Search

The objectives of this thesis are to describe the Subsea Well Intervention System (SWIS) andto test the hypothesis that this system has significant potential economic benefits over asemi-submersible rig-based system which is normally used for completing common subseawell intervention procedures. These interventions are carried out in water depths from 200mto 3,000m.This thesis describes SWIS and its applications to subsea well interventions, discusses themain technical issues involved and provides an economic analysis of the cost benefit incomparison to semi-submersible and Drill Ship rig-based systems. Examples of subsea wellinterventions discussed in this thesis include: de-sanding, de-scaling, re-entry drilling andwellhead recovery. A discussion and analysis of the vessel response to the likely operatingsea states and an analysis of heave compensation for the Coiled Tubing (CT) system isincluded as these are critical factors to the technical viability of SWIS.SWIS is designed to have a light to medium level well intervention capability and it willprovide a tool for common subsea well intervention procedures. It is not designed for tubingchange out which is classified as a heavy level workover. In this case a conventional rig or aHydraulic Workover rig supported by a semi-submersible would be used.SWIS will be designed to include the following capabilities: Well and field abandonment;Artificial Lift Services; Re-entry Drilling using CT including well side tracking anddeepening operations (Operations to include CT under-balanced drilling and ThroughTubing); Deployment and recovery of Sand Control Screens using CT as a conveying tool;Through Tubing Completions using CT as a conveying tool; Post-completion well clean-upoperations; Slick-line and electric line operations and sub-sea wellhead maintenance andrecovery.The SWIS concept vessel is a large scale wave piercing catamaran which will be maintainedon station and heading into the prevailing sea using a Dynamic Pos

The goal of our work is to develop a system for optical communications through the sea-air interface and to provide a predictive performance model for the system for different environmental conditions, source power levels, receiver range, etc. The scientific objectives of the project involve understanding the spectral and temporal effects of water constituents and surface characteristics on trans-interface communication. This involves the development of a system that utilizes several, separated, redundant, sources to reduce the data drop-out rate due to wave refraction. Engineering objectives of the project are the design and development of an intelligent optical receiver that can identify the positions of redundant sources within video imagery and control a micro electro-mechanical system (MEMS) device to direct radiance from only those sources to a high-speed sensor for demodulation. This spatial filtering should reduce interference from surface reflection of skylight.

The goal of our proposed work is to develop a system for optical communications through the sea-air interface and to provide a predictive, performance model for the system for different environmental conditions, source power levels, receiver range, etc., code 1 only.

Our research is directed toward development of an automated sensor for capturing 3-D images of manmade and natural objects in aqueous environments. We strive to construct a compact instrument capable of real-time imaging and classification of imaged objects using state-of-the-art optoelectronic technology. We expect that this work will have relevance to the in-water investigation and surveillance needs of branches of the U.S. Military, U.S. Intelligence agencies, as well as state and local law-enforcement agencies.

Real-time determination of the optical and bathymetric climate available for operation of various Navy and Coast Guard assets in the coastal zone using a mixture of AUV, ROV, surface-vessel, fixed moorings/towers, and air/space-borne observational assets. This includes advanced heat-budget modeling applicable to coastal regions, methods for early detection of K. brevis (red-tide) and other algal blooms, remote determination of optical properties (absorption and scattering) of the water, harmful algal blooms, depth and bottom albedo. These provide model inputs and validation data for predicting visibility and the performance of optical systems as well as heat budget and primary production models, useful in asset selection for Homeland Security operations., The original document contains color images.