Dr. Anwar B Al-Helal - Academia.edu (original) (raw)

Papers by Dr. Anwar B Al-Helal

International Petroleum Technology Conference, 2013

Geological Journal, Mar 1, 2023

This article aims to provide a simple and applicable method of measuring the rock accumulation ra... more This article aims to provide a simple and applicable method of measuring the rock accumulation rate and recording the depositional events based on the application of graphic correlation and similarity matrix of the Paleogene planktonic foraminifera in two surface sections in South Sinai. Fifteen continuous biozones and subzones were recorded spanning from P0 to E3. The average RAR of the Beida Formation was somewhat equal to that recorded for the Dakhla Formation, however, the Selandian‐Ypresian Garra Formation was more than twice that recorded for the Esna Formation. On the other hand, the Thebes Formation represents a reverse setting which is relatively higher in the south than the north. Seven (T1‐T7) and twelve (T1‐T12) terraces were recorded at different stratigraphic positions. The terraces diverged in the Palaeocene and converged in the Eocene, whereas they lengthen in the Palaeocene and shortened in the Eocene. Breaks identified in the SM support many of the poorly constrained terraces on the GC, however, the SM technique efficiently recorded around 60% of the terraces recorded by GC. For confirming the terraces identified, field and faunal parameters confirm all the recorded events, however, a further correlation with their equivalent in and outside Egypt has been made which confirms another support of the technique applied. Therefore, the integration between these techniques in recognizing the depositional events and sedimentation breaks supports further depositional and palaeobathymetical studies and regional correlation as well.

Reflux of a penesaline (186‰) brine and resulting water-rock interactions were simulated using a ... more Reflux of a penesaline (186‰) brine and resulting water-rock interactions were simulated using a modification of TOUGHREACT that incorporates the Pitzer ion-interaction theory. The brine is sourced from a 5 km wide brine pool in the interior of a 25 km wide platform and flows basinward through a 3 km thick sequence of grain-dominated packstone sediments. Ion interactions reduce dolomite supersaturation and anhydrite undersaturation predicted using the Pitzer approach compared with the DebyeHuckel approach, but increase calcite undersaturation. This increased undersaturation, combined with enhanced fluid flow above a shallower zone of anhydrite precipitation, results in more rapid dolomitization despite the lower initial dolomite saturation. The penesaline brines reflux at up to 7 my -1 , three times the maximum flow rate in identical simulations involving a mesohaline (85‰) brine, in direct proportion to the difference in the density gradient. However, dolomitization is an order of magnitude faster for the penesaline brine, with replacement of all limestone to a depth of 43 m within 50 ky. Even after 1 My of penesaline-brine reflux, alteration is largely limited to sediments underlying the brine pool. In contrast, the penesaline brine forms a tabular dolomite body extending some 20 km to the platform margin. The upper 200 m of porous dolomite, lacking significant primary dolomite cements, overlies a thick (>700 m) zone where anhydrite cements plug up to 25% of the porosity. Penesaline brine reflux forms less anhydrite cement, due both to slower anhydrite precipitation (driven by slower upstream dolomitization), and to more .rapid anhydrite dissolution once dolomitization is complete.

International Petroleum Technology Conference, 2013

American Journal of Environmental Sciences, 2017

Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respective... more Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respectively in Kuwait from March 2014 to February 2015, to study the air quality and heavy metals content and Total Petroleum Hydrocarbons (TPHs) in PM 10 samples. The annual average concentrations of PM 10 and PM 2.5 were 152 and 97.3 µg/m 3 , respectively, with an average PM 2.5 /PM 10 ratio of 70%. The contamination level of heavy metals in PM 10 samples was assessed in terms of Enrichment Factor (EF) using mathematical models. The elements associated with an anthropogenic activity in the PM 10 samples; i.e., Pb, Cu, Co, Cd and Zn, were 2.4, 12.9, 14.6, 42.6 and 156.2 times higher than the corresponding background values in Kuwait soil. TPH was the dominant pollutant in the PM 10 samples. In general, most daily average Air Quality Indices (AQI) of PM 10 concentrations fell under the categories of "good" and "moderate".

