Pyramids Of Egypt History

MEASUREMENT, CONSULTANCY AND FORECASTING IN THE MARINE ENVIRONMENT NO. 10 Taking pyramids to Egypt Taking pyramids to Egypt: shallow-water instrumentation systems in anti-trawl concrete housings Inside a shallow-water pyramid. On the left is the ADCP, with a pop-up float on the right. The diver location beacon (yellow) is at the top. All five systems worked well At US$4 million it’s the world’s largest single commercial oceanographic project. And it also gave the opportunity for Fugro GEOS to introduce some new pyramids to Egypt. The work is to provide data to support the planning of offshore drilling operations and the design of production facilities in the Nile Delta, offshore Egypt in the southeastern Mediterranean. The one-year contract was awarded to Fugro GEOS by the Belayim Petroleum Company (Petrobel) on behalf of various companies operating in the Nile Delta. Greg Bush, Fugro GEOS’ manager of the project, explained its significance: “What’s particularly interesting about our contract is that the operators have got together to lay out a grid which provides for oceanographic measurements over the whole area covered by their concessions. This gives them far more cost-effective and higher quality data than if each operator conducted an individual programme.” The work is in two phases. The first is inshore, covering an area some 269km wide to about 90km offshore. Within this area, currents, waves, tides and meteorological conditions in water depths from seven to 500 metres are being measured at 15 locations. Equipment includes 10 RDI Workhorse 300kHz ADCPs, Waverider buoys, meteorological stations, a Valeport pressure wave gauge and CTDs. “It’s an area of extensive trawling activity,” Greg Bush explained. “This means that we have had to mount equipment in the antitrawl, pyramid shaped frames, but we’ve still had problems with systems being dragged. In one instance a Waverider buoy broke from its moorings and despite being fitted with an Argos beacon it “disappeared” for two days before we started to get transmissions. “The other problem is visibility. The inshore moorings are serviced by divers and the western set is in zero visibility. So we are entirely dependent on Sonardyne’s ORT and DORT location beacons to which the divers navigate. Fortunately the acoustic systems have worked extremely well.” The inshore data-gathering network was established in February 1999 and scheduled to run for a year. Then in April 1999 it was decided to extend the study area further offshore with three further moorings in depths ranging from 1360 to 2000 metres. Each mooring had five Aanderaa recording current meters, a 75kHz RDI ADCP and Aanderaa WR7 tide gauge. A directional Waverider was installed at one of the sites and a meteorological station on a buoy. “There were also a further six CTD sites in the deepwater area and we conducted an Argos satellite-tracked drogue survey,” Bush said. Service visits to the sites were made out of Port Said, Egypt. In this issue. . . Save costly seismic infill time Wave recorders go on trial Measuring those GoM currents Keeping risers out of trouble RigADCP in action Mid-East met. buy Go-anywhere WeatherMonitor West Africa: the essential guide Fugro GEOS news p2 p3 p4 p5 p5 p6 p6 p7 p8 Record-breaking current profiles Fugro GEOS has measured the deepest-ever series of real-time current profiles. It was in support of the record-breaking exploration well drilled by BHP in Walker Ridge Block 425 in the Gulf of Mexico. At a depth of over 2680 metres the well is in the deepest water ever drilled in the Gulf and the second deepest in the world. BHP required real-time current measurements over the full ocean depth to support drilling operations from the drillship Glomar C R Luigs. This called for innovative techniques using acoustic Doppler current meters (ADCPs) mounted both on the drillship and on an ROV. Until now the limit on profiling range was set by the ADCPs and so for the Walker Ridge well, Fugro GEOS mounted an RDI 300kHz ADCP on an Oceaneering Magnum 51 ROV and current data was recorded as the vehicle descended to the seabed. Specially developed RovADCP software then mapped the individual data points to the correct depth and built up an average current velocity for each of the selected depths as the ADCP descended. Results were displayed in real time on board the Glomar C R Luigs with almost 2750m of water current data recorded in one profile each time the ROV made a descent. At times when the ROV was not deployed, current velocity data to depths of 450m below the drillship were obtained by a fixed 75kHz RDI ADCP mounted on the vessel using Fugro GEOS’ RigADCP system. Contact: Jan van Smirren, Houston WAVE RECORDERS GO ON TRIAL Right: Significant wave periods from surface and sub-surface