Jitendra Sangwai

The overall oil production worldwide has declined due to the increase in maturity of the oil reservoirs. In developing countries like India, the oil production and demand plays a crucial role for the development of economy of the country. However, the domestic crude oil production is insufficient to meet the requirement for energy. Thus, there is a big challenge to minimize the gap between the demand and supply for crude oil. Several methods to enhance oil recovery have been developed to increase the production from matured reservoirs and are referred to as enhanced oil recovery (EOR) methods. This chapter discusses in detail about the various EOR methods, their applicability, and the screening criteria for various reservoir types. The EOR methods are further discussed in Indian contexts. This chapter also summarizes the details of various oilfields in India. The chapter will in general, help to understand the recent trends and the need of EOR for Indian oil reservoirs.

Energy is an essential commodity for the survival and socioeconomic development of the human race. The energy supply sector primarily comprises of industrial, commercial, and domestic applications. The foremost challenges faced by the energy supply sector are growing consumption levels, limited accessibility, environmental concerns, viz-a-viz, climate change, and pollution of water and air resources. As conventional resources of energy have started to decline and are expected to get exhausted by 2040, the main focus has been shifted to unconventional sources [1]. In this category, natural gas resources such as gas hydrate, shale gas, coal bed methane will provide tremendous potential for meeting the demand. Gas hydrates are ice-like crystalline substance formed by a framework of water and natural gas molecules. Recent exploration programs by various agencies such as United States Geological Survey (USGS), National Gas Hydrate Program (India), Japanese Methane Gas Hydrate R&D have proved that massive amount of gas hydrate deposits lying across marine settings and permafrost environments. Hydrate deposits are currently estimated to be 5 × 1015 m3 of methane gas [2]. If this untapped resource of energy becomes feasible for the economic production, it could increase natural gas reserves to multifold. Moreover, this would be considerably greater than the total amount of all fossil fuels together. As reported by USGS, gas hydrates hold more than 50% of the entire world’s carbon. It has been estimated that commercial production of methane from 15% of natural gas hydrate can fulfill the energy requirement of the entire world for next 200 years [3]. Hence, natural gas hydrates are considered to be the vital sustainable energy resource. Many pilot production tests have been completed and are underway to recover methane from gas hydrate deposit across the world [4]. Preliminary studies and pilot tests have shown promising results in terms of methane recovery from natural gas hydrates by employing methods such as thermal stimulation, depressurization, inhibitor injection. Ongoing gas hydrate research programs throughout the world and advances in technology will certainly help to cater any technical challenges in order to potentially harness the huge amount of energy stored in the form of natural gas hydrates.

The role of energy has been central in day to day life. Non-renewables sources such as fossil fuels have been exploited to an extent that unless we find new reserves, it will be difficult to sustain the energy demand for future. Conversely, renewable forms of energy, such as biomass and solar, have shown to provide alternatives. India houses around 17% of the world’s population and is bound to play a deterministic role in driving the global energy demands in near future. Responsible usage of fossil fuels while compounding the role of renewable energy sources would pave the pathway to sustainable growth without burdening the environment. In this direction, the present chapter has deliberated the potential of two important renewable energy sources, i.e., biomass and solar. The authors have discussed the current state of technology development for converting the energy from these renewable sources to usable forms such as electricity, fuels, etc. Further, a detailed account of different policy initiatives taken up by the Government of India towards the promotion of their usage has been provided. In addition, the life cycle assessment (LCA) following a systems approach have been highlighted in the chapter as a mean to ensure the sustainable energy systems meeting the requirements of future. Lastly, the chapter has given insights on likely paths to optimize the usage of renewable energy sources.