IFP School

The majority of global energy scenarios anticipate a structural break in the relationship between energy consumption and gross domestic product (GDP), with several scenarios projecting absolute decoupling, where energy use falls while GDP continues to grow. However, there are few precedents for absolute decoupling, and current global trends are in the opposite direction. This paper explores one possible explanation for the historical close relationship between energy consumption and GDP, namely that the economy-wide rebound effects from improved energy efficiency are larger than is commonly assumed. We review the evidence on the size of economy-wide rebound effects and explore whether and how such effects are taken into account within the models used to produce global energy scenarios. We find the evidence base to be growing in size and quality, but remarkably diverse in terms of the methodologies employed, assumptions used, and rebound mechanisms included. Despite this diversity, the results are broadly consistent and suggest that economy-wide rebound effects may erode more than half of the expected energy savings from improved energy efficiency. We also find that many of the mechanisms driving rebound effects are overlooked by integrated assessment and global energy models. We therefore conclude that global energy scenarios may underestimate the future rate of growth of global energy demand.

Abstract A regional sequence stratigraphic model is proposed for the Oligo-Miocene Asmari and Pabdeh Formations in the Dezful Embayment of SW Iran. The model is based on both new detailed sedimentological observations in outcrops, core and well logs, and an improved high-resolution chronostratigraphic framework constrained by Sr isotope stratigraphy and biostratigraphy. A better understanding of the stratigraphic architecture distinguishes four, geographically separated types of Asmari reservoirs. Three Oligocene sequences (of Rupelian, early Chattian and late Chattian age) and three Miocene sequences (of early Aquitanian, late Aquitanian and early Burdigalian age) have been distinguished, representing a period of 15.4 Ma. The stratigraphic architecture of these sequences is primarily controlled by glacio-eustatic sea-level fluctuations, which determined the distribution of carbonates, sandstones and anhydrites in this sedimentary system. Tectonic control became important in the Burdigalian with a regional tilt down towards the NE. The lithological heterogeneity, the complex geometries, and both early and late diagenetic alterations are the basis for a classification of four main stratigraphic reference types for the Asmari Reservoirs: Type 1, sandstone dominated; Type 2, mixed carbonate-siliciclastic; Type 3, mixed carbonate-anhydrite; and Type 4, carbonate dominated. The sequence stratigraphic model predicts how and when these types change laterally from one to another.

Abstract In today’s race to find ways to produce cheap and green hydrogen, the natural hydrogen wells in Bourakebougou offer a promising solution and are a good example of how H 2 can be produced in the natural environment. Not only has one well been successfully exploited to generate electricity for the local village, but twenty-four other exploratory boreholes have also demonstrated the presence of natural H 2 in the surrounding area. The Bourakebougou H 2 field offers a unique opportunity for geoscientists to determine the key characteristics of natural hydrogen reservoirs. This paper presents the coring, logging, and geochemistry studies that were performed to better characterize the nature of the Bourakebougou H 2 -bearing reservoirs. The shallowest main reservoir, in which there is the highest content of H 2 , is made of dolomitic carbonate (Neoproterozoic cap carbonate). These carbonates are largely karstified and show a high degree of heterogeneity in porosity (0.21–14.32%). Based on the analysis of the drilling imagery of the carbonated reservoirs, the accumulation of hydrogen occurs in the karst (void) representing a secondary porosity in the rock matrix. Other reservoirs, especially the deepest ones, are porous sandstone rocks with much more homogeneous porosities (4.52–6.37%) compared to the massive carbonates. For the wells analysed, the neutron tool reacted in a specific way when there is the presence of hydrogen. Hence, it stands out as being the primary tool to detect the presence of natural hydrogen beyond simple gas logging. When comparing a H 2 reservoir system to classical oil and gas reservoir systems, the results show that the hydrogen reservoir is a dynamic system that is progressively recharged in H 2 -rich gas at the production timescale.

