1. Compaction and Rock Properties of Cenozoic Mudstones in the Quadrant 15, Offshore Norway
- Author
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M. Koochak Zadeh, Nazmul Haque Mondol, and Jens Jahren
- Subjects
Graben ,Sedimentary depositional environment ,Provenance ,Illite ,Compaction ,engineering ,engineering.material ,Petrology ,Hydrocarbon exploration ,Cenozoic ,Geology ,Diagenesis - Abstract
Compaction and evolution of rock properties of Cenozoic mudstones are investigated in the Quadrant 15, offshore Norway. The study area is a normally subsided basin located in the southern Viking Graben of the Norwegian North Sea. A suite of well log data from 41 exploration and appraisal wells is utilised to study the compaction behaviour of Cenozoic mudstones. The detailed petrophysical analyses suggest the occurrence of high quantities of smectite in the Eocene and Oligocene sediments, in general agreement with previous publications. The transition from mechanical to chemical compaction takes place between 70-90oC corresponding to depth 2-2.5 km. The geothermal gradient is higher in the south of the study area but, temperature alone is not sufficient to explain chemical diagenesis in the area. Initial mineralogy seems to be as important as temperature with respect to cementation. The degree of chemical compaction and cementation reflects the initial smectite content and the availability of potassium for the reaction of smectite to illite and quartz to take place. The overall results of this study contribute to delineate compaction processes controlled by geological processes (e.g. provenance and depositional environments) in a highly prosperous region in terms of hydrocarbon exploration and production.
- Published
- 2014