Journal of Arid Environments, Oct 1, 2005

Between 1998 and 2001, wind data from eight meteorological stations were analysed to examine sand... more Between 1998 and 2001, wind data from eight meteorological stations were analysed to examine sand drift potential (DP) in Kuwait, using Fryberger's [1979. In: McKee, ED (Ed.), A study of global sand seas. Professional Paper 1052, United States Geological Survey, US ...

Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform... more Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform carbonates. Reactive transport modeling (RTM) suggests that geothermal convection can form a wedge-shaped dolomite body thickest at the platform margin, while reflux can form a tabular body which thins away from the brine source. In natural systems flow will respond to both drives and vary through time with changes in platform top conditions, for example as brine pools develop and disappear, and this is likely to significantly impact both dolomitization and associated anhydrite precipitation. A model technique (TOUGHREACT) is used to investigate the dynamic interactions of geothermal convection and brine reflux. Reflux of brines (85‰) rapidly restricts geothermal convection to the platform margin where only minor dolomitization occurs. Brines infiltrate to considerable depth, but fluid flux is most rapid at shallow depth due to reducing permeability with depth, permeability anisotropy, and diagenetic modification of permeability. Simulations suggest complete dolomitization to 150-200 m depth within 1 My beneath the brine source. Reflux dolomitization may enhance reservoir quality at shallow depth where associated anhydrite precipitation occludes porosity beneath the main dolomite body. The predicted anhydrite volume is almost twice that suggested by earlier simulations that do not incorporate heat transport. Increasing geothermal heat flux has little effect on geothermal circulation, but does accelerate reflux diagenesis. Cooling the platform top from 40 to 25°C slows reactions and displaces the anhydrite zone downwards so it may become completely decoupled from the brine source. When brine-generating conditions cease, subsurface brines will continue to flow and have been suggested as a drive for continued dolomitization (a variant termed “latent reflux”). Our simulations demonstrate that latent reflux does not form a significant amount of dolomite due to prior Mg2+ consumption at shallow depth, although as geothermal circulation becomes re-established, platform margin dolomitization rates increase. RTM offers considerable potential for improving our understanding of diagenetic reactions and their impact on reservoir quality in such hybrid flow systems. However, the veracity and utility of predictions depend on the specification of meaningful boundary and initial conditions, and the temperature regime appears to play a critical role in the dolomitization and anhydritization story.

Pure and Applied Geophysics, May 4, 2023

Springer eBooks, Nov 22, 2022

This chapter reviews the subsurface stratigraphy of Kuwait targeting geosciences educators. The l... more This chapter reviews the subsurface stratigraphy of Kuwait targeting geosciences educators. The lithostratigraphy and chronostratigraphy of the reviewed formations (association of rocks whose components are paragenetically related to each other, both vertically and laterally) followed the formal stratigraphic nomenclature in Kuwait. The exposed stratigraphic formations of the Miocene-Pleistocene epochs represented by the Dibdibba, Lower Fars, and Ghar clastic sediments (Kuwait Group) were reviewed in the previous chapter as part of near-surface geology. In this chapter, the description of these formations is based mainly on their subsurface presence. The description of the subsurface stratigraphic formations in Kuwait followed published academic papers and technical reports related to Kuwait's geology or analog (GCC countries, Iraq and Iran) either from the oil and gas industry or from different research institutions in Kuwait and abroad. It is also true that studies related to groundwater aquifer systems also contribute to our understanding of the subsurface stratigraphy of Kuwait for the shallower formations. The majority of the published data were covered the onshore section of Kuwait. The subsurface stratigraphic nomenclature

