Diagenetic evolution of a shallow marine Kimmeridgian carbonate ramp (Jabaloyas, NE Spain): implications for hydrocarbon reservoir quality

2017 ◽  
Vol 10 (16) ◽  
Author(s):  
Galo San Miguel ◽  
Marcos Aurell ◽  
Beatriz Bádenas
Keyword(s):  
Carbonate Ramp ◽  
Reservoir Quality ◽  
Shallow Marine ◽  
Hydrocarbon Reservoir ◽  
Diagenetic Evolution ◽  
Ne Spain

scholarly journals Reservoir Quality of Upper Jurassic Corallian Sandstones, Weald Basin, UK

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 446
Author(s):  
Dinfa Vincent Barshep ◽  
Richard Henry Worden
Keyword(s):  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Upper Jurassic ◽  
Reservoir Quality ◽  
Main Process ◽  
Shallow Marine ◽  
Porosity And Permeability ◽  
Calcite Cement ◽  
Diagenetic Evolution

The Upper Jurassic, shallow marine Corallian sandstones of the Weald Basin, UK, are significant onshore reservoirs due to their future potential for carbon capture and storage (CCS) and hydrogen storage. These reservoir rocks, buried to no deeper than 1700 m before uplift to 850 to 900 m at the present time, also provide an opportunity to study the pivotal role of shallow marine sandstone eodiagenesis. With little evidence of compaction, these rocks show low to moderate porosity for their relatively shallow burial depths. Their porosity ranges from 0.8 to 30% with an average of 12.6% and permeability range from 0.01 to 887 mD with an average of 31 mD. The Corallian sandstones of the Weald Basin are relatively poorly studied; consequently, there is a paucity of data on their reservoir quality which limits any ability to predict porosity and permeability away from wells. This study presents a potential first in the examination of diagenetic controls of reservoir quality of the Corallian sandstones, of the Weald Basin’s Palmers Wood and Bletchingley oil fields, using a combination of core analysis, sedimentary core logs, petrography, wireline analysis, SEM-EDS analysis and geochemical analysis to understand the extent of diagenetic evolution of the sandstones and its effects on reservoir quality. The analyses show a dominant quartz arenite lithology with minor feldspars, bioclasts, Fe-ooids and extra-basinal lithic grains. We conclude that little compactional porosity-loss occurred with cementation being the main process that caused porosity-loss. Early calcite cement, from neomorphism of contemporaneously deposited bioclasts, represents the majority of the early cement, which subsequently prevented mechanical compaction. Calcite cement is also interpreted to have formed during burial from decarboxylation-derived CO2 during source rock maturation. Other cements include the Fe-clay berthierine, apatite, pyrite, dolomite, siderite, quartz, illite and kaolinite. Reservoir quality in the Corallian sandstones show no significant depositional textural controls; it was reduced by dominant calcite cementation, locally preserved by berthierine grain coats that inhibited quartz cement and enhanced by detrital grain dissolution as well as cement dissolution. Reservoir quality in the Corallian sandstones can therefore be predicted by considering abundance of calcite cement from bioclasts, organically derived CO2 and Fe-clay coats.

Lithofacies, Depositional Environment and Diagenetic Evolution of the Paleocene Patala Formation, Potwar Basin, Pakistan: Implication for Shale Gas Potential

2021 ◽  
Author(s):  
Nasar Khan ◽  
Rudy Swennen ◽  
Gert Jan Weltje ◽  
Irfan Ullah Jan
Keyword(s):  
Organic Matter ◽  
Shale Gas ◽  
Gas Reservoirs ◽  
Shallow Marine ◽  
Anoxic Conditions ◽  
Fine Grained ◽  
Potwar Basin ◽  
Diagenetic Evolution ◽  
Reservoir Assessment ◽  
Gas Potential

