Abstract Deep-marine gravity-driven deposits represent one of the more investigated depositional systems owing to their potential interest as targets for exploration and carbon capture and storage activities, as well as an important record of the depositional history of a basin through time. Although the Halten Terrace (Norwegian Sea) is one of the main successful exploration areas, we still have poor understanding of the post-rift Cretaceous interval. Here, 3D seismic reflection and borehole data are integrated to investigate the stratigraphic distribution and sedimentological characteristics of the Cenomanian–Turonian intra Lange Sandstones in the Gimsan Basin and Grinda Graben. The Lange Fm records the deposition in a deep-marine environment of a 1000 m-thick shale unit punctuated by gravity-driven coarse-grained sandstone intervals that are tens of metres-thick and sourced from the Norwegian mainland. The presence of gravity-driven deposits and the deep-marine setting are supported by seismic interpretation, architectural elements and the facies analysis of cored material acquired within the studied stratigraphic interval. Borehole data indicate the presence of both turbidites and hybrid-event beds rich in mud content. The results of this study have implications for understanding the distribution and reservoir potentiality of the Late Cretaceous Lange Fm in the Halten Terrace.

Abstract Geologic Problem Solving with Microfossils: A Volume in Honor of Garry D. Jones SEPM Special Publication No. 93, Copyright © 2009 SEPM (Society for Sedimentary Geology), ISBN 978-1-56576-137-7, p. 21–27. Biostratigraphy is making a significant contribution to value creation and realization when planning and drilling hydrocarbon development wells. Biosteering production wells provides the support to enable operators to drill more ambitious and technically challenging wells with increased levels of confidence. Precise biostratigraphic and lithostratigraphic control whilst drilling increases safety, saves money, and greatly increases the long-term potential of production wells at relatively small cost. Following the completion of four exploration and appraisal wells, the Kristin Field is currently under development utilizing twelve either highly deviated or horizontal production wells that are technically challenging and expensive to drill. Biostratigraphy, and in particular micropaleontology, is helping with both of these issues by providing quantitative real-time wellsite stratigraphic support, increasing confidence in the placement of casing shoes, by ensuring that wells are landed at the correct stratigraphic level with the correct hole angle, and by negating the necessity for costly lookahead vertical seismic profiles (VSPs). Depth of burial and thermal maturity precludes the use of palynology through most of the Kristin Mesozoic well sections. Micropaleontology has therefore been utilized as a stand-alone tool for stratigraphic calibration of the Upper Cretaceous Intra Lange Sands, the Lower Cretaceous “Albian Shale”, and the Middle Jurassic Melke Formation, all of which are critical in terms of drilling operations on the field.

Abstract In this paper we demonstrate the benefits of 3D seismic visualization techniques for fault interpretation where the structural geology is complex and the seismic data quality is often poor. Production from the Njord field is strongly influenced by a complex pattern of segmented and linked extensional faults. The current interpretation of the well test data and production history is that the faults form barriers to fluid flow, reducing oil production, and limiting effective gas injection and pressure support. Drilling results demonstrate that geometrical uncertainties remain in the seismic interpretation. An additional problem is that currently available commercial reservoir modelling technology cannot easily handle a very complex fault pattern, making simulation grid construction difficult. Accurate well placement and production forecasting requires that fault geometries and properties are suitably represented in the reservoir simulation model. 3D visualization of depth-scaled volumes and depth-converted interpretations helped to decide how to best simplify the fault geometry for simulation, and compare automatically generated geological model components against seismic interpretations and data. The reservoir simulation model runs resulted in the identification of a number of well targets. 3D visualization techniques were then used to predict faults and structures that the proposed well trajectories may intersect.