Petroleum reservoirA petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence of high heat and pressure in the Earth's crust. Petroleum reservoirs are broadly classified as conventional and unconventional reservoirs.
PetroleumPetroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both prolonged heat and pressure.
Petroleum engineeringPetroleum engineering is a field of engineering concerned with the activities related to the production of Hydrocarbons, which can be either crude oil or natural gas. Exploration and production are deemed to fall within the upstream sector of the oil and gas industry. Exploration, by earth scientists, and petroleum engineering are the oil and gas industry's two main subsurface disciplines, which focus on maximizing economic recovery of hydrocarbons from subsurface reservoirs.
Unconventional (oil & gas) reservoirUnconventional (oil & gas) reservoirs, or unconventional resources (resource plays) are accumulations where oil & gas phases are tightly bound to the rock fabric by strong capillary forces, requiring specialised measures for evaluation and extraction. Petroleum reservoir Oil and gas are generated naturally at depths of around 4 or 5 kms below Earth’s surface. Being lighter than the water, which saturates rocks below the water table, the oil and gas percolate up through aquifer pathways towards Earth's surface (through time) by buoyancy.
Petroleum geologyPetroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). Petroleum geology is principally concerned with the evaluation of seven key elements in sedimentary basins: Source Reservoir Seal Trap Timing Maturation Migration In general, all these elements must be assessed via a limited 'window' into the subsurface world, provided by one (or possibly more) exploration wells.
Extraction of petroleumPetroleum is a fossil fuel that can be drawn from beneath the earth's surface. Reservoirs of petroleum are formed through the mixture of plants, algae, and sediments in shallow seas under high pressure. Petroleum is mostly recovered from oil drilling. Seismic surveys and other methods are used to locate oil reservoirs. Oil rigs and oil platforms are used to drill long holes into the earth to create an oil well and extract petroleum. After extraction, oil is refined to make gasoline and other products such as tires and refrigerators.
Microbial ecologyMicrobial ecology (or environmental microbiology) is the ecology of microorganisms: their relationship with one another and with their environment. It concerns the three major domains of life—Eukaryota, Archaea, and Bacteria—as well as viruses. Microorganisms, by their omnipresence, impact the entire biosphere. Microbial life plays a primary role in regulating biogeochemical systems in virtually all of our planet's environments, including some of the most extreme, from frozen environments and acidic lakes, to hydrothermal vents at the bottom of deepest oceans, and some of the most familiar, such as the human small intestine, nose, and mouth.
Reservoir engineeringReservoir engineering is a branch of petroleum engineering that applies scientific principles to the fluid flow through a porous medium during the development and production of oil and gas reservoirs so as to obtain a high economic recovery. The working tools of the reservoir engineer are subsurface geology, applied mathematics, and the basic laws of physics and chemistry governing the behavior of liquid and vapor phases of crude oil, natural gas, and water in reservoir rock.
Abiogenic petroleum originThe abiogenic petroleum origin hypothesis proposes that most of earth's petroleum and natural gas deposits were formed inorganically. Scientific evidence overwhelmingly supports a biogenic origin for most of the world's petroleum deposits. Mainstream theories about the formation of hydrocarbons on earth point to an origin from the decomposition of long-dead organisms, though the existence of hydrocarbons on extraterrestrial bodies like Saturn's moon Titan indicates that hydrocarbons are sometimes naturally produced by inorganic means.
Reservoir modelingIn the oil and gas industry, reservoir modeling involves the construction of a computer model of a petroleum reservoir, for the purposes of improving estimation of reserves and making decisions regarding the development of the field, predicting future production, placing additional wells and evaluating alternative reservoir management scenarios. A reservoir model represents the physical space of the reservoir by an array of discrete cells, delineated by a grid which may be regular or irregular.
CultureCulture (ˈkʌltʃər) is an umbrella term which encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups. Culture is often originated from or attributed to a specific region or location. Humans acquire culture through the learning processes of enculturation and socialization, which is shown by the diversity of cultures across societies.
Petroleum industryThe petroleum industry, also known as the oil industry or the oil patch, includes the global processes of exploration, extraction, refining, transportation (often by oil tankers and pipelines), and marketing of petroleum products. The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, synthetic fragrances, and plastics.
Oil and gas reserves and resource quantificationOil and gas reserves denote discovered quantities of crude oil and natural gas (oil or gas fields) that can be profitably produced/recovered from an approved development. Oil and gas reserves tied to approved operational plans filed on the day of reserves reporting are also sensitive to fluctuating global market pricing. The remaining resource estimates (after the reserves have been accounted) are likely sub-commercial and may still be under appraisal with the potential to be technically recoverable once commercially established.
Sulfur-reducing bacteriaSulfur-reducing bacteria are microorganisms able to reduce elemental sulfur (S0) to hydrogen sulfide (H2S). These microbes use inorganic sulfur compounds as electron acceptors to sustain several activities such as respiration, conserving energy and growth, in absence of oxygen. The final product of these processes, sulfide, has a considerable influence on the chemistry of the environment and, in addition, is used as electron donor for a large variety of microbial metabolisms.
MetagenomicsMetagenomics is the study of genetic material recovered directly from environmental or clinical samples by a method called sequencing. The broad field may also be referred to as environmental genomics, ecogenomics, community genomics or microbiomics. While traditional microbiology and microbial genome sequencing and genomics rely upon cultivated clonal cultures, early environmental gene sequencing cloned specific genes (often the 16S rRNA gene) to produce a profile of diversity in a natural sample.
Marine ecosystemMarine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems.
Microbial metabolismMicrobial metabolism is the means by which a microbe obtains the energy and nutrients (e.g. carbon) it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles.
EcosystemAn ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present.
Anaerobic organismAn anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment. Anaerobes may be unicellular (e.g. protozoans, bacteria) or multicellular. Most fungi are obligate aerobes, requiring oxygen to survive. However, some species, such as the Chytridiomycota that reside in the rumen of cattle, are obligate anaerobes; for these species, anaerobic respiration is used because oxygen will disrupt their metabolism or kill them.
MicrobiomeA microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps et al. as "a characteristic microbial community occupying a reasonably well-defined habitat which has distinct physio-chemical properties. The term thus not only refers to the microorganisms involved but also encompasses their theatre of activity". In 2020, an international panel of experts published the outcome of their discussions on the definition of the microbiome.
