Structural style and reservoir development in the West Netherlands oil province

Abstract

The area of the Rijswijk Concession largely coincides with the onshore part of the West Netherlands Basin. To date, oil has been produced from ten fields, with a total Stock Tank Oil Initially In Place (STOUP) of ca. 210 x 106 m3 (1.3 x 109 bbls). Reservoirs comprise continental and shallow marine clastics of Late Jurassic to Early Cretaceous age, deposited in syn-rift and post-rift settings. The West Netherlands Basin was created during Late Jurassic and Early Cretaceous rifting, characterised by divergent oblique-slip faulting. This created a NW - SE trending block-faulted depression between the London-Brabant Massif and the Zandvoort Ridge. Shallow marine clastics and marls were deposited in the subsequent post-rift stage. During the latest Cretaceous and Early Tertiary, regional uplift and convergent oblique-slip faulting resulted in basin inversion and reverse reactivation of pre-existing normal faults. Due to the transpressional nature of the basin inversion, narrow asymmetrical anticlines were formed, often bounded by upwardly divergent reverse faults, in the hanging-wall blocks of former normal faults. These structures constitute the general trap geometry of all Cretaceous oil fields in the basin. The acquisition of 3D seismic data has resulted in significantly enhanced structural definition and has led to the development of new structural and depositional models which improve the prediction of reservoir development and risk assessment.