A block

of rock that forms a structural or topographic feature, such as a block of

igneous of metamorphic rock within an area of mountain building, or orogeny.

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A body

of rock exposed at the surface of the Earth

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A body

of rock whose fluid saturation, porosity and permeability permit production

of groundwater

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A boundary of colliding lithospheric plates

(a)  

A bounding surface in a reservoir above which predominantly gas occurs and

below which predominantly oil occurs

(a)  

A bounding surface in a reservoir above which predominantly gas occurs and

below which predominantly water occurs.

(a)  

A bounding surface in a reservoir above which predominantly oil occurs and

below which predominantly water occurs

(a)  

A break or planar surface in brittle rock across which there is observable

displacement

(a)  

A brief

report about a well from the time it is permitted through drilling and

completion

(a)  

A

carbonate sedimentary rock predominantly composed of calcite of organic,

chemical or detrital origin

(a)  

A carbon-rich sedimentary rock that forms from the remains of plants deposited

as peat in swampy environments

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A

cavity, void or large pore in a rock that is commonly lined with mineral

precipitates

(a)  

A

cessation in deposition of sediments during which no strata form or an

erosional surface forms on the underlying strata; a gap in the rock record

(a)  

A change

of preexisting rocks or minerals caused by the activity of hot solutions,

such as fluids accompanying or heated by magma

(a)  

A

characteristic sequence of sedimentary structures occurring in sedimentary

rocks deposited in areas of deep water sedimentation by turbidity currents,

which form deposits called turbidites

(a)  

A

chemical combination of water and another substance

(a)  

A

chemically resistant dioxide of silicon that occurs in crystalline (quartz),

amorphous (opal) and cryptocrystalline (chert) forms

(a)  

A

chronological chart of the stages and ages of events in the history of the

Earth, from its initial formation to present, that has been constructed on

the basis of the rock record.

(a)  

A class

of sedimentary minerals and sedimentary rocks that form by precipitation from

evaporating aqueous fluid

(a)  

A class of sedimentary rock whose chief mineral constituents (95% or more) are calcite and aragonite (both CaCo3) and dolomite [CaMg(CO3)2], a mineral that can replace calcite during the process of dolomitization

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A clastic sedimentary rock whose grains are predominantly sand-sized

(a)  

A coarse-grained, plutonic or intrusive igneous rock of felsic composition having large crystals of quartz, feldspar and mica. In the oil field, "granite" is sometimes used incorrectly to indicate any type of hard rock

(a)  

A complex mixture of naturally occurring hydrocarbon compounds found in rock

(a)  

A conceptual model for a style of hydrocarbon accumulation used by explorationists to develop prospects in a basin, region or trend and used by development personnel to continue exploiting a given trend

(a)  

A configuration of layers of rock that has the appearance of a fold, but might form simply through sagging or differential compaction of layers around a preexisting structure (such as a reef) or on an uneven surface

(a)  

A configuration of rocks suitable for containing hydrocarbons and sealed by a relatively impermeable formation through which hydrocarbons will not migrate.

(a)  

A connection of points from well to well in which the data suggest that the points were deposited at the same time (chronostratigraphic) or have similar and related characteristics

(a)  

A contour connecting points of equal true vertical thickness of strata, formations, reservoirs or other rock units

(a)  

A contour that connects points of equal thickness

(a)  

A crack or surface of breakage within rock not related to foliation or cleavage in metamorphic rock along which there has been no movement

(a)  

A crack or surface of breakage within rock not related to foliation or cleavage in metamorphic rock along which there has been no movement

(a)  

A crust of coarse sediments or weathered soil rich in calcium carbonate.

(a)  

A crystalline substance that is naturally occurring, inorganic, and has a unique or limited range of chemical compositions

(a)  

A dense sulfate mineral that can occur in a variety of rocks, including limestone and sandstone, with a range of accessory minerals, such as quartz, chert, dolomite, calcite, siderite and metal sulfides

(a)  

A deposit of sodium nitrate that is mined and used for fertilizer in parts of South America

(a)  

A depression in the crust of the Earth, caused by plate tectonic activity and subsidence, in which sediments accumulate

(a)  

A description of organisms that can survive in the absence of oxygen, particularly bacteria.

(a)  

A detrital grain between 0.0625 mm and 2 mm in diameter

(a)  

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

(a)  

A dimensionless term devised to adapt the Darcy equation to multiphase flow conditions

(a)  

A discrete void within a rock, which can contain air, water, hydrocarbons or other fluids. In a body of rock, the percentage of pore space is the porosity

(a)  

A fault surface parallel to a mechanically weak horizon or layer, or parallel to bedding, that detaches or separates deformed rocks above from undeformed or differently deformed rocks below

(a)  

A field of study in which basin-filling sedimentary deposits, called sequences, are interpreted in a framework of eustasy, sedimentation and subsidence through time in order to correlate strata and predict the stratigraphy of relatively unknown areas

(a)  

A fine layer (~ 1 mm thick) in strata, also called a lamina, common in fine-grained sedimentary rocks such as shale, siltstone and fine sandstone

(a)  

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

(a)  

A flat drawing board mounted on a tripod used in combination with an alidade to construct topographic or geologic maps in the field

(a)  

A general term for sedimentary rocks, although it can imply a distinction between rocks of interest to the petroleum industry and rocks of interest to the mining industry

(a)  

A general term for unrefined petroleum or liquid petroleum

(a)  

A geologic surface that separates younger strata from older strata and represents a time of nondeposition, possibly combined with erosion

(a)  

A geological feature produced by deformation of the Earth's crust, such as a fold or a fault

(a)  

A geological surface separating older from younger rocks and representing a gap in the geologic record.

