Constraining diagenetic timings, processes and reservoir quality in igneous-affected basins

• Main Author: CLARK, SAMANTHA,JEAN
• Format: Thesis
• Language: unknown
• Published: 2014
• Subjects: volcaniclastic; diagenesis; reservoir quality; igneous-affected basins; Rosebank; Staffa Formation; Mull; North Atlantic
• Online Access: http://etheses.dur.ac.uk/10827/; http://etheses.dur.ac.uk/10827/1/SamanthaClarkThesis2014.pdf; http://etheses.dur.ac.uk/10827/2/Supplementary_information.pdf

As the demand for hydrocarbons increases, more complex, non-conventional plays have been targeted in volcanic margin settings. Consequently, it is important to understand the role igneous rocks have in affecting hydrocarbon systems. This is particularly relevant to the Rosebank Field, offshore UK Continental Shelf, North Atlantic. The field was discovered in 2004 with the 213/27-1z well and encountered Palaeogene volcanic rocks interbedded with siliciclastic and volcaniclastic rocks, representing a brand new play type. Three appraisal wells were drilled and encountered good quality light oil (37° API) with drill steam tests achieving ~ 6000 STB per day (Duncan et al., 2009). Initially four companies had a stake in the field; Chevron (40%), Statoil (30%), OMV (20%) and Dong (10%) however in 2011, OMV bought out Statoil leaving them with a 50% stake. Chevron remain the operators. The importance of volcaniclastic sediments within these sequences has previously been overlooked and so a better understanding of how these rocks behave during burial is essential. This research quantitatively characterises and assesses the reservoir potential of a range of volcaniclastic and siliciclastic sedimentary rocks within such basins. The Rosebank Field comprises a range of volcaniclastic lithic arenites and lava flows interbedded with sublithic arenites and quartz arenites. However samples could only be taken from limited the limited cores. This made interpreting 3D architecture difficult and therefore it was decided that a onshore analogue was required. The Staffa Formation of the Palaeogene Mull Lava Field, NW Scotland, provides an excellent analogue to the Rosebank Field within the Faroe-Shetland Basin. It comprises basaltic lava flows interbedded with a variety of volcaniclastic and sedimentary rocks. A range of rock types occur within the Staffa Formation, including vent-proximal pyroclastic rocks, such as massive scoria rich tuffs to re-worked volcaniclastic lithic arenites to vent-distal facies where the siliciclastic ...