<p><span><strong>Abstract:</strong> Reservoir assessment of unconventional reservoirs poses numerous exploration challenges. These challenges relate to their fine-grained and heterogeneous nature, which are ultimately controlled by depositional and diagenetic processes. To illustrate such constraints on shale gas reservoirs, this study focuses on lithofacies analysis, paleo-depositional and diagenetic evolution of the Paleocene Patala Formation at Potwar Basin of Pakistan. Integrated sedimentologic, petrographic, X-ray diffraction and TOC (total organic carbon) analyses showed that the formation contained mostly fine-grained carbonaceous, siliceous, calcareous and argilaceous siliciclastic-lithofacies, whereas carbonate microfacies included mudstone, wackestone and packstone. The silicious and carbonaceous lithofacies are considered a potential shale-gas system. The clastic lithofacies are dominated by detrital and calcareous assemblage including quartz, feldspar, calcite, organic matter and clay minerals with auxiliary pyrites and siderites. Fluctuations in depositional and diagenetic conditions caused  lateral and vertical variability in lithofacies. Superimposed on the depositional heterogeneity are spatially variable diagenetic modifications such as dissolution, compaction, cementation and stylolitization. The δ</span><sup>13</sup><span>C and δ</span><sup>15</sup><span>N stable isotopes elucidated that the formation has been deposited under anoxic conditions, which relatively enhanced the preservation of mixed marine and terrigenous organic matter. Overall, the Patala Formation exemplifies deposition in a shallow marine (shelfal) environment with episodic anoxic conditions.</span></p><p><strong>Keywords</strong><strong>:</strong> Lithofacies, Organic Matter, Paleocene, Potwar Basin, Shale Gas, Shallow Marine.</p>

scholarly journals Lithostratigraphy and biostratigraphy of the Lower Carboniferous (Mississippian) carbonates of the southern Askrigg Block, North Yorkshire, UK

2016 ◽  
Vol 154 (2) ◽  
pp. 305-333 ◽  
Author(s):  
C. N. WATERS ◽  
P. CÓZAR ◽  
I. D. SOMERVILLE ◽  
R. B. HASLAM ◽  
D. MILLWARD ◽  
...  
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Carbonate Ramp ◽  
Fault System ◽  
Lower Carboniferous ◽  
Shallow Marine ◽  
Sea Level Fluctuations ◽  
Algal Assemblages ◽  
Lower Palaeozoic ◽  
Southern Flank

AbstractA rationalized lithostratigraphy for the Great Scar Limestone Group of the southeast Askrigg Block is established. The basal Chapel House Limestone Formation, assessed from boreholes, comprises shallow-marine to supratidal carbonates that thin rapidly northwards across the Craven Fault System, onlapping a palaeotopographical high of Lower Palaeozoic strata. The formation is of late Arundian age in the Silverdale Borehole, its northernmost development. The overlying Kilnsey Formation represents a southward-thickening and upward-shoaling carbonate development on a S-facing carbonate ramp. Foraminiferal/algal assemblages suggest a late Holkerian and early Asbian age, respectively, for the uppermost parts of the lower Scaleber Force Limestone and upper Scaleber Quarry Limestone members, significantly younger than previously interpreted. The succeeding Malham Formation comprises the lower Cove Limestone and upper Gordale Limestone members. Foraminiferal/algal assemblages indicate a late Asbian age for the formation, contrasting with the Holkerian age previously attributed to the Cove Limestone. The members reflect a change from a partially shallow-water lagoon (Cove Limestone) to more open-marine shelf (Gordale Limestone), coincident with the onset of marked sea-level fluctuations and formation of palaeokarstic surfaces with palaeosoils in the latter. Facies variations along the southern flank of the Askrigg Block, including an absence of fenestral lime-mudstone in the upper part of the Cove Limestone and presence of dark grey cherty grainstone/packstone in the upper part the Gordale Limestone are related to enhanced subsidence during late Asbian movement on the Craven Fault System. This accounts for the marked thickening of both members towards the Greenhow Inlier.

