A New Look at the Middle to Lower Cretaceous Stratigraphy, Offshore Kuwait

Abstract

Offshore exploration in Kuwait commenced in 1961 with the award of a 5,600 square kilometre offshore concession to Shell. Some 6,300 kilometres of 3-fold analogue seismic were acquired in 1961, and 3 wells were drilled during 1962 and 1963. In the same period, Kuwait Oil Company (KOC) also drilled their first 3 offshore exploration wells. In 1981, KOC embarked upon a second offshore exploration campaign, acquiring some 6,000 kilometres of seismic data and, during 1983 and 1984, drilling two wells. None of these wells was a commercial discovery. Between 1995 and 1997, an integrated team of KOC and Shell explorers undertook a review of the hydrocarbon potential of Offshore Kuwait. In order to establish an integrated sequence-stratigraphical framework for the prospective Lower to Middle Cretaceous interval, a quantitative biostratigraphical study was made. Some 790 biostratigraphical analyses (10% core samples; 90% cuttings) from eleven wells were carried out: the nanno-fossil data was particularly important in providing accurate chronostratigraphical calibration, and this data has been used to constrain a “Time-Rock Synopsis”. KOC’s lithostratigraphical nomenclature proved to be basically sound and has been maintained as the basis for the present stratigraphical framework. However, the study revealed the existence of two substantial and hitherto unsuspected hiati: one between the Ratawi and Zubair formations of Early Valanginian to Mid-Hauterivian age; and the other, representing the whole of the Early Albian, within the Burgan Formation. This latter result, if it can be further substantiated by more exhaustive study in the onshore area, would neccessitate a re-definition of the Burgan Formation and the erection of a new formation to describe the clastic sequence of Late Aptian age which lies between the Early Albian hiatus and the top of the Shu’aiba Formation, and which has hitherto been included within the Lower Burgan Formation.

Study of Light and Heavy Minerals and Their Effect on Oil Aggregation in the Zubair Formation for the Rumaila Oil Field in Southern Iraq

“…These subzone structures are long and relatively narrow anticlines separated by broader synclines, particularly in the east. The huge sandstone amount of Zubair formation (reservoir) results from erosion of the western Arabian Shield and the uplift in the Early Cretaceous [24]. It is difficult to determine the exact contact location of the rock outcrops in the extreme southeast of Iraq because of the thick layers that cover these outcrops from the Quaternary sediments [25], (Figure 2).…”

Marine Geology of Kuwait

“…4.6). Those data were used to perform a detailed paleoenvironmental and chronostratigraphic calibration of this data series (Al-Fares et al, 1998).…”

Provenance and Tectonic Setting of Late Lower Cretaceous (Albian) Kazhdumi Formation Sandstones (SW Iran)

“…Al-Fares [24] reported the existence of a major hiatus within the Albian clastics (traditionally named Burgan Formation). Subsequently, he suggested a redefinition of the Burgan Formation in offshore Kuwait.…”

“…Kazhdumi Formation is separated from the underlying Dariyan (Shuaiba) Formation by a regional erosional unconformity of late Aptian age (Figure 3). Scott et al [25] recognized duration of the unconformity around 2.2 million years, whereas Alfares et al [24]…”