An area of deposition or the deposit formed by a flowing sediment-laden current as it enters an open or standing body of water, such as a river spilling into a gulf

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Containing shale, a fine-grained, fissile, detrital sedimentary rock formed by consolidation of clay- and silt-sized particles into thin, relatively impermeable layers.

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Containing tuff, which is lithified volcanic ash

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Containing vugs, which are cavities, voids or large pores in a rock that are commonly lined with mineral precipitates

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Contaminated with sulfur or sulfur compounds, especially hydrogen sulfide

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Continental shelf, or the area at the edges of a continent from the shoreline to a depth of 200 m [660 ft], where the continental slope begins

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Dense, fine-grained carbonate mud or rocks composed of mud that forms by erosion of larger carbonate grains, organic precipitation (such as from algae), or inorganic precipitation

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Describing a relatively impermeable reservoir rock from which hydrocarbon production is difficult

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Describing material deposited in or growing in a marsh

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Describing parallel or subparallel, closely-spaced, overlapping or step-like minor structural features in rock, such as faults and tension fractures, that are oblique to the overall structural trend

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Describing rocks or sediments containing particles that are silt- or clay-sized, less than 0.625 mm in size

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Describing sandy-textured rock or sediment

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Describing sedimentary rock that contains clay minerals

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Describing the environment and conditions of the marine zone between low tide and the edge of the continental shelf, a depth of roughly 200 m [656 ft]

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Different from what is typical or expected, or different from what is predicted by a theoretical model

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Directionally uniform, such that the physical properties of the material do not vary in different directions

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Exploration activity located in offshore areas where water depths exceed approximately 600 feet [200 m], the approximate water depth at the edge of the continental shelf

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Fine-grained sediments less than 0.0039 mm in size

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Folded structures associated with strike-slip faults

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For hydrocarbons to move from their source into reservoir rocks

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Formation water with low salinity

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Gas produced from a relatively impermeable reservoir rock. Hydrocarbon production from tight reservoirs can be difficult without stimulation operations

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Gas that is dissolved in a liquid, such as water or oil

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Generally, the study of how matter deforms and flows, including its elasticity, plasticity and viscosity

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Geologic components and processes necessary to generate and store hydrocarbons, including a mature source rock, migration pathway, reservoir rock, trap and seal.

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Global sea level variations. Changes in sea level can result from movement of tectonic plates altering the volume of ocean basins, or when changes in climate affect the volume of water stored in glaciers and in polar icecaps

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Having directionally dependent properties

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In folded rocks, the imaginary surface bisecting the limbs of the fold

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In plate tectonics, a failed rift arm

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In sequence stratigraphy, a section of fine-grained sedimentary rocks that accumulated slowly, thereby representing a considerable span of time by only a thin layer

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In the case of a body of rock, to be exposed at the surface of the Earth

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In the original location or position, such as a large outcrop that has not been disturbed by faults or landslides

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Incorporation of water into the atomic structure of a mineral, i.e., the chemical combination of water and another substance

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Innermost layer of the Earth.

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Layers of sedimentary rock.

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Lithified volcanic ash

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Located down the slope of a dipping plane or surface

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Located up the slope of a dipping plane or surface. In a dipping (not flat-lying) hydrocarbon reservoir that contains gas, oil and water, the gas is updip, the gas-oil contact is downdip from the gas, and the oil-water contact is still farther downdip

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Location relative to the boundary of a tectonic plate, particularly a boundary along which plate tectonic activity is occurring or has occurred.

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Mass per unit of volume.

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Material deposited in an alluvial environment, typically detrital sediments that are poorly sorted

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Materials, especially rock masses, that formed in their present location and have not been transported

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Materials, especially rock masses, that formed in their present location and have not been transported

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Minute organisms that float or drift passively near the surface of oceans and seas

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Natural gas that contains less methane (typically less than 85% methane) and more ethane and other more complex hydrocarbons.

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Natural gas that occurs in the absence of condensate or liquid hydrocarbons, or gas that has had condensable hydrocarbons removed

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Natural gas, predominantly methane [CH4], generated during coal formation and adsorbed in coal

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Naturally-occurring, inflammable organic matter formed from kerogen in the process of petroleum generation that is soluble in carbon bisulfide.

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Oil at sufficiently low pressure that it contains no dissolved gas or a relatively thick oil or residue that has lost its volatile components

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Oil found in relatively impermeable reservoir rock

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Oil obtained by artificial maturation of oil shale.

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One of the three main classes of rock (igneous, metamorphic and sedimentary) that are formed at the Earth's surface through deposition of sediments derived from weathered rocks, biogenic activity or precipitation from solution.

