Jacket weight compensation and tidal ballasting of the barge were completed using the barge's main ballast system. An independent tidal ballast system was installed for use in the event of failure of the barge system. During the jacket loadout, ballast operations were properly controlled to keep the barge and jacket positions well within the allowable stress envelopes. This was confirmed with dimensional surveys of specific points on the barge and jacket mudline every 15 minutes during the critical loadout phases.

During the summer of 1980 three pipelines were constructed between the Hondo Platform, located in 835 feet of water, and the Hondo SALM, located approximately 1-1/2 miles away in 500 feet of water. Figure 1 shows the Hondo Platform, SALM, Offshore Storage and Treating (O.S.&T.) vessel, and pipelines. These pipelines, ranging from 6-inch to 12-inch in diameter, pipelines, ranging from 6-inch to 12-inch in diameter, were installed by the reverse J-tube procedure, a technique developed by Exxon especially for construction of deepwater pipeline systems. The technique may also be cost effective in certain shallow water applications. Introduction In the late 1960's Exxon Company, U.S.A. (then Humble) acquired several deep-water leases in the Santa Barbara Channel, offshore California. It was clear that the development of these leases wood require extension of existing offshore pipeline technology, including means for installing risers in any water depths where bottom-founded platforms could be used. To meet this objective, Exxon Production Research Company developed a new procedure (U.S. Patent 3,595,312 and foreign counterparts) for riser installation known as the reverse J-tube method. This method is based on construction of the pipeline from the deck structure of the platform. Pipe sections are aligned and welded in a vertical orientation. As the pipe string is assembled, it is lowered into a J-tube pipe string is assembled, it is lowered into a J-tube which has been previously installed in the platform during land fabrication. The J-tube provides an enclosed conduit which guides the pipeline from a vertical orientation at deck level to an orientation parallel and adjacent to the seafloor. The pipeline parallel and adjacent to the seafloor. The pipeline is pulled downwardly through the J-tube and along the seafloor to its destination by a moored barge or tug located some distance away. For short pipelines, the entire length may be installed through the J-tube without use of a laybarge. Longer lines may be initiated through a J-tube and subsequently retrieved aboard a laybarge to be completed by conventional pipelay operations. pipelay operations. This paper describes how the reverse J-tube method was used to in stall the three Hondo pipelines. Early model tests conducted to prove the technique and other full-scale reverse J-tube installations in the Gulf of Mexico and various locations overseas are briefly discussed. Finally, an assessment will be made concerning cost effective applications for this method. THEORY In the direct J-tube method the pipeline is pulled upward through a J-tube from the seafloor to pulled upward through a J-tube from the seafloor to the platform deck. This method has been used world- wide by numerous operators. In the reverse J-tube procedure, however, the direction of pipe movement is procedure, however, the direction of pipe movement is downward. This reversal of direction offers two advantages over a direct J-tube installation:Pulling forces and reaction forces on the platform structure are reduced to as little as 25percent of those characteristic of a direct J-tube pull. Referring to Figure 2, note that in a direct J-tube installation the pull force must overcome laybarge tension, pipe-to-soil friction, and pipe weight. Furthermore, the high levels of tension on both ends of a pipeline during direct J-tube pull produces a brake-band effect that further increases friction between pipeline and J-tube. On the other hand, two of the forces to be overcome in a direct pull, barge tension and pipe weight, act positively in are verse J-tube pull to move the pipeline in the desired direction and, although pipe-to-soil friction must be overcome, it does not contribute to reactions exerted on the J-tube and platform. The use of a non-polluting lubricant applied to the pipe further eases its passage through the conduit. The low installation forces characteristic of the reverse J-tube method make it suitable for significantly larger pipe diameters than the direct J-tube procedure. Depending on platform size and geometry, pipeline risers up to 24-inch can be installed by the reverse J-tube technique.

Oil and gas production has been underway in Exxon's Hondo Field since April 1981. The field is being developed using a 945-foot drilling and production platform, the Hondo Platform, and an production platform, the Hondo Platform, and an offshore storage and treating vessel, the Exxon Santa Ynez. The dedicated 50,000 dwt vessel is moored to a single anchor leg type production riser which provides the connection to the three subsea pipelines and a power cable from the Hondo Platform. This paper presents the installation Platform. This paper presents the installation techniques used to install the Single Anchor Leg Mooring. Introduction The installation of the first single anchor leg mooring (SALM) in United States waters was completed during October 1980 off the coast of California. This SALM forms the vital link between the Hondo Platform, located in 850 feet of water in the Santa Barbara Channel, and an offshore storage and treating vessel (OS and T) moored to the SALM 8,500 feet from the platform (Figure 1). The Hondo crude will undergo liquid/ gas separation on the platform and then be transported via submerged pipeline up through the SALM to the OS and T. The floating storage vessel will perform oil/water separation, oil treating, offloading to a tandem-moored shuttle tasker and electric power generation for the production platform. In addition to crude oil and fuel gas, platform. In addition to crude oil and fuel gas, the EOIN provides a link for returning produced water and transmitting electric power to the platform. The SALM is installed in 490-foot platform. The SALM is installed in 490-foot water depth and consists of three individual components — Base, Riser and Buoy. The Base was transported to the Santa Barbara Channel and installed in May 1980. After installing the Base, the Buoy and Riser are co-joined, towed to the Channel and installed in September 1980. The main emphasis of this paper is on the loadout and water phase construction of the SALM. A brief description of the physical features, design criteria and fabrication of the SALM components is also included. SALM PHYSICAL FEATURES STRUCTURE The overall configuration of the SALM is shown in Figure 2. The permanently moored OS and T vessel is connected to the SALM by a 160-foot long rigid yoke, hinged at the vessel end to allow relative pitch. At the top of the buoy, the triaxial universal joint provides the three (3) degrees of freedom required to allow the vessel to roll and pitch with respect to the Buoy and to weathervane around it. This structure, constructed of fabricated plate elements, is essentially a universal joint sitting on a rotating tearing table. The Buoy itself provides the buoyancy necessary to tension the riser below and thus generate a restoring force as the Buoy is displaced from the neutral position by the environmental forces acting on the vessel. The 820-ton, 234-foot long Buoy structure consists of an upper buoyancy section and a lower extension stem. The upper buoyancy section has a maximum diameter of 26 feet and the stiffened-plate structure is divided into 12 compartments for damage stability. The 16-foot diameter lower extension stem is a one-inch thick rolled cylinder with five (5) ring stiffeners. The use of conical transition sections and the absence of longitudinal stiffeners help avoid local stress concentrations that could lead to fatigue failures. The lower extension stem remains flooded after installation. The 425-ton, 265-foot Riser is similarly divided into an 18-foot diameter upper compartmented buoyancy chamber and a six-foot diameter lower extension stem. The Riser stem design again avoids any internal stiffening to help limit the potential for fatigue failure of the two-inch thick wall. Universal joints are employed at both the junction between the Buoy and Riser and between the Riser and Base.

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