Offshore the emissions of dihydrogen are highlighted by the smokers along the oceanic ridges. Onshore in situ measurements in ophiolitic contexts and in old cratons have also proven the existence of numerous H2 emissive areas. When H2 emanations affect the soils, small depressions and vegetation gaps are observed. These depressions, called fairy circles, have similarities with the pockmark and vent structures recognized for long time in the sea floor when natural gas escapes but also differences. In this paper we present a statistic approach of the density, size, and shape of the fairy circles in various basins. New data from Brazil and Australia are compared to the existing database already gathered in Russia, USA, and again Brazil. The comparison suggests that Australia could be one of the most promising areas for H2 exploration, de facto a couple of wells already found H2, whereas they were drilled to look for hydrocarbons. The sum of areas from where H2 is seeping overpasses 45 km2 in Kangaroo Island as in the Yorke Peninsula. The size of the emitting structures, expressed in average diameter, varies from few meters to kilometers and the footprint expressed in % of the ground within the structures varies from 1 to 17%. However, globally the sets of fairy circles in the various basins are rather similar and one may consider that their characteristics are homogeneous and may help to characterize these H2 emitting zones. Two kinds of size repartitions are observed, one with two maxima (25 m and between 220 m ± 25%) one with a simple Gaussian shape with a single maximum around 175 m ± 20%. Various geomorphological characteristics allow us to differentiate depressions of the ground due to gas emissions from karstic dolines. The more relevant ones are their slope and the ratio diameter vs. depth. At the opposite of the pockmark structures observed on the seafloor for which exclusion zones have been described, the H2 emitting structures may intersect and they often growth by coalescence. These H2 emitting structures are always observed, up to now, above Archean or Neoproterozoic cratons; it suggests that anoxia at the time the sedimentation and iron content play a key role in the H2 sourcing.

Abstract The recent evolution of ideas on the Mediterranean region has been triggered by very active data acquisition over the last 15 years. Seismic tomography provides an unique view of mantle heterogeneities, space geodesy leads to precise determinations of the present strain and velocity fields, the combination of structural geology, radiometric dating and metamorphic petrology allows the description of P-T-t-D paths of exhumed metamorphic rocks, and exploration geophysics, onshore and offshore, gives a detailed view of the crustal geometry. Extension started in the Gulf of Lion and propagated eastwards and southwestwards to form the Liguro-Provençal basin, Tyrrhenian Sea and the Alboran Sea. It also started, at much the same time, in the Panonnian basin as well as in the Aegean back-arc region. Thus a seminal event occurred some 30 Ma ago that produced a sharp change from overall compression to back-arc extension. Although gravitational forces due to the collapse of a thick crust have affected most basins, it is now almost certain that this event ultimately originated in the mantle, either by slab detachment, slab rollback or both processes acting in sequence.

Government innovation subsidies play an important role as a policy to incentivize green transformation of enterprises, but whether government innovation subsidies can reduce the carbon intensity of industrial enterprises is still unclear, the exploration of the impact pathway needs to be further developed. This study takes government innovation subsidies as the entry point. It takes Chinese industrial listed companies as the research object from 2007 to 2021, explores the internal mechanism of government innovation subsidies on carbon intensity of industrial enterprises, analyzes the heterogeneity of the impact of government innovation subsidies on the carbon intensity of government innovation subsidies, and finally compares the differences arising from the governance effects of the policies of government innovation subsidies and government non-innovation subsidies. The results of the study show that: 1. Government innovation subsidies are beneficial for improving the energy utilization efficiency of enterprises and significantly reducing carbon intensity, unit government innovation subsidies can reduce the carbon dioxide emissions of industrial enterprises by 11.069 tons per 10,000 yuan of output value; 2. Government innovation subsidies can effectively incentivize industrial enterprises to carry out green technological innovations, and improve the quantity and quality of green technological innovation; 3. Government innovation subsidies can reduce carbon intensity of industrial enterprises by incentivizing the green technological innovations of enterprises to "increase the quantity and improve the quality". In fact, carbon intensity of industrial enterprises could be significantly reduced by incentivizing green technological innovation. Heterogeneity analysis shows that the greater the pressure of environmental tax and the higher the degree of market competition, the stronger is the effect of government innovation subsidies in reducing carbon intensity. The inclusion of government non-innovation subsidies in the control study shows that government innovation subsidies with innovation orientation motivate industrial enterprises to reduce carbon emissions significantly more than those subsidies without innovation orientation. In conclusion, this study provides a practical reference for the promotion of green technological innovation in enterprises to "increase the quantity and improve the quality" and reduce carbon intensity, as well as a revelation for the adoption of differentiated policies for different enterprises.