Journal of Sedimentary Research, Mar 1, 2012

Both geothermal convection and brine reflux drive circulation of seawater derived fluids through ... more Both geothermal convection and brine reflux drive circulation of seawater derived fluids through carbonate platforms during early burial, but dynamic interactions between heat and solute transport and resulting diagenesis are at present poorly understood. This paper describes high-resolution reactive transport model (RTM) simulations that suggest that reflux of 85 ppt brines rapidly restricts geothermal convection to the platform margin, with flow focused in the more permeable shallow carbonates. In a baseline simulation, involving an elongate, 25-km-wide grain-dominated packstone platform, brine reflux resulted in complete dolomitization beneath the 5-km-wide brine pool in 335 ky. The dolomite body then extends downward at c. 22 m/100 ky into an underlying broad area of partial dolomitization. This process enhances porosity at shallow depth, but beneath the dolomite body precipitation of anhydrite occludes porosity and limits the depth of reflux. In contrast, geothermal convection at the platform margin forms a smaller partially dolomitized body over a longer time (, 60% dolomite after 1 My), with very minor associated anhydrite cementation. Reflux diagenesis is sensitive to platform geometry, with higher rates of fluid flow increasing the depth of alteration beneath the brine pool for a circular platform compared to the linear baseline. Fluid flow across thermal gradients enhances reaction rates, and ignoring heat transport by 85 ppt brine reflux underestimates the extent of reflux dolomite by 25% and associated anhydrite by 90%. The depth and rate of anhydritization is sensitive to the geothermal heat flux, whereas platform-top temperatures affect dolomitization rate. Reflux diagenesis is also sensitive to brine density, which affects both fluid flow and reaction rates. Sediment permeability and reactive surface area (RSA) are key intrinsic controls on diagenesis. Where the permeability structure permits sufficient fluid flow, diagenesis preferentially affects more reactive fine-grained sediments. However, as flow rates decline, reactions become focused in the more permeable but less reactive sediments. Simulations thus shed light on why in some settings reflux preferentially dolomitizes muddy sediments, but elsewhere favors grainstones. Once active reflux ceases, brines continue to flow in the subsurface, but this ''latent reflux'' causes only minor dolomitization due to prior Mg 2+ consumption at shallow depth.

GeoArabia, Journal of the Middle East Petroleum Geosciences, 2011

Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform... more Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform carbonates. Reactive transport modeling (RTM) suggests that geothermal convection can form a wedge-shaped dolomite body thickest at the platform margin, while reflux can form a tabular body which thins away from the brine source. In natural systems flow will respond to both drives and vary through time with changes in platform top conditions, for example as brine pools develop and disappear, and this is likely to significantly impact both dolomitization and associated anhydrite precipitation. A model technique (TOUGHREACT) is used to investigate the dynamic interactions of geothermal convection and brine reflux. Reflux of brines (85‰) rapidly restricts geothermal convection to the platform margin where only minor dolomitization occurs. Brines infiltrate to considerable depth, but fluid flux is most rapid at shallow depth due to reducing permeability with depth, permeability anisotropy, and diagenetic modification of permeability. Simulations suggest complete dolomitization to 150-200 m depth within 1 My beneath the brine source. Reflux dolomitization may enhance reservoir quality at shallow depth where associated anhydrite precipitation occludes porosity beneath the main dolomite body. The predicted anhydrite volume is almost twice that suggested by earlier simulations that do not incorporate heat transport. Increasing geothermal heat flux has little effect on geothermal circulation, but does accelerate reflux diagenesis. Cooling the platform top from 40 to 25°C slows reactions and displaces the anhydrite zone downwards so it may become completely decoupled from the brine source. When brine-generating conditions cease, subsurface brines will continue to flow and have been suggested as a drive for continued dolomitization (a variant termed “latent reflux”). Our simulations demonstrate that latent reflux does not form a significant amount of dolomite due to prior Mg2+ consumption at shallow depth, although as geothermal circulation becomes re-established, platform margin dolomitization rates increase. RTM offers considerable potential for improving our understanding of diagenetic reactions and their impact on reservoir quality in such hybrid flow systems. However, the veracity and utility of predictions depend on the specification of meaningful boundary and initial conditions, and the temperature regime appears to play a critical role in the dolomitization and anhydritization story.

