1. API Units
    A unit of measurement of gamma rays. American Petroleum Institute
  2. Auger
    A screlike boring tool used in relatively unconsolidated near surface materials
  3. Borehole Geophysics
    The science of recording and analyzing measurements of physical properties made in wells or test holes
  4. Caliper Log
    A well log that shows the variations with depth in the diameter of an uncased borehole
  5. Casing
    A heavy metal pipe lowered into a borehole and cemented in place to prevent cave-in, loss of dirlling fluid, and unwated fluids from entering the borehole
  6. Cone Penetrometer
    A cone-shaped tool at the end of a hollow steel rod is pushed into the ground to record resistance to insertion, formation pore pressure, and electrical resistivity of the subsurface geology
  7. Gamma Ray Log
    The radioactivity log curve of the intensity of natural gamma radiation emitted from the rocks in a borehole. It is commonly used to differentiate between shale (with a high gamma reading) and other sedimentary rocks
  8. 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
  9. Invaded Zone
    A transitional zone in a borehole located between the flushed zone and the uninvaded zone. It refers to the degreee ot which the mud filtrate penetrates the formation fluids, resulting in a transition from the mud filtrate saturation to the formation water saturation
  10. Neutron Log
    A radioactiviy log curve of the intensity of radiation produced when the rocks in a borehole are bombarded byt neutrons. It indicates the presence (but not type) of fluid. It is often used in association with the gamma ray log to distinguish porous and nonporous formations
  11. Normal-Resistivity Log
    A log that makes measurements of the resisitivity of formations using 4 electrodes set up in a stadard 16- or 64-inch spacing
  12. Percolation Test
    An in-situ test that determines the suitability of a soil for a sweage disposal system (leachfield)
  13. Resistivity Log
    A log that makes qantitative measurements of the specific resistance of a materail to the flow of an electric current
  14. Rippability
    The ease with which soil or rock can be excavated mechanically
  15. Rotary Drilling
    The chief method of drilling deep wells. A drill bit grinds a hole in the rock, and lubrication and cooling are provided by continuously circulating drilling mud which brings the well cuttings to the surface
  16. Seismic Reflection
    A survey method that utilizes the travel times of seismic waves that are reflected back from deep formations giving a deatailed picture of subsurface structures.
  17. Seismic Refraction
    A survey method based on the travel times of the seismic waves that pass through materials of differeing densities, in order to map the layers
  18. Shelby Tube
    A thin-walled, push-tube sampler that obtains undisturbed samples of cohesive soils
  19. Single-Point Resistivity Log
    A log that measures the resistivity using two electrodes and having a limited area of investigation from 5 to 10 times the electrode diameter
  20. Split-Spoon Sampler
    A thick-walled barrel sampler that obtains distrubed soil samples and that is used in the Standard Penetration Test
  21. Spontaneous Potential (SP) Log
    A log of the difference in DC voltage between an electrode in a well and an electrode at the surface. The difference in voltage is mostly a result of the electrochemical potentials that develop between dissimilar borehol and formation fluids
  22. Standard Penetration Test (SPI)
    A standardized soil sampling procedure in which a 140-pound hammer is dropped 30 inches, driving a two-inch split-spoon sampler 18 inches. The blow count to drive the sampler through the last 12 inches is correlated with soil conditions
  23. Test Pits
    A pit easliy dug with a backhoe to obtain bulk samples and to identify subsurface materials in situ
  24. Well Log
    A graphic record of the measured physical characteristics of a rock section encountered in a well plotted as a function of depth
  25. Purpose of Drilling Fluids?
    • 1. Bringing cuttings up from the bottom of the hole
    • 2. Suppoting the walls of the hole
    • 3. Preventing or reducing fluid loss through the wall of the borehole
    • 4. Keeping the drill bit cool and lubricated
Card Set
ASBOG Study Guide Chapter 7 Field Investigations