Page 343 - Geology and Geochemistry of Oil and Gas

304 APPENDIX C

unknown parameter (e.g., mean value of probability
distribution) will be in the confidence interval.
Confidence level supplements the level of significance
to 1 or 100% (often this probability is set at 0.95 or
95%). Syn: Level of confidence.
Confidence limits [stat] Either the upper or the lower value between which an
actual measurement or parameter will fall with a
stated probability (i.e., confidence level). An interval
between confidence limits is referred to as the
confidence interval.
Connate water Water ultimately of marine origin that has been
entrapped in sediment pores after its burial, and
which has been out of contact with the atmosphere
for an appreciable period of geologic time. Cf:
Meteoritic water.
Consolidation Any process (including the deposition of cement) that
changes loose sediment to a coherent rock. Syn:
Lithification.
Contact angle The angle which the oil–water interface makes with
the solid (rock). Usually, it is measured from the solid
through the liquid phase (if the other phase is a gas),
and through the water phase if oil and water are both
present, to the oil–water interface.
Continental slope The part of continental margin that is located
between the continental shelf and continental rise (or
oceanic trench). It is characterized by relatively steep
slope of 3–61.
Contour map A map with continuous lines connecting data points
of equal value, such as elevation, formation thickness,
rock porosity, etc.
Core A cylindrical sample of the rock taken from the well
during drilling operations.
Core sampling Taking a sample of geological strata for examination.
Syn: Coring.
Correlation The intensity of association or interdependence
between two or among several variables, e.g., a
tendency for variation in one variable to be
accompanied by linear variation in another.
Correlation ellipse An ellipse outlying correlated data points within
the given confidence level. Syn: Ellipse of
correlation.
Corrosion Chemical reaction (mainly loss of electrons) that

oxidize metals, e.g., Fe - Fe 2+ + 2e .
Corrosion inhibitor Chemicals added to minimize or prevent corrosion of
metals.