Uncertainty assessment methodology, procedures, and results are presented for most typical towing tank tests using a 3.048 m geosym of naval combatant DTMB model 5415, which is an established benchmark for computational fluid dynamics validation. The tests include resistance, sinkage and trim, wave profile, wave elevations, and nominal wake. The procedures are summarized and follow International Towing Tank Conference Quality Manual Procedures. The facility and measurement systems are briefly described, and detailed uncertainty assessment examples for each test are provided with descriptions of bias and precision limits and total uncertainties.
Alaska state requirements as well as sound engineering practice require that oil and gas operators investigate the zonal isolation in the annulus of water injection wells. Conventional cement evaluation can be a time-consuming and expensive process, especially in high-angle or horizontal wells in which the wireline tools must be conveyed with a tractor or on drillpipe. Cased-hole LWD sonic data was acquired in a North Slope, Alaska, well to evaluate the cement bond zonal isolation in the casing by attenuation and transmission analysis. The LWD data was compared with a traditional wireline cement evaluation logs to validate the application. This paper provides a case study of the techniques used to acquire process and interpret logging-while-drilling (LWD) sonic logs for cement evaluation.In this case study, a horizontal lateral section was drilled after setting and cementing the intermediate casing string. The interval to be evaluated for zonal isolation was behind this intermediate casing. LWD sonic data were acquired for cement evaluation purposes while tripping in the hole to drill out the intermediate casing cement shoe prior to drilling the horizontal section of this well. The ability to acquire cement evaluation data during the normal drilling practice provides significant cost savings over traditional wireline cement evaluation methodologies.This paper discusses the theoretical basis for using LWD sonic data for cement evaluation, planning procedures, data acquisition, and data processing. A comparison of the LWD sonic cement evaluation data with traditional wireline cement evaluation data that was used to validate this technique is provided. Additionally, the advantage of integrating the LWD cement evaluation option into the drilling process will be described.
Results from towing-tank experiments for David Taylor Model Basin model 5512 are presented for resistance, sinkage and trim, wave profile, and nominal wake tests and uncertainty assessment. The resistance and sinkage and trim data are for Froude numbers 0.05-0.45 and free-model condition. The wave profiles and nominal wake data are for Froude numbers 0.28 and 0.41 and fixed-model condition (at the dynamic sinkage and trim for each Fr). The test design, measurement systems, and uncertainty assessment are described. The uncertainty assessment methodology rigorously follows the AlAA Standard S-071-1995. The results are discussed with regard to the data ends and uncertainties, including Fr effects. Future work is mentioned. The data contributes to the surface-ship resistance and propulsion model-scale database for computational fluid dynamics validation, as part of an international collaborative project between Iowa Institute of Hydraulic Research, lstituto Nazionale per Studi ed Esperienze di Architettura Navale, and David Taylor Model Basin on experimental and computational fluid dynamics and uncertainty assessment for a combatant geometry.
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