Regional Geology Reviews

The fresh and brackish groundwater resources in the State of Kuwait are restricted to two main wa... more The fresh and brackish groundwater resources in the State of Kuwait are restricted to two main water-bearing formations (aquifers). These are the Dammam Formation and Kuwait Group. The Kuwait Group aquifer is generally unconfined, i.e., water table condition, whereas the Dammam fractured limestone Formation is a confined-semi confined aquifer. The quality of groundwater in Kuwait varies from brackish in the southwest to brine in the northeast of Kuwait. Fresh groundwater bodies of TDS less than 1000 mg/l occur on saline groundwater of TDS 100,000 mg/l in the north and the northeast, e.g. Raudhatain and Umm Al-Aish water fields. Generally, the water table varies from zero at the Arabian Gulf Coast to about 90 m below the surface in the southwest. Significant ongoing and future groundwater projects include monitoring groundwater level and water quality, establishing hydrological, geological and hydrochemical databases, reducing groundwater levels, long-term monitoring for groundwater ...

Journal of Sedimentary Research, 2012

Both geothermal convection and brine reflux drive circulation of seawater derived fluids through ... more Both geothermal convection and brine reflux drive circulation of seawater derived fluids through carbonate platforms during early burial, but dynamic interactions between heat and solute transport and resulting diagenesis are at present poorly understood. This paper describes high-resolution reactive transport model (RTM) simulations that suggest that reflux of 85 ppt brines rapidly restricts geothermal convection to the platform margin, with flow focused in the more permeable shallow carbonates. In a baseline simulation, involving an elongate, 25-km-wide grain-dominated packstone platform, brine reflux resulted in complete dolomitization beneath the 5-km-wide brine pool in 335 ky. The dolomite body then extends downward at c. 22 m/100 ky into an underlying broad area of partial dolomitization. This process enhances porosity at shallow depth, but beneath the dolomite body precipitation of anhydrite occludes porosity and limits the depth of reflux. In contrast, geothermal convection at the platform margin forms a smaller partially dolomitized body over a longer time (, 60% dolomite after 1 My), with very minor associated anhydrite cementation. Reflux diagenesis is sensitive to platform geometry, with higher rates of fluid flow increasing the depth of alteration beneath the brine pool for a circular platform compared to the linear baseline. Fluid flow across thermal gradients enhances reaction rates, and ignoring heat transport by 85 ppt brine reflux underestimates the extent of reflux dolomite by 25% and associated anhydrite by 90%. The depth and rate of anhydritization is sensitive to the geothermal heat flux, whereas platform-top temperatures affect dolomitization rate. Reflux diagenesis is also sensitive to brine density, which affects both fluid flow and reaction rates. Sediment permeability and reactive surface area (RSA) are key intrinsic controls on diagenesis. Where the permeability structure permits sufficient fluid flow, diagenesis preferentially affects more reactive fine-grained sediments. However, as flow rates decline, reactions become focused in the more permeable but less reactive sediments. Simulations thus shed light on why in some settings reflux preferentially dolomitizes muddy sediments, but elsewhere favors grainstones. Once active reflux ceases, brines continue to flow in the subsurface, but this ''latent reflux'' causes only minor dolomitization due to prior Mg 2+ consumption at shallow depth.

American Journal of Environmental Sciences, 2017

Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respective... more Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respectively in Kuwait from March 2014 to February 2015, to study the air quality and heavy metals content and Total Petroleum Hydrocarbons (TPHs) in PM 10 samples. The annual average concentrations of PM 10 and PM 2.5 were 152 and 97.3 µg/m 3 , respectively, with an average PM 2.5 /PM 10 ratio of 70%. The contamination level of heavy metals in PM 10 samples was assessed in terms of Enrichment Factor (EF) using mathematical models. The elements associated with an anthropogenic activity in the PM 10 samples; i.e., Pb, Cu, Co, Cd and Zn, were 2.4, 12.9, 14.6, 42.6 and 156.2 times higher than the corresponding background values in Kuwait soil. TPH was the dominant pollutant in the PM 10 samples. In general, most daily average Air Quality Indices (AQI) of PM 10 concentrations fell under the categories of "good" and "moderate".

