Assessing Natural Gas Versus CO2 Potential Underground Storage Sites in Greece: A Pragmatic Approach †

Although subsurface traps have been regularly explored for hydrocarbon exploration, natural gas and CO2 storage has drawn industrial attention over the past few decades, thanks to the increasing demand for energy resources and the need for greenhouse gas mitigation. With only one depleted hydrocarbon field in Greece, saline aquifers, salt caverns and sedimentary basins ought to be evaluated in furtherance of the latter. Within this study the potential of the Greek subsurface for underground storage is discussed. An overview and re-evaluation of the so-far studied areas is implemented based on the available data. Lastly, a pragmatic approach for the storage potential in Greece was created, delineating gaps and risks in the already proposed sites. Based on the above details, a case study for CO2 storage is presented, which is relevant to the West Katakolo field saline aquifer.

Do Oil and Gas Lease Stipulations in the Northwestern Gulf of Mexico Need Expansion to Better Protect Vulnerable Coral Communities? How Low Relief Habitats Support High Coral Biodiversity

The continental shelf of the northwestern Gulf of Mexico harbors extensive reefs and banks that support diverse coral reefs and mesophotic communities. Mesophotic communities range in depth from 40 to 200 m and, in this region, foster some of the densest coral forests [aggregations of mesophotic octocoral, antipatharian, and branching stony coral communities] reported in published literature (10.23 ± 9.31 col/m2). The geologic features underlying the exposed substrates that harbor mesophotic communities are targeted for extensive hydrocarbon exploration and extraction, as they often contain oil and/or natural gas. The Bureau of Ocean Energy Management regulates offshore energy development in the United States and is tasked with protecting sensitive biological communities from impacts related to oil and gas activities. This study analyzed alpha and beta diversity of mesophotic coral forests on fourteen topographic banks in the northwestern Gulf of Mexico. The objective of the study was to examine differences in structure and community in relation to lease stipulations established by the Bureau of Ocean and Energy Management. It was determined that dense and diverse mesophotic coral forests and carbonate producers exist in present regulatory zones that prohibit oil and gas activities; however, the coral communities exist in higher densities, diversity, and richness in low relief substrates outside of these regulatory zones. Our findings suggest low relief hard substrates serve as important habitat for mesophotic coral forests; thus, we suggest the expansion of current stipulations should be considered to provide better protection to vulnerable coral communities on low relief features. Furthermore, additional studies to refine the relationship between low relief structures and biodiversity are needed to develop more meaningful habitat definitions to support resource management and improve resource protection in the future.

Arc-parallel shears in collisional orogens: Global review and paleostress analyses from the NW Lesser Himalayan Sequence (Garhwal region, Uttarakhand, India)

Interest in hydrocarbon exploration from the the Lesser Himalayan Sequence (LHS) has recently been revived amongst petroleum geoscientists. Understanding the paleostress regime and the deformation processes are the two important steps to understand the structural geology of any (petroliferous) terrane. Arc-parallel shear is an integral deformation process in orogeny. The scale of the consequent deformation features can range from micro-mm up to regional scale. Unlike orogen-perpendicular shear, different driving forces can produce orogen-parallel shears. We review these mechanisms/theories from several orogens including the Himalaya and compile 44 locations worldwide with reported orogen-parallel shear. Due to continuous crustal shortening by the India-Eurasia collision, the squeezed rock mass at the plate interface has produced the Himalayan Mountain chain. In addition, the rock mass also escapes laterally along the orogenic trend. Tectonic stress-field governs this mass flow. Field study and microstructural analysis in the northwest LHS (India) reveals orogen-parallel brittle and ductile shear movement. Y- and P- brittle shear planes, and the S- and C- ductile shear planes reveal the following shears documented on the ~ NW-SE trending natural rock selections: (i) top-to-NW up, (ii) top-to-SE up, (iii) top-to-NW down, and (iv) top-to-SE down. Our paleostress analysis indicates top-to-SE down and top-to-NW down shears occurred due to stretching along ~ 131°-311° (Dext), whereas top-to-SE up and top-to-NW up shear fabric originated due to shortening along ~133.5°-313.5° (Dcompr). Previous authors considered that the orogen-parallel extension generated ~ 15-5 Ma due to vertical thinning of the Himalaya. The NE-trending Delhi-Haridwar Ridge below the LHS plausibly acted as a barrier to the flowing mass and piled up the rock mass in the form of NW-SE/orogen-parallel compression. The NW-SE compression can be correlated with the D3 of Hintersberger et al. (2011) during ~ 4-7 Ma.

Applications of Nanomaterials in the Oil and Gas Industry

The petroleum industry has been an ever-growing industry. New technologies are always being introduced to encompass the challenges that are encountered. Nanomaterials are being included in these technologies to improve the operation of different processes. Their distinctive physical and chemical characteristics encourage their use in different sectors such as the upstream, midstream, and downstream of the oil and gas industry. In this chapter, the nanomaterials that are utilized in the oil and gas industries are highlighted. Their implementation in various applications is also provided. These applications include hydrocarbon exploration, well drilling and completion, production operations, enhanced oil recovery mechanisms, transportation, and refining operations. There is also a discussion about existing problems and possibilities for future uses.

Significance of petroleum seepages in hydrocarbon exploration-case study of Khourian Desert, Central Iran

Hydrocarbon exploration has long been based on such costly and time-intensive methods as geophysical surveys, geological studies, and drilling. In recent years, however, researchers have started to consider such inexpensive alternatives as surface geochemistry for hydrocarbon exploration. Some 100 years ago, the leakage of hydrocarbons onto the surface in the form of micro- and macro-seepages motivated researchers toward drilling a well in the Khourian Desert in the south of Semnan Province, Iran. Upon drilling the well, researchers found evidences of non-released (free) hydrocarbons. These findings drove further study of the area using surface geochemistry while considering the nearby hydrocarbon accumulation in Qom Formation. Conventional and indirect surface geochemical methods provide an insight into the relationship between surface and subsurface hydrocarbons. In the present work, the results of the Rock–Eval pyrolysis showed total organic carbon (TOC) values in the range of 0.31–4.13 wt.% and S1 peaks between 0.07 and 27.35. Sulfur isotope analysis showed a sulfur isotopic value of −0.4. The study of hydrocarbon-oxidizing bacteria showed the presence of bacterial colonies in MSM at 1.22 × 106 cfu/g of soil sample. We further investigated surface changes due to the presence of free hydrocarbons and pH variations (4.9–8) resulted from the changes in the concentrations of calcium carbonate and iron. According to the results and given the presence of organic sulfur in the samples, the occurrence of Gach-i-turush and alike phenomena was proposed in this area. The results of geo-microbial prospecting method, surface secondary changes, and sulfur isotope studies were well in agreement with the characteristics of the existing hydrocarbon reserves in this area. Surface geochemical surveys can precede other geochemical and geophysical surveys to identify surface anomalies and hence focus on more probable locales of hydrocarbon accumulation in the Khourian Desert, central Iran.