Copyright 2007, Offshore Technology Conference This paper was prepared for presentation at the 2007 Offshore Technology Conference held in Houston, Texas, U.S.A., 30 April3 May 2007. This paper was selected for presentation by an OTC Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Papers presented at OTC are subject to publication review by Sponsor Society Committees of the Offshore Technology Conference. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian, OTC, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435. Abstract The Shah Deniz high-pressure gas platform development in the Azerbaijan sector of the landlocked Caspian Sea required a unique execution plan, the key components being:

Selection of a production jack-up for a continuous operational life of up to 30 years

Fabrication of major components outside of the Caspian

Transport of major components as self floating strips towed through a canal network into the Caspian Sea

Assembly in Azerbaijan Reactivation of a largely abandoned construction yard The use of the worlds largest skirted spud cans with

their associated challenges of fabrication, transportation and connection using a unique assisted pendulum methodology

Installation of foundation utilizing a novel controlled punch-through technique

This paper describes the overall execution plan and the key

technical challenges that the project team successfully overcame.

Introduction At the start of the development planning for the Shah Deniz gas production platform, all available installation facilities (crane vessels and transport barges) in the Caspian, along with construction yards in Azerbaijan, were fully committed to a series of offshore oil production platforms. Consequently, the design brief for the Shah Deniz platform included the requirement that it should not have any impact on those facilities. The result was the selection of a self-installing jack-up production facility with an execution plan based on maximizing the out-of-country construction coupled with transportation of large self-floating strips into the landlocked Caspian via a canal network for final assembly in-country. It

also included re-activating a largely abandoned in-country construction yard (Zykh).

The selected platform concept is a TPG 500 which totalled 32,500 tonne (t) (36,000 short tons) dry weight in its final configuration during the sail-away to site and was successfully installed in April 2006 (Fig. 1).

Fig. 1: Shah Deniz platform installed April 2006

This paper presents the projects unique execution plan and outlines the major technical challenges associated with it. Key steps in the project execution were:

1 Out-of-country (Singapore) fabrication of the hull strips incorporating topside process, utility and ancillary facilities including the living quarters

2 Transportation from Singapore to Baku (Fig. 2): Loading of the initial 4 strips onto the Mighty

Servant 3 (MS3) Offloading of strips at Kerch Tow of the strips through the canal network to

the Caspian and on to Baku Separate shipping of the last strip (strip 0 -

wellbay & manifolds) 3 In-country (Baku) assembly and completion:

Hull strips mating in a floating dry dock Skidding of the drilling equipment set (DES)

onto the platform and its integration Mating of the last strip sections (strip 0)

4 Spud cans the largest ever in-country fabrication and transportation to the connection site

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Execution of a Major Gas Development in the Landlocked Caspian SeaP.A. Thomas and P. Kergustanc, Technip

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5 Innovative platform installation Foundations connected to the platform utilizing a

novel assisted pendulum concept. Final positioning, penetration of the spud cans

skirts and elevation to final air gap

Fig. 2: Strip transportation route from Singapore to Baku

Concept selection and associated technical challenges For the development of the Shah Deniz gas field operated by BP in Azerbaijan, the difficulties of access to the landlocked Caspian Sea and the saturation of the in-country construction yard and naval facilities was critical in arriving at the concept selection, a Technips TPG 500 self-installing jack-up drilling, production and quarters platform. The in-country facilities were fully stretched by the development of the Azeri, Chirag and Gunashli (ACG) oil fields which are also operated by BP. The lack of construction capacity in-country led to a concept selection based the delocalization of a major part of fabrication (approximately half of the total construction hours) outside the Caspian Sea. This was coupled with re-activating an effectively abandoned construction yard for the in-country work (Zykh, which is owned by Azerbaijans state oil company SOCAR and operated by Technip Marine Offshore Limited). The lack of the availability of marine equipment set another criterion: self-installation.

The compatibility of the TPG 500 concept with a high degree of modularization, construction in a series of self floating strips and its capacity for self-installation made it possible to answer the field partners requirement for a development plan that would not impact on ACG, yet would deliver a fast development of the field.

The initial studies evaluating the possibility of employing the TPG 500 concept were undertaken by the operator in 2001. The outcome of the concept selection process and follow-on definition engineering resulted in a contract award to Technip in April 2003 and the platform was installed on site in April 2006, only 18 days after the sailing from the Zykh yard in Baku.

