Global Reserves Research Articles

Detailed investigations of the influence of catalyst packing porosity on the performance of THAI-CAPRI process for in situ catalytic upgrading of heavy oil and bitumen

Heavy oils and bitumen are indispensable resources for a turbulent-free transition to a decarbonized global energy and economic system. This is because according to the analysis of the International Energy Agency’s 2020 estimates, the world requires up to 770 billion barrels of oil from now to year 2040. However, BP’s 2020 statistical review of world energy has shown that the global total reserves of the cheap-to-produce conventional oil are roughly only 520.2 billion barrels. This implies that the huge reserves of the practically unexploited difficult-and-costly-to-upgrade-and-produce heavy oils and bitumen must be immediately developed using advanced upgrading and extraction technologies which have greener credentials. Furthermore, in accordance with climate change mitigation strategies and to efficiently develop the heavy oils and bitumen resources, producers would like to maximize their upgrading within the reservoirs by using energy-efficient and environmentally friendly technologies such as the yet-to-be-fully-understood THAI-CAPRI process. The THAI-CAPRI process uses in situ combustion and in situ catalytic reactions to produce high-quality oil from heavy oils and bitumen reservoirs. However, prolonging catalyst life and effectiveness and maximizing catalytic reactions are a major challenge in the THAI-CAPRI process. Therefore, in this work, the first ever-detailed investigations of the effects of alumina-supported cobalt oxide–molybdenum oxide (CoMo/γ-Al2O3) catalyst packing porosity on the performance of the THAI-CAPRI process are performed through numerical simulations using CMG STARS. The key findings in this study include: the larger the catalyst packing porosity, the higher the accessible surface area for the mobilized oil to reach the inner coke-uncoated catalysts and thus the higher the API gravity and quality of the produced oil, which clearly indicated that sulphur and nitrogen heteroatoms were catalytically removed and replaced with hydrogen. Over the 290 min of combustion period, slightly more oil (i.e. an additional 0.43% oil originally in place (OOIP)) is recovered in the model which has the higher catalyst packing porosity. In other words, there is a cumulative oil production of 2330 cm3 when the catalyst packing porosity is 56% versus a cumulative oil production of 2300 cm3 in the model whose catalyst packing porosity is 45%. The larger the catalyst packing porosity, the lower the mass and thus cost of the catalyst required per m3 of annular space around the horizontal producer well. The peak temperature and the very small amount of produced oxygen are only marginally affected by the catalyst packing porosity, thereby implying that the extents of the combustion and thermal cracking reactions are respectively the same in both models. Thus, the higher upgrading achieved in the model whose catalyst packing porosity is 56% is purely due to the fact that the extent of the catalytic reactions in the model is larger than those in the model whose catalyst packing porosity is 45%.

The geopolitical weight of the major producers in the world oil map

Since crude oil is one of the most important sources of energy, and the focus of global conflict revolves around it at present, it is necessary to track the production of crude oil, which is one of the most important factors affecting global economic growth, and the geopolitics of both producing and consuming countries. The research problem was summed up in that crude oil has become the main engine of international conflicts on the global political map. The speed of changes in the global oil map requires research and continuous monitoring of the events and conflicts caused by crude oil. The research reached a number of results, most notably, that the main actors in the map of global oil reserves, whether they are regions or countries, are the same actors in the map of global crude oil production, and they are the same longest-lived in the global depletion of crude oil. This importance was the reason for it to gain geopolitical weight, which directly contributed to igniting the struggle of the major powers to control it by all possible means, politically, militarily, and economically