instruments over a weekend of the trials. “One of the most significant problems faced by any commercial oceanographic company is keeping up with advances in instrument technology while at the same time providing valid data from new oceanographic instrumentation” explained Garry Mardell, Fugro GEOS’ Operations Director. “We are constantly bombarded by manufacturers’ claims regarding the performance of their new ‘all singing all dancing’ instruments that everyone in the industry has to have. As most of our contracts are on a ‘no data no pay’ basis, it is of primary importance to provide valid data to our clients”. To solve this problem, Fugro GEOS funded a trial of most of the self-recording wave measuring instrumentation available worldwide to find which instrument lived up to the manufacturers’ claims and provided the most valid and reliable data. The marine conservation area around Skomer Island off the UK’s South Wales coast was the trials site for the nine instruments, reports Ian Bellamy. seconds Trial Data Tp Periods 30 25 20 15 10 5 0 23-Mar 18:00 24-Mar 06:00 24-Mar 18:00 25-Mar 06:00 25-Mar 18:00 26-Mar 06:00 26-Mar 18:00 Time/Date RDI’s ADCP on the Magnum ROV The trials were undertaken by Fugro GEOS in conjunction with the Countryside Council of Wales who own the seabed lease. “We tested two groups of instruments surface buoys and sub-surface - for almost a month,” Ian Bellamy explained. The surface instruments were the Datawell Waverider and the Triaxys buoy; the subsurface units were the Falmouth Instruments’ 3-D Acoustic Current Meter, the InterOcean S4 DW, Nortek’s Wavepro, Aquadopp and Vector, RD Instruments’ 1200kHz ADCP and Valeport’s 730D. “We used the CCW’s vessel Skalmey to deploy the instruments,” Ian Bellamy said. “The surface buoys went into 30 metres of water off Skomer Island and the subsurface equipment in stainless steel cruciform frames on the seabed in 12 metres of water,” Ian Bellamy said. “The results showed widespread variation in the data recorded by the instruments and we were rather disappointed with the results from some of them”. “We also had a lot of problems with the software supplied by the manufacturers and this meant a delay in processing results,” he added. “On a more optimistic note we have been able to work with a number of manufacturers to improve their instruments and software and we are now more confident in using some of these new instruments. Overall it has been a very successful exercise.” Save costly seismic infill time It’s all very well having an ADCP on your seismic ship. But are you getting the best from it? You know that strong, highly variable ocean surface currents frequently disrupt your operations: the data gaps they create along survey lines mean increased infill work; equipment can be damaged during launch and recovery and because of tangling during streamer stacking; and the hampering of cable laying during ocean bottom seismic surveys can result in incorrect touchdown positions and equipment damage. That’s why you installed an Acoustic Doppler Current Profiler: you knew that the increased costs these disruptions cause can be significantly reduced by having a clear representation of the forces that are acting on the equipment at the time. However, the quality of ADCP data can vary, interpretation by non-specialists can be tricky and there is a need for regular quality checks. Fugro GEOS’ SeisADCP software package unravels the problems associated with displaying and interpreting ADCP data as well as offering regular (as often as weekly if required) QC checks. SeisADCP displays surface current data in real time for use by the navigators. A number of features and the influence they will have on operations can be readily identified. They include: rapid changes in current velocities (valuable when shooting lines and deploying equipment); longer-term changes in current velocity (necessary when planning the shooting of lines and deploying equipment); and current velocity shear with depth (for stacking streamers and deploying ocean bottom cables). “The ADCP system was a key factor in contributing to the notable reduction of infill incurred during this survey” - Seismic specialist after a 50-day 3-D survey in the Gulf of Mexico. SeisADCP has several custom-designed displays including: • Combination display for on-line use showing current data for the last five data points, a current direction profile, and two user-defined time series of a wide range of parameters; • Cross-current display for on-line use showing cross-track current data for the last 24 hours together with useful summary data information; • Current profile display for on-line use showing current data values for the last data point as three independent parameters profiles; • Current speed and direction time series display