General information Attribute Value Lithostrat. unitThe lithostratigraphic unit's official name.HAUGESUND FM NPDID lithostrat. unitNPD's unique id for lithostratigraphic units.57 LevelIndicates the lithostratigraphic unit's level. Legal values: GROUP, FORMATION, MEMBER.FORMATION Lithostrat. unit, parentThe parent lithostratigraphic unit's official name. See also level. Will be empty if Level = GROUP.
Level belowLithostrat. unit
NameAfter the town of Haugesund on the west coast of Norway.Well type sectionNorwegian well 2/7-3 (Phillips) from 3695 to 4191 m, coord N 56°23'02.9", E 03°15'45.9'7, (Fig 3.40) .
See “remarks” for qualification of this well type section.Well reference sectionsNorwegian well 3/5-2 (Gulf) from 3182.5 to 3345 m, coord N 56°32', 56°32'34.46", E 04°23 '11.1", (Fig 3.42) . and 2/8-3 (Amoco) from 3761 m to 4115 m (TD.), coord N 56°18'31", E03°26'54.1", (Fig 3.41) .Thickness496 m in the type well, 162.5 m in 3/5-2 , and 354 m in 2/8-3 . The formation is thickest in the axis of the Central Graben and thins towards the flanking highs, where it passes partially or entirely into the sandy lithology of the Ula Formation .LithologyThe Haugesund Formation consists predominantly of shale ranging in colour from light grey to brownish black. The shale is often carbonaceous and calcareous, and contains frequent thin sandstone interbeds. In general the upper part of the formation represents an overall "coarsening-upward cycle", becoming sandier and siltier upwards.BoundariesIn the type well, 2/7-3 , the Haugesund Formation overlies Zechstein salt and the base of the formation is therefore obvious from both logs and cuttings. However, the Zechstein salt is almost certainly penetrative at this location and does not therefore provide a true stratigraphic base for Haugesund Formation (see “remarks”). In the reference well 2/8-3 and elsewhere in the Central Graben the base of the Haugesund Formation is often found overlying the Vestland Group . This is shown in the reference well 3/5-2 where the upward change from the sandy Bryne Formation to the shales of the Haugesund Formation produces the expected gamma ray/sonic log break (see (Fig 3.42) .
The top of the Haugesund Formation in the type well is the contact with the sandy Eldfisk Formation . In areas of the Central Graben where the Eldfisk Formation is absent, the top of the Haugesund Formation is picked at a clearly correlatable gamma ray minimum, above which the gamma ray increases to the higher values of the basal Farsund Formation (e.g. well 2/8-3 ).DistributionThe formation is ubiquitous in the Central Graben and widely distributed around the flanks of the basin and intra-basinal highs. It is absent in the Ula Field where it is entirely replaced by time-equivalent sands of the Ula Formation , and is also absent on the crest of the Southern Vestland Arch and intra-basinal highs.AgeCallovian to Early Kimmeridgian. In neither the type nor the reference wells have pre-late Oxfordian ages been proven but Callovian mudstones assignable to the Haugesund Formation occur in the vicinity of the reference well 3/5-2 .Depositional environmentThe bulk of the shales of the Haugesund Formation were deposited in a marine, low energy, basinal environment. The common thin sand interbeds may represent sporadic turbidite influxes emanating from the adjacent shelf where coarser elastics (i.e. the Ula Formation ) were being deposited. The "coarsening-upward" nature of the sequence represents an overall regression which was terminated by a further transgression and the deposition of the Farsund Formation shales.RemarksThe type well 2/7-3 penetrated a thick development of the Haugesund Formation, considered to be typical of the formation as it is commonly encountered in the Central Graben. However, the inadequately defined base of the formation makes 2/7-3 ultimately unsatisfactory as a type well. None of the other Central Graben wells available to this study establish a base for this formation, and penetrations on the flanks of the basin (such as the reference well 3/5-2 are fewer, atypical and potentially controversial stratigraphically. Penetration of a well-defined base for the Haugesund Formation by a future well in the Central Graben would perhaps provide a rare instance in which replacement of a type well might be justified.Source
Vollset, J. and Doré, A. G. (eds.) 1984: A revised Triassic and Jurassic lithostratigraphic nomenclature for the Norwegian North Sea. NPD-Bulletin No. 3, 53 pp.
Wellbores with cores