The Shearwater Field – understanding the overburden above a geologically complex and pressure-depleted high-pressure and high-temperature field

2017 ◽  
Vol 8 (1) ◽  
pp. 429-443 ◽  
Author(s):  
D. W. Jones ◽  
B. J. Taylor ◽  
C. E. Gill ◽  
M. Bevaart ◽  
P. F. van Bergen ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
North Sea ◽  
Initial Development ◽  
The North ◽  
Well Design ◽  
Stress Changes ◽  
As Stress ◽  
The Uk ◽  
Over Time

AbstractThe Shearwater Field, located in Block 22/30b in the UK Central Graben, remains one of the best-known fields in the UK Continental Shelf (UKCS). At the time of the initial development, Shearwater represented one of the most complex and technically challenging high-pressure and high-temperature (HPHT) developments of its kind in the North Sea. During the early life of the field, pressure depletion resulted in compaction of the Fulmar reservoir, leading to mechanical failure of the development wells. The compaction also resulted in weakening of the overburden due to an effect known as stress arching. Over time, this resulted in in situ stress changes in the overburden which have been observed from 4D seismic datasets and are in line with geomechanical modelling. This is particularly true for the Hod Formation in the Chalk Group, and resulted in the need to make changes to infill well design, including the use of new drilling technologies, to ensure safe and effective well delivery. The insights presented here, which relate to the understanding of pore pressure and fluid fill in the overburden, and how the overburden has responded to stress changes over time, are of relevance to current and future HPHT field developments in both the UK North Sea and elsewhere.

Extreme High-Pressure and/or High-Temperature Wireline-Data Acquisition: Planning for Success

2014 ◽  
Vol 17 (04) ◽  
pp. 444-448 ◽  
Author(s):  
J.. Owens ◽  
G.. Parry ◽  
B.. Taylor
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Data Acquisition ◽  
North Sea ◽  
Extreme Environments ◽  
Successful Operation ◽  
The North ◽  
Risk Management Process ◽  
The North Sea ◽  
Acquisition Planning

Summary Data acquisition in extreme environments of high pressure and/or high temperature (HPHT) with pressures up to 30,000 psi and temperatures up to 500°F requires not only specialist technology capable of surviving these conditions but also many months of preparation and planning to ensure a successful operation. The aim of this publication is to provide an overview of what is involved in the planning, preparation, and execution of an extreme HPHT wireline data acquisition—from the customer setting the information objectives through to data delivery. This includes developing an agreed quality plan between the data provider and the customer covering testing and deployment of the latest extreme HPHT logging equipment. One must consider all aspects to minimize risks including detailed tailoring of the logging programs to manage time in hole, to ensure accurate depth control, and, by using a deployment risk-management process, to ensure that what goes in the hole comes out again. The implementation of these procedures is illustrated with a case history of a series of HPHT exploration wells drilled in the Central Graben of the North Sea (the "HPHT Heartland" of the North Sea). Bottomhole conditions were predicted to approach 400°F and 15,000 psi. These extreme conditions negated the use of conventional wireline tools, and so, from initial early planning discussions between client and service provider, new detailed programs were designed and implemented as a specific "Quality Plan" to use the advanced HPHT wireline-logging tools.

Blame the Barbarians

2021 ◽  
pp. 39-82
Author(s):  
Arika Okrent ◽  
Sean O’Neill
Keyword(s):  
The Netherlands ◽  
Old English ◽  
North Sea ◽  
Religious Texts ◽  
The North ◽  
The People ◽  
Latin Language ◽  
The North Sea ◽  
Germanic Languages ◽  
Over Time

This chapter tells the story of how English got to be the weird way it is, which begins with the Germanic languages and the barbarians who spoke them. During the 5th century, an assortment of them poured across the North Sea, from what is today Denmark, the Netherlands, and Northern Germany, and conquered most of England. After about a century of the Germanic tribes taking over and settling in, the Romans returned. This time it was not soldiers but missionaries who arrived. The monks who came to convert the island to Christianity brought their Latin language with them, and they also brought the Latin alphabet. They set about translating religious texts into the language of the people they encountered, a language that by this time had coalesced into something that was Old English. However, there is another group of barbarians to blame: the Vikings. Their language was similar enough to Old English that they could communicate with the Anglo-Saxons without too much difficulty, and over time their own way of speaking mixed into the surrounding language, leaving vocabulary and expressions behind that do not quite fit the rest of the pattern at the old Germanic layer.