(a)  

A geological surface that separates younger overlying sedimentary strata from eroded igneous or metamorphic rocks and represents a large gap in the geologic record

(a)  

A grade scale for classifying the diameters of sediments.

(a)  

A graphic display, with geologic time along the vertical axis and distance along the horizontal axis, to demonstrate the relative ages and geographic extent of strata or stratigraphic units in a given area, also known as a Wheeler diagram

(a)  

A graphical display of three-dimensional data and interpretations in two-dimensional perspective view

(a)  

A green silicate mineral found in sedimentary rocks and formed on continental shelves characterized by slow sedimentation and organic matter, such as fecal pellets, present in an oxidizing environment

(a)  

A group of clay minerals formed during the alteration of silicate minerals such as mica and feldspar and commonly found in marine shales

(a)  

A group of clay minerals that includes montmorillonite. This type of mineral tends to swell when exposed to water

(a)  

A group of minerals found mostly in limestone and dolostone that includes aragonite, calcite and dolomite

(a)  

A group of relatively conformable strata that represents a cycle of deposition and is bounded by unconformities or correlative conformities.

(a)  

A group of rock-forming minerals in which SiO4 tetrahedra combine with cations

(a)  

A group of rock-forming silicate minerals that are essential constituents of igneous rocks and are common in sandstones

(a)  

A group of rock-forming, hydrous aluminum silicate minerals that are platy in structure and can form by the alteration of silicate minerals like feldspar and amphibole

(a)  

A group of sheet silicates characterized by a platy appearance and basal cleavage most common in igneous and metamorphic rocks.

(a)  

A highly insoluble sulfate mineral that is the first to precipitate from evaporating seawater

(a)  

A horizon cemented by precipitation of calcite just below the sea floor

(a)  

A layer of rock or sediment that is not horizontal

(a)  

A layer of sediment or sedimentary rock, or stratum

(a)  

A line on a map that represents a constant value of the parameter being mapped

(a)  

A linear, commonly concave-based depression through which water and sediment flow and into which sediment can be deposited in distinctive, often elongated bodies

(a)  

A long linear or gently curving feature on the surface of a terrestrial planet or moon that is suggestive of an underlying geologic structure or contact

(a)  

A low-density, high-API gravity liquid hydrocarbon phase that generally occurs in association with natural gas

(a)  

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

(a)  

A map displaying lines that include points of equal value and separate points of higher value from points of lower value

(a)  

A map on which primary data and interpretations can be plotted

(a)  

A map showing the type and spatial distribution of rocks at the surface of the Earth

(a)  

A mappable subdivision of a stratigraphic unit that can be distinguished by its facies or lithology-the texture, mineralogy, grain size, and the depositional environment that produced it

(a)  

A material composed of clay minerals, predominantly montmorillonite with minor amounts of other smectite group minerals, commonly used in drilling mud

(a)  

A measure of a material’s strength, the maximum axial compressive stress that a right-cylindrical sample of material can withstand under unconfined conditions—the confining stress is zero

(a)  

A measure of deviation from a straight line. It is the ratio of the actual distance traveled between two points, including any curves encountered, divided by the straight line distance.

(a)  

A measure of the geometric complexity of a porous medium

(a)  

A measure of the thermal maturity of organic matter. This analytical method was developed to rank the maturity of coals and is now used in other rocks to determine whether they have generated hydrocarbons or could be effective source rocks

(a)  

A measurement of the maturity of organic matter with respect to whether it has generated hydrocarbons or could be an effective source rock.

(a)  

A microscopic, single-celled, freshwater or saltwater algae that has a silica-rich cell wall called a frustule

(a)  

A minor, secondary fault, usually one of a set, whose sense of displacement is opposite to its associated major and synthetic faults

(a)  

A mound, ridge, or buildup of sediment or sedimentary rock, most commonly produced by organisms that secrete shells such as corals

(a)  

A mushroom-shaped or plug-shaped diapir made of salt, commonly having an overlying cap rock.

(a)  

A naturally occurring mixture of hydrocarbon gases that is highly compressible and expansible

(a)  

A naturally occurring organic compound comprising hydrogen and carbon

(a)  

A naturally occurring, typically slow leakage of fluid water, oil or gas at the Earth's surface

(a)  

A near-surface, possibly unconsolidated layer of low seismic velocity

(a)  

A normal fault that flattens with depth and typically found in extensional regimes

(a)  

A petroleum industry worker who tracks competitive exploration and production activity, either for a company or on a free-lance basis

(a)  

A phenomenon that occurs after the deposition of some sediments such that different parts of the sedimentary accumulation develop different degrees of porosity or settle unevenly during burial beneath successive layers of sediment

(a)  

A particular type of strike-slip fault that is a boundary of an oceanic tectonic plate

(a)  

A plate tectonic process in which one lithospheric plate descends beneath another into the asthenosphere during a collision at a convergent plate margin

(a)  

A platy, pale green mineral of the mica group of sheet silicates, also considered to be a type of clay mineral, found in sedimentary and low-grade metamorphic rocks

(a)  

A porous marine limestone composed of fine-grained remains of microorganisms with calcite shells, coccolithophores, such as the White Cliffs of Dover (UK)

(a)  

A porous sand layer or sand body charged with natural gas

(a)  

A porous sand layer or sand body filled with oil.

(a)