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A composite drilling riser is technically and commercially feasible in 3,000 feet of water subjected to the Gulf of Mexico environment. Comparison to a similar steel drilling riser configuration shows that the composite riser requires 72 percent Iess foam weight and reduces total deck weight by 739 kips. Performance comparison shows that the steel riser must be disconnected for a 20-year storm. The composite riser can remain connected even for the 1OO-year storm. INTRODUCTION Top tension, deck weight and buoyancy requirements of drilling riser systems are very sensitive to water depth. The cost for these requirements increases with water depth. Deep water drilling and exploration is limited by the vessel's deck capacity and the weight and foam requirements of the steel drilling riser technology. Alternative technologies deserve serious considerations if they reduce the riser weight, foam requirements and improve the down time during operation. The objective of this work is to compare weight, cost and operational advantages of a steel and composite drilling riser systems in 3,000 feet of water subjected to the Gulf of Mexico environment. This paper advances the state of the art of composite drilling risers by addressing the problems related to composite to metal end connection and internal wear. APPROACH The design of the two riser systems used the same vessel, water depth and environment; therefore, the make ups of the steel and composite riser systems are similar, but analyses determined that the composite riser does not require a lower flex joint. Several frequency domain analyses determined the riser performance for storms of different severity and four operating conditions defined by API RP 2Q. The storm severity for each riser was increased until the reduced safety factor for bottom angle and or extreme stress at any location along the riser reached the value of 1 (1.5 for the composite riser). A plot of the reduced combined axial extreme stress versus significant wave height determines the limits of the weather window for riser operation. Deterministic and spectral analyses determined the fatigue life for both risers. The fatigue life analysis follows recommendations of API W 16Q (in draft form). The steel riser uses the API RP 2A's X allowable S-N curve, The composite riser uses the SN curve recommended by Curtis3 for fibrous composite materials. Discussion of cost comparison for the two risers includes the impact on cost of the down time during operation. SYSTEM CONFIGURATION The riser configuration reflects a typical deep water system offered in the market place for the Gulf of Mexico in 3,000 feet of water. The system consists of a BOP stack LMRP, lower flex joint (steel riser only), pup joint, riser joints with and without foam modules, telescopic joint and diverter flex joint. The riser joint includes choke and kill lines, booster line and hydraulic lines, The choke and kill lines are 5-inch OD designed for 15,000 psi WI?. The booster line is 5-inch OD designed for 5,000 psi W. The hydraulic lines are 2.25-inch OD.

ABSTRACT. This paper presents an online interactive webpage [http://connectivity-dispersion.cicese.mx/] that provides users with results of both the three-dimensional connectivity and spatial dispersion of particles in the Gulf of California (GC). These results were originated by means of a three-dimensional numerical model of circulation adapted to the GC from which the advection of particles were generated between different regions of the gulf. Particle connectivity and dispersion results were generated for and are limited to temporal scales to seasonal tides, which may aid in the interpretation of larval connectivity and contaminants within the gulf.

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This study presents the technical feasibility of replacing a connector and flex-joint with a titanium stress joint and a collet connector as components of a tendon system for a Tension Leg Platform (TLP). A detailed analysis of this new tendon system is presented for 2,000 feet of water depth in the Gulf of Mexico. The main conclusion of this study is that this new approach is feasible and replaces effectively the flex-joint used in previous TLP tendon designs. The new system has no moving parts, long fatigue life and works even better for the deep water cases. INTRODUCTION Figure 1 shows the general layout of a TLP platform with a tendon system anchored to the foundation template. The purpose of this study is to demonstrate the technical feasibility of replacing the connnector and flex-joint used in conventional TIP tendon design, with a titanium stressjoint and collet connector tha thas a stinger. The titanium stress joint provides the required flexibility for the maximum angular offset at both ends of the tendon. The collet connector provides the latching capabilities of the tendon to the receptacle of the foundation template. A stress joint connection at the bottom or top receptacles induce high bending moments at both ends of the tendon due to the lateral motion of the TLP. The stinger increases significantly the strength of the connector to resist high bending moments. The new tendon system uses the stinger approach at both ends of the tendon. Hutton and Jolliet, the only two TLP platforms installed as of 1992, use a flex-joint at both ends of the tendon system. Hutton TIP uses at the bottom a Vicker's connector design with a collet locking system that engages the male stinger into the female receptacle located on the ocean floor. The Murdock flex-joint is built into the anchor housing. The fabrications of these joints use alternate layers of elastomer and partial spheres of stainless steel reinforcements to provide the required axial and angular spring area to accommodate a maximum angular offset of 16.6 degrees. The design of the tendon system for Snorre TLP follows very closely the design adopted for Hutton. Jolliet follows a different design with a different latching mechanism at the bottom. Figure 2 shows the approach used in Jolliet for the bottom connection. The fabrication of the receptacle for the bottom tendon connection uses a load ring forging that has a cone shaped rolled plate skirt. The load ring assembly is welded into a structural stiffener fabrication which makes up the foundation template. The shroud of the connector has a slot that allows the lateral engagement of the male back flange of the tendon. The load ring and skirt assembly match the outward orientation of the tendon receptacle slot. The flex-joint is a ring built into the bottom part of the tendon. Several layers of elastomer bearings and metal sheets define the flex-joint. The fabrication of thetop tendon connection receptacle also uses a load ring forging with a cone shaped rolled plate skirt.