The TPG 500 platform concept is based on the principle of a jack-up, a technology which is widely used in the oil and gas industry for shallow water drilling rigs. Like a conventional jack-up, it uses three legs of a lattice structure supporting a hull on which the production, drilling and quarters (PDQ) units are installed. The platform floats on its buoyant hull for transport to site and then lowers its legs to the seabed and lifts the hull out of the water using its own jacking systems. This not only results in self-installation, but also permits equipment integration and pre-commissioning at the construction site which minimizes offshore hook-up and commissioning. However, unlike a jack-up drilling rig, a production platform has to remain on site for the full production life of the field, up to 30 years in the case of Shah Deniz. Hence, a production jack-up must fully comply with fixed platform design codes and all of the other requirements of a major production facility, particularly safety aspects. It is compliance with these requirements that sets the TPG 500 concept apart from other jack-up designs used for drilling rigs.

The TPG 500 platform concept had already proved its

reliability in the North Sea, on the Harding field (also operated by BP) and on the Elgin-Franklin development operated by Total.

The Harding platform has a deck dry weight of 17,000 t supported on legs totalling 5,500 t, was built in South Korea and was installed in January 1996 on a concrete oil storage base which allows the temporary storage of 500,000 bbl of oil.

The Elgin process, quarters and utility (PUQ) platform is the largest jack-up platform ever installed having a dry deck weight of 28,000 t and legs of 6,000 t. It was built in Scotland and was installed in July 2000. It rests directly on the seabed, each leg ending in a spud can that is piled into the seabed with a total spud cans plus piles weight of 5,500 t.

The first unique technical challenge for the Shah Deniz

project was to adapt the hull design into several elements, called strips (Fig. 3) that could be towed individually through the canal network to the Caspian Sea. They also had be designed for assembly in a safe and economic way in Azerbaijan within the schedule and without degrading the characteristics and performance of the final platform. A key aspect of the strip fabrication was the schedule as the canal is closed for about 6 months each year from mid-October to end of March due to freezing.

The second, more technical, set of challenges related to the foundations. Soil conditions are poor and it is a seismic area. Skirted spud cans were selected, but they are huge resulting in issues with fabrication, transportation, connection to the platform legs and, finally, installation in soils with a weak layer requiring a controlled punch-through.

Strip load out in Singapore

Tow across Caspian Sea from Astrakhan to Baku

Canal tow from Rostov to Astrakhan

Float-off operation

Tow across Sea of Azov to Rostov

Strip transport on semi-sub

vessel

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Fig. 3: Strip sections and topside assembly

Project outline Produced gas from Shah Deniz is delivered to an onshore processing plant, the Sangachal terminal near Baku in Azerbaijan, through a new 93 km 660 mm gas pipeline with separated condensate flowing to the plant via a parallel 300 mm pipeline. From there, the treated gas is exported via the new 686 km long South Caucasus Pipeline to the Turkish border with off-takes in Azerbaijan and Georgia. The associated condensate, after stabilisation, is exported via the Baku-Tbilisi-Ceyhan (BTC) oil pipeline to the Mediterranean Sea.

The Shah Deniz platform in its towing configuration weighed approximately 32,500 t including the three-skirted foundations. It fulfils the functions of drilling, production of gas (900 MMscfd), production of condensate (up to 65,000 bpd) and providing living quarter for 120 people. The platform is designed for 15 very high-pressure (758 barg) well completions.

The platforms hull is trapezoidal in shape and measures 88 x 75 x 8 m. The legs, of triangular section of 17 m, are 136 m long and uses forged node technology (a proprietary item) as well as high strength steel (700 MPa) for the toothed racks. The components of the legs were manufactured in France and assembled in Azerbaijan. Their strength and fatigue characteristics ensure the platform complies with fixed jacket design codes (as opposed to jack-up design codes).

The water depth is 101 meters and the area is highly seismic, which had major consequences on the foundations sizing. Each foundation (spud can) is 30 m in diameter by 12.3 m high and weighs 1,350 t. The elevated weight was 23,700 t and was lifted using 72 jacking units which are proprietary items manufactured in France. Once at the desired air gap, the hull was locked to the legs using 9 proprietary design locking units. The total weight of the platform in operation is 39,200 t.

An integrated team, BP and Technip, was in charge of the management and the realization of the contract. Management and supervision represented approximately 600 people mobilized on the project.

Construction strategy and associated logistics The foundations were fabricated in Azerbaijan. The leg components were manufactured in France and the legs constructed in Azerbaijan at Zykh. The DES was built in Norway and integrated in Zykh.