WORLD AND TURKEY’S NATURAL GAS DEMAND SCENARIO

Although the global energy demand varies from country to country, it is constantly increasing on a global scale. As per IEA’s projections, the usage of two energy sources will increase (renewable with 12% and natural gas with 28%) in the global energy demand until 2040. In the study, 48 number of experts/managers (Decision Makers-DM) working in the energy sector were interviewed to establish/determine 10 main criteria and 43 sub-criteria used in demand scenarios. In the study, fuzzy multi-objective mathematical model (by using fuzzy AHP, and fuzzy TOPSIS) is developed to calculate World's and Turkey’s natural gas demand under high and low demand scenarios. By the help of model, the usage of natural gas amount in World by regions between 2020 and 2030 is calculated. In Scenario-High it will increase by approx. 26 % between 2020 and 2030 and reached 4.800 bcm in 2040. In Scenario-Low it will increase by approx. 5 % from 2020 to 2030 and reached 4.000 bcm in 2030. It is the only fossil fuel expected to grow beyond 2030 since it is clean energy source. In Scenario-High natural gas demand by region is calculated/projected as follows: in 2030 North America 1250 bcm, Central and South America 250 bcm, Europe 650 bcm, Middle East 750 bcm, Eurasia 650 bcm, Asia Pacific 1250 bcm. In the study, under the high demand scenario it has been calculated that the usage of natural gas in Turkey will increase by 52% between 2020 and 2030 and reach approximately 76 bcm, and in the low demand scenario Turkey's total natural gas demand will decrease by approximately 9% and reach approximately 45 bcm. In the study by using Fuzzy TOPSIS method, 10 number of sectors are examined and “Energy sector” was the first and “Industry sector” was the second in the ranking of the sectors in terms of global and Turkey’s natural gas demand scenario. In the study, the usage of natural gas is the only fossil resource that is expected to increase in the global energy mix among fossil fuels in 2030. This is due to high reserve amount of natural gas, i.e. global conventional natural gas reserves with 206 trillion m3 and unconventional unexplored natural gas reserves with 354 trillion m3, and as well as being a clean and environmental-friendly energy source. Since it is a clean fossil fuel and it pollutes nature & air much less than other fossil fuels and has a minimum greenhouse gas emission amount compared to other fossil sources.

Patient Blood Management in intensive care patients

Patients admitted to ICUs are a heterogeneous group, displaying multiple anaemia risk factors and comorbidities. Clinicians should therefore take all possible measures to identify modifiable risks. Patient Blood Management (PBM) is an approach promoting the timely application of evidence-based interventions designed to maintain patients own blood mass. Within ICU-patients, anaemia is highly prevalent. Generally, anaemia is associated with impaired outcome and need of blood transfusion. Currently, with ICUs working at full capacity and the global blood reserves exhausted, the SARS-CoV-2 pandemic reinforces the need for PBM implementation. For instance, implementation of a comprehensive coagulation management and measures to avoid iatrogenic blood loss may prevent bleeding-associated complications and adherence to blood transfusion guidelines may reduce adverse events associated with transfusion. Critically ill patients display various morbidities often requiring individualized treatment. PBM offers patient-centred measures to improve outcome any time during hospital stay.

Improving heavy oil production rates in THAI process using wells configured in a staggered line drive (SLD) instead of in a direct line drive (DLD) configuration: detailed simulation investigations

As governments around the world prepare for a transition period to a decarbonised energy and economic future, petroleum is needed to smoothen that transition. Based on the analysis of the International Energy Agency’s 2020 projections, around 770 billion barrels of oil are required to meet demand from now to 2040. However, according to British Petroleum’s Statistical Review of World Energy 2020, as at the end of 2019, the global total reserves of recoverable conventional and unconventional oils is approximately 1734 billion barrels. Out of that, the conventional easy-to-produce light oil accounts for only 30% (i.e. accounts for only 520.2 billion barrels). Therefore, the remaining 249.8 billion barrels of oil needed to satisfy demand up to 2040 must come from unconventional oils, namely heavy oils and bitumen. However, these unconventional resources are very difficult to produce and the current production methods have very high environmental footprints. Consequently, in accordance with climate crisis mitigations, the vast reserves of the virtually unexploited heavy oils and bitumen must be developed using advanced and greener extraction technologies, such as the yet-to-be-fully-understood THAI process which provides partial upgrading of heavy oil/bitumen via in situ combustion. Using validated numerical models which are developed using the CMG’s reservoir thermal simulator, the STARS, which is also used in this study, field scale reservoir simulations of the THAI process were performed with the wells arranged in staggered line drive (SLD) and direct line drive (DLD). Over the 834 days of operating time, the cumulative oil recovery in SLD is 32% of oil originally in place (OOIP) which is equivalent to 26,100 m3 whilst that in DLD is 27% OOIP. This shows that more oil (i.e. an additional 5% OOIP) was cumulatively recovered in SLD compared to in DLD model. It is found that smaller reservoir volume was swept by the combustion front in DLD and thus making the heat-affected reservoir volume smaller than that in SLD model. Furthermore, in DLD, due to the nearness of the injector well to the toe of the horizontal producer (HP) well, oxygen production began much earlier, compared to in the SLD. It is also found that the temperature of the mobile oil zone is higher in the SLD model compared to that in the DLD model. This implies that higher quality oil is produced when the wells are configured in the SLD pattern. Therefore, this first-of-a-kind work has shown that SLD arrangement is far more efficient, safer, and produces higher quality oil than DLD pattern and that actual process engineering designs should use SLD wells configuration.

