Field Investigations Flashcards
API Units
A unit of measurement of gamma rays. American Petroleum Institute.
ASTM
American Society for Testing and Materials International.
ASTM develops numerous standards by consensus and publishes them annually.
Auger
A screw like boring tool used in relatively unconsolidated near-surface materials.
Azimuth
For radar images. it is the dimension parallel to the flight path.
Borehole Geophysics
The science of recording and analyzing measurements of physical properties made in wells or test holes.
Caliper Log
A well log that shows the variations with depth in the diameter of an uncased borehole.
Casing
A heavy metal pipe lowered into a borehole and cemented in place to prevent cave-in, loss of drilling fluid, and unwanted fluids from entering the borehole.
Cone of Depression
A depression in the potentiometric surface of groundwater that has the shape of an inverted cone and develops around a well from which water is being drawn.
It also defines the area of influence of a well.
Cone Penetrometer
A tool consisting of a cone-shaped tip on the end of a hollow steel rod that is pushed into the ground to record resistance to insertion.
CPT
Cone Penetration Test.
The test measures the resistance of the cone to penetration and the friction on the rod.
Used widely in engineering and environmental industries.
Drawdown
The amount of water level in a well is lowered due to withdrawal of water.
Dutch Cone
A specific kind of Cone Penetrometer.
Gamma Ray Log
The radioactivity log curve of the intensity of natural gamma radiation emitted from the rocks in a borehole.
Used to differentiate between shale (high gamma reading) and other sedimentary rocks.
GPS
Global Positioning System.
A radio navigation system that provides the exact position on Earth and time information
Gravity Survey
A series of measurements made by a gravimeter at a number of different locations in the field to determine the density distribution by evaluating the gravitational pull.
Ground-Penetrating Radar
The application of radar or radio waves to the subsurface using a radar impulse as the source and a receiver.
Low frequency antennas examine the subsurface at great depths while the higher frequencies are used close to the surface.
It can see as deep as a 100 feet.
InSAR
Interfermotric Synthtic Aperature Radar.
A remote sensing method that is used to study ground deformation, particularly in subsidence, volcanic, and fault studies.
Invaded Zone
A transitional zone in a borehole located between the flushed zone and the uninvaded zone.
It refers to the degree to which the mud filtrate penetrates the formation fluids, resulting in a transition from the mud filtrate saturation to the formation water saturation.
LiDAR
Light Detection and Ranging.
A remote sensing method using laser beams to record topographic changes.
Lysimeter
A device for collecting water from the pore spaces of soils to determine the soluble constituents removed by drainage.
It is used to sample water chemistry in the vadose zone, and measure deep percolation and evapotranspiration.
Neutron Log
A radioactivity log curve of the intensity of radiation produced when the rocks in a borehole are bombarded by neutrons.
It indicates the presence (not type) of fluid.
It is often used with gamma ray logs to distinguish porous and nonporous formations.
Normal-Resistivity Log
A log that makes measurements of the resistivity of formation using 4 electrodes set up in a standard 16- or 64-inch spacing.
Packer Test
An aquifer test in which two inflatable seals (or packers) are set in an open borehole to prevent movement of groundwater in the test section while the permeability of the isolated rock is determined.
Percolation (Perc) Test
An in-situ test that determines the suitability of a soil for a sewage disposal system (leachfield). This test made by digging a hole, filling it with water, and measuring the rate of decline of the water table.
Piezometer
A device that measures in situ pore water pressures, often an open standpipe to monitor water levels in permeable materials, or an enclosed electronic pressure transducer used in impermeable soils.