The hull and topsides were constructed in five principle strips in Singapore (Fig. 4) and were transported to the Sea of Azrov by a semi-submersible vessel. The heaviest strip weighed 3,800 t and its dimensions were 87 x 16 x 16 m. Then, in floating mode, they were towed (Fig. 5) through the canals network connecting the Sea of Azov to the Caspian Sea. After arrival in Baku, the initial four elements, strips 1 to 4, were assembled in a floating dry dock (Fig. 6). After the completion of mating, the platform was positioned against the quay in Zykh to commence the integration activities. The last two major hull components, strip 0 north and south, were transported through the canal network the following year after it was re-opened following the winter closure.

Fig. 4: Strips 1 - 4 during fabrication in Singapore dry dock

Fig. 5: Towing of a strip for canal transportation

Strip 4

Strip 0 north

Strip 1 Strip 2

Strip 3

Strip 0 south

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Fig. 6: Strip mating in floating dry dock

The use of the Zykh site required the rebirth a construction yard that was only being used for supporting marine operations, not major construction activities. The yard, owned by SOCAR, was being used by Technip Marine Offshore Limited (TMOL) as a supply base and TMOL took on the task of reactivating it as a construction yard.

The legs were assembled at Zykh from components manufactured in France. This was performed by Azeris who were trained in the construction techniques and welding procedures, a total of 200 being trained for these activities. Of these, approximately a dozen were sent to France to be trained in the most demanding welding processes to ensure a rapid startup of the critical activities.

To carry out the assembly of the legs, and to finalize the integration of the units, two giant Mammoet cranes of 2000 and 3000 t capacity were mobilized in Azerbaijan.

At the peak of the activities in Zykh, there were over 3,500 people working in the yard on the project, over 80% of whom were Azerbaijani nationals. Additionally, some 257 local companies were utilised to provide equipment, materials and services to the yard. The yard also achieved an exemplary safety performance - over 13 million manhours were worked in Zykh without a lost time accident (Ref. 1).

The difficulties of the logistics and material supply into the landlocked Caspian required detailed analysis and careful schedule management of the various means used to convey the total of 50,000 t of material and equipment necessary to the realization of this major project, the overall work culminating in the installation of the largest platform in Caspian Sea.

Foundation design, logistics and installation The use of a spud can foundation design and the particular geology of the site required very large foundations; each has a diameter of 30 meters (to give a surface area of 700 m2), is 12.3 m high (including a skirt section of 8.7 5m) and weighs 1350 t. This represents a world record in terms of size for this type of platform foundation.

The foundations were fabricated at the Caspian Shipyard

Company and completed at Zykh prior to being transported into deep enough water to perform the connection of them to the platforms legs.

Their size and the soil conditions introduced three major challenges for the installation operations: the transportation of the foundation to the connection site, the connection of the foundations to the legs and penetration of the soil during the platform installation (Ref. 2 and 3).

Transportation of foundations to the connection site: The

water depth at the quayside of the spud can fabrication yard and Zykh restricted the maximum draft to less than the depth required for the spud cans to be stable. Hence, floating at the quay they would be unstable, rather like tying to float a cup upside-down in water. This was overcome by building a cradle into which they were lifted and towed into deeper water (Fig. 7) where they could be suitably flooded to be stable.

Fig. 7: Cradle and spud can

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The analysis of the behaviour of the spud can and cradle during the tow and, particularly, the separation phase required an extensive campaign of model basin tests (Fig. 8).

Fig. 8: Basin test cradle/skirt Spud can/leg connection: The connection of the

foundations to each leg was performed in a water depth of approximately 70 m. The completed platform was towed from Zykh (Fig. 9) to the foundation connection site where the foundations had already been positioned and were free floating.

Fig. 9: Platform being towed from Zykh Each floating foundation in turn was connected to the

platform by suspension cables running under the platform and up the leg and were also connected to a hold-back tug that asserted a constant bollard pull on it. The foundation was then submerged by ballasting and allowed to swing in an arc to come in position under the legs. The leg was then lowered onto the spud cans and an automatic latching device connected them together. Figure 10 illustrates the overall operation

Analysis of the operation required extensive technical development; hydrodynamic analyses (including use of Computational Fluid Dynamics tools), basin tests, the use of a damping system to reduce the shock impact on the foundations and legs, and the use of connection mechanisms activated

from the surface. This operation, performed three times, was a first-of-a-kind.

Fig. 10: Leg/foundation connection by assisted pendulum method

Once equipped with its three foundations, the platform was

towed to the production location. Once on site, four tug boats were used to position the platform above the pre-installed well template through which a number of pre-drilled wells had been drilled. The required accuracy of the platform positioning was of the order of half a meter in any direction and less than one degree in heading. This operation was carried out with the assistance of an underwater acoustic positioning system achieving placement well within the specified tolerances.