for user-defined four depth cells; • Vessel pitch, roll, heading and water temperature time series. All data are logged to user-defined directories via the operating PC. Data files can also be easily transferred to Fugro GEOS’ FTP site for regular weekly data QC checking. Live data can be plotted directly from the real-time displays while historical data plots can also be generated to assist planning of operations. Plots available include: • Time series of current speed and direction; • Time series of vessel pitch, roll, heading and temperature; • Individual data point current profiles; • Current data scatter plot and occurrence table; • ASCII export facility for reading data into Microsoft Excel or Word for operations reports. “Navigators get real-time surface current data which is invaluable for shooting lines, launching equipment, stacking streamers and deploying ocean bottom cables” Ian Lucas gets friendly with a Waverider Single source for regional studies Now there’s a single source for integrated regional metocean studies and operational forecasts for both engineering and environmental applications to the offshore and marine industries. It’s called Ocean Numerics Ltd and it’s a joint company formed by the Nansen Environmental and Remote Sensing Center, Norway, and Fugro GEOS. It builds on the strengths of the parent companies to provide services which use advanced numerical models and forecasting techniques, validated and tested with oceanographic field measurements that have been designed and collected specifically for this purpose. “We’ve built up a strong working relationship with the Nansen Center over the past 18 months during our participation in the Atlantic Margin Metocean Project (AMMP),” said Fugro GEOS’ Dave Szabo who is now also managing director of Ocean Numerics Ltd. (AMMP is the combined measurement and modelling project covering the northeast Atlantic Ocean described in the last issue of Aqua.) The Nansen Center is an independent research institute affiliated to the University of Bergen, Norway. It conducts basic and applied environmental research aimed at understanding, monitoring and forecasting the world’s environment and climate on regional and global scales. More details from Dave Szabo, Houston. Nansen Center model of the Atlantic Page 2 Page 3 MEASURING THOSE DEEP GULF OF MEXICO CURRENTS An ambitious joint industry deepwater current monitoring project in the Gulf of Mexico has been initiated by Fugro GEOS Inc, Houston. Aimed at assessing the impact of potentially dangerous deepwater currents on offshore exploration and the design of production facilities, the Gulf Lower Layer (GULL) current measurement project began with the deployment of 19 current meter moorings in water depths ranging from 1500m to 3300m on the Gulf of Mexico Outer Continental Shelf (OCS). Until now, strong currents in the deepwater OCS have only been monitored in isolated programmes but it is known that they extend from near the sea floor to about 1000m with little change in direction or speed. During these events the currents are often about one knot but some observers believe they can exceed two knots. The events have been the subject of a Safety Alert from the US Department of the Interior’s Mineral Management Service (Safety Alert Number 180) as well as a recent CNN article. Analyses of datasets show that the events have the characteristics of Topographic Rossby Waves which have been identified in other ocean basins. These are large-scale features characterised by little change in speed and direction with elevation above the seabed. They actually intensify as the seabed is approached until the effect of friction at the seabed reduces the speed. However, the sparse existing data does not show what is forcing these waves, nor the extent of their penetration up the continental rise and slope, nor how their character might change from east to west. GULL is scoped to provide a coordinated programme to overcome these problems with data collected simultaneously over a broad area of the northern Gulf of Mexico. Participation in GULL is open to all. Further information is on the Fugro GEOS website: http://www.geos.com or by contacting Dave Szabo, Houston. Keeping risers out of trouble Stroke Top Slope Current Profile in the Faeroes-Shetland Channel, there are: southward-moving cold Arctic bottom currents; branches of the Gulf Stream extension at the surface which flow both northward and south-westerly; barotropic tidal currents; and interactions between all of these at various locations and depths. The challenge, therefore, is to be able to break down each current profile into its significant constituent processes and model the correlations between them. Using a technique known as “Empirical Orthogonal Function” (EOF) analysis, the significant