International Petroleum Technology Conference, 2013

Geological Journal, Mar 1, 2023

This article aims to provide a simple and applicable method of measuring the rock accumulation ra... more This article aims to provide a simple and applicable method of measuring the rock accumulation rate and recording the depositional events based on the application of graphic correlation and similarity matrix of the Paleogene planktonic foraminifera in two surface sections in South Sinai. Fifteen continuous biozones and subzones were recorded spanning from P0 to E3. The average RAR of the Beida Formation was somewhat equal to that recorded for the Dakhla Formation, however, the Selandian‐Ypresian Garra Formation was more than twice that recorded for the Esna Formation. On the other hand, the Thebes Formation represents a reverse setting which is relatively higher in the south than the north. Seven (T1‐T7) and twelve (T1‐T12) terraces were recorded at different stratigraphic positions. The terraces diverged in the Palaeocene and converged in the Eocene, whereas they lengthen in the Palaeocene and shortened in the Eocene. Breaks identified in the SM support many of the poorly constrained terraces on the GC, however, the SM technique efficiently recorded around 60% of the terraces recorded by GC. For confirming the terraces identified, field and faunal parameters confirm all the recorded events, however, a further correlation with their equivalent in and outside Egypt has been made which confirms another support of the technique applied. Therefore, the integration between these techniques in recognizing the depositional events and sedimentation breaks supports further depositional and palaeobathymetical studies and regional correlation as well.

Reflux of a penesaline (186‰) brine and resulting water-rock interactions were simulated using a ... more Reflux of a penesaline (186‰) brine and resulting water-rock interactions were simulated using a modification of TOUGHREACT that incorporates the Pitzer ion-interaction theory. The brine is sourced from a 5 km wide brine pool in the interior of a 25 km wide platform and flows basinward through a 3 km thick sequence of grain-dominated packstone sediments. Ion interactions reduce dolomite supersaturation and anhydrite undersaturation predicted using the Pitzer approach compared with the DebyeHuckel approach, but increase calcite undersaturation. This increased undersaturation, combined with enhanced fluid flow above a shallower zone of anhydrite precipitation, results in more rapid dolomitization despite the lower initial dolomite saturation. The penesaline brines reflux at up to 7 my -1 , three times the maximum flow rate in identical simulations involving a mesohaline (85‰) brine, in direct proportion to the difference in the density gradient. However, dolomitization is an order of magnitude faster for the penesaline brine, with replacement of all limestone to a depth of 43 m within 50 ky. Even after 1 My of penesaline-brine reflux, alteration is largely limited to sediments underlying the brine pool. In contrast, the penesaline brine forms a tabular dolomite body extending some 20 km to the platform margin. The upper 200 m of porous dolomite, lacking significant primary dolomite cements, overlies a thick (>700 m) zone where anhydrite cements plug up to 25% of the porosity. Penesaline brine reflux forms less anhydrite cement, due both to slower anhydrite precipitation (driven by slower upstream dolomitization), and to more .rapid anhydrite dissolution once dolomitization is complete.

International Petroleum Technology Conference, 2013

American Journal of Environmental Sciences, 2017

Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respective... more Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respectively in Kuwait from March 2014 to February 2015, to study the air quality and heavy metals content and Total Petroleum Hydrocarbons (TPHs) in PM 10 samples. The annual average concentrations of PM 10 and PM 2.5 were 152 and 97.3 µg/m 3 , respectively, with an average PM 2.5 /PM 10 ratio of 70%. The contamination level of heavy metals in PM 10 samples was assessed in terms of Enrichment Factor (EF) using mathematical models. The elements associated with an anthropogenic activity in the PM 10 samples; i.e., Pb, Cu, Co, Cd and Zn, were 2.4, 12.9, 14.6, 42.6 and 156.2 times higher than the corresponding background values in Kuwait soil. TPH was the dominant pollutant in the PM 10 samples. In general, most daily average Air Quality Indices (AQI) of PM 10 concentrations fell under the categories of "good" and "moderate".

