QUAD 53 - SOUTHERN NORTH SEA

NON-EXCLUSIVE PROJECT

Project Background and Objectives

Despite the close proximity to the huge S North Sea gas fields, and the potential for accumulation of hydrocarbons generated from known Carboniferous source rocks, to date most of Quad 53 has been only lightly explored by drilling. The absence of thick Zechstein salts makes the traditional Permian gas reservoir targets potentially more risky than in the areas to the north, but other parts of the section including the Carboniferous remain prospective. The basin margin setting and the potential for hydrocarbon generation over a long period of geological time make proper assessment of thermal history, the timing of maturity development and the timing of major episodes of structuring, uplift and erosion a vital part of prospect evaluation in this region.

The history of maturity development in the Carboniferous section, and the timing and amount of uplift and erosion during the main tectonic phases are critical and presently unknown factors. Maturity modelling using stratigraphic, structural and geochemical data is greatly hampered here by the difficulties in reconstructing reliable burial histories, due to the episodes of deep erosion which have removed most of the Jurassic and the upper parts of the Lower Cretaceous sections. In addition, extensive AFTA studies carried out by Geotrack in Quads 48 and 49 have revealed major erosional episodes in the early and mid Tertiary, which might also have significant effects in the Quad 53 region.

This project aims to resolve these problems by acquiring direct data on the Carboniferous to Tertiary thermal history by AFTA integrated with new high quality vitrinite reflectance data. The objectives include recognition of the major thermal episodes affecting the Carboniferous section through the basin's history; quantification of the timing and magnitude of maximum or peak paleotemperatures and the degree of maturity attained during each thermal episode; measurement of paleogeothermal gradients and estimation of the timing and amount of uplift and erosion at each study well location; recognition of any non-burial related thermal effects, caused for example by heat flow variation or fluid movement; regional synthesis of thermal, burial and uplift history and implications for maturity development and oil and gas generation.

The thermal history techniques developed by Geotrack provide a unique method for reconstruction of thermal and burial history in this geological setting. AFTA includes microprobe measurement of apatite composition for each grain analysed. The data are rigorously interpreted using the multi-compositional apatite annealing model to ensure the best resolution of time-temperature history that modern methods allow. The vitrinite reflectance data will be produced to a high standard using the exacting Romax method by Prof. Alan Cook.

Database

The project is based on new AFTA results from approximately 60 samples and new vitrinite reflectance data from approximately 165 samples from the following 17 Southern North Sea wells:

52/5-1, 52/5-11, 53/1-6, 53/1-2, 53/2-5, 53/4-4, 53/4-2, 53/7-1, 53/7-2, 53/8-1, 53/10-1 53/12-1, 53/14-1, 53/16-1, 53/19-1, 54/1-1, 54/11-1

Stratigraphic and present-day temperature data from each of the above wells and regional structural and stratigraphic information will also be taken account of in data interpretation and modelling of thermal and burial/uplift histories.

For further details please contact us