current processes may indeed be identified. EOF analysis produces a set of multi-directional current profiles (or “modes”) through depth that vary in strength over time, and which, when combined, produce the total measured currents. Each mode has an overall magnitude associated with it that allows ranking of the importance of each mode and a time-series which describes how the mode varies over the course of the measurement period. Critically, this time-series is suitable both for extrapolation purposes and for modelling how each current mode is 523 correlated with every other one. One more challenge now remains: the quantitative estimation of realistic combinations of modes under extreme conditions. This is achieved by extrapolating the most significant current mode to, say, its 100-year maximum and then using the correlation between this mode and the others to estimate the most realistic worst case scenario for the riser. This will inevitably introduce some conservatism into the process (no bad thing when estimating extreme events from relatively short time-series) but will produce realistic combinations of modes. This procedure can be used to produce a whole series of modal combinations that are likely to be exceeded, say, once in every 100 years. Now the riser loading analysis package can be used once again to identify which of these is associated with the most severe riser responses. This, finally, identifies either one, or a series, of multi-directional current profiles which are representative of extreme events. This process of deriving extreme measured current profiles utilising advanced numerical manipulative techniques maximises the return from any measurement campaign and produces results which focus on the specific information needed for drilling. The new technique was used when Fugro GEOS derived wave and current criteria to support a proposed drilling programme at Enterprise Oil’s Errigal prospect off Ireland. Contact: Graham Feld, Aberdeen. Total force from 2-D current profile Bottom Slope Above: Fig 1. The new approach converts a time series of measured current profiles into a time series of riser responses - top and bottom angles, total horizontal force and stroke. It’s not every day that you come across an “Empirical Orthogonal Function Analysis” (EOF), but that’s what’s at the heart of a Fugro GEOS technique. It’s part of a new approach to deriving extreme current profiles to support deepwater drilling operations, and it is described in this article by Graham Feld, a Senior Oceanographer based in the Aberdeen office (see p8). The new approach concentrates on those currents that create maximum riser response. It ensures that estimates of extreme conditions are actually based upon the most damaging current profiles. Along with techniques that split the current profiles into constituent components, this gives a much greater understanding of how the current conditions affect riser operations and also enhances the modelling of likely extreme events. This approach has already proved useful as part of the specification of environmental conditions for drilling programmes in several locations along the Atlantic Margin. Traditionally, extreme currents have been derived by ignoring both the time dependency between currents at different depths and their directions. This typically results in a current profile which has the highest speed at the surface and the lowest at the seabed, and which is assumed to be uni-directional. As well as being unrepresentative of the currents at a specific location it may not represent the worst type of profile for the operation of a deployed riser. The new approach converts a time-series of measured current profiles into a time-series of static riser responses: top and bottom angles, total horizontal force, and stroke (Fig 1). This allows the complexity of real, measured profiles to be reduced to the more manageable time-series of the four riser responses (Fig 2). A Peak Over Threshold (POT) approach can then be used on each of the riser response timeseries to identify the maximum effect of each discrete current event. Those current profiles that give the largest riser response are then used in the further analysis. Having identified which currents are problematic, how do we then extrapolate these currents to estimate the worst currents in, say, 100 years? Bearing in mind that each current profile is likely to be complex, multi-directional and made up of both tidal and residual elements, a simple fitting to one or even a whole host of probability distributions is not appropriate. For example, The riser on R&B Falcon’s semi-sub Jack Bates Total Force (kN) 0 14-Feb-1999 4 18-Feb-1999 22-Feb-1999 26-Feb-1999 02-Mar-1999 RIG ADCP IN ACTION Recent successes with Fugro GEOS’ RigADCP: On Texaco’s Torridon