Fossil Energy Development Research Articles

Understanding inter-term fossil energy consumption pathways in China based on sustainable development goals

Sustainable development goals (SDGs) and fossil energy are the core elements of almost all major challenges and opportunities for achieving social development. Particularly, energy sustainability has become one of the pivotal drivers of China's economy. This study constructed a comprehensive evaluation index system for the provincial-level sustainable development of fossil energy in China covering three major dimensions (socio-economic, resource, and environmental). Moreover, a set of criteria for measuring the SDGs of fossil energy at the national level in China was developed. Based on the provincial panel data collected from 30 provinces from 2010 through 2019, a spatial econometric model was applied to empirically evaluate the effects of SDGs on fossil energy consumption. The results showed that the SDGs not only promote the reduction of fossil energy consumption with substantial negative spatial spillover effects, but also revealed differences between northern and southern China. To promote the early achievement of sustainable fossil energy development in China, the transformation and upgradation of fossil energy systems should be conducted early and inter-regional cooperation should be strengthened according to local conditions to jointly achieve the SDGs.

Thermal-Hydraulic-Mechanical Coupling Simulation of CO2 Enhanced Coalbed Methane Recovery with Regards to Low-Rank but Relatively Shallow Coal Seams

CO2 injection technology into coal seams to enhance CH4 recovery (CO2-ECBM), therefore presenting the dual benefit of greenhouse gas emission reduction and clean fossil energy development. In order to gaze into the features of CO2 injection’s influence on reservoir pressure and permeability, the Thermal-Hydraulic-Mechanical coupling mechanism of CO2 injection into the coal seam is considered for investigation. The competitive adsorption, diffusion, and seepage flowing of CO2 and CH4 as well as the dynamic evolution of fracture porosity of coal seams are considered. Fluid physical parameters are obtained by the fitting equation using MATLAB to call EOS software Refprop. Based on the Canadian CO2-ECBM project CSEMP, the numerical simulation targeting shallow low-rank coal is carried out, and the finite element method is used in the software COMSOL Multiphysics. Firstly, the direct recovery (CBM) and CO2-ECBM are compared, and it is confirmed that the injection of CO2 has a significant improvement effect on methane production. Secondly, the influence of injection pressure and temperature is discussed. Increasing the injection pressure can increase the pressure difference in the reservoir in a short time, so as to improve the CH4 production and CO2 storage. However, the increase in gas injection pressure will also lead to the rapid attenuation of near-well reservoir permeability, resulting in the weakening of injection capacity. Also, when the injection temperature increases, the CO2 concentration is relatively reduced, and the replacement effect on CH4 is weakened, resulting in a slight decrease in CBM production and CO2 storage.

Thermodynamic assessment of hydrothermal combustion assisted fossil fuel in-situ gasification in the context of sustainable development

Developing countries cannot get rid of the fate of relying on fossil energy development in the short term, so the low-carbon transformation must be carried out in the development process to achieve the goal of net zero emissions. This work proposed a novel hydrothermal combustion assisted fossil fuel in-situ gasification (HC-ISG) system combining renewable energy, supercritical hydrothermal combustion technology and supercritical water gasification technology. The system has the advantages of high thermal efficiency, high hydrogen yield, carbon dioxide utilization and storage, and landfill of hazardous waste. Firstly, based on the concept of energy grade, the effects of renewable energy and auxiliary fuel on the characteristics of energy grade change in HC-ISG system is studied. Then, the Gibbs free energy minimization method is conducted to discuss the effects of fossil fuels, oxidants, sub- and supercritical water on the key parameters of the system. The results indicated that for HC-ISG system, the energy grade and input amount of renewable energy have the optimal values. Compared with coke and methane, the system with methanol as an auxiliary fuel for hydrothermal combustion owned better the matching between energy quantity and energy grade. Moreover, increasing the reaction temperature could reduce the exergy destruction of the system and increase the energy grade change of the input energy. When the combustion coefficient was 0.2–0.3, the molar fraction of H2 reached the maximum value. When fossil fuel with high carbon content was used, the maximum H2 yield could reach 89.4 mol/kg, and the carbon emission was 3.9 kg CO2/kg H2, so the HC-ISG system could produce clean hydrogen. The system proposed in this study may provide a promising method for efficient and low-carbon in-situ conversion of fossil energy to hydrogen production.

Numerical simulation of stress regime transformation during unconventional fossil energy development in Sichuan Basin: from strike-slip stress regime to reverse stress regime via hydraulic fracturing

Numerical simulation of stress regime transformation during unconventional fossil energy development in Sichuan Basin: from strike-slip stress regime to reverse stress regime via hydraulic fracturing

The Incidental Environmental Agency

State oil and gas conservation agencies are the gatekeepers to oil and gas development: as the agencies charged with granting drilling permits, they decide if, when, where, and how oil and gas will be developed. As such, oil and gas conservation agencies sit on the front lines in the emerging, and increasingly irresolvable, struggle between fossil energy development and the environment. Current oil and gas conservation regulation is designed to promote development, maximize recovery of the resource, and protect the individual property rights of mineral owners. However, advocacy by environmental constituencies, including surface owners and local governments, has challenged the entrenched paradigm whereby production must be maximized at the expense of all other interests. These efforts are pushing courts to redefine oil and gas conservation according to 21st century environmental values. This article examines the emergent environmental regulation function of oil and gas conservation agencies and identifies opportunities for these agencies to regulate according to their historic mandates in a manner that is inclusive of public values.

Predicting the fracture initiation pressure for perforated water injection wells in fossil energy development

Water injection is widely performed to enhance oil recovery in fossil energy development. The fracture initiation pressure (FIP) is a key parameter for designing the reasonable injection pressure for micro-fracturing water injection (MFWI). In this work, a modified method was presented to accurately predict the FIP, in which the thermal effect and plugging effect were considered; moreover, the stress around perforations was analyzed. To validate our method, the field tests, including a step rate test (SRT) and a well test, were conducted to obtain the actual FIP for perforated water injection wells, and then the FIP calculated by our method was compared with a low relative error of about 1.7%. Results show that (i) a greater temperature difference between the injected water and the formation forms a greater thermal stress around perforations, resulting in a greater change in the FIP; (ii) a larger skin factor causes a greater pressure drop for the injected water flowing through a plugged area, resulting in a stronger effective stress reduction around perforations and further producing a larger FIP. Therefore, our present work illustrates a better understanding of the stress distribution around a perforated wellbore, and paves a path for a more accurate prediction of the FIP in perforated water injection wells.

Water management at BedZED: some lessons

The Beddington zero fossil energy development (BedZED) in London, UK, is something of a modern icon in terms of assembling simultaneously on the same site new construction methods, the best of available ‘green’ technology and social engineering combined with new peri-urban lifestyles. The development also includes a number of ‘alternative’ water systems. As with many innovative and exploratory departures, however, not everything went according to plan. This paper describes the bold vision, highlights some of the issues and seeks to learn and disseminate lessons for the future, with special reference to the integrated water and wastewater services.