Will Plant Genome Editing Play a Decisive Role in "Quantum-Leap" Improvements in Crop Yield to Feed an Increasing Global Human Population?

Growing scientific evidence demonstrates unprecedented planetary-scale human impacts on the Earth’s system with a predicted threat to the existence of the terrestrial biosphere due to population increase, resource depletion, and pollution. Food systems account for 21–34% of global carbon dioxide (CO2) emissions. Over the past half-century, water and land-use changes have significantly impacted ecosystems, biogeochemical cycles, biodiversity, and climate. At the same time, food production is falling behind consumption, and global grain reserves are shrinking. Some predictions suggest that crop yields must approximately double by 2050 to adequately feed an increasing global population without a large expansion of crop area. To achieve this, “quantum-leap” improvements in crop cultivar productivity are needed within very narrow planetary boundaries of permissible environmental perturbations. Strategies for such a “quantum-leap” include mutation breeding and genetic engineering of known crop genome sequences. Synthetic biology makes it possible to synthesize DNA fragments of any desired sequence, and modern bioinformatics tools may hopefully provide an efficient way to identify targets for directed modification of selected genes responsible for known important agronomic traits. CRISPR/Cas9 is a new technology for incorporating seamless directed modifications into genomes; it is being widely investigated for its potential to enhance the efficiency of crop production. We consider the optimism associated with the new genetic technologies in terms of the complexity of most agronomic traits, especially crop yield potential (Yp) limits. We also discuss the possible directions of overcoming these limits and alternative ways of providing humanity with food without transgressing planetary boundaries. In conclusion, we support the long-debated idea that new technologies are unlikely to provide a rapidly growing population with significantly increased crop yield. Instead, we suggest that delicately balanced humane measures to limit its growth and the amount of food consumed per capita are highly desirable for the foreseeable future.

CORRELATION OF OIL AND GAS RESOURCES OF THE CASPIAN COUNTRIES

The Caspian Sea is the largest body of water in Eurasia: After the collapse of the USSR, the water area of this region is a zone of interest for many states. [1] The Caspian region rightfully serves as one of the most significant regions for most countries interested in the mineral resources that the Caspian is rich in. The Caspian Sea has a significant hydrocarbon reserves. According to the Energy Information Administration (EIA), hydrocarbon resources in the Caspian basin have the following values: oil - 48 billion barrels of oil, natural gas - 292 trillion. cubic feet (found and probable reserves), of which 75% and 67%, respectively, are produced or may be produced offshore. The northern part of the Caspian Sea contains most of the oil reserves, while the southern sector of the Caspian Sea is rich in natural gas.[2] It should be emphasized that the list of states that have the rights to use the resources of the Caspian Sea is as follows: Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. It is impossible to correlate the importance of the oil and gas resources of the Caspian reservoir for each of the above countries, for the following reasons: Azerbaijan and Turkmenistan are countries for which the hydrocarbon potential of the Caspian is the most important predictor of the formation and development of the economy, while for Kazakhstan, the use of oil and gas resources of the Caspian Sea plays an important , but not the most decisive role, since oil and gas deposits in this country are not limited to the Caspian region, but its economy is developing in other directions. Iran and Russia, however, are interested in influencing the direction of flows of oil and gas raw materials, including their transit through the territory of the countries. [3] The last years for the Caspian region have become the years of a shift in the development of the oil and gas industry of the Caspian "five", which account for 17.6% of oil reserves and 46.4% of gas reserves in terms of global reserves. It is assumed that on the territory of the Caspian shelf, which belongs to Russia, oil reserves amount to 270 million tons, natural gas reserves - 0.5 trillion cubic meters. m of gas. [4] Of course, it is worth noting that the potential of the Russian sector of the Caspian Sea is significantly lower than the oil and gas potential of Yamal or Western Siberia, but the development of this region is important for the strategic development of the oil and gas sector, in particular offshore drilling.

