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Keywords: approximation
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Proceedings Papers

Paper presented at the Offshore Technology Conference, May 2–5, 2022
Paper Number: OTC-32072-MS
... are often nonlinear elastic rocks. This study investigates how to optimize the mechanical parameters used in the hydraulic fracture design to best approximate the rock elastic properties under in-situ formation conditions, and show how to derive them from well logs. We performed uniaxial strain...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 1–4, 2017
Paper Number: OTC-27693-MS
... suggested by DNVGL are compared to results attained by calculating the actual low-frequency motions due to waves and wind. Low-frequency wave-induced exciting moments calculated with Newman's approximation and the full QTF are compared to assess the approximation's validity for this problem. Finally a full...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 2–5, 2016
Paper Number: OTC-26962-MS
... the largest contribution for semisubmersibles in storm sea states. The drift coefficients represent the diagonal of the difference frequency quadratic transfer function, and because Newman’s approximation is implied by the method, these drift coefficients will give rise to both mean and slowly varying forces...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 5–8, 2008
Paper Number: OTC-19450-MS
... Abstract The prediction of slow drift motions for the design of a mooring system is usually made using the Newman approximation [1], based on the assumption of a very low resonance frequency of the system and small contribution of the second order wave fields. This hypothesis is commonly...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 3–6, 2004
Paper Number: OTC-16923-MS
... of approximations of the partioning phenomena such as the Shuey or the Fatti et al approximations, while acceptable at small offsets are increasingly erroneous with offset. The error is even greater for the gas case. Left - Comparison of Zoeppritz (red) and Fatti (blue) AVO calculations for a porous type 2 water...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 1–4, 2000
Paper Number: OTC-12050-MS
... a good approximation to this ideal. Missing near offsets can usually be estimated by appropriate extrapolation of the recorded near offset traces (Ref. 9) and when the source spacing exceeds the receiver spacing, the missing sources can be estimated by interpolation. Unlike the 2D case, the application...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 4–7, 1998
Paper Number: OTC-8682-MS
... records was used for all the wavefield reconstructions to simulate sparse sampling associated with 3- D data. Our technique has been demonstrated on real 3-D data. Hourglass approximation While full wavefield reconstruction is capable of de-aliasing severely undersampled prestack seismic data, it can...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 5–8, 1997
Paper Number: OTC-8567-MS
... in determining movable and residual hydrocarbons. In the past, the borehole electrical logs have been mostly interpreted using curve matching or approximate modeling techniques. This often resulted in underestimating the hydrocarbons in the subsurface and/or misled distinction between the water and oil bearing...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 1996
Paper Number: OTC-7981-MS
... ronen geometry conventional dmo amplitude equation dmo upstream oil & gas reservoir characterization geophysics operator inversion approximation irregularity migration irregularly sesismic acquisition cost migrathm extrapolate nichol acquisition cost calculation cube...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 1–4, 1995
Paper Number: OTC-7709-MS
... frequency components do not significantly interfere with each other because of vety different time scales. They are subsequently assessed separately in the framework of this approximation. The low frequency component is usually obtained by time domain simulations which solve at each time step a vectorial...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 3–6, 1993
Paper Number: OTC-7142-MS
... subsea system prediction floating production system deep draft floater oscillation amplitude fpso otc 7142 platform frequency load upstream oil & gas ddf ship extreme value interaction riser sea load faltinsen frequency slowdrift motion frequency motion approximation...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 4–7, 1992
Paper Number: OTC-6813-MS
...- venient linear combination (weighted sum) of the axial leg strains at that elevation. Calling the chosen linear combination s, the OTM/s ra- tio is therefore a constant for each mode. If the leg strains are well-approximated by the two- mode model, the OTM/s ratio for motion in ei- ther principal...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 1991
Paper Number: OTC-6651-MS
... with the response predicted from the proposed approximate method. The validity of the fInite element analysis was verifIed by comparison of the calculated and the experimental results. For the two large-diameter, fabricated specimens (PI and P2), the correlation was not as good as for the smaller, manufactured...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 1991
Paper Number: OTC-6593-MS
... the line tension a. the motion of the line within the envelope is approximately sinusoidal Due to this sinusoidal motion at the top end the line elements will move within a certain "envelope" as shown in Fig The vertical distance between the upper and lower boundary of the envelope is denoted by azo' Let...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 1991
Paper Number: OTC-6608-MS
... but using other simplifications of Eq.(3) gives For structures with significant dynamic responses, such as deepwater compliant offshore structures, the fluid-structure interaction effect must be included as in Eq.(2b). One approximation which retains some of the interaction effect but gives a linear...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 2–5, 1988
Paper Number: OTC-5802-MS
... unit relative motion capsize approximation characteristic downfloodlng reduction generic unit criteria prediction assessment OTC 5802 Development of a New Stability Criteria for Mobile Offshore Drilling Units by S.G. Stiansen, Stanley G. Stiansen Inc., and V.S. Shin and G. Shark, American...
Proceedings Papers

Paper presented at the Offshore Technology Conference, April 27–30, 1987
Paper Number: OTC-5579-MS
... are derived from "approximate theory" of continuous Orandom distributions in mathematical statistics. Their applicability is investigated through comparisons with the measured results. INTRODUCTION If the static restoring force by mooring lines is very small, a highly tuned resonance of motions...
Proceedings Papers

Paper presented at the Offshore Technology Conference, April 27–30, 1987
Paper Number: OTC-5456-MS
... for choosing this particular approximation, and it is therefore worth investigating other [ x ~an(l S(fn) l)* approximatione n=1to determine whether they can ease the computational task. It is shown below that by approximating the slowly varying drift x exp[ -2mi(fn-fo)t + On] force coefficients...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 5–8, 1986
Paper Number: OTC-5139-MS
... loading effects has recently been developed. Four similar fixed offshore platforms designed for water depths ranging between 400 ft (122 m) and 1000 ft (328 m) are used to illustrate the methodology. The importance of considering both the wave-structure interaction and a third order approximation...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 1985
Paper Number: OTC-5065-MS
... of a perturbative nature. At their best they cover the weak-scattering limit in the Born-approximation. For strong scattering they rely on diagrammatic methods to approximately sum infinite perturbation series. In this limit, their works shed no light on the question of best indicators nor is it possible to assess...

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