Significant Surge and Swab Offshore Brazil Induced by Rig Heave during Drillpipe Connections

2021 ◽  
pp. 1-8
Author(s):  
John-Morten Godhavn ◽  
Banzi Olorunju ◽  
Dmitri Gorski ◽  
Martin Kvernland ◽  
Mateus Sant`Ana ◽  
...  
Keyword(s):  
North Sea ◽  
Sampling Rate ◽  
Drilling Mud ◽  
Long Distance ◽  
Pressure Oscillations ◽  
The North ◽  
Order Of Magnitude ◽  
Measurement While Drilling ◽  
Well Trajectory ◽  
The North Sea

Summary In this paper, we describe measured and simulated downhole pressure variations (“surge and swab”) during drillpipe connections when drilling an ultradeepwater well offshore Brazil on Bacalhau (former Carcará) Field. Floating rig motion caused by waves and swell (“rig heave”) induces surge and swab when the drillstring is suspended in slips to make up or break a drillpipe connection and topside heave compensation is temporarily deactivated. This is a known issue in regions with harsh weather, such as the North Sea, where pressure oscillations of up to 20 bar have been reported during connections. Recorded downhole drilling data from Bacalhau Field reveals significant pressure oscillations downhole (in the same order of magnitude as in the North Sea) each time the drillstring was suspended in slips to make a connection in the subsalt 8½-in. section of the well. Mud losses were experienced around the same well depth, and they might have been caused by surge and swab. Measured surge and swab pressure variations have been reproduced in an advanced proprietary surge and swab simulator that considers rig heave, drillpipe elasticity, well friction, non-Newtonian drilling mud, well trajectory, and geometry. Moreover, findings in this paper suggest that surge and swab was in fact significantly higher than recorded by the measurement while drilling (MWD) tool. The true magnitude of surge and swab is not captured in the recorded MWD data due to low sampling frequency of the downhole pressure recording (one measurement every 6 seconds, a standard downhole pressure sampling rate used on many operations today). This work shows that surge and swab during drillpipe connections on floaters may challenge the available pressure window for some wells, even in regions with calm weather such as Brazil. Managed pressure drilling (MPD) is a technique that improves control of the downhole pressure. It is, however, not possible to compensate fast downhole pressure transients, such as heave-induced surge and swab, using MPD choke topside. This is due to the long distance between the choke and the bit, which translates into a time delay in the same order of magnitude as typical wave and heave periods. A downhole choke combined with continuous circulation is one of the potential solutions. Surge and swab during drillpipe connections can result in a loss or an influx and should be considered in the well planning phase when mud weight, section lengths, etc. are selected.

Maritime and River Traders, Landing Places, and Emporia Ports in the Merovingian Period in and Around the Low Countries

2020 ◽  
pp. 763-796
Author(s):  
Dries Tys
Keyword(s):  
North Sea ◽  
Institutional Economics ◽  
New Institutional Economics ◽  
Central Position ◽  
Economic Activities ◽  
Early Medieval ◽  
Low Countries ◽  
Long Distance ◽  
The North ◽  
The North Sea

The origin, rise, and dynamics of coastal trade and landing places in the North Sea area between the sixth and eighth centuries must be understood in relation to how coastal regions and seascapes acted as arenas of contact, dialogue, and transition. Although the free coastal societies of the early medieval period were involved in regional to interregional or long-distance trade networks, their economic agency must be understood from a bottom-up perspective. That is, their reproduction strategies must be studied in their own right, independent from any teleological construction about the development of trade, markets, or towns for that matter. This means that the early medieval coastal networks of exchange were much more complex and diverse than advocated by the simple emporium network model, which connected the major archaeological sites along the North Sea coast. Instead, coastal and riverine dwellers often possessed some form of free status and large degrees of autonomy, in part due to the specific environmental conditions of the landscapes in which they dwelled. The wide estuarine region of the Low Countries, between coastal Flanders in the south and Friesland in the north, a region with vast hinterlands and a central position in northwestern Europe, makes these developments particularly clear. This chapter thus pushes back against longstanding assumptions in scholarly research, which include overemphasis of the influence of large landowners over peasant economies, and on the prioritization of easily retrievable luxuries over less visible indicators of bulk trade (such as wood, wool, and more), gift exchange, and market trade. The approach used here demonstrates that well-known emporia or larger ports of trade were embedded in the economic activities and networks of their respective hinterlands. Early medieval coastal societies and their dynamics are thus better understood from the perspective of integrated governance and economy (“new institutional economics”) in a regional setting.