Comparative analysis of copper dissolution and mineral transformations in coarse chalcopyrite for different oxidant/lixiviant systems at elevated temperature (110 °C and 170 °C)

Chalcopyrite (CuFeS2) is the most common copper-bearing mineral and represents more than half of global copper mineral reserves. The decrease in copper reserves and increase in demand for copper has led to an increased interest in hydrometallurgical approaches to copper mining. Copper extraction from copper sulfides such as chalcopyrite, requires oxidant addition for dissolution. Although numerous lixiviants have been evaluated, limited information is available regarding fluid–rock interactions during the leaching of coarse chalcopyrite samples at high temperature, including their stabilities and secondary product formation. This study compares the thermal stability of eleven oxidant/lixiviant systems (sulfuric acid, methanesulfonic acid, ammonium hydroxide, hydrochloric acid and glycine, and oxidants, including oxygen, iron(III), copper(II), dichromate, sodium nitrate, peroxydisulfate and hydrogen peroxide) and their ability to leach copper from chalcopyrite at 110 °C (below the sulfur melting point) and 170 °C (above the sulfur melting point) under similar conditions. Tests were conducted for up to 576 h using solid cuboids (4 mm side lengths) to simulate in-situ recovery conditions. Sealed batch and Parr reactors were used to simulate an anoxic environment that may be encountered in a subterranean application. This paper presents the findings from the study and compares the leaching systems at 110 °C and 170 °C based on copper release into solution, reaction products, passivation phenomena and textural analysis. The application potential of the systems for in-situ recovery from deep copper ore bodies is discussed based on the performance of the chosen systems.

Influence of Particle Size Distribution on the Physical Characteristics of Pore-Filling Hydrate-Bearing Sediment

Nature gas hydrates (NGHs) are regarded as a potential alternative energy source due to their huge reserves and wide distribution. According to the geophysical surveys, the pore-filling hydrates occupy a large proportion of the global hydrate reserves, especially for the marine regions. Therefore, with a novel pore-scale 3D morphological modeling algorithm, this study systematically studied the effect of the particle size on the physical characteristics of the pore-filling hydrate-bearing sediment (HBS). The pore system evaluations and permeability simulations were performed by utilizing pore network modeling (PNM), and the thermal and electrical simulations were conducted by utilizing a finite volume method (FVM). The results show that for the HBS with smaller particle size, the average radius of the pores and throats would also be reduced, and the fractal dimension of the pore system would be increased. In addition, with the increasing hydrate saturation, the fractal dimension of the pore system will increase firstly and then decrease. And these parameter evolutions could impact the physical properties correspondingly; specifically, the decreasing particle size in the HBS would reduce the permeability and electrical conductivity of HBS and enhance the apparent thermal conductivity of HBS.

Influence of Wetting on Viscous Fingering Via 2D Lattice Boltzmann Simulations

We present simulations of two-phase flow using the Rothman and Keller colour gradient Lattice Boltzmann method to study viscous fingering when a “red fluid” invades a porous model initially filled with a “blue” fluid with different viscosity. We conducted eleven suites of 81 numerical experiments totalling 891 simulations, where each suite had a different random realization of the porous model and spanned viscosity ratios in the range Min [0.01,100] and wetting angles in the range theta _win [180^circ ,0^circ ] to allow us to study the effect of these parameters on the fluid-displacement morphology and saturation at breakthrough (sweep). Although sweep often increased with wettability, this was not always so and the sweep phase space landscape, defined as the difference in saturation at a given wetting angle relative to saturation for the non-wetting case, had hills, ridges and valleys. At low viscosity ratios, flow at breakthrough is localized through narrow fingers that span the model. After breakthrough, the flow field continues to evolve and the saturation continues to increase albeit at a reduced rate, and eventually exceeds 90% for both non-wetting and wetting cases. The existence of a complicated sweep phase space at breakthrough, and continued post-breakthrough evolution suggests the hydrodynamics and sweep is a complicated function of wetting angle, viscosity ratio and time, which has major potential implications to Enhanced Oil Recovery by water flooding, and hence, on estimates of global oil reserves. Validation of these results via experiments is required to ensure they translate to field studies.

