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The impact of diagenesis on the heterogeneity of sandstone reservoirs: A review of the role of depositional facies and sequence stratigraphy
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
King Fahd Univ Petr & Minerals, Dept Earth Sci, Dhahran, Saudi Arabia .
2010 (English)In: American Association of Petroleum Geologists Bulletin, ISSN 0149-1423, Vol. 94, no 8, 1267-1309 p.Article in journal (Refereed) Published
Abstract [en]

Diagenesis exerts a strong control on the quality and heterogeneity of most elastic reservoirs. Variations in the distribution of diagenetic alterations usually accentuate the variations in depositional porosity and permeability. Linking the types and distribution of diagenetic processes to the depositional facies and sequence-stratigraphic framework of clastic successions provides a powerful tool to predict the distribution of diagenetic alterations controlling quality and heterogeneity. The heterogeneity patterns of sandstone reservoirs, which determine the volumes, flow rates, and recovery of hydrocarbons, are controlled by geometry and internal structures of sand bodies, grain size, sorting, degree of bioturbation, provenance, and by the types, volumes, and distribution of diagenetic alterations. Variations in the pathways of diagenetic evolution are linked to (1) depositional facies, hence pore-water chemistry, depositional porosity and permeability, types and amounts of intrabasinal grains, and extent of bioturbation; (2) detrital sand composition; (3) rate of deposition (controlling residence time of sediments at specific near-surface, geochemical conditions); and (4) burial thermal history of the basin. The amounts and types of intrabasinal grains are also controlled by changes in the relative sea level and, therefore, can be predicted in the context of sequence stratigraphy, particularly in paralic and shallow marine environments. Changes in the relative sea level exert significant control on the types and extent of near-surface shallow burial diagenetic alterations, which in turn influence the pathways of burial diagenetic and reservoir quality evolution of elastic reservoirs. Carbonate cementation is more extensive in transgressive systems tract (TST) sandstones, particularly below parasequence boundaries, transgressive surface, and maximum flooding surface because of the abundance of carbonate bioclasts and organic matter, bioturbation, and prolonged residence time of the sediments at and immediately below the sea floor caused by low sedimentation rates, which also enhance the formation of glaucony. Eogenetic grain-coating berthierine, odinite, and smectite, formed mostly in TST and early highstand systems tract deltaic and estuarine sandstones, are transformed into ferrous chlorite during mesodiagenesis, helping preserve reservoir quality through the inhibition of quartz cementation. The infiltration of grain-coating smectitic clays is more extensive in braided than in meandering fluvial sandstones, forming flow barriers in braided amalgamated reservoirs, and may either help preserve porosity during burial because of quartz overgrowth inhibition or reduce it by enhancing intergranular pressure dissolution. Diagenetic modifications along sequence boundaries are characterized by considerable dissolution and kaolinization of feldspars, micas, and mud intraclasts under wet and warm climates, whereas a semiarid climate may lead to the formation of calcrete dolocrete cemented layers. Turbidite sandstones are typically cemented by carbonate along the contacts with interbedded mudrocics or carbonate mudstones and marls, as well as along layers of concentration of carbonate bioclasts and intraclasts. Commonly, hybrid carbonate turbidite arenites are pervasively cemented. Proximal, massive turbidites normally show only scattered spherical or ovoid carbonate concretions. Improved geologic models based on the connections among diagenesis, depositional facies, and sequence-stratigraphic surfaces and intervals may not only contribute t optimized production through the design of appropriate simulation models for improved or enhanced oil recovery strategies, as well as for CO2 geologic sequestration, but also support more effective hydrocarbon exploration through reservoir quality prediction.

Place, publisher, year, edition, pages
2010. Vol. 94, no 8, 1267-1309 p.
National Category
Earth and Related Environmental Sciences
URN: urn:nbn:se:uu:diva-94611DOI: 10.1306/04211009178ISI: 000280654400007OAI: oai:DiVA.org:uu-94611DiVA: diva2:168511
Available from: 2006-05-05 Created: 2006-05-05 Last updated: 2013-09-25Bibliographically approved
In thesis
1. Impact of Diagenetic Alterations on Reservoir Quality and Heterogeneity of Paralic and Shallow Marine Sandstones: Links to Depositional Facies and Sequence Stratigraphy
Open this publication in new window or tab >>Impact of Diagenetic Alterations on Reservoir Quality and Heterogeneity of Paralic and Shallow Marine Sandstones: Links to Depositional Facies and Sequence Stratigraphy
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis constrains the distribution of diagenetic alterations and their impact on reservoir-quality and heterogeneity evolution pathways in relation to depositional environments and sequence stratigraphy (systems tracts and key sequence stratigraphic surfaces) of four selected paralic and shallow marine siliciclastic successions.

Typical eogenetic alterations encountered include the dissolution and kaolinitization of framework silicates, which are closely associated to shoreface facies of forced regressive systems tract (FRWST), lowstand systems tract (LST), upper part of the highstand systems tract (HST), and below the sequence boundary (SB). These alterations are attributed to incursion of meteoric water owing to rapid and considerable fall in the relative sea level. Extensive carbonate cementation is most evident below marine and maximum flooding surfaces (MFS), whereas dissolution of carbonate cement and detrital dolomite occur in LST, HST and below SB. Parameters controlling the patterns and texture (microcrystalline vs. poikilotopic) of calcite cement have been constrained within sequence stratigraphic framework of the sandstones. Coarse crystalline to poikilotopic calcite textures of meteoric water origin are thus closely linked to the FRWST, LST and upper part of the HST sandstones and occur mainly as stratabound concretions, whereas microcrystalline calcite, which was precipitated from marine porewaters, occurs as continuously cemented layers in the transgressive systems tract (TST) and lower part of the HST sandstones.

Eogenetic alterations impose, in turn, profound control on the distribution pattern of mesogenetic alterations, and hence on reservoir quality evolution (destruction vs. preservation) pathways of sandstones. Eogenetic infiltrated clays, which occur in the tidal estuarine TST and HST sandstones, have helped preserving porosity in deeply buried sandstone reservoirs (≈ 5 km) through inhibition of extensive cementation by quartz overgrowths. Other essential findings of this thesis include deciphering the control on the formation of authigenic illite and chlorite by ultra-thin (≤ 1 µm thick), grain-coating clay mineral substrate.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 57 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 195
Bedrock geology, Siliciclastic, Diagenesis, Sequence stratigraphy, Paralic and shallow marine, Heterogeneity, Reservoir quality, Berggrundsgeologi
urn:nbn:se:uu:diva-6928 (URN)91-554-6588-9 (ISBN)
Public defence
2006-05-31, Hambergssalen, Geocentrum, Villavägen 16, Uppsala, 10:00
Available from: 2006-05-05 Created: 2006-05-05Bibliographically approved

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