Reservoir quality variation on an Eocene carbonate ramp, El Garia Formation, offshore Tunisia: Structural control of burial corrosion and dolomitisation

Beavington-Penney, Simon James; Nadin, P. A.; Wright, V. Paul; Clarke, Ed; McQuilken, J; Bailey, H. W.

doi:10.1016/j.sedgeo.2008.06.006

Cited by 60 publications

(30 citation statements)

References 21 publications

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“…H Field, approximately 5 by 3 km, is variously interpreted to be a horst block which trends NNW-SSE, bounded by a system of left stepping en echelon faults (e.g. Klett, 2001;Racey et al, 2001;Vennin et al, 2003), or an anticline created by salt-uplift (Beavington-Penney et al, 2008). The main reservoir in the area of H Field consists of redeposited Lower Eocene nummulitic limestones of the G Formation (Racey et al, 2001; Fig.…”

Section: Geological Settingmentioning

confidence: 99%

“…But, as already pointed out by Beavington-Penny et al (2008), the drilling of the well HSW (located on the SW of well H4) disproved the details of the model of Racey (2001) of H Field forming the more distal section of a land-attached ramp. Instead Well HSW showed that H Field is isolated within the facies trend by deep water embayments, and is surrounded on all sides by time-equivalent deposits of B Formation (source rock) (Beavington-Penney et al, 2008). The G Formation trends parallel to the strike of the ramp, but its depositional geometry is frequently disrupted by structural controlled pelagic embayments on its basinward margin (Racey et al, 2001).…”

Section: Geological Settingmentioning

confidence: 99%

“…The G Formation trends parallel to the strike of the ramp, but its depositional geometry is frequently disrupted by structural controlled pelagic embayments on its basinward margin (Racey et al, 2001). Deposition in the north-east margin of H Field was affected by the earlier stages of salt mobilisation that didn't cease until the Miocene (Beavington-Penney et al, 2008). …”

Section: Geological Settingmentioning

confidence: 99%

“…Beavington-Penney et al, 2008). Although primary intraparticle porosity of the Nummulites' tests can be high, it is largely ineffective and significant permeabilities generally depend on secondary processes such as dolomitisation and biomouldic porosity, fractures and faulting.…”

Section: Reservoir Quality: Porosity and Permeability Distributionmentioning

confidence: 99%

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Improving the Estimation of Porosity and Permeability Distribution by Linking Basin Modelling to Diagenetic Evolution of Carbonate Reservoirs

Mangione¹,

Lewis²,

Geiger³

et al. 2013

All Days

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Carbonate reservoirs have petrophysical property distributions largely controlled by a combination of the depositional, diagenetic, and structural (burial/uplift) histories of the reservoir itself and also of the basins that contain them. Carbonates are very prone to diagenetic alteration; porosity and permeability can be strongly affected by the thermal state, fluid-pressure and pore fluid chemistry through their geological history. We use a novel workflow, adapted from basin modelling, to investigate how the burial/uplift history of an offshore carbonate reservoir and its basin, taken as a system, can have controlled the fluid and heat movement within, into and out of the reservoir. The reservoir rock properties and diagenetic history are assessed, as is the local and regional geological evolution for potential contributory factors to the diagenesis. A model of the potential basin system is developed, observed reservoir diagenetic history being added to the normal basin modelling constraints. This model provides good estimates of geometry and property evolution, and of fluid transport, through geological time. Since fluid and heat fluxes are important in the diagenetic evolution of the carbonate pore system, these results are complemented by simulating the movement of heat and brine in the reservoir using finite element-finite volume simulations. These simulations capture the complex geological structures, especially fault-fracture systems, and better represent the flow physics and chemistry that control reservoir diagenesis. Results from these simulations will later be returned to the basin model to improve the calibration of the timing, depth, and rates of diagenetic events. This new workflow is applied to a Lower Eocene offshore carbonate reservoir with a complex diagenetic history which seems to have a strong basin evolution influence. Importantly this workflow is generic and can be applied to any carbonate reservoir to enhance the link between geological models at the basin scale and reservoir scale models.