Abstract As current action remains insufficient to meet the goals of the Paris agreement let alone to stabilize the climate, there is increasing hope that solutions related to demand, services and social aspects of climate change mitigation can close the gap. However, given these topics are not investigated by a single epistemic community, the literature base underpinning the associated research continues to be undefined. Here, we aim to delineate a plausible body of literature capturing a comprehensive spectrum of demand, services and social aspects of climate change mitigation. As method we use a novel double-stacked expert—machine learning research architecture and expert evaluation to develop a typology and map key messages relevant for climate change mitigation within this body of literature. First, relying on the official key words provided to the Intergovernmental Panel on Climate Change by governments (across 17 queries), and on specific investigations of domain experts (27 queries), we identify 121 165 non-unique and 99 065 unique academic publications covering issues relevant for demand-side mitigation. Second, we identify a literature typology with four key clusters: policy, housing, mobility, and food/consumption. Third, we systematically extract key content-based insights finding that the housing literature emphasizes social and collective action, whereas the food/consumption literatures highlight behavioral change, but insights also demonstrate the dynamic relationship between behavioral change and social norms. All clusters point to the possibility of improved public health as a result of demand-side solutions. The centrality of the policy cluster suggests that political actions are what bring the different specific approaches together. Fourth, by mapping the underlying epistemic communities we find that researchers are already highly interconnected, glued together by common interests in sustainability and energy demand. We conclude by outlining avenues for interdisciplinary collaboration, synthetic analysis, community building, and by suggesting next steps for evaluating this body of literature.

The lack of precise mathematical model of nonlinear systems, such as electric machines, brings certain limits to design a powerful controller for such systems. This article presents a model-free-adaptive-control (MFAC) scheme as a good alternative to the commonly used model-based-control (MBC) methods in order to improve the controller design limitations due to the need for system model information. In this regard, an MFAC is developed in this article for current control of a wound rotor synchronous machine (WRSM) drive system and compared with a proportional-integral (PI) controller as a well-known model-based controller. Since the controller performance can be affected by unexpected phenomena, such as model errors, parameter variations, and changes in operating point, beforehand, the robustness of developed MFAC is first tested under the mentioned conditions in the simulation area. Then, through experimental validation on a specifically designed test bench, a satisfactory performance was obtained for the MFAC scheme.

Between 35 and 71% of the decarbonization of aviation is expected to be achieved through sustainable aviation fuels (SAF). This ambition implies that energy production must swiftly start supplying large quantities of SAF, considering the current total dependency on fossil fuels. This review analyzes the factors influencing present and future SAF market availability – namely resources, technologies, and costs – and attempts to assess the credibility of SAF development scenarios. Our findings highlight two main challenges: (1) short-term capacity building of a SAF industry still stuck in its infancy, and (2) mid to long-term disproportionate resource requirements. Significant investments from all the industry players, not just energy providers and states, as well as dedicated regulations, are required to overcome the technology, energy, investment, and cost barriers hindering SAF development. Another issue concerns the sustainability of the sector’s future demand expansion. The envisioned growth rates will induce excessive biomass, hydrogen, and electricity consumption, jeopardizing other sectors’ transition pathways. Overall, the analysis questions the relevance of the resource allocation implicitly used in current industry scenarios for 2050, an assumption with essential environmental, social, and ethical implications. Against this background, policies aimed at lowering demand expansion seem unavoidable if there is any chance of achieving net zero by 2050. • SAF is not developing fast enough to reach aviation decarbonization goals. • SAF technologies are less energy efficient than fossil fuel, and hence more costly. • High and rapid investment from all the aviation actors is needed to scale up SAF. • Current aviation market predictions are unsustainable by 2050. • Policy is needed allocate decarbonization resources fairly among sectors.

