Waste heat mapping: A UK study Albert, Max D.A.; Bennett, Katherine O.; Adams, Charlotte A. ...
Renewable & sustainable energy reviews,
20/May , Volume:
160
Journal Article
Peer reviewed
Open access
The following study considers the spatial distribution, grade and seasonal variation of waste-heat from industrial sectors in the United Kingdom in 2018. Opportunities to offset the emissions caused ...by heat generation through the use of waste-heat recovery schemes have been examined. Reducing heat waste is a key intermediate step in avoiding climate disaster until fully decarbonised industrial practices have been developed and implemented. The findings of this study are presented as a ‘UK waste heat map’. Data containing information on the natural gas consumption of different industries are used as a proxy for waste heat. This report finds that waste heat is concentrated around densely populated areas and areas with a traditionally strong industrial base. Such areas generate a large amount of the waste heat suitable for heat reuse, such as in a district heating scheme. The total waste heat from UK industry and electricity generation is estimated to be nearly 391,000 GWh per year. The data are represented in the accompanying UK waste heat map as point location data and by waste heat per Local Authority. Opportunities have been identified within each major industrial sector to reclaim and utilise this waste heat.
•Waste heat from UK industry are mapped to identify potential waste-heat recovery.•UK industrial waste heat was estimated to be 391,000 GWh in 2018.•Waste heat is concentrated in areas of high population density.•Report details the methodology behind and interpretation of the UK waste heat map.•District heating from certain industries could increase reliance on natural gas.
Proximal to distal fan change in grain size, clay matrix content, and grain-coating clays have been identified as key contributing factors for eservoir quality evolution of submarine fan turbidite ...sandstones. This study evaluated the role played by grain-coating and pore-filling clays, depositional facies, and diagenesis in reservoir quality evolution of the Paleocene Forties submarine fan sandstones (Central North Sea) from proximal to distal fan settings. To help provide a comprehensive understanding of the role played by pore-filling and grain-coating clays in destroying and preserving reservoir quality, respectively, in turbidite sandstones, we have used a multi-disciplinary approach including petrography, burial history, scanning electron microscopy, and stable isotopes analysis. Results of the study showed that reservoir quality is influenced by both depositional facies and diagenesis. The proximal-fan, amalgamated sandstones facies have the best reservoir quality due to coarser grain size, lower pore-filling clays, and lower amount of ductile grains. In contrast, the distal-fan, mud-prone heterolithic facies have the poorest reservoir quality due to finer grain size, higher pore-filling clays, and higher amount of ductile grains. Pore-filling clays between 10 and 30% have a deleterious effect on reservoir quality, reducing porosities and permeabilities to generally <10% and <1 mD, respectively. Based on the relatively shallow, present-day burial depths of the studied Forties Sandstone Member (2200–3100 m TVDSS), the percentage of clay-coating coverage to significantly inhibit quartz cementation ranges from 40 to 50%. Detrital, grain-coating smectites, probably inherited from the shelf/continental environments and/or emplaced through sediment dewatering, have transformed into chlorite, illite, and illite-smectite. Calcite and siderite, where well-developed, have arrested mechanical compaction and also occluded porosity, thereby rapidly degrading reservoir quality in the sandstones; however, their dissolution by acidic pore fluids could potentially create secondary intergranular porosity, enhancing reservoir quality of the sandstones. Evidence presented demonstrates that, high quality reservoir sandstones that deviate from normal porosity-depth trends for submarine fans sandstones can be attributed to facies changes (composition and grain size) with a complex interplay of mechanical compaction, detrital clays and authigenic clay coatings inhibiting quartz cement precipitation.
•Reservoir quality of submarine fan turbidites is controlled by depositional facies and diagenesis.•Down-fan fining and change in clay content impact significantly on reservoir quality of submarine fan turbidites.•Grain-coating and pore-filling clays play a significant role in reservoir quality control of submarine fan turbidite sandstones. The percentage of clay-coat coverage to inhibit quartz cementation ranges between 40 and 50%. Quartz cementation in turbidite sandstones is inhibited by grain-coating clays such as chlorite and illite/illite-smectite.•Carbonate cements, where well-developed, have affected reservoir quality of the sandstones.