Facies and depositional sequence evolution controlled by high-frequency sea-level changes in a shallow-water carbonate ramp (late Kimmeridgian, NE Spain)

2004 ◽  
Vol 141 (6) ◽  
pp. 717-733 ◽  
Author(s):  
M. AURELL ◽  
B. BÁDENAS
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Early Stage ◽  
Local Variation ◽  
Carbonate Ramp ◽  
Sequence Evolution ◽  
Sea Level Changes ◽  
Depositional Sequence ◽  
Ne Spain

The outcrops of the Sierra de Albarracín (NE Spain) allow a precise reconstruction of the shallow sedimentary domains of a late Kimmeridgian carbonate ramp, developed in western marginal areas of the Iberian Basin. The sedimentary record shows a hierarchical sequence stratigraphic organization, which implies sea-level changes of different frequencies. The studied succession is arranged in a long-term transgressive–regressive sequence, which is likely to reflect local variation in the subsidence rates. This sequence includes four higher-order sequences A to D, which have variable thickness (from 3 to 21 m). The similar sedimentary evolution observed in distant localities suggests the existence of high-frequency sea-level fluctuations controlling the sequence development. The average amplitude of these cycles would range from 5 to 10 m. The precise estimation of their duration (some few hundreds of kyr) and their possible assignment to any of the long-term orbital cycles (the 100 or the 400 kyr eccentricity cycles) is uncertain. Sequences A and B, formed during the long-term transgressive interval, are relatively thin (from 3 to 9 m) give-up sequences that were never subaerially exposed. These sequences are locally formed by five shallowing-upward elementary sequences. Sequences C and D are catch-down sequences with evidence of emersion of subtidal facies. Sequence C, formed during the stage of maximum gain of long-term accommodation, is the thickest sequence (from 13 to 21 m) and includes coral–microbial reefs (pinnacles up to 16 m in height). The increased production rates were able to fill part of the accommodation created during the early stage of high-frequency sea-level rise and the shallow platform was eventually exposed to subaereal erosion and meteoric cementation.

scholarly journals Dolomitization of the Lower Ordovician Aguathuna Formation carbonates, Port au Port Peninsula, western Newfoundland, Canada: implications for a hydrocarbon reservoir

2008 ◽  
Vol 45 (7) ◽  
pp. 795-813 ◽  
Author(s):  
Karem Azmy ◽  
Denis Lavoie ◽  
Ian Knight ◽  
Guoxiang Chi
Keyword(s):  
Crystal Size ◽  
Early Stage ◽  
Pore System ◽  
Shallow Marine ◽  
Molar Ratios ◽  
Hydrocarbon Reservoir ◽  
Subaerial Exposure ◽  
Lower Ordovician ◽  
Pee Dee ◽  
Marine Carbonates

The Lower Ordovician Aguathuna Formation (∼100 m thick) is formed of shallow-marine carbonates, which constitute the uppermost part of the St. George Group of western Newfoundland. Sedimentation was paused by a major subaerial exposure (St. George Unconformity), which likely developed a significant pore system in the underlying carbonates by meteoric dissolution. The sequence has been affected by multiphase dolomitization that caused complex changes in the rock porosity. The Aguathuna dolomites are classified into three main generations ranging in crystal size between ∼4 µm and 2 mm. The occurrence of fabric-retentive dolomicrites implies that dolomitization likely started during the early stages of diagenesis. Although dolomitization is pervasive in the upper part of the formation and significantly occludes the pores, some intervals in the lower part have higher porosity. The development of lower permeable layers overlain by an impermeable (seal) cap suggests a possible potential diagenetic trap. Unlike sabkha deposits, the Aguathuna carbonates do not have evaporite interlayers. Furthermore, the low Sr contents (∼96 ppm) and the δ18O values of earlier dolomites (–3.3‰ to –6.9‰ VPDB (Vienna Pee Dee Belemnite)) are also difficult to reconcile with a brine origin. The Sr/Ca molar ratios (0.0067–0.0009), calculated for the earliest dolomitizing fluid, suggest a modified seawater origin, likely mixed sea and meteoric waters. The least radiogenic 87Sr/86Sr values of the earliest dolomite are consistent with those of early Ordovician seawater, which supports an early-stage diagenesis. Petrography, geochemistry, and fluid inclusions of the late dolomites suggest precipitation at higher temperatures (∼73–95 °C) in deeper burial environments from hydrothermal solutions.

