Multi-Scale Characterization and Modeling of Heterolithic Tidal Systems, Offshore Mid-Norway

Abstract

The Lower Jurassic Tilje Formation on the Halten Terrace, offshore mid-Norway, forms an important reservoir in a number of hydrocarbon fields. A high volume fraction (80 percent) of the formation is heterolithic in nature, showing various styles of sandstone-mudstone intercalated bedding at several scales. The depositional model is based on a general facies classification scheme applicable to all fields. The stratigraphic interval discussed was deposited in a narrow basin during overall rising relative sea level as a tide/wave-dominated, mud-rich delta with well-developed prodelta, delta-front, and estuarine-type distributary-channel facies. The main heterolithic deposits are found in the prodelta, delta-front, and distal parts of the estuarine-type distributary-channel-mouth areas, whereas relatively “clean” facies occur in medial areas of these distributaries. Lithofacies associations are modeled in 3D using stochastic, object-based methods, and the heterolithic architecture at the lithofacies scale is modeled using a process-based sedimentary architecture tool. Multiple data sources (core, log, and outcrop-analogs) are used to establish a data-rich procedure for estimating the effective reservoir properties within a step-wise upscaling procedure. Our results show the importance of integrating multiscale data with good sedimentary models to accurately estimate reservoir properties in these heterolithic formations. We derive effective property functions (for example kv/kh) for different facies and identify important reservoir flow units using flow simulations of stochastic realizations.

Axisymmetric gravity currents in anisotropic porous media

“…Before discussing the flow scenario, we first briefly discuss the geological context of anisotropy in porous media. In subsurface geological reservoirs it is common for the permeability of rocks to differ significantly depending on the direction of the flow (Corbett & Jensen 1992;Martinius et al 1999). This may result from post-depositional compaction of the formation or from the deposition of successive layers of fine and coarse material.…”

“…If one extends the analysis to account for different permeabilities in the horizontal and vertical directions, k H and k V , the assumption of hydrostatic pressure in the flow means that the vertical permeability does not feature in the solution, which is the same as for the isotropic case. This is curious since the vertical permeability of the porous medium may be much smaller than the horizontal permeability owing to the original geological processes of formation and compaction of the medium (Corbett & Jensen 1992;Martinius et al 1999;Woods 2015). The key to this apparent paradox is to assess the vertical pressure gradient required to drive the vertical flow which is implicit in the gravity current solution.…”

Three-dimensional reservoir characterization and flow simulation of heterolithic tidal sandstones

“…A normalized permeability of unity corresponds to an effective permeability equal to the sandstone permeability (k s ), whereas a normalized permeability of zero corresponds to an effective permeability equal to the mudstone permeability (k m ). The normalized effective permeability of each rock specimen model was calculated for a range of sandstone/mudstone permeability ratios, which are representative of those measured in analogous subsurface facies using a minipermeameter on slabbed cores (e.g., Martinius et al, 1999).…”

Sedimentology and Seismic Geomorphology of the Tidaldominated Estuarine Incised Valley Fill: Late Miocene Qawasim Reservoir, Onshore East Nile Delta

“…The importance of tidal deposits as hydrocarbon reservoirs have been recognized over the last decade in different parts of the world (e.g., Wightman and Pemberton, 1997;Marjanac and Steel, 1997;Martinius et al, 2001). The tidal deposits form some of the largest and most architecturally complicated hydrocarbon fields (Verdier et al, 1980;Carneiro de Castro, 1983;Marjanac & Steel, 1997;Higley, 1994;Ambrose et al, 1995;White et al, 1995;White and Barton, 1999;Martinius et al, 2000). Literature on tide-dominated or tide-influenced sedimentary systems, and generally on estuaries, is particularly vast.…”