Producing and delivering North West Australia (NWA) deepwater gas reserves to LNG plants poses unique challenges. These include extreme metocean conditions, unique geotechnical conditions, long distances to infrastructure and high reliability/availability requirement of supply for LNG plants. A wet or dry tree local floating host platform will be required in most cases. Whereas semisubmersible, TLP, Spar and floating LNG (FLNG) platform designs all have the attributes to be a host facility, none has been installed in this region to date.
This paper will address important technical, commercial and regulatory factors that drive the selection of a suitable floating host platform to develop these deepwater gas fields off NWA. Linkages between key reservoir and fluid characteristics and surface facility requirements will be established. A focus will be on the unique influence of regional drivers and site characteristics including metocean and geotechnical conditions, water depths and remoteness of these fields.
There have been 17 FPSOs producing oil in Australian waters. These facilities have been chosen because of the remoteness of the fields and the lack of pipeline and process infrastructure. Storing oil on the FPSO for offloading and shipping from the fields becomes an obvious solution. Semisubmersible, TLP or Spar platforms show little advantage in such developments.
For deepwater gas developments, the product has to be processed, compressed and piped to shore for liquefaction. As host processing facilities, Semisubmersible, TLP and Spar platforms have clear advantages over FPSOs because of their superior motion performance in the harsh Australian metocean environment and other benefits such as facilitating drilling, dry tree completion and well services. FPSOs or FSOs may be applied for storage of associated oil and condensates. For marginal and remote gas field developments, an LNG FPSO (FLNG) may be an attractive option as it eliminates long pipelines and land-based liquefaction plants.
As discussed by Dorgant and Stingl (2005), a deepwater field development life cycle following discovery usually involves five distinct phases, Figure 1. The "select?? phase occurs after a discovery has been appraised sufficiently to further evaluate it for development. It consists of evaluating multiple development concepts and scenarios and selecting the one that will most likely achieve the identified commercial and strategic goals. Selecting a floating platform and its functions for a deepwater development is an important subset of the select phase and the overall field development planning.
The process of field development planning involves a complex iterative interaction of its key elements (subsurface, drilling and completions, surface facilities) subject to regional and site constraints (D'Souza, 2009). The objective is to select a development plan that satisfies an operator's commercial, risk and strategic requirements. It entails developing a robust and integrated reservoir depletion plan with compatible facility options. The selection occurs while uncertainty in critical variables that determine commercial success (well performance, reserves) is high. One of the challenges is to select a development plan that manages downside reservoir risk (considering the very large capital expense involved) while having the flexibility to capture its upside potential.
The first hydraulically operated completion was installed in Australia in 2004 (Guatelli et al 2004). Since then, a number of intelligent completions have been installed in offshore Australia. The remoteness of offshore Australia, particularly in the Timor Sea area, means intervention vessels are not readily available and well interventions are costly operations. For this reason, intelligent completion is considered to be an attractive alternative, by providing a down-hole solution to actively manage the reservoir production life and delay potential water breakthrough.
The Kitan oil field is remotely located in the Joint Petroleum Development Area (JPDA) between East Timor and Australia. The Kitan oil field production facilities consist of three vertical producing wells, subsea flowlines, risers, and one Floating Production Storage and Offloading (FPSO) facility. The wells were completed with an intelligent design and cleaned up using a rig before the FPSO arrived on location.
The intelligent completion design consists of two multi-stage hydraulic down-hole Flow Control Valves (FCVs) and three Down-Hole Gauges (DHGs) to independently control and monitor two different production zones. The FCVs have a total of 8 positions (fully opened, fully closed and 6 intermediate choke positions).
It is planned to close the lower FCV to shut off water production from the lower zone while the upper FCV remains fully opened over the field life. The different FCV choke positions were utilized during the field startup and during the early stages of production while the water cut was still low, to overcome unforeseen technical limitations in the production system, and to optimize hydrocarbon production.
This paper describes various aspects of the Kitan oil field intelligent well completion from design through installation and field startup to early stage of production operations, and includes technical problems encountered during the field startup as well as lessons learnt.
Demand for natural gas is increasing more rapidly than anticipated in Far East markets because (1) China has modified its policies in order to increase reliance on gas, in part to mitigate the growth in its coal consumption (which now stand at almost half of world coal production), (2) Japan has announced its intention to eventually shutdown its nuclear power industry, and (3) India, which currently has more than 400 million people without electricity, desires to accelerate electrification. This analysis investigates the potential role of stranded gas from Central Asia, Russia, Southeast Asia, and Australia in meeting Asia's future demand for gas imports. It initially surveys the discovered or known gas in stranded gas accumulations in Central Asia, Russia, Australia, Indonesia, and Malaysia. It then examines the primary gas import markets of China, India, Japan, and South Korea by describing energy use, gas demand trends, and domestic gas supplies to establish boundaries that encompass the wide variation in gas import demands in these markets during the two decades following 2020.