Changes in reservoir quality determined from the diagenetic evolution of Triassic and Lower Lias sedimentary successions (Balazuc borehole, Ardèche, France)

1996 ◽  
Vol 13 (6) ◽  
pp. 685-694 ◽  
Author(s):  
Charlotte Vinchon ◽  
Denis Giot ◽  
Fabienne Orsag-Sperber ◽  
François Arbey ◽  
Jacques Thibieroz ◽  
...  
Keyword(s):  
Reservoir Quality ◽  
Diagenetic Evolution

scholarly journals Carbon and oxygen stable isotope record of upper Kimmeridgian shallow-marine ramp carbonates (Iberian Basin, NE Spain): the imprint of different burial and tectonic histories

2021 ◽  
Vol 19 ◽  
Author(s):  
Cristina Sequero ◽  
Giovanna Della Porta ◽  
Beatriz Bádenas ◽  
Marcos Aurell
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Tectonic Uplift ◽  
Shallow Marine ◽  
Meteoric Diagenesis ◽  
Iberian Basin ◽  
Stable Isotope Signatures ◽  
Marine Carbonates ◽  
Oxygen Stable Isotope ◽  
Ne Spain

Bulk carbon and oxygen stable isotopes of ancient shallow-marine carbonates can record the effects of multiple palaeoenvironmental factors, but also the imprint of several post-depositional processes, which may alter the original marine isotopic composition. In this study, carbon and oxygen stable isotope analyses were performed on bulk carbonate, bivalve calcitic-shell (Trichites) and calcite vein samples from two stratigraphic sections (Tosos and Fuendetodos, present-day distance 15km), representing proximal inner- and distal mid-ramp environments, respectively, of the uppermost Kimmeridgian ramp facies deposited in the northern Iberian Basin (NE Spain). These successions underwent different diagenetic pathways that altered the primary marine isotopic composition in each section in different ways. Different burial histories, tectonic uplift and a variable exposure to meteoric diagenesis from the end of the Kimmeridgian to the Cenozoic (following Alpine tectonic uplift) are reflected in the different alteration patterns of the carbon and oxygen stable isotope signatures. A significant deviation to lower values in both δ13O and δ18O is recorded in those carbonates mostly exposed to meteoric diagenesis (distal mid-ramp Fuendetodos section), because of post-depositional tectonic uplift (telogenesis). On the other hand, the deposits mainly affected by burial diagenesis (proximal inner-ramp Tosos section) only record low δ18O with respect to expected values for pristine Kimmeridgian marine carbonates. The different burial and tectonic uplift histories of these deposits in each sector, due to their different tectonic evolution in this part of the basin, resulted in a variable degree of diagenetic resetting. However, in spite of the different diagenetic resetting reported of the carbon and oxygen stable isotope signatures in each section, these carbonates show similar cement types in termsof fabrics and cathodoluminescence properties. The diagenetic resetting reported for these carbonates prevents the use of the δ13O and δ18O records for addressing palaeoenvironmental interpretations, but instead highlights useful features regarding the variable diagenetic overprint of the studied shallow-marine carbonate successions concerning their specific post-depositional history.

Oncoid distribution in the shallow domains of a Kimmeridgian carbonate ramp (Late Jurassic, NE Spain)

2020 ◽  
Vol 398 ◽  
pp. 105585
Author(s):  
Cristina Sequero ◽  
Marcos Aurell ◽  
Beatriz Bádenas
Keyword(s):  
Late Jurassic ◽  
Carbonate Ramp ◽  
Ne Spain
Sign in / Sign up

Export Citation Format

Share Document