Relationships between stylolites and cementation in sandstone reservoirs: Examples from the North Sea, U.K. and East Greenland Martin Baron ⁎ , John Parnell Department of Geology and Petroleum Geology, Meston Building, University of Aberdeen, King's College, Aberdeen, AB24 3UE, UK Received 14 November 2005; received in revised form 26 April 2006; accepted 28 April 2006 Abstract The reservoir potential of hydrocarbon sandstone reservoirs may be significantly reduced by compartmentation as a result of the development of stylolites. A petrographic and fluid inclusion microthermometric study was performed on sandstones containing abundant stylolites from the Buchan, Galley and Scott Fields in the Outer Moray Firth, offshore Scotland, and from a palaeo-oil bearing sequence in East Greenland. The main objective of this study was to further constrain the temperatures and burial depths at which stylolitization occurs in sandstone reservoirs. The sandstones containing abundant stylolites are also characterized by their highly cemented nature. Numerous occurrences of quartz overgrowths clearly truncated by sutured stylolites are evident in all of the samples. Fluid inclusion microthermometry reveals that quartz cementation, which is interpreted to be coeval with stylolitization, occurred at minimum temperatures of between 86 and 136 °C. Basin modelling of the Scott and Galley Fields indicates that quartz cementation and stylolite development formed at depths greater than 2.5 km which were attained during rapid Tertiary burial. The occurrence of hydrocarbon fluid inclusions within healed microfractures orientated at high angles to the stylolites suggests that these microfractures provided pathways for hydrocarbon migration in the highly cemented, low permeability zones associated with highly stylolitized sandstones. © 2006 Elsevier B.V. All rights reserved. Keywords: Stylolites; Diagenesis; Fluid inclusions; Basin modelling 1. Introduction Pressure solution is the process by which material is removed by solution or diffusion from a discrete surface, the sides of which remain in close contact (Groshong, 1988). Pressure solution in sandstones is commonly divided into two types: intergranular pres- sure solution and stylolitization. Intergranular pressure solution (sometimes referred to as grain-to-grain stylo- litization) takes the form of adjacent detrital grains having interpenetrating sutured or smooth contacts (Trurnit, 1968). In contrast, stylolites are intergranular serrated surfaces that are lined by insoluble constituents of the enclosing rock (Tada and Siever, 1989). Both the processes are the same; the only difference is one of scale. Stylolites are common in carbonates and sandstones, but are also known to occur in a variety of other rock types, including cherts (Cox and Whitford-Stark, 1987), pegmatites and other igneous rocks (Burg and Ponce de Leon, 1985). They can be divided in to those which are Sedimentary Geology 194 (2007) 17 – 35 www.elsevier.com/locate/sedgeo ⁎ Corresponding author. Present address: Badley Ashton and Associates, Winceby House, Winceby, Horncastle, Lincolnshire, LN9 6PB, UK. E-mail address: martinbaron@badley-ashton.co.uk (M. Baron). 0037-0738/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.sedgeo.2006.04.007