Tension leg platforms and flare boom

tension leg platform – плавучее основание с

натяжным вертикальным якорным креплением

tether - привязывать, ограничивать

tendon – трос, арматура

embed –прикреплять

The tension leg platform (TLP) is yet another structure used for deep water drilling and production. The world's first was designed and built by Conoco for use in the North Sea's Button field in 1984 at a cost of $1.7 billion.

Despite that high cost, TLPs can actually be less expensive than other forms of offshore platforms. Instead of being a solid structure extending all the way from the surface to the sea floor, the TLP is actually a buoyant floating platform tethered by hollow steel tendons to a base embedded on the bottom. The tendons are kept under constant tension and allow no up and down movement; however, there can be a horizontal movement of up to 20 ft (Рис. 63).

Рис. 67

Tension leg platform

The second TLP was installed in the Jolliet Field in the Gulf of Mexico in 1,760 ft of water 170 mi from shore in 1989. At the time, this set a world produc­tion record for water depth. However, engineers claim that TLPs can successfully be used at depths of 8,000 to 10,000 ft. This may open many fields which have previously been inaccessible to man. Jolliet itself is estimated to contain 65 million bbl of oil.

1. What is the tension leg platform used for?

2. Describe the design of the tension leg platform.

3. What are its advantages?

Flare boom

flare boom – факельная стрела

bum off - сжигать

start-ups –пуск, ввод в эксплуатацию

relief – сброс

winch – лебедка

pilot burner – вспомогательная горелка

Many production platforms are equipped with a flare boom facility (Рис.64 ). This is used to bum off excess amounts of gas at a safe distance from the platform, during production start-ups and maintenance periods, and also to al­low for the rapid relief of high pressures winch may build up in production units during emergencies. The facility consists of a base which supports a triangular-section, steel-lattice tower, and a steel bridge which links the flare tower to the production platform. When in operation, the excess gas is carried by pipe along the connecting bridge from the platform to the flare boom; the boom, which is located at the extreme (flare-tower) end of the pipe, is equipped with a pilot burner which ig­nites the gas as it leaves the boom.

Рис. 68

Flare boom

1. What are flare boom’s functions?

2. What is the design of the flare boom?

3. What is the excess gas carried by ?

Bp’s 8 golden rules

confined -ограниченный

stored energy – накопленная энергия

hoist- подъемник

Management of change – управление изменениями

self-propelled – самоходный

trench - траншея

depression - каверна

1.Permit to work : Before conducting work that involves confined space entry, work on

energy systems, ground disturbance or hot work in potentially explosive environments, a permit must be obtained. This should be authorized by a responsible person; it should also identify hazards, assess risk and establish control measures.

2. Working at heights: Working at heights of two metres or higher above the ground cannot

begin unless the workers are competent to do the work, and the correct equipment is in place and has been inspected.

3: Energy isolation: An isolation of energy systems, mechanical, electrical, process,

hydraulic and others, cannot proceed unless the method and discharge of stored energy are agreed and executed by a competent person. They should also test that the isolation is effective and continue to monitor effectiveness periodically.

4. Confined space entry: Entry into any confined space cannot proceed unless all other options

have been ruled out and the area has been tested for safety. All affected personnel, including a stand-by person, should be competent and issued with a permit.

Рис. 70

5. Lifting operations: Lifts utilizing cranes, hoists, or other mechanical lifting devices will

not commence unless an assessment of the lift has been completed. The equipment must be certified for use and examined before each lift. The operators must be trained, and the rigging of the load must be done by a competent person.

6 Management of change (MOC): Work arising from temporary and permanent changes to organization, personnel, systems, process, procedures, equipment, products, materials or substances, and laws and regulations cannot proceed unless a Management of change process is completed. This should include a risk assessment conducted by all affected by the changes, authorization of the changes and a clear work plan for the changes.

7.Driving safety: All categories of vehicle, including self-propelled mobile plant, must

not be operated unless the vehicle has been inspected and is in good working order, and safety equipment (such as helmets and seat belts) is used. Drivers must be trained and certified, should not use radios or hand-held phones and should not be under the influence of drugs and alcohol.

8 Ground disturbance: Work that involves a manmade cut, cavity, trench or depression in the

Earth's surface formed by earth removal cannot proceed unless a hazard assessment is completed and all underground hazards have been identified and isolated where necessary.

(adapted from BP's Golden Rules of Safety and used with the permission of BP pic)

1.Who should a permit to work be authorized by?

2. In what way should a competent person test the isolation?

3. What does a Management of change process include?

4. What are safety requirements for drivers?

5. Tell about ground disturbance.

6. How similar or different are these rules to the rules you thought of? Discuss which ones you think are most relevant or important to you.