deepwater well in the deepwater Atlantic Margin, Dennis O’Hare, the Texaco rep on board reports that the system worked well and was “a great help, particularly when doing the open water work at the start and end of the well”. He comments that the strength of the currents took Texaco by surprise and “had we not had your system in place we could have been faced with some downtime. The ability to predict when the current would be highest enabled us to re-shuffle the work sometimes and keep going.” Meanwhile, drilling on the Snadd well off Norway, BP Amoco’s Ian Mills was pleased with the system and the speed with which it was installed. It confirmed low current speeds and, as the daily log noted, “real-time current measurements ensured that the dual derrick capability of the West Navion was exploited by running the BOP and casing from separate derricks at the same time.” Top slope (degrees) 0 14-Feb-1999 9 18-Feb-1999 22-Feb-1999 26-Feb-1999 02-Mar-1999 Bottom slope (degrees) 0 14-Feb-1999 3 18-Feb-1999 22-Feb-1999 26-Feb-1999 02-Mar-1999 Stroke (m) 0 14-Feb-1999 18-Feb-1999 22-Feb-1999 26-Feb-1999 02-Mar-1999 Above: Fig 2. Time series of riser responses from observed (black) and reconstructed using the first three EOF modes (red). Threshold and selected peaks are shown for total force (blue). Page 5 Go-anywhere WeatherMoni tor gets worldwide acclaim It is fast becoming the accepted standard for real-time offshore metocean monitoring. It’s the Fugro GEOS WeatherMonitor and it’s already in wide use in the North Sea, in the Caspian and off Sarawak. What’s more, because data transmission only happens if a parameter value changes, network traffic is kept to a minimum. WeatherMonitor is network-based. Data are input to a client’s existing data management and transmission network. The system is configured so that it can be read via e-mail, FTP, WAN, LAN and any other system. It can be upgraded and maintained remotely thus saving on costly offshore visits - and, because it is web-based, is readily integrated with other web services and applications. It also provides data for the derivation of operating criteria for future field developments since all data are archived, allowing historical data to be used by third parties. In real time mode on manned structures, WeatherMonitor acts in a policing role during adverse weather conditions. It conforms to international standards for aviation requirements. It enables drilling rig, platform and FPSO operators to decide when conditions are too hazardous for supply boat operations. It triggers alarms in cranes when sea states and wind conditions are beyond prescribed limits. WeatherMonitor is already at work in major offshore E&P provinces worldwide and is set to become an industry standard. “One of the great features of WeatherMonitor software is that we can quickly interface it to existing sensors,” said Anthony Gill, Project Manager for the MetNet system with Fugro GEOS. “It’s been tried and tested over many applications so we don’t have to re-write it for each installation - only the configuration is changed, so there’s no costly development time. “Then there’s its flexibility to cover a wide range of functions. It doesn’t just take input from a wide range of metocean sensors but we can set it up to monitor, QC and even control systems on unmanned production platforms. For example, it could take data from met. sensors, the results of which would automatically switch on de-icing systems on helidecks,” Anthony Gill explained. Examples of WeatherMonitor screen displays show its flexibility. It is easily integrated with other web-based systems and services. MID-EAST MET. BUY Fugro GEOS has acquired the marine weather forecast division of International Aeradio (Emirates) LLC (IAL). “This acquisition expands Fugro GEOS’ existing weather forecasting capabilities into the Gulf, Arabian Sea and the Gulf of Oman which are IAL’s existing areas of expertise,” explained Ralph Rayner, Fugro GEOS’ managing director. IAL’s staff operates out of Fugro’s Middle East offices in Abu Dhabi. More staff are being recruited to increase capabilities. The office is well placed to offer marine weather forecasting services in neighbouring areas such as the Caspian, Eastern Mediterranean and Red Seas, as well as the Indian Ocean. As with the Singapore office, forecasts will be available 24 hours a day, 365 days per year. The Fugro GEOS marine weather forecast products include highly accurate forecasts available for an area now covering the Middle East to Japan and Australasia. They are delivered by fax, e-mail, or via a password-protected webpage browser. Contact Alan Douglas, Abu Dhabi. WEST AFRICA: THE ESSENTIAL GUIDE It’s called a “Docket” which rather demeans it since it’s a high-density 200page volume, also available on CD-ROM. It’s