Abstract The Edradour Field, located in Licence P1453 on Block 206/4a of the Faroe–Shetland Basin, was put on production in August 2017. It lies c. 50 km NW of the Shetland Islands in a water depth of c. 300 m, and consists of one subsea well that produces gas condensate from the Albian Black Sail Member of the Commodore Formation. It is part of a joint development scheme along with the Glenlivet Field that sees the commingled multiphase production transported to the Shetland Gas Plant via tieback to the pre-existing Laggan–Tormore flowlines. The Edradour single well development has reserves of 21 MMboe from a gas initially-in-place of 142 bcf. It is operated by Total E&P UK Ltd under the P1453 licence with Ineos E&P (UK) Ltd and SSE E&P UK Ltd as partners.

Abstract The Glenlivet Field, located in Block 214/30a within the Faroe–Shetland Basin, was put on production in August 2017. It lies approximately 70 km NW of the Shetland Islands, in a water depth of c. 440 m. The development consists of two subsea wells that produce gas condensate from the Paleocene Vaila Formation, which comprises deep-water turbidite deposits with excellent petrophysical properties. It is part of a joint development scheme along with the Edradour Field that sees the commingled multiphase production transported to the Shetland Gas Plant via tie-back to the pre-existing Laggan–Tormore flowlines. Glenlivet is operated by Total E&P UK Ltd under the P1195 licence since September 2014 with Ineos E&P (UK) Ltd and SSE E&P UK Ltd as partners.

Abstract The Laggan and Tormore fields are found within the Flett sub-basin of the Faroe–Shetland Basin. Situated 120 km west of the Shetland Islands in 600 m water depth, they are part of the deepest subsea development in the UK to date with a 143 km subsea tie-back to onshore facilities. The reservoirs are found within the T35 biostratigraphic sequence of the Paleocene Vaila Formation and comprise sand-rich turbiditic channelized lobes with good reservoir properties, separated by metric to decimetric shale packages. Laggan is a gas-condensate field, whereas Tormore fluid is a richer gas with a saturated oil rim. Seismic reservoir characterization is a key to the field development where differentiation of fluid type proved challenging. Both fields came on stream in 2016 as part of the Greater Laggan area development scheme.

Abstract The Laggan–Tormore development was sanctioned in 2010: the two fields are produced by subsea systems, tied back to the Shetland Islands where the hydrocarbons are processed in the Shetland Gas Plant. A key aspect of the Laggan–Tormore development was the inclusion of in-line tees in the flowlines to allow future tie-ins. This paper highlights the opportunities now available for further gas developments West of Shetland and describes the efforts performed by Total and its co-venturers during the period 2010–15 in order to take advantage of the new gas infrastructure. Three exploration wells were drilled by Total and its co-venturers around the facilities during this period. The Tomintoul well turned out to be dry despite a positive amplitude v. offset (AVO) anomaly. Edradour, whilst a gas discovery, was not big enough to make an economical tie-back to the Laggan–Tormore facilities. The third exploration well Spinnaker was disappointing. All undeveloped gas resources around the facilities were evaluated and Glenlivet was clearly the most attractive. Studies demonstrated that a joint Edradour–Glenlivet development would be economical; the Field Development Plan was approved in March 2015 and the Glenlivet development drilling campaign took place during the summer of 2015. Total continues an intensive exploration programme West of Shetland on its wide acreage, hoping to bring additional projects in the future.

Abstract Spectral decomposition analyses seismic reflectivity data in the frequency domain, providing images of the subsurface that complement conventional seismic interpretation. It is a highly visual tool that allows additional value to be extracted from seismic data, to aid in the identification of geological information and to be used in conjunction with more traditional methods such as amplitude extraction and attribute analysis. The methods of spectral decomposition chosen utilized a top reservoir seismic reflection surface, with the selected dominant frequency volumes coloured and recombined in a spatial context to produce various red–green–blue (RGB) blends. Application of spectral decomposition to the Laggan and Tormore fields revealed the varied distribution of turbiditic sands, as well as extensive east–west faults that have previously been inferred from seismic reflection data. These enhanced images of the reservoir provide a more detailed interpretation of the field architecture and have been captured in DONG E&P UK Ltd's own fault and reservoir models, leading to a greater understanding of potential field development outcomes and future well placement decisions. Attempts to distinguish hydrocarbon effects using spectral decomposition proved difficult, although interesting frequency variations around a known gas–oil contact (GOC) were noted.

Abstract The seismic geomorphology of a succession of alternating gravity-flow-dominated and bottom-current-dominated deposits along the continental slope and rise off western Nova Scotia demonstrates the importance of inherited geomorphology on subsequent deposition patterns in mixed turbidite and contourite depositional systems. In the study area, widespread mass wasting and channel incision during the Miocene created a steep ramp with a complex geomorphology along the lower continental slope. In the Late Miocene and Pliocene, a sediment drift was constructed on the continental rise, forming a 50-km-wide terrace that onlapped the steeper slope. The location, style, and evolution of sediment waves associated with this sediment drift appear strongly linked to the morphology of the underlying surface. The orientation and extent of wave crests show strong correspondence to underlying geomorphic elements, with the most prominent sediment waves forming downcurrent of seafloor perturbations like failure escarpments and salt diapirs. The erosional and constructional morphology of the contour-current-swept seafloor in turn strongly influenced the trajectory and response of subsequent down-slope-oriented submarine sediment gravity flows later in the Pliocene. Preferential accumulation took place above a regional terrace constructed as the sediment drift evolved, promoting deposition from sediment gravity flows that may have otherwise been transported into deeper water. The positive relief of wave crests guided sediment gravity flows down the slope, with erosion and deposition focused along wave troughs. This study highlights the complex feedback that exists between along-slope and down-slope constructional and degradational processes.

Abstract A seismic amplitude anomaly has been identified at the Upper Paleocene T38 level in the northern Judd Basin and will be tested by the drillbit in 2009. Prospectivity at shallower levels has been largely ignored due to the fact that the main regional seal in the area was recognized to be the T35/T36 mudstones below the Kettla Tuff. Seismo-stratigraphic analysis of the T38 sequence directly above the tuff marker has identified the potential for a new play type, especially adjacent to fault zones where these mudstones are breached, allowing hydrocarbons to migrate from the Upper Jurassic source kitchen into any traps identified above the seal. In this area, the T38 is represented by a series of northerly prograding low-angle clinoforms representing the final marine infill of sediments into the basin from the south. Erosion of top sets in a more marginal setting is observed, along with deposition of basin floor fans at the toe of the prograding clinoforms. The overlying seals are basinal sediments as well as mudstones and siltstones of subsequent progradational sequences. Mild structural modification of potential stratigraphic traps in the Judd Basin occurred during the Oligo-Miocene inversion associated with continued opening of the North Atlantic. Drilling seismic amplitude anomalies in the West of Shetlands area has often been unsuccessful. Therefore, a fully integrated geophysical and geological evaluation was carried out on the T38 anomaly comprising rock physics, amplitude variation with offset analysis, fault seal analysis and the acquisition of a CSEM survey which, supported by a valid geologic model, have reduced the risk from high to moderate. The results indicate that the anomaly has the potential to be sand-bearing and contain oil and gas. It is proposed that an integrated evaluation can reduce the level of uncertainty associated with an anomaly much more effectively and so improve the chance of exploration success.