Journal of Arid Environments, Oct 1, 2005

Between 1998 and 2001, wind data from eight meteorological stations were analysed to examine sand... more Between 1998 and 2001, wind data from eight meteorological stations were analysed to examine sand drift potential (DP) in Kuwait, using Fryberger's [1979. In: McKee, ED (Ed.), A study of global sand seas. Professional Paper 1052, United States Geological Survey, US ...

Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform... more Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform carbonates. Reactive transport modeling (RTM) suggests that geothermal convection can form a wedge-shaped dolomite body thickest at the platform margin, while reflux can form a tabular body which thins away from the brine source. In natural systems flow will respond to both drives and vary through time with changes in platform top conditions, for example as brine pools develop and disappear, and this is likely to significantly impact both dolomitization and associated anhydrite precipitation. A model technique (TOUGHREACT) is used to investigate the dynamic interactions of geothermal convection and brine reflux. Reflux of brines (85‰) rapidly restricts geothermal convection to the platform margin where only minor dolomitization occurs. Brines infiltrate to considerable depth, but fluid flux is most rapid at shallow depth due to reducing permeability with depth, permeability anisotropy, and diagenetic modification of permeability. Simulations suggest complete dolomitization to 150-200 m depth within 1 My beneath the brine source. Reflux dolomitization may enhance reservoir quality at shallow depth where associated anhydrite precipitation occludes porosity beneath the main dolomite body. The predicted anhydrite volume is almost twice that suggested by earlier simulations that do not incorporate heat transport. Increasing geothermal heat flux has little effect on geothermal circulation, but does accelerate reflux diagenesis. Cooling the platform top from 40 to 25°C slows reactions and displaces the anhydrite zone downwards so it may become completely decoupled from the brine source. When brine-generating conditions cease, subsurface brines will continue to flow and have been suggested as a drive for continued dolomitization (a variant termed “latent reflux”). Our simulations demonstrate that latent reflux does not form a significant amount of dolomite due to prior Mg2+ consumption at shallow depth, although as geothermal circulation becomes re-established, platform margin dolomitization rates increase. RTM offers considerable potential for improving our understanding of diagenetic reactions and their impact on reservoir quality in such hybrid flow systems. However, the veracity and utility of predictions depend on the specification of meaningful boundary and initial conditions, and the temperature regime appears to play a critical role in the dolomitization and anhydritization story.

Pure and Applied Geophysics, May 4, 2023

Springer eBooks, Nov 22, 2022

This chapter reviews the subsurface stratigraphy of Kuwait targeting geosciences educators. The l... more This chapter reviews the subsurface stratigraphy of Kuwait targeting geosciences educators. The lithostratigraphy and chronostratigraphy of the reviewed formations (association of rocks whose components are paragenetically related to each other, both vertically and laterally) followed the formal stratigraphic nomenclature in Kuwait. The exposed stratigraphic formations of the Miocene-Pleistocene epochs represented by the Dibdibba, Lower Fars, and Ghar clastic sediments (Kuwait Group) were reviewed in the previous chapter as part of near-surface geology. In this chapter, the description of these formations is based mainly on their subsurface presence. The description of the subsurface stratigraphic formations in Kuwait followed published academic papers and technical reports related to Kuwait's geology or analog (GCC countries, Iraq and Iran) either from the oil and gas industry or from different research institutions in Kuwait and abroad. It is also true that studies related to groundwater aquifer systems also contribute to our understanding of the subsurface stratigraphy of Kuwait for the shallower formations. The majority of the published data were covered the onshore section of Kuwait. The subsurface stratigraphic nomenclature