the West Africa Environmental Briefing Docket and it’s a comprehensive review of metocean conditions - and more besides - off West Africa. It’s produced by the Maritime Environment Information Centre of the UK Hydrographic Office in association with Fugro GEOS and will be an essential piece of bridge equipment on all Royal Navy ships operating in the area. Now it’s available, via Fugro GEOS, to anyone operating in the area and will, of course, be of particular interest to the offshore exploration and production industries. The Docket has general information on the area - ports, anchorages, bathymetry, topography, sediment types, wrecks and so on - then highly detailed material on meteorology, climatology and oceanography, with hundreds of maps and diagrams. There’s even a section on the distribution of dangerous species. Example: “Stokes sea snake: One of the largest sea snakes, reaching a length of 2.5m. It has a mouth that can go around a human arm . . .” This is an essential guide for anyone with offshore West Africa interests. Other “Dockets” are planned for the South China Sea, Indonesia, Australia and Brazil. Contact Peter Owrid, Swindon. Abu Dhabi - seen here as the centre of the universe! An example of one of the many hundreds of maps, diagrams and plots in the Docket. This shows physiographic features. Page 6 Page 7 News about Fugro GEOS people... welcome... ABERDEEN • Peter Wilson oceanographer • Paul Gomez systems engineer • Kathy Han accounts executive • Susie Lim office administrator • Jimmy Lorenzo shift supervisor (forecaster) • Alice Soh operations secretary • Gareth Dew IT support manager • Anthony Gill project manager • Anthony Osbourn oceanographic engineer • Peter Owrid sales coordinator • Tejal Patel report secretary • Diana Philpott accounts assistant • Dan Rudman oceanographer • Jackie Saunders divisional secretary • Elaine Shaw database administrator • Louise Slattery administrative assistant • Mary Smith divisional secretary ABU DHABI Abu Dhabi office Here are (from left) Terry Jones, Alan Douglas (forecast manager), Pierre Foucaud and Joe Parsons. They are the key personnel in Fugro GEOS’ Abu Dhabi office. (see page 6) which expands weather forecasting activities so that they now cover an area from the Middle East to Japan and Australia. • Alan Douglas forecast manager • Pierre Foucaud marine forecaster • Terry Jones senior forecaster • Joe Parsons senior forecaster SOUTHAMPTON • Kerstin Personage administrator • Martin Williams senior oceanographer Bangor bursary Fugro GEOS provided a Bursary and two months of summer work to Richard Williamson, a second-year Joint Honours Marine Biology and Oceanography student at Bangor University. “I enjoyed the experience,” Richard said, “and everyone in the office made me very welcome”. HOUSTON • Sam Berry oceanographer SWINDON MALAYSIA • Chang Chee Foong senior forecaster • Yeong Nam Heh forecast manager • Mohd. Nasir Abdullah senior oceanographic engineer • Sue Bagwell logistics secretary • Ian Bellamy principal oceanographer • David Cheeseman junior IT support engineer • Daniel Davies database administrator Adrian’s back Adrian Smith, one of the Fugro Group’s most experienced oceanographers has returned from a secondment to the offices of clients QGPC in Qatar. There, he reviewed metocean and design criteria for the region which led to recommendations for further work in other areas. Adrian was able to call on Fugro GEOS’ Seadata experience in the region (including work on the South Pars and Dolphin pipeline projects) as well as on the extensive regional knowledge of Fugro GEOS weather forecasters in Abu Dhabi. SINGAPORE • Leo Ares marine forecaster • Arnold Doray r&d software engineer SWINDON (UK Head Office) Gemini House, Hargreaves Road, Swindon, Wiltshire SN2 5AZ • Tel: ++ (44) 1793 725766 • Fax: ++ (44) 1793 706604 • e-mail: uk@geos.com • Contact ROB SMITH ABERDEEN • Tel: ++ (44) 1224 791766 • Fax: ++ (44) 1224 791974 • e-mail: uk@geos.com • Contact GRAHAM FELD SOUTHAMPTON • Tel: ++ (44) 2380 596009 • Fax: ++ (44) 2380 596509 • e-mail: uk@geos.com • Contact: NIGEL BELLAMY HOUSTON • Tel: ++ (1) 713 773 5699 • Fax: ++ (1) 713 773 5909 • e-mail: usa@geos.com • Contact JAN VAN SMIRREN ABU DHABI • Tel: ++ (971) 255 45 101 • Fax: ++ (971) 255 45 059 • e-mail: uae@geos.com • Contact ALAN DOUGLAS SINGAPORE • Tel: ++ (65) 543 4404 • Fax: ++ (65) 543 4454 • e-mail: singapore@geos.com • Contact MARK WIMSHURST On your Aberdeen doorstep The establishment of our Aberdeen office nearly two years ago is paying dividends. Oil company clients are finding that having consultants on the doorstep to discuss requirements leads to a fast and effective solution to operational planning and design engineering problems. Resident oceanographers in Aberdeen are Graham Feld and Peter Wilson. Page 8