1.—The Competitors and the Result

1906 ◽  
Vol 10 (40) ◽  
pp. 50-51
Keyword(s):  
Great Britain ◽  
North Sea ◽  
English Channel ◽  
Long Distance ◽  
The North ◽  
The North Sea ◽  
The Way

No fewer than seven nations tried to win the Gordon Bennett Cup in the race which started from the Tuileries Gardens, in Paris, on September 30th. But the wind was in an unfavourable direction for the accomplishment of a long distance record. To some, the English Channel barred the way, to some, the North Sea.The cup offered for the greatest distance covered has been accorded to the American aeronaut, Mr. Frank P. Lahm, who descended 15 miles north of Scarborough.It will be seen in another part of this Journal that in December next, Members of the Aëronautical Society of Great Britain will hear an account of the Gordon-Bennett race from Colonel J. E. Capper, who took part in the race, having accompanied Mr. Rolls in the “ Britannia.” In this account, therefore, it will suffice to merely tabulate the competitors and results.

Storm surges in the North Sea during the winter 1953-4

1956 ◽  
Vol 235 (1201) ◽  
pp. 260-274 ◽  
Keyword(s):  
Sea Level ◽  
North Sea ◽  
Storm Surges ◽  
Rate Of Change ◽  
The North ◽  
Order Of Magnitude ◽  
The North Sea ◽  
Sea Ports ◽  
Phase Angles

Records of sea level for several North Sea ports for the winter of 1953-4 have been in vestigated. They were split into 14-day intervals, and each 14-day record was Fourieranalyzed to determine if any non-astronomical periods were present. There was evidence of some activity between 40 and 50 h period, and a determination of the phase angles at different ports showed that the activity could be due to a disturbance travelling southwards from the north of the North Sea. The disturbance was partly reflected somewhere near the line from Lowestoft to Flushing, so that one part returned past Flushing and Esbjerg towards Bergen while the other part travelled towards Dover, and there was evidence of its existence on the sea-current records taken near St Margaret's Bay. These results were confirmed by subtracting the predicted astronomical tidal levels from the observed values of sea level and cross-correlating the residuals so obtained for each port with those found at Lowestoft. The residuals at Lowestoft and Aberdeen were compared with the meteorological conditions, and it was found that, although they could be attributed to a large extent to conditions within the North Sea, there was an additional effect due to a travelling surge which was of the same order of magnitude at both Lowestoft and Aberdeen and which was closely related to the rate of change with time of the atmospheric pressure difference between Wick and Bergen.

High-resolution reservoir characterization by an acoustic impedance inversion of a Tertiary deltaic clinoform system in the North Sea

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. O57-O67 ◽  
Author(s):  
Daria Tetyukhina ◽  
Lucas J. van Vliet ◽  
Stefan M. Luthi ◽  
Kees Wapenaar
Keyword(s):  
North Sea ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Structural Information ◽  
Sampling Rate ◽  
Seismic Inversion ◽  
Acoustic Properties ◽  
The North ◽  
The North Sea ◽  
Well Data

Fluvio-deltaic sedimentary systems are of great interest for explorationists because they can form prolific hydrocarbon plays. However, they are also among the most complex and heterogeneous ones encountered in the subsurface, and potential reservoir units are often close to or below seismic resolution. For seismic inversion, it is therefore important to integrate the seismic data with higher resolution constraints obtained from well logs, whereby not only the acoustic properties are used but also the detailed layering characteristics. We have applied two inversion approaches for poststack, time-migrated seismic data to a clinoform sequence in the North Sea. Both methods are recursive trace-based techniques that use well data as a priori constraints but differ in the way they incorporate structural information. One method uses a discrete layer model from the well that is propagated laterally along the clinoform layers, which are modeled as sigmoids. The second method uses a constant sampling rate from the well data and uses horizontal and vertical regularization parameters for lateral propagation. The first method has a low level of parameterization embedded in a geologic framework and is computationally fast. The second method has a much higher degree of parameterization but is flexible enough to detect deviations in the geologic settings of the reservoir; however, there is no explicit geologic significance and the method is computationally much less efficient. Forward seismic modeling of the two inversion results indicates a good match of both methods with the actual seismic data.