This paper deals with the principle of pollutant emissions defined by Leontief in 1971, based on a fixed coefficient model. I have tested the plausibility of this model by attempting to replicate data on French emissions of SO2 and NOx by combustion and processes.

Green enhanced oil recovery (GEOR) is an environmentally friendly enhanced oil recovery (EOR) process involving the injection of green fluids to improve macroscopic and microscopic sweep efficiencies while boosting tertiary oil production. Carbon nanomaterials such as graphene, carbon nanotube (CNT), and carbon dots have gained interest for their superior ability to increase oil recovery. These particles have been successfully tested in EOR, although they are expensive and do not extend to GEOR. In addition, the application of carbon particles in the GEOR method is not well understood yet, requiring thorough documentation. The goals of this work are to develop carbon nanoparticles from biomass and explore their role in GEOR. The carbon nanoparticles were prepared from date leaves, which are inexpensive biomass, through pyrolysis and ball-milling methods. The synthesized carbon nanomaterials were characterized using the standard process. Three formulations of functionalized and non-functionalized date-leaf carbon nanoparticle (DLCNP) solutions were chosen for core floods based on phase behavior and interfacial tension (IFT) properties to examine their potential for smart water and green chemical flooding. The carboxylated DLCNP was mixed with distilled water in the first formulation to be tested for smart water flood in the sandstone core. After water flooding, this formulation recovered 9% incremental oil of the oil initially in place. In contrast, non-functionalized DLCNP formulated with (the biodegradable) surfactant alkyl polyglycoside and NaCl produced 18% more tertiary oil than the CNT. This work thus provides new green chemical agents and formulations for EOR applications so that oil can be produced more economically and sustainably.

Different surface seismic surveys have been recorded on an experimental hydrogeological site that has been developed for several years near Poitiers (France). The paper shows how 3D seismic imaging can be used to describe the near-surface heterogeneous aquifer. The acquisition spread is designed to perform both 3D refraction and reflection seismic surveying. Refraction survey enables us to obtain a 3D image in depth of a low velocity superficial zone contrasting with the underlying water – bearing carbonates. Variogram analysis and geostatistical filtering allow to filter random and structured acquisition noise. Factorial kriging is used to filter the small scale structures (cubic structure with a range of 55 m and nugget) in order to make the large scale structures appear and to determine their orientation: a main orientation N90 and a secondary orientation N50. These two directions have been selected to implement two deviated wells C3 and C4. Reflection survey enables us to get a 3D seismic pseudo velocity block in depth. The vertical resolution is enhanced thanks to deconvolution after depth conversion. A Wiener filter, defined at a reference well C1 has been applied to the seismic traces to convert into velocity the amplitude sections. The results obtained are validated at four wells (MP6, MP5, M8, M9) in which acoustic data have been recorded. The 3D seismic pseudo velocity block shows the large heterogeneity of the aquifer reservoir in the horizontal and vertical planes, confirms the main structural orientations (N90 and N50) pointed out by refraction survey. At a given depth, the velocity distribution shows preferential connections between wells. As an example, well pumping tests and pressure interference confirm the hydrodynamic connection between wells M13 and M21 defined by a low velocity zone at 88 m depth.