Then the cost of developing and delivering gas through overland pipelines from selected stranded gas fields in Central Asia and Russia to China is examined. Analysis shows that for the Shanghai market in China, the costs of developing and delivering Russia's stranded gas from the petroleum provinces of eastern Siberia are competitive with costs estimated for stranded gas from Central Asia. However, for the Western Siberian Basin, delivered gas costs are at least 3 US dollars per thousand cubic feet (USD/Mcf) higher than delivered gas from Central Asia.
The extraction and transport costs to a liquefaction plant for gas from stranded gas fields located in Australia, Indonesia, Malaysia, and the basins of eastern Siberia are then evaluated. The resource cost functions presented show development and extraction costs as a function of the volume of stranded gas developed for each country. The analysis demonstrates that, although the Russian fields in areas of eastern Siberia are large with relatively low extraction costs, distances to a potential liquefaction plant at Vladivostok make them initially the high cost suppliers of the liquefied natural gas (LNG) market. For the LNG markets examined, Australia and Malaysia are initially the lowest cost suppliers. For the Shanghai market, a comparison of the cost of supplying gas by pipeline with the cost of supplying LNG shows that the pipeline costs from areas of eastern Siberia and Central Asia are generally lower than delivered cost of gas as LNG from the LNG supply sources considered.
New oil and gas frontiers are presently looking at projects offshore of theGulf of Mexico and South Atlantic, including West African and Brazilian watersand soon after Asia Pacific. New technologies are required to performinstallation in a cost efficient and safe method; they must encompass the stateof art equipment in order to provide effective solutions. The new ships FDS2and CastorONE are Saipem's replies to the forthcoming challenges indeep/ultra-deep water field development and pipe lying. The new vessels willoperate by using new welding, NDT and field joint coating technologies,including innovative installation equipment able to generate added value forthe implemented solutions. Field development projects include complex risersystems and the new fleet is designed to offer reliable solutions for thefuture configurations, which are designed to route the oil and gas fluids tothe floating treatment units. Saipem FDS2 is described by indicating hercapabilities and her equipment, including those required for project in shallowwater and those specifically designed for deep waters installation.Furthermore, sea keeping and naval features are offered in order to demonstrateher versatility and ability to solve main installation challenges relevant tothe deep water fields. Trunk line projects will be addressed to transportationof large gas volumes over long distances across harsh environments and Saipemvessel CastorONE is presented by showing off her capabilities for the ultradeep water installation. Information on the new state of art rigid stinger isprovided together with some conceptual solutions designed to increase theefficiency of the working stations and of the method to transfer the pipes withspecific equipment. The paper concentrates on the installation requirements forthe in-field production gathering systems and on the oil and gas exportpipelines.
Field development: the leading market trends
Since 1998, numerous deep water field development projects, mainly in the SouthAtlantic region both in West Africa and in Brazil were carried outsuccessfully. The vision for the future leads towards two major trends: evendeeper waters and new surprising geographical regions. Moving in bothdirections, thanks to its top class technologies and assets, Saipem aim to leadthe path towards the even tougher future challenges.
The scope of the work of deep water projects, within EPCI type contracts, hasnormally included all major and minor technical aspect, supplies andinstallation/operations from A to Z, with contract values typically in therange of half to one billion USD. Key of this market segment - which nowrepresents a significant portion of turnover and backlog - has been theintegrated development of original technical solutions and dedicatedfit-for-purpose installation vessels.
Leveraging on its notable competence, track record and offshore constructionfleet, the two main lines of evolution for the offshore field developmentmarket were, are and will be tackled, namely ultra-deep waters and new frontierregions as follows:
• On one hand, the ultra-deep water developments, emerging in the traditionaloil provinces in the Gulf of Mexico and South Atlantic, will require theIndustry to make available new technologies and equipment to support the safeand effective implementation of the relevant production schemes;
• Simultaneously, the development of subsea oil and gas fields is taking placein new world regions bringing quite new challenges from both the technical andexecution standpoints.
Exploitation of oil and gas reservoirs in water depths in excess of 2,000m (?6600') is progressively emerging as the new market. Gulf of Mexico, offshoreBrazil and West of Africa are nowadays showing the greatest concentration offield development projects. In addition, subsea developments in new areas suchas East India, Indonesia, Offshore China and Western Australia are appearing inthe offshore oil and gas theatre both for relatively moderate and for deeperwater depths.
Perdido Regional Development in the Western Gulf of Mexico and the Walker Ridgearea in the Central Gulf of Mexico will be significant and challenging offshoreprojects.
Installation of offshore platforms in carbonate soils is challenging, asevidenced by numerous incidents and accidents. The installation process ofmobile jack-up drilling rigs is no exception. The prevalence of these soils insome oil and gas producing regions, such as offshore Australia, necessitatesthorough understanding of the foundation behaviour as well as predictionmethods capable of capturing the salient features. This contribution thereforedevelops a method to predict footing penetration in uncemented carbonate sand.The method directly correlates the cone penetrometer tip resistance with thefooting load-penetration, i.e. without the requirement of selection of afriction angle. The development is based on centrifuge model experiments aswell as large deformation finite element analyses incorporating an advancedconstitutive model for the soil. The direct use of in situ site investigationdata increases the confidence in load-penetration predictions for rig moves inthese challenging soil conditions, while at the same time reducing the timerequired to obtain a prediction.