Elevation and Volume Changes in Greenland Ice Sheet From 2010 to 2019 Derived From Altimetry Data

Long-term altimetry data are one of the major sources to analyze the change in global ice reserves. This study focuses on the elevation and volume changes in the Greenland ice sheet (GrIS) from 2010 to 2019 derived from altimetry observations. In this study, the methods for determining surface elevation change rates are discussed, and specific strategies are designed. A new elevation difference method is proposed for CryoSat-2 synthetic aperture interferometric (SARin) mode observations. Through validation with Airborne Topographic Mapper (ATM) data, this new method is proved to be effective for slope terrains at the margins of the ice sheet. Meanwhile, a surface fit method is applied for the flat interior of the ice sheet where low resolution mode (LRM) observations are provided. The results of elevation change rates in the GrIS from 2010 to 2019 are eventually calculated by combining CryoSat-2 and ATM observations. An elevation change rate of −11.83 ± 1.14 cm·a−1 is revealed, corresponding to a volume change rate of −200.22 ± 18.26 km3·a−1. The results are compared with the elevation changes determined by Ice, Cloud, and Land Elevation Satellite (ICESat) from 2003 to 2009. Our results show that the overall volume change rate in the GrIS slowed down by approximately 10% during the past decade, and that the main contributor of GrIS ice loss has shifted from the southeast coast to the west margin of the ice sheet.

Surface Defect-Induced Site-Specific Dispersion of Pd Nanoclusters on TiO2 Nanoparticles for Semihydrogenation of Phenyl Acetylene

Currently, the wide application of heterogeneous noble metal catalysts is greatly limited due to their high cost and scarcity in global reserves. Thus, an effective strategy is to design highly eff...

Mixed electron-ion-water transfer in macromolecular radicals for metal-free aqueous batteries

Metal-free aqueous batteries offer environmentally friendly energy storage without depleting the global reserves of strategic elements. These batteries consist of solid, redox-active polymeric anodes and cathodes with a water-based electrolyte. However, the performance of available active polymers remains inferior, and design principles to guide future development are lacking. Here, we report on the coupled mass, electron, and water transfer behavior for a series of non-conjugated nitroxide radical polymers in a water-based electrolyte-containing organic salt for guiding future design. In situ monitoring of the charge-discharge process reveals the important role of polymer-water interactions. Specifically, improved polymer-water interactions manifest in accelerated kinetics, which promote capacity retention at higher discharge rates. The most hydrophilic polymer, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl acrylamide) (PTAm), yielded a capacity of 115 mAh/g, or 97% of its theoretical value, at 0.05 mA/cm2. At 5 mA/cm2, the PTAm capacity remained relatively high at 50 mAh/g, whereas comparable polymer capacities were much lower.

What's in Our Future? An Earth 'Twin' Will Tell Us [Environment Digital Twin

MISFORTUNES never come singly, says an old proverb. And so, as the Covid-19 pandemic continued wreaking havoc in the world, the UN Food and Agriculture Organization (FAO) revealed in January 2021 that prices of key crops had been rising at the highest rate in six years. Wars, pest infestations, droughts, hurricanes and floods disrupted agriculture in many parts of the world over the course of the ill-fated 2020 and suddenly, there was less produce left in global reserves. The price of soy shot up by 56 per cent compared to the previous year; corn gained 45 per cent. While not as serious as the global food crises of the late 2000s, the trend was concerning especially for poorer countries, according to FAO.