This paper examines the performance of the spatial arbitrages carried out between two regional markets for wholesale natural gas linked by a pipeline system. We develop a new empirical methodology to (i) detect if these markets are integrated, i.e., if all the spatial arbitrage opportunities between the two markets are being exploited, and (ii) decompose the observed spatial price differences into factors such as transportation costs, transportation bottlenecks, and the oligopolistic behavior of the arbitrageurs. Our framework incorporates a new test for the presence of market power and it is thus able to distinguish between physical and strategic behavior constraints on marginal cost pricing. We use the case of the "Intercon-nector" pipeline linking Belgium and the UK as an application. Our empirical findings show that all the arbitrage opportunities between the two zones are being exploited but confirm the presence of market power.

Sensorless control theory is considered as one of the most important keys to reduce the cost of manufacturing and maintenance in automotive applications. This article presents a current sensorless control algorithm of a wound rotor synchronous machine using a model-free-adaptive control (MFAC). The only controlled variable in this method is the rotor speed, and no observation or estimation will be performed on the phase currents. The presented controller is also compared with a current sensorless control method that uses a Lyapunov-based observation of phase currents in the control algorithm. The developed control algorithm is first tested in simulation under several operating conditions, such as starting, tracking, parameter variation, and load step. Then, experimental tests validated the effective performance of MFAC in a current sensorless control algorithm. According to these results, the control of phase currents is guaranteed with a small error but without using any current sensors.

ABSTRACT Nowadays, geostatistics is commonly applied for numerous gridding or modelling tasks. However, it is still under used and unknown for classical geophysical applications. This paper highlights the main geostatistical methods relevant for geophysical issues, for instance to improve the quality of seismic data such as velocity cubes or interpreted horizons. These methods are then illustrated through four examples. The first example, based on a gravity survey presents how a geostatistical interpolation can be used to filter out a global trend, in order to better define real anomalies. In the second case study, dedicated to refraction surveying, geostatistical filtering is used to filter out acquisition artefacts and identify the main geological structures. The third one is an example of porosity being integrated geostatistically with a seismic acoustic impedance map. The last example deals with geostatistical time to depth conversion; the interest of performing geostatistical simulations is finally discussed.

In many major oil companies 3-D surveys increased exponentially from 1990 to 1996 to cover the majority of their offshore fields. Nowadays 3-D surveys are also widely used for onshore fields. Specific pre-planning tools were developed to estimate all characteristics of the future acquisition such as offset, fold and azimuth distributions, effects of surface obstacles, make up shots, etc. The pre-planning aims at defining the geological targets of the 3-D with the associated geophysical parameters, design and costs. This paper introduces the terminology used in 3-D technology. The first part is an illustrated glossary. The methodology described in the second part offers to the 3-D planner to very quickly and safely select the most important geophysical parameters based on wave propagation fundamentals and principles. In addition many practical rules, similar to rules of the thumb, are given.

The large-scale diffusion of Carbon Capture, transport and Storage (CCS) imposes the construction of a sizeable CO2 pipeline infrastructure. This paper examines the economics of a CO2 pipeline project and analyzes the conditions for a widespread adoption of CCS by a group of emitters that can be connected to that infrastructure. It details a modeling framework aimed at assessing the break-even value for joint CCS adoption, that is the critical value in the charge for CO2 emissions that is required for each of the emitters to decide to implement capture capabilities. This model can be used to analyze how the tariff structure and the regulatory constraints imposed on the CO2 pipeline operator modify the overall cost of CO2 abatement via CCS. This framework is applied to the case of a real European CO2 pipeline project. We find that the obligation to use cross-subsidy-free pipeline tariffs has a minor impact on the minimum CO2 price required to adopt the CCS. In contrast, the obligation to charge non-discriminatory prices can either impede the adoption of CCS or significantly raises that price. Besides, we compared two alternative regulatory frameworks for CCS pipelines: a common European organization as opposed to a collection of national regulations. The results indicate that the institutional scope of that regulation has a limited impact on the adoption of CCS compared to the detailed design of the tariff structure imposed to pipeline operators.