Moving across the North Sea

2011 ◽  
Author(s):  
Robert Van de Noort
Keyword(s):  
Bronze Age ◽  
Middle Ages ◽  
North Sea ◽  
Long Distance ◽  
Prestige Goods ◽  
The North ◽  
Southern Scandinavia ◽  
The Social ◽  
The North Sea ◽  
The Bronze Age

Movements between different lands around the North Sea have always been taking place. While the North Sea was evolving gradually, over the millennia, following the melting of the Devensian ice sheet, close contacts across what remained of the North Sea Plain never ceased, as evidenced by near-parallel developments of the Maglemosian-type tools in southern Scandinavia and Britain (Clark 1936), and by particular practices such as the deliberate deposition of barbed points (see chapter 3). Connections across the North Sea throughout the Mesolithic and the beginning of the Neolithic would have been made easier because of the number of islands surviving within the rising sea. The polished axes from Dogger Bank and Brown Bank either represent human presence on these islands in the early Neolithic or else indicate that the existence of these islands sometime in the pre-Neolithic past was embedded in the social memory of later periods. Both possibilities emphasize the fact that the North Sea was a knowable and visited place. Movements across the North Sea took various forms: as exchange between elites from different regions of exotic or ‘prestige’ goods, and possibly of marriage partners; as trade in both luxury and bulk commodities; and in the transfer of people, in some cases as individuals such as pilgrims and missionaries, and in other cases as groups of pirates or as part of larger-scale migrations. Over time, connectedness across the North Sea changed both in nature and in intensity; this was due in no small part to changes in the nature of the craft available. An outline of the movement of goods from the Neolithic through to the end of the Middle Ages illustrates this. Contacts across the North Sea for the Neolithic and the Bronze Age are demonstrated in the long-distance exchange of exotic objects and artefacts, including Beaker pottery, jewellery, or other adornments of gold, amber, faience, jet, and tin; also copper and bronze weapons and tools, and flint daggers, arrowheads, and wrist guards (e.g. Butler, 1963; O’Connor, 1980; Bradley 1984; Clarke, Cowie, and Foxon 1985).

Monitoring of cycle tourism on long distance trails: the North Sea Cycle Route

2004 ◽  
Vol 12 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Les Lumsdon ◽  
Paul Downward ◽  
Andy Cope
Keyword(s):  
North Sea ◽  
Long Distance ◽  
The North ◽  
The North Sea

The impact of oily discharges on the meiobenthos of the North Sea

1987 ◽  
Vol 316 (1181) ◽  
pp. 525-544 ◽  
Keyword(s):  
Species Richness ◽  
North Sea ◽  
Seasonal Pattern ◽  
Oil Refinery ◽  
Slight Reduction ◽  
Drilling Mud ◽  
Subtle Change ◽  
The North ◽  
The North Sea ◽  
The Impact