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One of three main classes of rock (igneous, metamorphic and sedimentary) that form from the alteration of preexisting rocks by changes in ambient temperature, pressure, volatile content, or all of these

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Organisms that live at the bottom of a body of water

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Parallel strata that have undergone a similar geologic history, deposited in succession without interruption

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Particles of rock derived from the mechanical breakdown of preexisting rocks by weathering and erosion

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Permanent mechanical or physical alteration that does not include rupture

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Pertaining to a condition in which two fluids are incapable of forming molecularly distributed mixtures or attaining homogeneity at that scale

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Pertaining to a condition in which two or more fluids can mix in all proportions and form a single homogeneous phase

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Pertaining to a depositional environment or organisms from a marsh

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Pertaining to a diagram of a vertical section through a volume, as opposed to the surface, "bird's eye," or plan view of a map

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Pertaining to a diatom, which is a microscopic, single-celled, freshwater or saltwater algae that has a silica-rich cell wall called a frustule

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Pertaining to a hiatus, a cessation in deposition of sediments during which no strata form or an erosional surface forms on the underlying strata

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Pertaining to a hydrocarbon source rock that has generated as much hydrocarbon as possible and is becoming thermally altered

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Pertaining to a hydrocarbon source rock that has not fully entered optimal conditions for generation

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Pertaining to a major episode of plate tectonic activity in which lithospheric plates collide and produce mountain belts, in some cases including the formation of subduction zones and igneous activity

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Pertaining to a material that can deform permanently without rupturing

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Pertaining to a material that can undergo stress, deform, and then recover and return to its original shape after the stress ceases

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Pertaining to a rock that is incapable of transmitting fluids because of low permeability

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Pertaining to a sedimentary rock, such as sandstone or limestone, that contains only minimal amounts of clay minerals

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Pertaining to a strike-slip fault or right-lateral fault in which the block across the fault moves to the right

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Pertaining to a strike-slip or left-lateral fault in which the block across the fault moves to the left

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Pertaining to a type of metamorphic rock with shearing and granulation of minerals caused by high mechanical stress during faulting or dynamic metamorphism, typically during episodes of plate tectonic activity

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Pertaining to a zone, an interval or unit of rock differentiated from surrounding rocks on the basis of its fossil content or other features, such as faults or fractures

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Pertaining to a rock's ability to transmit fluids

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Pertaining to an anticline, an arch-shaped fold in rock in which rock layers are upwardly convex

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Pertaining to an environment of deposition affected by tides, the area between high tide and low tide.

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Pertaining to an environment of deposition by a river or running water

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Pertaining to an environment of deposition in lakes, or an area having lakes

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Pertaining to an estuary, a semi-enclosed coastal environment of deposition in which a river mouth permits freshwater to contact and mix with seawater

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Pertaining to biostratigraphy, the application of plant and animal fossils to date and correlate strata in order to elucidate Earth history, combining the principles of paleontology and stratigraphy

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Pertaining to crude oil or natural gas lacking appreciable amounts of sulfur or sulfur compounds.

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Pertaining to diagenesis, which is the physical, chemical or biological alteration of sediments into sedimentary rock at relatively low temperatures and pressures that can result in changes to the rock's original mineralogy and texture

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Pertaining to eustasy, a term for global sea level and its variations. Changes in sea level can result from movement of tectonic plates altering the volume of ocean basins, or when changes in climate affect the volume of water stored in glaciers and in polar icecaps

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Pertaining to exploration, the initial phase in petroleum operations that includes generation of a prospect or play or both, and drilling of an exploration well

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Pertaining to geology, the study of the Earth-its history, structure, composition, life forms and the processes that continue to change it

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Pertaining to geology, the study of the Earth-its history, structure, composition, life forms and the processes that continue to change it.

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Pertaining to geology, the study of the Earth-its history, structure, composition, life forms and the processes that continue to change it.

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Pertaining to hot fluids, particularly hot water, or the activity of hot water, or precipitates thereof

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Pertaining to isostasy, the state of gravitational equilibrium between the lithosphere and the asthenosphere of the Earth such that lithospheric plates "float" at a given elevation depending on their thickness

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Pertaining to lithology, the macroscopic nature of the mineral content, grain size, texture and color of rocks

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Pertaining to lithostratigraphy, the study and correlation of strata to elucidate Earth history on the basis of their lithology, or the nature of the well log response, mineral content, grain size, texture and color of rocks

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Pertaining to materials, particularly rock masses, that formed somewhere other than their present location, and were transported by fault movements, large-scale gravity sliding, or similar processes

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Pertaining to minerals or igneous rocks composed of minerals such as quartz and feldspar that are relatively light in color and density

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Pertaining to minerals or igneous rocks composed of minerals that are rich in iron and magnesium, dense, and typically dark in color

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Pertaining to minerals or materials that grow in place with a rock, rather than having been transported and deposited

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Pertaining to minerals or rock fragments that formed in one location but were transported to another location and deposited

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Pertaining to one of three main classes of rocks that crystallize from molten rock, or magma, with interlocking mineral crystals

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Pertaining to one or more volcanoes, surface features of the Earth that allow magma, ash and gas to erupt. The vent can be a fissure or a conical structure

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Pertaining to particles of rock derived from the mechanical breakdown of preexisting rocks by weathering and erosion

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