DAKS™ Content Release

Highlights include:

Gannet Complex (UK) – Updated reports for four fields from the Gannet cluster; Gannets A-D, located in the Central North Sea, which produce oil and gas variously from Paleocene-Eocene Forties, Rogaland/Tay and Andrew submarine fan sandstones. The complex contains a total EUR of 377 MMBO and 609 BCF within seven individual fields (A-G), trapped mainly within salt-diapir anticlines except for Gannet A, the largest of the fields, containing EUR of 108 MMBO and 212 BCF within a compaction anticline. Recovery factors are 28-54% (oil) and up to 86% (gas). The fields are produced using horizontal wells and 4-D time-lapse seismic has been instrumental in tracking aquifer encroachment and targeting unswept oil zones with infill wells.

Grieve (USA) – Onstream since 1954, the field has a STOIIP of 68.4 MMBO and an EUR of 34.5 MMBO for a 50.4% recovery factor, occurring mostly in the Lower Cretaceous fluvial-estuarine Muddy sandstone. Average reservoir porosity and permeability are 20.4% and 220 mD. Light oil (37 °API) is trapped by lateral depositional pinch-out on a regional homocline. Production is mainly by gas-cap expansion aided initially by gas recycling and later by CO2 miscible flood.

Groningen (Netherlands) – Located onshore in the Permian Basin, this is the largest gas field in Europe with a GIIP of 114 TCF and EUR of 102 TCF, giving a 90% recovery factor. It contains a large gas column of 1250 ft trapped in Permian aeolian dune and fluvial sandstones of the Slochteren Formation, within a highly faulted horst structure. Reservoir quality with permeabilities up to 3 D, is best in dune sandstones and there is only one significant flow barrier in the north. This excellent connectivity has resulted in high well EURs of ~310 BCF/well from >300 producers. Production was capped owing to concerns with production-induced seismicity and the field was largely shut-in in 2023 having produced ~78 TCF. Abandonment is scheduled for October 2024.

Romashkino (Russia) – A textbook-class field in the Volgal-Ural Basin boasts a STOIIP of 38.8 BBO and an EUR of 23.3 BBO (recovery factor 60%) in the main Pashiy-Kynov and 21 minor reservoirs. Production of the light oil began in 1952 by water injection adopting a stepwise development strategy due to the vast field area (>4000 km2) in a gentle anticline. A variety of IOR methods have found their applications in the field, including infill and step-out drilling, pattern- and cyclic water injection, high-salinity waterflood, hydraulic fracturing, sidetracking, extended-reach drilling, and chemical injection. By end-2000, the field had produced 16.2 BBO, 15.1 BBO from the Pashiy-Kynov reservoir.

Sabalo (Bolivia) – Onstream since 2003, most reserves occur in the Lower Devonian Huamampampa-Icla reservoir, which has a GIIP of 7371 BCF and CIIP of 181 MMBC with an EUR of 4974 BCF (68% RF) and 86 MMBC (48% RF). A 1444 m gas-condensate column is contained in an anticline within three thrust sheets by faulting and dip-closure. Production is from highly fractured offshore and coastal bar sandstones with a bulk porosity of 3.2% and well-test permeability of 57 mD. Recovery by gas-expansion drive has been improved by horizontal drilling.

Widuri (Indonesia) – Located offshore SE Sumatra, the field came onstream in 1990. It has a STOIIP of 758 MMBO and an EUR of 376 MMBO (recovery factor ~50%). A 325-ft oil column is trapped in a drape anticline closed by a combination of structural and stratigraphic elements. 82 ft of net pay occurs in unconsolidated, fine- to coarse-grained sandstones, which are well-connected at the base, becoming increasingly isolated up the section. Horizontal wells with gravel packs have proved effective in countering sand production and water coning. While 3-D seismic imaging has been instrumental in mapping sandbody geometry and connectivity, 4-D seismic has been used effectively to monitor fluid movement. By end-2013, the field had produced 361 MMBO.

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Updated/rewritten reports:

All the reports included in this release were chosen for updating due to the publication of significant new engineering information, new production data, new reserve/resource information and/or revised geological models. This update includes a wide global spread of reports, including: 15 from Latin America, 12 from Africa, 10 from North America, 7 from Russia and the Caspian, 6 from Europe, 5 from the Middle East, and 3 from Asia-Pacific.

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