The soil penetration: The soil included a particularly weak

layer at approx 4 m. Because of this, it was necessary to achieve a controlled punch-through of this layer by controlling the egress of water from each spud can by a system of valves.

However, because of the general non-homogeneity of the soils, throughout the whole spud can penetration operation rigorous control of the penetration rate of each spud can was required to avoid differential settlement. Consequently, a system of valves operated from the platform was used to independently control the water pressure within each spud can and hence control the penetration rate.

The final hold point was reached with a penetration of 2 m and the non-return decision was made. From then on, adjustment of the water vent valves and the jacking rate/platform elevation and ballasting were used to control the spud can penetration rate and depth. The lack of precision in the soil data (lower and higher bounds) necessitated real time determination of the soils resistance based on measured parameters (pressures, penetration, horizontality, etc) to assist in the decision making regarding increasing the bearing load on the foundations and adjusting pressure levels within each spud can. This penetration operation was another first for the Shah Deniz project.

After achieving the target depth, grout was injected to displace the remaining water above the soil and thereby fill any void space.

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The process of developing new technology The complex execution plan for the Shah Deniz platform made it an atypical project requiring innovation and technical innovation.

The logistics of transportation into the landlocked Caspian Sea via a canal network with major schedule constraints, plus performing significant fabrication works out of the region, required not only a unique approach to the construction methodology (i.e. self floating strips), but also careful management of logistics.

The soil conditions made the foundation design a challenge for all possible design options. Consequently, several alternatives were evaluated in parallel, the two primary ones being a large skirted spud can or a pre-installed piled structure. Having selected the spud can option, alternative leg to foundation mating methods were considered. The initially preferred option was placement on the seabed but once geotechnical data was obtained, it indicated an excessive mud mat requirement (1,000 2,000 m2) and a number of other alternatives were evaluated in parallel to arrive at the pendulum method.

To ensure a suitable pendulum motion, the maximum apparent weight was restricted to 50 t, but even relatively small shifts in this value and, more particularly, the centre of gravity (CoG) would increase the dynamic effects in the suspension lines. Therefore, to adjust the CoG to within +/- 150 mm, approximately 120 t of concrete was added. Extensive analysis was required to arrive at the design of the suspension lines and to ensure suitable load sharing, by considering all potential off-design behaviour.

As site specific geotechnical data was refined, the size of the spud cans had to be increased leading to the loadout becoming a challenge. After considerable evaluation of the alternatives, all of which had to be fully reversible in the event of a problem with the connection operation, a custom designed cradle was selected.

The various selections required the organisation of technical and risk review workshops drawing on the expertise of not only engineering specialists but also construction and operational personnel (including sub-contractors) drawn from a wide range of organisations; the operator (BP), the design contractor (Technip), the marine warranty surveyor, certification organisations, local authorities, suppliers, etc. Both peer review and risk analysis were an important part of the selection process.

To develop the concepts into executable designs, various first-of-a-kind developments had to be progressed. For this, technical support was used from a number of entities within the Technip Group and external organisations, some of whom had not previously worked together.

Combining the specialist expertise of such entities with the project design team incorporating naval architects and structural, geotechnical and mechanical engineers, etc to develop innovative alternatives was achieved using multi-discipline brainstorming sessions and, as ideas were developed and detailed designs progressed, risk identification and evaluation to assist the design selection and development process.

The project lessons learned are: Do not eliminate possible solutions too early. Even

though this requires alternatives to be developed in parallel and additional engineering resources, the benefit of a trouble free first-of-a-kind operation far outweighs the engineering cost.

When drawing on the expertise of multi-discipline and multi-company personnel, they need to be involved early and to understand their contribution within the overall project execution if they are to contribute fully. This was achieved via technical workshops.

Identification of risks and opportunities via formal risk review workshops with the various participants and independent peers is a very useful methodology for option selection and technical decision making

Acknowledgements The authors would like to thank our Client BP and the management of Technip for granting the permission to publish this paper. The authors express their special appreciation to their colleagues of the Shah Deniz project team for their support and advice.

References 1. T Bayatli, BP Developments, Azerbaijan International,

Summer 2006 (14.2) from the web site: www.azer.com/aiweb/categories/magazine/ai142_folder/142_articles/142_bp_developments.html

2. P.A. Thomas, J.M. Cholley, N. Tcherniguin, C. Hough, Technip: Large Production Jack-up Foundation: Experience and new solution Jack-Up Asia conference, held in Singapore, December 2006.

3. V. Alessandrini, G. Lebois, Technip: A case of using very large skirt can for self-installing platform, paper OTC 18688, presented at the Offshore Technology Conference, held in Houston Texas, 30th April 3rd May 2007.