Journal of Sedimentary Research, Mar 1, 2012

Both geothermal convection and brine reflux drive circulation of seawater derived fluids through ... more Both geothermal convection and brine reflux drive circulation of seawater derived fluids through carbonate platforms during early burial, but dynamic interactions between heat and solute transport and resulting diagenesis are at present poorly understood. This paper describes high-resolution reactive transport model (RTM) simulations that suggest that reflux of 85 ppt brines rapidly restricts geothermal convection to the platform margin, with flow focused in the more permeable shallow carbonates. In a baseline simulation, involving an elongate, 25-km-wide grain-dominated packstone platform, brine reflux resulted in complete dolomitization beneath the 5-km-wide brine pool in 335 ky. The dolomite body then extends downward at c. 22 m/100 ky into an underlying broad area of partial dolomitization. This process enhances porosity at shallow depth, but beneath the dolomite body precipitation of anhydrite occludes porosity and limits the depth of reflux. In contrast, geothermal convection at the platform margin forms a smaller partially dolomitized body over a longer time (, 60% dolomite after 1 My), with very minor associated anhydrite cementation. Reflux diagenesis is sensitive to platform geometry, with higher rates of fluid flow increasing the depth of alteration beneath the brine pool for a circular platform compared to the linear baseline. Fluid flow across thermal gradients enhances reaction rates, and ignoring heat transport by 85 ppt brine reflux underestimates the extent of reflux dolomite by 25% and associated anhydrite by 90%. The depth and rate of anhydritization is sensitive to the geothermal heat flux, whereas platform-top temperatures affect dolomitization rate. Reflux diagenesis is also sensitive to brine density, which affects both fluid flow and reaction rates. Sediment permeability and reactive surface area (RSA) are key intrinsic controls on diagenesis. Where the permeability structure permits sufficient fluid flow, diagenesis preferentially affects more reactive fine-grained sediments. However, as flow rates decline, reactions become focused in the more permeable but less reactive sediments. Simulations thus shed light on why in some settings reflux preferentially dolomitizes muddy sediments, but elsewhere favors grainstones. Once active reflux ceases, brines continue to flow in the subsurface, but this ''latent reflux'' causes only minor dolomitization due to prior Mg 2+ consumption at shallow depth.

GeoArabia, Journal of the Middle East Petroleum Geosciences, 2011

Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform... more Geothermal heating and brine reflux have been invoked to explain early dolomitization of platform carbonates. Reactive transport modeling (RTM) suggests that geothermal convection can form a wedge-shaped dolomite body thickest at the platform margin, while reflux can form a tabular body which thins away from the brine source. In natural systems flow will respond to both drives and vary through time with changes in platform top conditions, for example as brine pools develop and disappear, and this is likely to significantly impact both dolomitization and associated anhydrite precipitation. A model technique (TOUGHREACT) is used to investigate the dynamic interactions of geothermal convection and brine reflux. Reflux of brines (85‰) rapidly restricts geothermal convection to the platform margin where only minor dolomitization occurs. Brines infiltrate to considerable depth, but fluid flux is most rapid at shallow depth due to reducing permeability with depth, permeability anisotropy, and diagenetic modification of permeability. Simulations suggest complete dolomitization to 150-200 m depth within 1 My beneath the brine source. Reflux dolomitization may enhance reservoir quality at shallow depth where associated anhydrite precipitation occludes porosity beneath the main dolomite body. The predicted anhydrite volume is almost twice that suggested by earlier simulations that do not incorporate heat transport. Increasing geothermal heat flux has little effect on geothermal circulation, but does accelerate reflux diagenesis. Cooling the platform top from 40 to 25°C slows reactions and displaces the anhydrite zone downwards so it may become completely decoupled from the brine source. When brine-generating conditions cease, subsurface brines will continue to flow and have been suggested as a drive for continued dolomitization (a variant termed “latent reflux”). Our simulations demonstrate that latent reflux does not form a significant amount of dolomite due to prior Mg2+ consumption at shallow depth, although as geothermal circulation becomes re-established, platform margin dolomitization rates increase. RTM offers considerable potential for improving our understanding of diagenetic reactions and their impact on reservoir quality in such hybrid flow systems. However, the veracity and utility of predictions depend on the specification of meaningful boundary and initial conditions, and the temperature regime appears to play a critical role in the dolomitization and anhydritization story.