The Emerald Field, Blocks 2/10a, 2/15a, 3/11b, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 111-116 ◽  
Author(s):  
D. M. Stewart ◽  
A. J. G. Faulkner
Keyword(s):  
North Sea ◽  
Water Injection ◽  
Maximum Flow ◽  
Oil Field ◽  
Injection Wells ◽  
Initial Development ◽  
Flexible Risers ◽  
Northern North Sea ◽  
The Uk ◽  
Gas Lift

AbstractThe Emerald Oil Field lies in Blocks 2/10a, 2/15a and 3/1 lb in the UK sector of the northern North Sea. The field is located on the 'Transitional Shelf, an area on the western flank of the Viking Graben, downfaulted from the East Shetland Platform. The first well was drilled on the structure in 1978. Subsequently, a further seven wells have been drilled to delineate the field.The Emerald Field is an elongate dip and fault closed structure subparallel to the local NW-SE regional structural trend. the 'Emerald Sandstone' forms the main reservoir of the field and comprises a homogeneous transgressive unit of Callovian to Bathonian age, undelain by tilted Precambrian and Devonian Basement Horst blocks. Sealing is provided by siltstones and shales of the overlying Healther and Kimmeridge Clay Formations. The reservoir lies at depths between 5150-5600 ft, and wells drilled to date have encountered pay thicknesses of 42-74 ft. Where the sandstone is hydrocarbon bearing, it has a 100% net/ gross ratio. Porosities average 28% and permeabilities lie in the range 0-1 to 1.3 darcies. Wireline and test data indicate that the field contains a continouous oil column of 200 ft. Three distinct structural culminations exist on and adjacent to the field, which give rise to three separate gas caps, centred around wells 2/10a-4, 2/10a-7 and 2/10a-6 The maximum flow rate achieved from the reservoir to date is 6822 BOPD of 24° API oil with a GOR of 300 SCF/STBBL. In-place hydrocarbons are estimated to be 216 MMBBL of oil and 61 BCF of gas, with an estimated 43 MMBBL of oil recoverable by the initial development plan. initial development drilling began in Spring 1989 and the development scheme will use a floating production system. Production to the facility, via flexible risers, is from seven pre-drilled deviated wells with gas lift. An additional four pre-drilled water injection wells will provide reservoir pressure support.

Towards a vulnerability assessment of the UK and northern European coasts: the role of regional climate variability

2005 ◽  
Vol 363 (1831) ◽  
pp. 1329-1358 ◽  
Author(s):  
M.N Tsimplis ◽  
D.K Woolf ◽  
T.J Osborn ◽  
S Wakelin ◽  
J Wolf ◽  
...  
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
North Sea ◽  
Positive Response ◽  
Sea Level Change ◽  
Empirical Relationships ◽  
Level Change ◽  
The North ◽  
The North Sea ◽  
The Uk

Within the framework of a Tyndall Centre research project, sea level and wave changes around the UK and in the North Sea have been analysed. This paper integrates the results of this project. Many aspects of the contribution of the North Atlantic Oscillation (NAO) to sea level and wave height have been resolved. The NAO is a major forcing parameter for sea-level variability. Strong positive response to increasing NAO was observed in the shallow parts of the North Sea, while slightly negative response was found in the southwest part of the UK. The cause of the strong positive response is mainly the increased westerly winds. The NAO increase during the last decades has affected both the mean sea level and the extreme sea levels in the North Sea. The derived spatial distribution of the NAO-related variability of sea level allows the development of scenarios for future sea level and wave height in the region. Because the response of sea level to the NAO is found to be variable in time across all frequency bands, there is some inherent uncertainty in the use of the empirical relationships to develop scenarios of future sea level. Nevertheless, as it remains uncertain whether the multi-decadal NAO variability is related to climate change, the use of the empirical relationships in developing scenarios is justified. The resulting scenarios demonstrate: (i) that the use of regional estimates of sea level increase the projected range of sea-level change by 50% and (ii) that the contribution of the NAO to winter sea-level variability increases the range of uncertainty by a further 10–20 cm. On the assumption that the general circulation models have some skill in simulating the future NAO change, then the NAO contribution to sea-level change around the UK is expected to be very small (<4 cm) by 2080. Wave heights are also sensitive to the NAO changes, especially in the western coasts of the UK. Under the same scenarios for future NAO changes, the projected significant wave-height changes in the northeast Atlantic will exceed 0.4 m. In addition, wave-direction changes of around 20° per unit NAO index have been documented for one location. Such changes raise the possibility of consequential alteration of coastal erosion.

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