Dissolution of feldspars and precipitation of secondary minerals (kaolinite, illite and quartz) are significant diagenetic processes in arkosic sandstones. We examined moderately buried sandstones in ...the Eocene Shahejie Formation from two sags in the Bohai Bay Basin, East China. Three different types of mineral assemblages (MA) were identified: extensively leached feldspars with a large amount of authigenic kaolinite and quartz cement (MA-1), extensively leached feldspars with a large amount of authigenic kaolinite and minor quartz cement (MA-2), and extensively leached feldspars with a small amount of both authigenic kaolinite and quartz cement (MA-3).
Numerical simulations at the continuum scale using Geochemist’s Workbench 9.0 were conducted to decipher the origin of the different mineral assemblages. The physicochemical reactions including feldspar dissolution, transport of Al3+ and SiO2(aq), and precipitation of kaolinite and quartz are coupled together in these simulations, with constraints of chemical reactions, kinetic law, dispersion, and advection. Modeling results suggest that a dissolution zone, a transitional zone, and a precipitation zone can be formed in a sandstone unit with suitable constraints of temperature, flow rate, fluid composition and mineral reaction rate. And MA-3, MA-2, and MA-1 assemblages develop in these three zones respectively. The higher SiO2(aq) concentration required for the saturation of quartz than for kaolinite and the low Al3+ concentration needed for the saturation of kaolinite lead to the precipitation of only kaolinite in the transitional zone in a geochemical system with feldspar dissolution serving as the dominant source of SiO2(aq) and Al3+.
Comparisons between modeling results and observations of natural sandstone diagenesis suggest that an MA-1 assemblage is likely to occur in buried sandstones at high temperatures (>70–80°C) and low flow rates. An MA-2 assemblage may occur in moderately buried sandstones at moderate temperatures (40–70°C), in deeply buried sandstones with faults and fractures serving as conduits of meteoric freshwater, or in shallow sandstones where meteoric water is not abundant. An MA-3 assemblage tends to occur in shallow sandstones at low temperatures (<40–50°C) and high flow rates, or in buried sandstones where faults and fractures develop widely and serve as freshwater conduits. These proposals are valid in natural arkosic sandstones and of great significance in deciphering the diagenetic environments where the feldspar dissolution and secondary mineral precipitation have occurred.
•Sedimentary facies, diagenesis, and volcanic tuffaceous sediment affect reservoirs.•Main reservoir spaces consist of dissolved and intercrystalline pores.•Porosity is majorly reduced by compaction ...and cementation.•Depositional processes play a prominent role in controlling reservoir formation.
The Permian Shan 2 and He 1 members (Shan 2-He 1 Mbr) are the main tight gas-producing intervals in the Ordos Basin. This reservoir mainly comprises low-permeability and ultra-low-permeability fluvial–deltaic sandstones. However, the formation of tight sandstone reservoirs, particularly those associated with volcanic tuffaceous sediment, remains poorly understood. Therefore, in this study, we aimed to identify the most favourable mechanism for reservoir formation using petrological, mineralogical, scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, and porosity and permeability analyses to investigate the characteristics and porosity changes of the Shan 2-He 1 Mbr. The reservoir consists predominantly of lithic and lithic quartz sandstones, with an average porosity of 6.07% and average permeability of 0.434 mD. Depositional processes were crucial in controlling reservoir formation. Different sedimentary microfacies exhibited varying physical properties, of which coarse-grained braided bars and channel fill that formed in high-energy environments exhibited superior petrophysical properties. Rapid early compaction was the main cause of reservoir densification. Additionally, illite cement, secondary quartz grain enlargement, and late-stage carbonate cement negatively affected the reservoir quality. Secondary pores formed through the dissolution of terrigenous clasts, volcanic tuffaceous sediment (VTS), and carbonate cement. Diagenetic processes introduced heterogeneity and modified the reservoir, resulting in an effective reservoir space that comprises dissolution and intercrystalline pores, with limited primary pores. The reservoir physical properties were influenced by the sedimentary facies, siliceous mineral content, diagenetic processes, and the presence of VTS. Therefore, a comprehensive understanding of these factors is vital for identifying favourable reservoir formation conditions in the Shan 2-He 1 Mbr.
