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Abstract Because many fundamental questions concerning the dynamics of the Earth and itsstructure remain unanswered, the Integrated Ocean Drilling Program (IODP) hasrecently completed a feasibility study for drilling and coring a hole 500meters (1,640 feet) through the Mohorovicic seismic discontinuity into theupper mantle of the oceanic crust from three candidate locations in the PacificOcean (Cocos Plate, Baja California, and offshore Hawaii). The main challenges discussed in this paper are threefold. First, drilling withriser in ultra-deepwater environments with water depths around 4,000 meters(13,120 feet) which will set a new world record. Secondly, drilling and coringin very high temperature igneous rocks with bottom-hole temperatures that areestimated to be as high as 250°C (480°F). Finally, drilling and coring a verydeep hole with a total drilled and/or cored interval around 6,000 meters(19,685 feet) in the oceanic crust below the Pacific Ocean seafloor in order toreach the upper mantle which will constitute a major achievement for theworldwide scientific community. This paper presents detailed analyses and several discussions concerning marinedrilling riser options by first reviewing the capabilities of the current riserconfiguration that is onboard the IODP scientific drilling drill-ship Chikyuand then evaluating alternative designs such as titanium riser, hybridtitanium-steel riser, slim-riser and lighter buoyancy modules. Furthermore, thedeepwater subsea equipment, drill-pipe design, wellbore design, down-holetools, drilling fluids, circulating temperature, cementing methods and variousadvanced technologies that would be required for this type of operation arealso reviewed. In addition, operational time and cost estimations for differentscientific drilling cases are provided (borehole continuously cored to totaldepth, continuous cores only across the major lithologic and geophysicaltransition intervals, spot coring and when only the mantle section iscored). Finally, this study helps evaluate critical issues in terms of current andtrending technologies in oilfield and geothermal industries that need to beresolved before embarking upon such a challenging project. The results of thiswork show that drilling to the mantle is certainly feasible, and that there areexisting solutions to many of the technological challenges based on work beingdone in the oilfield, offshore and geothermal industries.
- Europe (1.00)
- Asia (1.00)
- North America > United States > Texas (0.46)
- (2 more...)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
- Well Drilling > Wellbore Design (1.00)
- Well Drilling > Drillstring Design (1.00)
- Well Drilling > Drilling Operations > Coring, fishing (1.00)
- (8 more...)
Abstract The design of a conductor casing is significantly different than that of the other tubulars in a well. Conductors are drag-dominated structures that enable conducting drilling operations from offshore fixed platforms or jack-up rigs through the seawater column. To date, the majority of technical papers concerning conductor design have focused on a particular aspect of the conductor pipe but very few of them have detailed the design of conductors in response to the combination of hydrodynamic loads, external and internal loads acting on this casing string as well as the soil-conductor interaction. This paper discusses the design of both platform conductors and jack-up supported conductors used in open water by first providing the essential steps (i.e. deriving and presenting equations) that need to be followed to ensure the structural integrity of the conductor casing along its entire length. Then, in order to illustrate the methodology, four case studies were performed to investigate the performance of well conductors at different shallow water locations (the Gulf of Mexico, South America, the North Sea and South-east Asia). For all analyses, the conductor pipe has been checked for three failure modes: strength, stability and fatigue and finite element analyses have been computed to solve the hydrodynamic loading, the statically indeterminate problem and the complex soil-structure interaction. The results show that, in general, stability controls the conductor design which means that the conductor will buckle before it yields; and therefore, there is a requirement to apply tension at the Texas Deck for a jack-up. Also, in some instances (i.e. rougher water environments) or with smaller size conductors (13.375-in. and 20-in.), the fatigue analysis may become the most important failure mode for both the conductor pipe body and the connectors.
- Europe > United Kingdom > North Sea (0.26)
- Europe > Norway > North Sea (0.26)
- Europe > Netherlands > North Sea (0.26)
- (2 more...)
- North America > Cuba > Gulf of Mexico (0.89)
- Europe > United Kingdom > North Sea (0.89)
- Europe > Norway > North Sea (0.89)
- (2 more...)