Abstract This paper proposes an assessment of long-term climate strategies for oil- and gas-producing countries—in particular, the Gulf Cooperation Council (GCC) member states—as regards the Paris Agreement goal of limiting the increase of surface air temperature to 2°C by the end of the twenty-first century. The study evaluates the possible role of carbon dioxide removal (CDR) technologies under an international emissions trading market as a way to mitigate welfare losses. To model the strategic context, one assumes that a global cumulative emissions budget will have been allocated among different coalitions of countries—the GCC being one of them—and the existence of an international emissions trading market. A meta-game model is proposed in which deployment of CDR technologies as well as supply of emission rights are strategic variables and the payoffs are obtained from simulations of a general equilibrium model. The results of the simulations indicate that oil and gas producing countries and especially the GCC countries face a significant welfare loss risk, due to “unburnable oil” if a worldwide climate regime as recommended by the Paris Agreement is put in place. The development of CDR technologies, in particular direct air capture (DAC) alleviates somewhat this risk and offers these countries a new opportunity for exploiting their gas reserves and the carbon storage capacity offered by depleted oil and gas reservoirs.

Abstract The calculation of effective flow properties of naturally fractured reservoir (NFR) has been the purpose of research works for many years. Based on a static characterization of the fracture system (orientations and densities), equivalent flow properties provide continuum representations of discrete systems from which multiphase flows can be simulated using dual-permeability and dual-porosity models. Common flow properties include anisotropic permeability tensors attached to the fracture system itself, and block sizes or shape-factors, which characterize the capability of the fracture and matrix media, to exchange fluids. Analytical and numerical calculation methods are now proposed by different commercial software tools, or have been the purpose of in-house developments. All methods rely on some conceptual models that are necessarily simplified representations of actual fracture systems, both complex and very partially known. Whether the underlying conceptual models are relevant certainly depends on the particular features of each fracture system. More important is the capability of models to capture features that are consequential for reservoir production. Only then can one expect to build meaningful NFR models likely to be calibrated to match production history data and to perform reliable reservoir forecasting. The CPU-time or memory requirements of implemented methods may also be a concern, as potentially relevant methods or software are unable to get through the calculations when full-field modelling is required. It follows that the comparison and validation of equivalent flow-property calculation methods and NFR modelling software is anything but an easy task. As a first contribution to this end, we review and compare several equivalent permeability calculation methods available from two commercial software suites and from our own proprietary tool (GoFraK). We first present the numerical and analytical methods that were tested, including the original ones we developed which were expected to show better calculation and speed performances. We then detail the realistic benchmark case studies used to compare the different methods, from the calculation of equivalent flow properties to the multiphase flow simulation of forecast production. The results are finally presented and discussed. They show that the numerical methods offered by commercial products, based on 3D discrete fracture networks (DFN) to compute equivalent permeability tensors, are generally unable to manage full-field models, and that their simpler analytical methods are to be used with great caution because of important underlying assumptions. These results also validate the approach and methods we developed in GoFraK and demonstrate their robustness and efficiency. Multiphase flow simulations were carried out to evaluate the impact of dual-media models on production forecast. They confirm that permeability tensors are not the only important effective flow properties, block sizes and more generally fracture/matrix transfer functions being also highly consequential. We finally end with preliminary conclusions about the ease of building NFR models and the reliability that can be given to such models.

This article studies the cost function for the natural gas transmission industry. In addition to a tribute to H.B. Chenery, it firstly offers some further comments on a recent contribution (Yépez 2008 Yépez, R. A. 2008. A cost function for the natural gas industry. The Engineering Economist, 53(1): 68–83. [Taylor & Francis Online] , [Google Scholar]): a statistical characterization of long-run scale economies and a simple reformulation of the long-run problem. An extension is then proposed to analyze how the presence of seasonally varying flows modifies the optimal design of a transmission infrastructure. Lastly, the case of a firm that anticipates a possible random rise in its future output is also studied to discuss the optimal degree of excess capacity to be built into a new transmission infrastructure.