STUDYING THE COST AND BENIFIT TO INCREASE THE ADDED VALUE OF THE ILEMENIT MINERAL EXTRACTED FROM THE EGYPTIAN BLACK SAND USING A SHREDDER

The researchers aim to shed light on the economic importance of the Egyptian black sands and the economic minerals extracted from them, and to determine the global and Egyptian reserves from them. The study also deals with raising the added value of ilmenite extracted from Egyptian black sand in order to produce ferotitanium alloy, and prepare an integrated vision to determine the possibility of establishing industrial projects to raise the economic value of ilmenite through the application of methods used in rationalizing costs, using the descriptive analytical method in order to increase the national product accordingly. This study was applied to the black sands of the Rosetta site in the North Delta, which is one of the field work sites of the Nuclear Materials Authority. Ferrotitanium alloy is one of the most widely used alloys in the steel and stainless steel industries, the paint industry, and the missile and aircraft industry. The study concluded that it is possible to increase the revenue generated from the production of ferotitanium alloy and raise the economic added value of ilmenite by using raw materials in different mixing methods that lead to rationalization of costs, achieving sustainable development goals and increasing national income. The researchers recommend expanding the application of the proposal to use the shredder machine in extracting the aluminite metal due to the rationalization of costs, an increase in the revenue, and raising the added value of the aluminite mineral, the need to maintain the quality of production and the introduction of continuous improvements to rationalize the indirect costs, as well as the necessity to supply the Nuclear Materials Authority with supplies, tools and devices used in the exploration of black sand areas throughout Egypt, and the use of fuel derived from solid waste plastic (RDF) instead of natural gas to save energy costs.

World’s Largest Gas-Producing Nations: Natural Gas Will Keep the Lights on for the Next Generation

Natural gas is almost certain to be the fastest-growing fossil fuel in the global energy mix for decades to come, comprising 28% of the global energy mix by 2050. Together with renewables, natural gas will likely fuel 60% of global electricity production, be it as pipeline gas, liquefied natural gas (LNG), or blue hydrogen. These are among the forecasts that appear in the 2020 edition of the GECF (Gas Exporting Countries Forum) Global Gas Outlook 2050 released in February 2021 and providing short-, medium-, and long-term energy projections based on assumptions regarding macroeconomic conditions, energy prices, and policies. The report is updated yearly and is the flagship publication of the organization, which represents countries that control 71% of global gas reserves. It is unique in that it focuses exclusively on the global gas industry, which today is providing for 23% of global energy needs. Headquartered in Doha, Qatar, the GECF is an intergovernmental organization comprising 11 member countries and nine observer states, established in 2001 by Russia and Iran. Moscow and Tehran had hoped that GECF would eventually morph into a “Gas OPEC” but that never happened. The organization’s analyses and forecasts do, however, present a worthwhile snapshot of how the world’s largest gas producers see the industry. Member states in GECF include Algeria, Bolivia, Egypt, Equatorial Guinea, Iran, Libya, Nigeria, Qatar, Russia, Trinidad and Tobago, and Venezuela. Observer countries are Angola, Azerbaijan, Iraq, Kazakhstan, Malaysia, Norway, Oman, Peru, and the UAE. Unconventional Gas To Play Growing Role In its report, the GECF noted that unconventional resources will be playing a growing role in the market and that gas producers will need to emphasize unconventional projects to satisfy growing demand, as well as to invest heavily into exploration to identify and tap into new gas reserves and develop greenfield projects. “It is also important to highlight the increasing interest in hydrogen as a lever to support the deep decarbonization of the world’s economies,” Yury P. Sentyurin, GECF’s Secretary General, wrote in his introduction to the annual outlook. In mentioning hydrogen, Sentyurin is speaking about “blue hydrogen” which is produced from natural gas, and which, when combined with CCUS (carbon capture, utilization, storage) can marry commercial and environmental interests, further positioning natural gas as a transition fuel to bridge the gap between fossil fuels and renewable sources of energy. Blue hydrogen is in fact expected to satisfy half of the hydrogen demand projected worldwide by 2050, Sentyurin points out. Policies being set by countries in the European Union have focused more on costly “green hydrogen” produced from renewable sources; but not in the policies of other nations in regions of the world where growth in energy demand is expected to be the highest. Growth in European energy demand is largely flat.

