March 16, 2010
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Home / Issue Archive / 2010 / February #2 / High Performance Flexible Lines for the Oil Industry

№ 2 (February 2010)

High Performance Flexible Lines for the Oil Industry

Bonded flexible pipes are suitable for various oilfield applications, and are used especially offshore, including deep water and harsh environment. They have specific advantages as risers and flow lines, or even floating high pressure lines for live crude oil transport in marginal fields, because of simple installation, without high mobilization costs.

By This article was provided courtesy of ContiTech Rubber Industrial Kft.

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   Mid-water oil export lines are protected from wave effects, offering longer lifetime than conventional oil suction and discharge hoses. Water intake systems can be custom designed for the given environment, offering high operational safety and easy installation. High pressure flexible lines can be preformed to fit tight configurations even in 3000 meters water depth.

Transport of Live Crude Oil and Gas in Case of Use of Floating Production Facilities

   In offshore oil production, as deeper and deeper waters are explored emphasis was shifted to floating production facilities from fixed platforms. Besides large fields with well developed but costly infrastructure oil (and occasionally gas) has been produced on marginal remote fields. The advantages of bonded flexible pipes make them especially economical in marginal fields. Since bonded flexibles are produced in limited length, they can be transported easier on sea and land.
Bonded flexibles can be installed with simple equipment, with cranes available locally without expensive mobilization of pipe laying vessels. Another advantage of bonded flexibles is that their properties can be varied according to the requirement of the configuration, based on dynamic analysis results.

   An example of recent development at ContiTech Rubber Industrial Kft. is the TauroBend preformed bonded flexible pipe which is vulcanized to a curved shape (Patent pending), enabling easy installation in extreme tight spaces. A comparison of conventional and preformed 6-inch line installation is shown on Fig. 1. Another unique ContiTech development is high pressure floating production line. They transport live crude oil on some marginal fields in the Mediterranean from buoy to floating production vessels, and can be installed from simple supply boats.

Deepflo™ Bonded Flexible Lines for Oil Export in Deep Water

   In deepwater applications, especially in harsh environment, usual oil suction and discharge hoses may have limited lifetime. In order to overcome this limitation, Dunlop Oil and Marine (a ContiTech company) developed a new product family called Deepflo for the transport of refined gas free sweet crude oil.

   Deepflo lines can be installed as so called mid-water hose, which means that the line is submerged to a depth, where waves have little effect, but it is not laid to the seabed, rather floating between the seabed and the surface. A typical configuration is shown in Fig. 2. Deepflo lines are designed to last for deacades in the subsea environment.

   The new hose family can be manufactured up to a 30-inch (750 millimeter) bore size. Both the rubber materials and the reinforcement were rigorously tested to demonstrate their aging and fatigue properties. The patented aramid containing hybrid reinforcement allows minimizing weight and maximizing flexibility in large bore constructions. Fatigue performance has been demonstrated on full scale hoses. The lifetime of the hoses is also depending on coupling corrosion. To prevent direct exposure of metal parts to seawater couplings can be moulded completely in rubber.

Water Uptake Systems

   Eddelbüttel & Schneider GmbH (a ContiTech company) developed a system for water intake of floating oil production facilities. The product is custom designed for every installation, and backed up with sophisticated dynamic analysis, fatigue, clashing etc. calculations.

   A specific feature of the rubber water uptake systems is their easy installation. Despite of the large bore size installation can be carried out with the crane of the vessel, without the need to mobilize expensive equipment.

   The system found wide acceptance and is in use on several floating production units offshore Brazil, Angola and elsewhere, in bore sizes ranging from about 16 inches (400 millimeters) to more than 40 inches (1000 millimeters).

Flexible Lines for Deepwater Drilling

   Various flexible lines of ContiTech Rubber Industrial Kft. are used for deepwater drilling. These include high pressure mud hoses (rotary, vibrator and mud jumper) up to a 5-inch (127 millimeter) internal diameter and 51.7 MPa (7500 psi) working pressure, cement hoses with a 3-inch (76-millimeter) internal diameter and 103.4 MPa (15,000 psi) working pressure. All hoses meet the strict new requirements of API Spec. 7K Addendum 2 (2006). Rotary and vibrator hoses are baked up by high frequency, high temperature (100 C) pulsation test too. If required, hoses can be built also for gas drilling.

   The flexible choke and kill line developed at ContiTech Rubber Industrial Kft. for subsea application was thoroughly tested according to API Spec. 16C for 121 C operating temperature, as well as for hydrostatic collapse resistance above 36 MPa, representing 3600 meters water depth, internal “survival” temperature exceeded 180 C. A new unique feature of this pipe is that it can be manufactured as preformed TauroBend flexible line, to fit tight spaces on subsea BOP stacks. This possibility has an effect on the design of the BOP stacks themselves, they can be made shorter, because earlier the allowed bending radius of the flexible line was the limiting factor in the geometry of the top of the BOP.

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