The Buchan Formation sandstone reservoirs from the Ardmore Field in the UK Central North Sea are fluvial-aeolian deposits and provide examples of porosity preservation in deeply-buried reservoirs ...(2.7–3.2 km) caused by grain-coating illite/smectite (I/S). Here, high reservoir quality commonly correlates with the occurrence of grain-coating I/S and consequent inhibition of quartz cementation in the aeolian dune and interdune sandstones. Porosity is lower in fluvial sandstones lacking grain coating I/S but with intense quartz overgrowths. We propose that the presence of I/S reflects concentration of the smectitic-rich clay bearing water which would have been the deposits of the interdune and/or distal sector of fluvial distributary system, and were introduced into aeolian deposits by mechanical infiltration. Petrographic relationships indicate that these coatings grew mainly before the mechanical compaction as the clays occur at grain contacts. The use of empirical model suggested that about 6–7% porosity have been preserved. The burial-thermal history of the Ardmore area contributed to the high quality reservoir because throughout much of the time since deposition, the Devonian sandstones have been little buried. Only from the Palaeogene the reservoir temperatures exceeded about 70 °C and rapidly buried to today’s maximum depth, which have minimized the negative effect generally ascribed to smectitic clays on reservoir quality. The circumstances of porosity preservation shown in this study may be unusual, but nonetheless have profound consequences for exploration. It is possible to identify new Buchan Formation prospects in areas hitherto dismissed because they were generally assumed to be poor reservoir.
Berea sandstone has been used by the petroleum industry as a representative model siliciclastic rock for a number of years. However, only incomplete data has been reported in the literature regarding ...its petrographic, geochemical, and petrophysical properties. In particular knowledge of the mineral distribution along the pore walls is particularly scarce, despite the fact that mineral exposed in the pore space will be crucial in determining the rock-fluid interactions that occur during core-flooding experiments. In this paper, four Berea sandstone samples (with 4 different permeability ranges from <50mD, 50–100mD. 100–200mD, and 500–1000mD) were subjected to a multi-technique characterization with an emphasis on determining the mineral composition, and distribution at the pore surface as well as pore structure and connectivity analysis. The mineral distribution was measured in two-dimensions by chemical mapping using energy dispersive X-ray spectroscopy–scanning electron microscopy (SEM–EDX). The bulk composition of the Berea sandstones was also measured by X-ray diffraction and micro-X-ray computed tomography. From this, it was found that authigenic minerals, especially clay minerals, make up a small portion of the bulk rock volume (3.3–8%) but are over-represented at the pore surfaces and in pore spaces compared to the other major mineral constituents of the rock (quartz and feldspar). The effective mineralogy, from the standpoint of rock-fluid interactions, is the mineralogy that predominates at pore surfaces. For the Berea sandstone samples studied, the effective mineralogy is represented, mainly, by kaolinite, illite, and chlorite. For 3 of the four permeability ranges studied, kaolinite is the predominant pore lining mineral observed. In the remaining sample (50–100mD), illite is the predominant mineral. In addition to SEM, we used atomic force microscopy to show that the nano-sized particles with the shape and size of clay crystals are observed on the surface of recrystallised quartz grains in a Berea sample. Regardless of their origin and identity, the presence of these particles shows that the quartz grain surfaces in Berea sandstone are more heterogeneous than previously assumed. Carbonate cement was somewhat localized throughout two of the Berea sandstone specimens, however, quartz cement is common in all of the Berea cores studied and include both microcrystalline quartz and amorphous silica phases. The pore structure within the four different Berea samples was studied using a combination of X-ray computed tomography, mercury injection porosimetry and high resolution scanning electron microscopy. Results show that two Berea sandstone permeability ranges have a bimodal pore-throat-size distribution whereas the other two were dominated by a unimodal pore-throat size distribution. SEM imaging of the pore network showed that permeability is mainly controlled by pore connectivity in the clay mineral matrix. Next to the pore connectivity, three-dimensional pore space showing both pore-to-pore and pore-to-pore-throat-to-pore relationships are also important.
•The difference in permeability is related to porosity and clay mineral composition.•Nanoscale particles may play a crucial role in defining pore surface chemistry.•Berea sandstone shows a high degree of heterogeneity across multiple length scale.
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