Regional Geology Reviews

The fresh and brackish groundwater resources in the State of Kuwait are restricted to two main wa... more The fresh and brackish groundwater resources in the State of Kuwait are restricted to two main water-bearing formations (aquifers). These are the Dammam Formation and Kuwait Group. The Kuwait Group aquifer is generally unconfined, i.e., water table condition, whereas the Dammam fractured limestone Formation is a confined-semi confined aquifer. The quality of groundwater in Kuwait varies from brackish in the southwest to brine in the northeast of Kuwait. Fresh groundwater bodies of TDS less than 1000 mg/l occur on saline groundwater of TDS 100,000 mg/l in the north and the northeast, e.g. Raudhatain and Umm Al-Aish water fields. Generally, the water table varies from zero at the Arabian Gulf Coast to about 90 m below the surface in the southwest. Significant ongoing and future groundwater projects include monitoring groundwater level and water quality, establishing hydrological, geological and hydrochemical databases, reducing groundwater levels, long-term monitoring for groundwater ...

Journal of Sedimentary Research, 2012

Both geothermal convection and brine reflux drive circulation of seawater derived fluids through ... more Both geothermal convection and brine reflux drive circulation of seawater derived fluids through carbonate platforms during early burial, but dynamic interactions between heat and solute transport and resulting diagenesis are at present poorly understood. This paper describes high-resolution reactive transport model (RTM) simulations that suggest that reflux of 85 ppt brines rapidly restricts geothermal convection to the platform margin, with flow focused in the more permeable shallow carbonates. In a baseline simulation, involving an elongate, 25-km-wide grain-dominated packstone platform, brine reflux resulted in complete dolomitization beneath the 5-km-wide brine pool in 335 ky. The dolomite body then extends downward at c. 22 m/100 ky into an underlying broad area of partial dolomitization. This process enhances porosity at shallow depth, but beneath the dolomite body precipitation of anhydrite occludes porosity and limits the depth of reflux. In contrast, geothermal convection at the platform margin forms a smaller partially dolomitized body over a longer time (, 60% dolomite after 1 My), with very minor associated anhydrite cementation. Reflux diagenesis is sensitive to platform geometry, with higher rates of fluid flow increasing the depth of alteration beneath the brine pool for a circular platform compared to the linear baseline. Fluid flow across thermal gradients enhances reaction rates, and ignoring heat transport by 85 ppt brine reflux underestimates the extent of reflux dolomite by 25% and associated anhydrite by 90%. The depth and rate of anhydritization is sensitive to the geothermal heat flux, whereas platform-top temperatures affect dolomitization rate. Reflux diagenesis is also sensitive to brine density, which affects both fluid flow and reaction rates. Sediment permeability and reactive surface area (RSA) are key intrinsic controls on diagenesis. Where the permeability structure permits sufficient fluid flow, diagenesis preferentially affects more reactive fine-grained sediments. However, as flow rates decline, reactions become focused in the more permeable but less reactive sediments. Simulations thus shed light on why in some settings reflux preferentially dolomitizes muddy sediments, but elsewhere favors grainstones. Once active reflux ceases, brines continue to flow in the subsurface, but this ''latent reflux'' causes only minor dolomitization due to prior Mg 2+ consumption at shallow depth.

American Journal of Environmental Sciences, 2017

Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respective... more Hourly PM 10 and PM 2.5 samples were simultaneously collected at 10 and 3 urban sites, respectively in Kuwait from March 2014 to February 2015, to study the air quality and heavy metals content and Total Petroleum Hydrocarbons (TPHs) in PM 10 samples. The annual average concentrations of PM 10 and PM 2.5 were 152 and 97.3 µg/m 3 , respectively, with an average PM 2.5 /PM 10 ratio of 70%. The contamination level of heavy metals in PM 10 samples was assessed in terms of Enrichment Factor (EF) using mathematical models. The elements associated with an anthropogenic activity in the PM 10 samples; i.e., Pb, Cu, Co, Cd and Zn, were 2.4, 12.9, 14.6, 42.6 and 156.2 times higher than the corresponding background values in Kuwait soil. TPH was the dominant pollutant in the PM 10 samples. In general, most daily average Air Quality Indices (AQI) of PM 10 concentrations fell under the categories of "good" and "moderate".