QUAD 53 - SOUTHERN
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.
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:
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
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
For further details please contact