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Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Reservoir Quality: Porosity and Permeability Distributionmentioning

confidence: 99%

See 2 more Smart Citations

Improving the Estimation of Porosity and Permeability Distribution by Linking Basin Modelling to Diagenetic Evolution of Carbonate Reservoirs

Mangione¹,

Lewis²,

Geiger³

et al. 2013

All Days

View full text Add to dashboard Cite

show abstract

“…The LBF banks grade laterally to restricted inner platform micritic facies with gastropods and bivalves where meteoric water dissolution-enhanced secondary porosity reaches 40% in Tunisia (Bishop 1988). Nummulites were transported from inner to mid-platform settings (Beavington-Penney et al 2005) where secondary porosity was enhanced by preferential dolomitization of micritic facies (Beavington-Penney et al 2008). …”

Section: Climate Control On the Cenozoic Mediterranean Limestone Recordmentioning

confidence: 99%

Climatic controls on facies in Palaeogene Mediterranean subtropical carbonate platforms

Gatt

Gluyas

2012

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Cenozoic carbonate platforms in the central Mediterranean region show distinct vertical changes in carbonate skeletal assemblages and porosity characteristics that reflect shifts in environmental conditions affecting the western Tethys. The Photozoan Association produced by carbonate ecosystems adapted to low nutrient environments and the Heterozoan Association favoured by mesotrophic conditions alternate through time over the Malta Platform and nearby carbonate platforms, although not in phase with trans-Mediterranean Oligocene carbonates. This anomaly reflects the transitional nature of Cenozoic climate as well as continental convergence of the Tethyan margins. Restricted conditions amplified the effect of nutrient flux from North African fluvial systems, which was controlled by meridional shifts in the inter-tropical convergence zone (ITCZ) precipitation belt. We model the climate-carbonate interaction by comparing the global oxygen isotope proxy to ice volume and meridional position of the ITCZ to changes in trophic level of carbonate ecosystems. The results show that the development of Palaeogene Mediterranean photozoan assemblages coincides with periods when the ITCZ had shifted away from North Africa (as is the case presently), whereas the heterozoan assemblages thrived during increased nutrient flux when the precipitation belt was located over the Sahara. The climatic controls resulted in facies characteristics that exert a fundamental influence on porosity in carbonate reservoirs. Downloaded from fig. 2. Location and name of Oligocene formations referred to in text. Biotas include coralline red algae (CRA), large benthic foraminifera (LBF), bryozoans (Bry) and coral recorded in outcrops from the inner, mid-and outer platform environment.

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Hydrothermal silicification and its impact on Lower–Middle Ordovician carbonates in Shunnan area, Tarim Basin, NW China

Huang

et al. 2022

Geological Journal

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The Shunnan area is a newly discovered hydrocarbon field in Shuntuoguole lower uplift, in which the host rocks are Lower–Middle Ordovician carbonates. The carbonate reservoirs are well affected by hydrothermal silicification with well‐preserved intercrystalline pore of replacement quartz and megaquartz cements. Based on the petrography, pore types, and diagenetic processes, this research evaluated the reservoir quality and re‐constructed the porosity evolution in different diagenetic stages. Samples are collected from 7‐cored wells distributed along NNE‐ or ENE‐trending sinistral strike‐slip faults. Nine types of lithofacies were identified in the study area, including mudstone, bioclast wackestone, peloidal bioclast packstone, boundstone, peloidal grainstone, ooid grainstone, slightly silicified limestone (silica less than 25%), strongly silicified limestone (silica around 50%), and chert. Chert has better porosity (average 21.3%) and permeability (average 44.7 mD) than other lithofacies. The main reservoir pores are mainly developed in forms of fractures, intercrystalline replacement quartz and dissolved vugs. The porosity evolution shows that the primary porosity was limited due to cementation and compaction, and the earlier secondary porosity was occlusive as a result of coarse calcite cementation. Therefore, the precursor limestones may be tight, and the reservoir quality of the Lower–Middle Ordovician carbonates was controlled by hydrothermal silicification. During the hydrothermal silicification event, the burial depth of the Lower–Middle Ordovician carbonates was more than 3,000 m and their stratum temperature was higher than 120°C, representing a deep burial condition. The statistical data of porosity‐depth/temperature trends for carbonates suggest that the early secondary pores would be significantly reduced when the burial temperature reaches 100°C (or depth of strata reaches 3,000 m). Therefore, the dissolved vugs in strongly silicified limestone or hydrothermal chert are caused by hydrothermal silicification and not inherited from precursor carbonate rocks.

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Reservoir quality variation on an Eocene carbonate ramp, El Garia Formation, offshore Tunisia: Structural control of burial corrosion and dolomitisation

Cited by 60 publications

References 21 publications

Improving the Estimation of Porosity and Permeability Distribution by Linking Basin Modelling to Diagenetic Evolution of Carbonate Reservoirs

Improving the Estimation of Porosity and Permeability Distribution by Linking Basin Modelling to Diagenetic Evolution of Carbonate Reservoirs

Climatic controls on facies in Palaeogene Mediterranean subtropical carbonate platforms

Hydrothermal silicification and its impact on Lower–Middle Ordovician carbonates in Shunnan area, Tarim Basin, NW China

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