The impact of hydrocarbon discharges on the intertidal and subtidal meiobenthos of the North Sea is examined primarily by a consideration of two field investigations. The first study examines the effects of an oil refinery discharge on intertidal meiofauna in the Firth of Forth, while the second describes the impact of oil platform discharges on the surrounding meiobenthos. The impact of the refinery effluent is only clearly distinguishable upstream of the discharge, as downstream the effects are confused with those of a second petrochemical discharge. The meiofaunal community is only strongly affected on the upper shore and this appears to be chiefly the result of an organic enrichment effect causing a raising of the redox potential discontinuity (RPD) layer. All meiofaunal taxa examined are sharply reduced in density and species richness within 320 m of the discharge but at 600-900 m from the discharge meiofaunal densities are enhanced or depressed, relative to clean sediments, dependent upon the seasonal pattern of the RPD layer. Farther down the shore the impact is only felt at most by a slight reduction in species richness and subtle change in species abundance patterns on the middle shore for a distance of about 600 m. The meiofaunal responses to the petrochemical discharges seem similar to those described for the macrofauna in the same area, although a small meiofaunal population persists in the most polluted sediments in the absence of macrofauna. The discharge of drilling cuttings, contaminated with oil-based drilling mud, was found to strongly modify meiofaunal densities within 800 m of the Beryl A Platform. Nematode densities are strongly reduced in the vicinity of the platform and it is thought that the impact on this infaunal taxon may be due to slow degradation within the sediment of toxic fractions of the diesel base of the drilling mud. By contrast copepod densities were greatly enhanced in one survey and the difference in impact is considered to be due to the epibenthic habit of the species involved, enabling them to flourish in conditions of high food or low predation and competition or all three. The species involved seem typical members of meiofaunal communities of organically enriched sediments. Some improvement in meiofaunal densities throughout the period 1984-85 is thought to be possibly the result of a switch from diesel-based to lowtoxicity drilling muds. It is concluded from these and other studies that hydrocarbon discharges into the North Sea are unlikely to be causing extensive damage to meiofaunal communities.

An archaeological theory of the sea

2011 ◽  
Author(s):  
Robert Van de Noort
Keyword(s):  
Bronze Age ◽  
North Sea ◽  
Archaeological Theory ◽  
Medieval Period ◽  
Early Medieval ◽  
Long Distance ◽  
Early Medieval Period ◽  
The North ◽  
The Social ◽  
The North Sea

Despite the wealth of information available on the North Sea, surprisingly few archaeologists have set out to study how people related to and connected to this sea, and other seas, in the past. In fact, we can distinguish four established traditions in archaeological research of the sea, all of which originated in the 20th century. First, many (or most) land-locked archaeologists working on any side of the North Sea have simply disregarded the sea itself, seeing it merely as the natural boundary of their study areas rather than considering its role in any significant way. At best, they are seeing the sea from the land, without genuinely engaging with it (cf. Cooney 2003: 323), although the panorama is slowly changing (e.g. cf. Bradley 1984 with Bradley 2007). Second, there are those archaeologists with an interest in long-distance exchange and exotic objects, who focused initially on the Neolithic and Bronze Age periods but have also been concerned, in more recent decades, with the early medieval period. Although these archaeologists have recognized the seas as conduits of long-distance exchange, they have rarely questioned how the practice of travel across the sea impacted on the social products of such exchange (e.g. Butler 1963, O’Connor 1980, Bradley 1984, Clarke, Cowie, and Foxon 1985, for the Neolithic and early Bronze Age; Hodges 1982, Loveluck and Tys 2006, for the early medieval period). Third, a group of archaeologists have studied the exploitation of the sea, especially for fish and salt, and the occupation and the reclamation of the edges of the sea in the Roman period and afterwards; but these studies have generally not strayed beyond the functional utilization of the sea and coast both for food and for land for food production (e.g. Clark 1961; Van den Broeke 1985; Andersen 1995, 2007; Rippon 2000; Smart 2003; Milner et al. 2004; De Kraker and Borger 2007). And fourth, maritime archaeologists’ focus has been on ships and waterside structures directly relating to shipping activities, but the development of a fuller appreciation of the significance of the sea and seafaring to past societies remains something of a distant aspiration (e.g. Ellmers 1972; McGrail 2003: 1).

scholarly journals THE DISASTER IN THE NETHERLANDS CAUSED BY THE STORM FLOOD OF FEBRUARY 1, 1953

2000 ◽  
Vol 1 (4) ◽  
pp. 18 ◽  
Author(s):  
P. J. Wemelsfelder
Keyword(s):  
The Netherlands ◽  
North Sea ◽  
Average Width ◽  
The North ◽  
Order Of Magnitude ◽  
The North Sea

It will be useful to show first a sketch of the situation of our low lying area with regard to the North Sea (Fig. 1). We might idealize the North Sea in the shape of a rectangular pocket, nearly 400 miles wide and 500 miles long, open to the Atlantic in the line Duncansby (Scotland) - Bergen (Norway). For its size the North Sea is relatively shallow. The depth is of the order of magnitude of 60 m. The funnel-like Southern part, between England and the Netherlands, is not more than 40 m deep. The average width of this part is 250 miles.

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