Spatial variability in depositional reservoir quality of deep-water channel-fill and lobe deposits

Autor: Anna Pontén, Stephen S. Flint, Daniel Bell, David M. Hodgson, Bonita J. Barrett, Ian A. Kane
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Bell, D, Kane, I, Ponten, A, Flint, S, Hodgson, D M & Barrett, B J 2018, ' Spatial variability in depositional reservoir quality of deep-water channel-fill and lobe deposits ', Marine and Petroleum Geology, vol. 98, pp. 97-115 . https://doi.org/10.1016/j.marpetgeo.2018.07.023
ISSN: 0264-8172
Popis: Initial porosity and permeability in deep-water systems are controlled by primary sedimentary texture and mineralogy. Therefore, understanding the sedimentary processes that control changes in primary texture is critical for improved reservoir quality predictions. A well-constrained, exhumed submarine lobe in the Jaca Basin, and a submarine channel-fill element in the Ainsa Basin, northern Spain, were studied to characterize the depositional reservoir quality in axial to marginal/fringe positions. Construction of architectural panels and strategic sampling enabled analysis of the spatial changes in textural properties, and their relationship to reservoir quality distribution. Samples were analyzed in thin-section to establish how depositional processes inferred from outcrop observations affect textural properties. Results show that high-density turbidites are concentrated in lobe- and channel-axis positions and exhibit good depositional reservoir quality. Lobe off-axis deposits contain high- and low-density turbidites and have moderate depositional reservoir quality. Conversely, low-density turbidites dominate lobe fringe and channel-margin positions and have relatively poor depositional reservoir quality. There is a sharp decrease in depositional reservoir quality between the lobe off-axis and lobe fringe due to: 1) an abrupt increase in matrix content; 2) an abrupt decrease in sandstone amalgamation; and 3) a decrease in grain-size. There is an abrupt increase in depositional reservoir quality from channel margin to channel axis corresponding to: 1) an increase in total sandstone thickness and amalgamation; 2) an increase in grain-size, 3) a decrease in matrix content. Rates of change of key properties are up to two orders of magnitude greater between channel-fill sub-environments compared to lobe sub-environments. Spatial variability in properties of discrete architectural elements, and rates of changes, provides input to reservoir models during exploration, appraisal, and development phases of hydrocarbon fields.
Databáze: OpenAIRE
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