Optimising development and production of naturally fractured reservoirs using a large empirical dataset

Naturally fractured reservoirs are important contributors to global petroleum reserves and production. Existing classification schemes for fractured reservoirs do not adequately differentiate between certain types of fractured reservoirs, leading to difficulty in understanding fundamental controls on reservoir performance and recovery efficiency. Three hundred naturally fractured reservoirs were examined to define a new classification scheme that is independent of the type of fracturing and describes fundamentally different matrix types, rock properties, fluid storage and flow characteristics. This study categorises fractured reservoirs in three groups: (1) Type 1: characterized by a tight matrix where fractures and solution-enhanced fracture porosity provide both storage capacity and fluid-flow pathways; (2) Type 2: characterized by a macroporous matrix which provides the primary storage capacity where fractures and solution-enhanced fracture porosity provide essential fluid-flow pathways; and (3) Type 3: characterized by a microporous matrix which provides all storage capacity where fractures only provide essential fluid-flow pathways. Differentiation is made between controls imparted by inherent natural conditions, such as rock and fluid properties and natural drive mechanisms, and human controls, such as choice of development scheme and reservoir management practices. The classification scheme presented here is based on reservoir and production characteristics of naturally fractured reservoirs and represents a refinement of existing schemes. This refinement allows accurate comparisons to be made between analogous fractured reservoirs, and trends and outliers in reservoir performance to be identified. Case histories provided herein demonstrate the practical application of this new classification scheme and the benefits that arise when applying it to the understanding of naturally fractured reservoirs.

Fracture Properties of Nash Point Limestone and Implications for Fracturing of Layered Carbonate Sequences

Carbonate reservoirs accommodate a significant proportion of global hydrocarbon reserves. However they are often tight and permeability is therefore usually dependent on either flow through existing fractures or through those produced by hydraulic stimulation. Hence, understanding how fracture networks develop in carbonate reservoir rocks is key to efficient and effective production. However, despite their prevalence as reservoir rocks, there is a paucity of data on key fracture properties of carbonate rocks, particularly in more than one orientation. Here, therefore we report measurements of both the tensile strength and fracture toughness of Nash Point limestone in the three principal fracture orientations to determine what effect any mechanical anisotropy might have on fracture propagation. We find Nash Point limestone to be essentially isotropic in terms of both its microstructure and its fracture properties. When comparing the fracture toughness of Nash Point limestone with that of others limestones, we find that fracture toughness decreases with increasing porosity, although this dependency is not as strong as found in other porous rocks. Finally, as many so-called carbonate reservoirs actually comprise layered sequences, we extend our analysis to consider the layered sequence of limestones and shales at Nash Point. We find that the fracture toughness of Nash Point limestone is higher than Nash Point shale but that the fracture energy is lower. We therefore discuss how the implications of fracturing through multi-layered sequences could be explored in future work.

Optimization of Criterion for Rock Crack Propagation under Acid Izing Treatment

Since most of the conventional oil and gas resources have been intensively investigated, unconventional oil and gas resources such as deep marine carbonate reservoirs and heavy oil reservoirs have become the primary focus in the exploration and development of oil and gas. The oil and gas reservoirs with complex fracture geometries account for nearly 45% of the global oil and gas reserves, and the production of such complex fractured oil and gas reservoirs accounts for nearly 60% of the total natural gas production. Consequently, fractured oil and gas reservoirs have received considerable research attention in recent years. Further, fractures determine the permeability and productivity of petroliferous reservoirs. In this paper, we have investigated the current status of research on petroliferous rock under the action of acid etching. At the same time, we have summarized the existing rock fracture propagation criterion and crack propagation criterion theory, and selected the most common crack propagation criterion for setting simulation parameters. Subsequently, the Brazilian split test and the rock acidification sensitivity experiment are combined, and the comparative experiment method is used to obtain the hydrochloric acid concentration and acidification treatment time that can meet the DIC optical test. Through the DIC method, the expansion of rock cracks from the moment of loading of experimental species to the moment when the completion of splitting is recorded, the strain and displacement of each point on the rock surface during the Brazilian splitting test are obtained. Finally, through the ABAQUS software, different fracture propagation criteria are used to simulate the fracture propagation process in the rock samples in the Brazilian fracturing test, and the results are recorded. Then, the expansion model is selected that best fits the carbonate fracture before and after acid etching. The in-situ stress field of the fault zone in the Shunbei area is exceedingly complex. Based on the Shunbei area, the model is set up. Furthermore, the features of plane geomechanics are studied, and the fracture propagation laws of acid salt reaction are analyzed. The results provide the basis for optimizing the acid fracturing technology and construction parameters in the Shunbei area.

The material foundations of a low-carbon economy

The material foundations of a low-carbon economy